Contamination Health Dictionary

Contamination: From 1 Different Sources


Occurs when the treatment assigned to people in one study group is also used by some or all members of another group.
Health Source: Community Health
Author: Health Dictionary

Food Poisoning

This illness is characterised by vomiting, diarrhoea and abdominal pain, and results from eating food contaminated with metallic or chemical poisons, certain micro-organisms or microbial products. Alternatively, the foods – such as undercooked red kidney beans or ?sh of the scombroid family (mackerel and tuna) – may contain natural posions. Food poisoning caused by chemical or metallic substances usually occurs rapidly, within minutes or a few hours of eating. Among micro-organisms, bacteria are the leading cause of food poisoning, particularly Staphylococcus aureus, Clostridium perfringens (formerly Cl. welchii), Salmonella spp., Campylobacter jejuni, and Escherichia coli O157.

Staphylococcal food poisoning occurs after food such as meat products, cold meats, milk, custard and egg products becomes contaminated before or after cooking, usually through incorrect handling by humans who carry S. aureus. The bacteria produce an ENTEROTOXIN which causes the symptoms of food poisoning 1–8 hours after ingestion. The toxin can withstand heat; thus, subsequent cooking of contaminated food will not prevent illness.

Heat-resistant strains of Cl. perfringens cause food poisoning associated with meat dishes, soups or gravy when dishes cooked in bulk are left unrefrigerated for long periods before consumption. The bacteria are anaerobes (see ANAEROBE) and form spores; the anaerobic conditions in these cooked foods allow the germinated spores to multiply rapidly during cooling, resulting in heavy contamination. Once ingested the bacteria produce enterotoxin in the intestine, causing symptoms within 8–24 hours.

Many di?erent types of Salmonella (about 2,000) cause food poisoning or ENTERITIS, from eight hours to three days after ingestion of food in which they have multiplied. S. brendeny, S. enteritidis, S. heidelberg, S. newport and S. thompson are among those commonly causing enteritis. Salmonella infections are common in domesticated animals such as cows, pigs and poultry whose meat and milk may be infected, although the animals may show no symptoms. Duck eggs may harbour Salmonella (usually S. typhimurium), arising from surface contamination with the bird’s faeces, and foods containing uncooked or lightly cooked hen’s eggs, such as mayonnaise, have been associated with enteritis. The incidence of human S. enteritidis infection has been increasing, by more than 15-fold in England and Wales annually, from around 1,100 a year in the early 1980s to more than 32,000 at the end of the 1990s, but has since fallen to about 10,000. A serious source of infection seems to be poultry meat and hen’s eggs.

Although Salmonella are mostly killed by heating at 60 °C for 15 minutes, contaminated food requires considerably longer cooking and, if frozen, must be completely thawed beforehand, to allow even cooking at a su?cient temperature.

Enteritis caused by Campylobacter jejuni is usually self-limiting, lasting 1–3 days. Since reporting of the disease began in 1977, in England and Wales its incidence has increased from around 1,400 cases initially to nearly 13,000 in 1982 and to over 42,000 in 2004. Outbreaks have been associated with unpasteurised milk: the main source seems to be infected poultry.

ESCHERICHIA COLI O157 was ?rst identi?ed as a cause of food poisoning in the early 1980s, but its incidence has increased sharply since, with more than 1,000 cases annually in the United Kingdom in the late 1990s. The illness can be severe, with bloody diarrhoea and life-threatening renal complications. The reservoir for this pathogen is thought to be cattle, and transmission results from consumption of raw or undercooked meat products and raw dairy products. Cross-infection of cooked meat by raw meat is a common cause of outbreaks of Escherichia coli O157 food poisoning. Water and other foods can be contaminated by manure from cattle, and person-to-person spread can occur, especially in children.

Food poisoning associated with fried or boiled rice is caused by Bacillus cereus, whose heat-resistant spores survive cooking. An enterotoxin is responsible for the symptoms, which occur 2–8 hours after ingestion and resolve after 8–24 hours.

Viruses are emerging as an increasing cause of some outbreaks of food poisoning from shell?sh (cockles, mussels and oysters).

The incidence of food poisoning in the UK rose from under 60,000 cases in 1991 to nearly 79,000 in 2004. Public health measures to control this rise include agricultural aspects of food production, implementing standards of hygiene in abattoirs, and regulating the environment and process of industrial food production, handling, transportation and storage.... food poisoning

Anís Chiquito

Anise, anise burnet-saxifrage (Pimpinella anisum).

Plant Part Used: Fruit (seed).

Dominican Medicinal Uses: The seeds are traditionally prepared as a decoction and taken orally for colic (in children and adults), common cold, empacho, flatulence, flu, gastrointestinal disorders, headache, indigestion, nervous tension, pasmo and stress.

Safety: The seeds are generally regarded as safe for human consumption in moderation and widely used as a culinary spice. Caution is advised if this herbal remedy is combined with anís de estrella due to potential contamination with a toxic look-alike (see entry for “Anís de estrella”).

Contraindications: Studies show conflicting recommendations regarding safety of internal use during pregnancy and lactation. Use of this herb in combination with anís de estrella is contraindicated in children (due to potential for contamination with the toxic look-alike Illicium anisatum (see “Anís de estrella”); however, anís chiquito is considered safe for children when used appropriately.

Drug interactions: Anticoagulants, NSAIDS, antiplatelet drugs, warfarin: Avoid use of anís chiquito if taking any of these medications due to potential risk of excessive bleeding as a result of interaction with coumarin derivatives.

Clinical Data: No clinical trials of the oral use of this herb have been identified in the available literature. One open clinical trial has evaluated the pediculicidal effects of anise oil in combination with other ingredients.

Laboratory & Preclinical Data: The following biological activities of this plant have been investigated in laboratory studies using in vitro or animal models: anticonvulsant, antidiuretic, antiflatulent, antifungal, antimicrobial, antispasmodic, estrogenic, expectorant, hypotensive, liver regeneration, muscle stimulant and mutagenic.

* See entry for Anís chiquito in “Part 3: Dominican Medicinal Plant Profiles” of this book for more information, including references.... anís chiquito

Anís De Estrella

Chinese star anise (Illicium verum).

Plant Part Used: Fruit, seed.

Dominican Medicinal Uses: The fruits or seeds are traditionally prepared as a decoction and taken orally for flatulence, headache, indigestion, stomach ache, upper respiratory tract infection and cleansing the intestines.

Safety: The fruit is generally considered safe for human consumption in small amounts and is widely used as a culinary spice. When taken in excessive quantities, isolated compounds from the fruit have shown neurotoxic effects in animal studies. Caution is advised due to possible adulteration with the highly poisonous look-alike, Japanese star anise (Illicium anisatum).

Contraindications: Avoid use in small children due to potential contamination with misidentified toxic look-alike. Caution and avoidance is advised in patients with a history of convulsive disorders including epilepsy due to case reports of seizures associated with internal use of the tea. Caution advised in patients prior to surgery due to potential risk of increased bleeding.

Drug Interactions: Anticoagulants, antiplatelet medications and NSAIDS: based on animal studies in mice, star anise increases cytochrome P450 dependent 7-ethoxycoumarin O-deethylase activity which may affect the metabolism of these drugs.

Clinical Data: No human clinical trials evaluating this plant species have been identified in the available literature.

Laboratory & Preclinical Data: The following biological activities of this plant have been demonstrated in laboratory and preclinical studies using in vitro or animal models: antiangiogenic, antibacterial, antimicrobial, insecticidal, neurotropic and sepsis prevention.

* See entry for Anís de estrella in “Part 3: Dominican Medicinal Plant Profiles” of this book for more information, including references.... anís de estrella

Cadmium Poisoning

Cadmium poisoning is a recognised hazard in certain industrial processes, such as the manufacture of alloys, cadmium plating and glass blowing. Sewage sludge, which is used as fertiliser, may be contaminated by cadmium from industrial sources; such cadmium could be taken up into vegetable crops and cadmium levels in sewage are carefully monitored.

A tin-like metal, cadmium accumulates in the body. Long-term exposure can lead to EMPHYSEMA, renal failure (see KIDNEYS, DISEASES OF) and urinary-tract CALCULI. Acute exposure causes GASTROENTERITIS and PNEUMONITIS. Cadmium contamination of food is the most likely source of poisoning. The EU Directive on the Quality of Water for Human Consumption lays down 5 milligrams per litre as the upper safe level.... cadmium poisoning

Cheese

Nutritional Profile Energy value (calories per serving): Moderate to high Protein: Moderate to high Fat: Low to high Saturated fat: High Cholesterol: Low to high Carbohydrates: Low Fiber: None Sodium: High Major vitamin contribution: Vitamin A, vitamin D, B vitamins Major mineral contribution: Calcium

About the Nutrients in This Food Cheese making begins when Lactobacilli and/or Streptococci bacteria are added to milk. The bacteria digest lactose (milk sugar) and release lactic acid, which coagulates casein (milk protein) into curds. Rennet (gastric enzymes extracted from the stomach of calves) is added, and the mixture is put aside to set. The longer the curds are left to set, the firmer the cheese will be. When the curds are properly firm, they are pressed to squeeze out the whey (liquid) and cooked. Cooking evaporates even more liquid and makes the cheese even firmer.* At this point, the product is “fresh” or “green” cheese: cottage cheese, cream cheese, farmer cheese. Making “ripe” cheese requires the addition of salt to pull out more moisture and specific organisms, such as Penicil- lium roquefort for Roquefort cheese, blue cheese, and Stilton, or Penicillium cambembert for Camembert and Brie. The nutritional value of cheese is similar to the milk from which it is made. All cheese is a good source of high quality proteins with sufficient amounts of all the essential amino acids. Cheese is low to high in fat, mod- erate to high in cholesterol. * Natural cheese is cheese made direct ly from milk. Processed cheese is natural cheese melted and combined wit h emulsifiers. Pasteurized process cheese foods contain ingredients t hat allow t hem to spread smoot hly; t hey are lower in fat and higher in moisture t han processed cheese. Cholesterol and Saturated Fat Content of Selected Cheeses Mozzarella Source: USDA, Nutritive Value of Foods, Home and Garden Bullet in No. 72 (USDA, 1989). All cheeses, except cottage cheese, are good sources of vitamin A. Orange and yellow cheeses are colored with carotenoid pigments, including bixin (the carotenoid pigment in annatto) and synthetic beta-carotene. Hard cheeses are an excellent source of calcium; softer cheeses are a good source; cream cheese and cottage cheese are poor sources. The R DA for calcium is 1,000 mg for a woman, 1,200 mg for a man, and 1,500 mg for an older woman who is not on hormone- replacement therapy. All cheese, unless otherwise labeled, is high in sodium.

Calcium Content of Cheese  
  Cheese   Serving   Calcium (mg)
Blue oz. 150
Camembert wedge 147
Cheddar oz. 204
Cottage cheese    
creamed cup 135
uncreamed cup 46
Muenster oz. 203
Pasteurized processed American oz. 174
Parmesan grated tbsp. 69
Provolone oz. 214
Swiss oz. 272
  Source: Nutritive Value of Foods, Home and Gardens Bullet in No. 72 (USDA, 1989).

The Most Nutritious Way to Serve This Food With grains, bread, noodles, beans, nuts, or vegetables to add the essential amino acids miss- ing from these foods, “complete” their proteins, and make them more nutritionally valuable.

Diets That May Restrict or Exclude This Food Antiflatulence diet Controlled-fat, low-cholesterol diet Lactose- and galactose-free diet (lactose, a disaccharide [double sugar] is composed of one unit of galactose and one unit of glucose) Low-calcium diet (for patients with kidney disease) Sucrose-free diet (processed cheese)

Buying This Food Look for: Cheese stored in a refrigerated case. Check the date on the package. Avoid: Any cheese with mold that is not an integral part of the food.

Storing This Food Refrigerate all cheese except unopened canned cheeses (such as Camembert in tins) or grated cheeses treated with preservatives and labeled to show that they can be kept outside the refrigerator. Some sealed packages of processed cheeses can be stored at room temperature but must be refrigerated once the package is opened. Wrap cheeses tightly to protect them from contamination by other microorganisms in the air and to keep them from drying out. Well-wrapped, refrigerated hard cheeses that have not been cut or sliced will keep for up to six months; sliced hard cheeses will keep for about two weeks. Soft cheeses (cottage cheese, ricotta, cream cheese, and Neufchatel) should be used within five to seven days. Use all packaged or processed cheeses by the date stamped on the package. Throw out moldy cheese (unless the mold is an integral part of the cheese, as with blue cheese or Stilton).

Preparing This Food To grate cheese, chill the cheese so it won’t stick to the grater. The molecules that give cheese its taste and aroma are largely immobilized when the cheese is cold. When serving cheese with fruit or crackers, bring it to room temperature to activate these molecules.

What Happens When You Cook This Food Heat changes the structure of proteins. The molecules are denatured, which means that they may be broken into smaller fragments or change shape or clump together. All of these changes may force moisture out of the protein tissue, which is why overcooked cheese is often stringy. Whey proteins, which do not clump or string at low temperatures, contain the sulfur atoms that give hot or burned cheese an unpleasant “cooked” odor. To avoid both strings and an unpleasant odor, add cheese to sauces at the last minute and cook just long enough to melt the cheese.

How Other Kinds of Processing Affect This Food Freezing. All cheese loses moisture when frozen, so semisoft cheeses will freeze and thaw better than hard cheeses, which may be crumbly when defrosted. Drying. The less moisture cheese contains, the less able it is to support the growth of organ- isms like mold. Dried cheeses keep significantly longer than ordinary cheeses.

Medical Uses and/or Benefits To strengthen bones and reduce age-related loss of bone density. High-calcium foods protect bone density. The current recommended dietary allowance (R DA) for calcium is still 800 mg for adults 25 and older, but a 1984 National Institutes of Health (NIH) Conference advisory stated that lifelong protection for bones requires an R DA of 1,000 mg for healthy men and women age 25 to 50 ; 1,000 mg for older women using hormone replacement therapy; and 1,500 mg for older women who are not using hormones, and these recommendations have been confirmed in a 1994 NIH Consensus Statement on optimal calcium intake. A diet with adequate amounts of calcium-rich foods helps protect bone density. Low-fat and no-fat cheeses provide calcium without excess fat and cholesterol. Protection against tooth decay. Studies at the University of Iowa (Iowa City) Dental School confirm that a wide variety of cheeses, including aged cheddar, Edam, Gouda, Monterey Jack, Muenster, mozzarella, Port Salut, Roquefort, Romano, Stilton, Swiss, and Tilsit—limit the tooth decay ordinarily expected when sugar becomes trapped in plaque, the sticky film on tooth surfaces where cavity-causing bacteria flourish. In a related experiment using only cheddar cheese, people who ate cheddar four times a day over a two-week period showed a 20 percent buildup of strengthening minerals on the surface of synthetic toothlike material attached to the root surfaces of natural teeth. Protection against periodontal disease. A report in the January 2008 issue of the Journal of Periodontology suggests that consuming adequate amounts of dairy products may reduce the risk of developing periodontal disease. Examining the dental health of 942 subjects ages 40 to 79, researchers at Kyushu University, in Japan, discovered that those whose diets regularly included two ounces (55 g) of foods containing lactic acid (milk, cheese, and yogurt) were significantly less likely to have deep “pockets” (loss of attachment of tooth to gum) than those who consumed fewer dairy products.

Adverse Effects Associated with This Food Increased risk of heart disease. Like other foods from animals, cheese is a source of choles- terol and saturated fats, which increase the amount of cholesterol circulating in your blood and raise your risk of heart disease. To reduce the risk of heart disease, the USDA /Health and Human Services Dietary Guidelines for Americans recommends limiting the amount of cholesterol in your diet to no more than 300 mg a day. The guidelines also recommend limit- ing the amount of fat you consume to no more than 30 percent of your total calories, while holding your consumption of saturated fats to more than 10 percent of your total calories (the calories from saturated fats are counted as part of the total calories from fat). Food poisoning. Cheese made from raw (unpasteurized) milk may contain hazardous microorganisms, including Salmonella and Listeria. Salmonella causes serious gastric upset; Lis- teria, a flulike infection, encephalitis, or blood infection. Both may be life-threatening to the very young, the very old, pregnant women, and those whose immune systems are weakened either by illness (such as AIDS) or drugs (such as cancer chemotherapy). In 1998, the Federal Centers for Disease Control (CDC) released data identif ying Listeria as the cause of nearly half the reported deaths from food poisoning. Allergy to milk proteins. Milk is one of the foods most frequently implicated as a cause of allergic reactions, particularly upset stomach. However, in many cases the reaction is not a true allergy but the result of lactose intolerance (see below). Lactose intolerance. Lactose intolerance—the inability to digest the sugar in milk—is an inherited metabolic deficiency that affects two thirds of all adults, including 90 to 95 percent of all Orientals, 70 to 75 percent of all blacks, and 6 to 8 percent of Caucasians. These people do not have sufficient amounts of lactase, the enzyme that breaks the disaccharide lactose into its easily digested components, galactose and glucose. When they drink milk, the undi- gested sugar is fermented by bacteria in the gut, causing bloating, diarrhea, flatulence, and intestinal discomfort. Some milk is now sold with added lactase to digest the lactose and make the milk usable for lactase-deficient people. In making cheese, most of the lactose in milk is broken down into glucose and galactose. There is very little lactose in cheeses other than the fresh ones—cottage cheese, cream cheese, and farmer cheese. Galactosemia. Galactosemia is an inherited metabolic disorder in which the body lacks the enzymes needed to metabolize galactose, a component of lactose. Galactosemia is a reces- sive trait; you must receive the gene from both parents to develop the condition. Babies born with galactosemia will fail to thrive and may develop brain damage or cataracts if they are given milk. To prevent this, children with galactosemia are usually kept on a protective milk- free diet for several years, until their bodies have developed alternative pathways by which to metabolize galactose. Pregnant women who are known carriers of galactosemia may be advised to give up milk and milk products while pregnant lest the unmetabolized galactose in their bodies cause brain damage to the fetus (damage not detectable by amniocentesis). Genetic counseling is available to identif y galactosemia carriers and assess their chances of producing a baby with the disorder. Penicillin sensitivity. People who experience a sensitivity reaction the first time they take penicillin may have been sensitized by exposure to the Penicillium molds in the environment, including the Penicillium molds used to make brie, blue, camembert, roquefort, Stilton, and other “blue” cheeses.

Food/Drug Interactions Tetracycline. The calcium ions in milk products, including cheese, bind tetracyclines into insoluble compounds. If you take tetracyclines with cheese, your body may not be able to absorb and use the drug efficiently. Monoamine oxidase (MAO) inhibitors. Monoamine oxidase inhibitors are drugs used to treat depression. They inactivate naturally occurring enzymes in your body that metabolize tyra- mine, a substance found in many fermented or aged foods. Tyramine constricts blood ves- sels and increases blood pressure. If you eat a food such as aged or fermented cheese which is high in tyramine while you are taking an M AO inhibitor, your body may not be able to eliminate the tyramine. The result may be a hypertensive crisis.

Tyramine Content of Cheeses High Boursault, Camembert, Cheddar, Emmenthaler, Stilton Medium to high Blue, brick, Brie, Gruyère, mozzarella, Parmesan, Romano, Roquefort Low Processed American cheese Very little or none Cottage and cream cheese Sources: The Medical Letter Handbook of Adverse Drug Interactions (1985); Handbook of Clinical Dietetics ( The A merican Dietet ic Associat ion, 1981). False-positive test for pheochromocytoma. Pheochromocytomas (tumors of the adrenal glands) secrete adrenalin that is converted by the body to vanillyl-mandelic acid ( VM A) and excreted in the urine. Tests for this tumor measure the level of VM A in the urine. Since cheese contains VM A, taking the test after eating cheese may result in a false-positive result. Ordinarily, cheese is prohibited for at least 72 hours before this diagnostic test.... cheese

Eggs

Nutritional Profile Energy value (calories per serving): Moderate Protein: High Fat: High Saturated fat: Moderate Cholesterol: High Carbohydrates: Low Fiber: None Sodium: Moderate to high Major vitamin contribution: Vitamin A, riboflavin, vitamin D Major mineral contribution: Iron, calcium

About the Nutrients in This Food An egg is really three separate foods, the whole egg, the white, and the yolk, each with its own distinct nutritional profile. A whole egg is a high-fat, high-cholesterol, high-quality protein food packaged in a high-calcium shell that can be ground and added to any recipe. The proteins in eggs, with sufficient amounts of all the essential amino acids, are 99 percent digestible, the standard by which all other proteins are judged. The egg white is a high-protein, low-fat food with virtually no cholesterol. Its only important vitamin is riboflavin (vitamin B2), a vis- ible vitamin that gives egg white a slightly greenish cast. Raw egg whites contain avidin, an antinutrient that binds biotin a B complex vitamin for- merly known as vitamin H, into an insoluble compound. Cooking the egg inactivates avidin. An egg yolk is a high-fat, high-cholesterol, high-protein food, a good source of vitamin A derived from carotenes eaten by the laying hen, plus vitamin D, B vitamins, and heme iron, the form of iron most easily absorbed by your body. One large whole egg (50 g/1.8 ounce) has five grams fat (1.5 g satu- rated fat, 1.9 g monounsaturated fat, 0.7 g polyunsaturated fat), 212 mg cholesterol, 244 IU vitamin A (11 percent of the R DA for a woman, 9 percent * Values are for a whole egg. of the R DA for a man), 0.9 mg iron (5 percent of the R DA for a woman, 11 percent of the R DA for a man) and seven grams protein. The fat in the egg is all in the yolk. The protein is divided: four grams in the white, three grams in the yolk.

The Most Nutritious Way to Serve This Food With extra whites and fewer yolks to lower the fat and cholesterol per serving.

Diets That May Restrict or Exclude This Food Controlled-fat, low-cholesterol diet Low-protein diet

Buying This Food Look for: Eggs stored in the refrigerated dair y case. Check the date for freshness. NOTE : In 1998, the FDA and USDA Food Safety and Inspection Service (FSIS) proposed new rules that would require distributors to keep eggs refrigerated on the way to the store and require stores to keep eggs in a refrigerated case. The egg package must have a “refrigera- tion required” label plus safe-handling instructions on eggs that have not been treated to kill Salmonella. Look for: Eggs that fit your needs. Eggs are graded by the size of the yolk and the thick- ness of the white, qualities that affect appearance but not nutritional values. The higher the grade, the thicker the yolk and the thicker the white will be when you cook the egg. A Grade A A egg fried sunny side up will look much more attractive than a Grade B egg prepared the same way, but both will be equally nutritions. Egg sizes ( Jumbo, Extra large, Large, Medium, Small) are determined by how much the eggs weigh per dozen. The color of the egg’s shell depends on the breed of the hen that laid the egg and has nothing to do with the egg’s food value.

Storing This Food Store fresh eggs with the small end down so that the yolk is completely submerged in the egg white (which contains antibacterial properties, nature’s protection for the yolk—or a developing chick embryo in a fertilized egg). Never wash eggs before storing them: The water will make the egg shell more porous, allowing harmful microorganisms to enter. Store separated leftover yolks and whites in small, tightly covered containers in the refrigerator, where they may stay fresh for up to a week. Raw eggs are very susceptible to Salmonella and other bacterial contamination; discard any egg that looks or smells the least bit unusual. Refrigerate hard-cooked eggs, including decorated Easter eggs. They, too, are suscep- tible to Salmonella contamination and should never be left at room temperature.

Preparing This Food First, find out how fresh the eggs really are. The freshest ones are the eggs that sink and lie flat on their sides when submerged in cool water. These eggs can be used for any dish. By the time the egg is a week old, the air pocket inside, near the broad end, has expanded so that the broad end tilts up as the egg is submerged in cool water. The yolk and the white inside have begun to separate; these eggs are easier to peel when hard-cooked. A week or two later, the egg’s air pocket has expanded enough to cause the broad end of the egg to point straight up when you put the egg in water. By now the egg is runny and should be used in sauces where it doesn’t matter if it isn’t picture-perfect. After four weeks, the egg will float. Throw it away. Eggs are easily contaminated with Salmonella microorganisms that can slip through an intact shell. never eat or serve a dish or bever age containing r aw fr esh eggs. sa lmonella is destroyed by cooking eggs to an inter nal temper atur e of 145°f ; egg-milk dishes such as custar ds must be cooked to an inter nal temper atur e of 160°f. If you separate fresh eggs by hand, wash your hands thoroughly before touching other food, dishes, or cooking tools. When you have finished preparing raw eggs, wash your hands and all utensils thoroughly with soap and hot water. never stir cooked eggs with a utensil used on r aw eggs. When you whip an egg white, you change the structure of its protein molecules which unfold, breaking bonds between atoms on the same molecule and forming new bonds to atoms on adjacent molecules. The result is a network of protein molecules that hardens around air trapped in bubbles in the net. If you beat the whites too long, the foam will turn stiff enough to hold its shape even if you don’t cook it, but it will be too stiff to expand natu- rally if you heat it, as in a soufflé. When you do cook properly whipped egg white foam, the hot air inside the bubbles will expand. Ovalbumin, an elastic protein in the white, allows the bubble walls to bulge outward until they are cooked firm and the network is stabilized as a puff y soufflé. The bowl in which you whip the whites should be absolutely free of fat or grease, since the fat molecules will surround the protein molecules in the egg white and keep them from linking up together to form a puff y white foam. Eggs whites will react with metal ions from the surface of an aluminum bowl to form dark particles that discolor the egg-white foam. You can whip eggs successfully in an enamel or glass bowl, but they will do best in a copper bowl because copper ions bind to the egg and stabilize the foam.

What Happens When You Cook This Food When you heat a whole egg, its protein molecules behave exactly as they do when you whip an egg white. They unfold, form new bonds, and create a protein network, this time with molecules of water caught in the net. As the egg cooks, the protein network tightens, squeez- ing out moisture, and the egg becomes opaque. The longer you cook the egg, the tighter the network will be. If you cook the egg too long, the protein network will contract strongly enough to force out all the moisture. That is why overcooked egg custards run and why overcooked eggs are rubbery. If you mix eggs with milk or water before you cook them, the molecules of liquid will surround and separate the egg’s protein molecules so that it takes more energy (higher heat) to make the protein molecules coagulate. Scrambled eggs made with milk are softer than plain scrambled eggs cooked at the same temperature. When you boil an egg in its shell, the air inside expands and begins to escape through the shell as tiny bubbles. Sometimes, however, the force of the air is enough to crack the shell. Since there’s no way for you to tell in advance whether any particular egg is strong enough to resist the pressure of the bubbling air, the best solution is to create a safety vent by sticking a pin through the broad end of the egg before you start to boil it. Or you can slow the rate at which the air inside the shell expands by starting the egg in cold water and letting it warm up naturally as the water warms rather than plunging it cold into boiling water—which makes the air expand so quickly that the shell is virtually certain to crack. As the egg heats, a little bit of the protein in its white will decompose, releasing sulfur that links up with hydrogen in the egg, forming hydrogen sulfide, the gas that gives rot- ten eggs their distinctive smell. The hydrogen sulfide collects near the coolest part of the egg—the yolk. The yolk contains iron, which now displaces the hydrogen in the hydrogen sulfide to form a green iron-sulfide ring around the hard-cooked yolk.

How Other Kinds of Processing Affect This Food Egg substitutes. Fat-free, cholesterol-free egg substitutes are made of pasteurized egg whites, plus artificial or natural colors, flavors, and texturizers (food gums) to make the product look and taste like eggs, plus vitamins and minerals to produce the nutritional equivalent of a full egg. Pasteurized egg substitutes may be used without additional cooking, that is, in salad dressings and eggnog. Drying. Dried eggs have virtually the same nutritive value as fresh eggs. Always refrigerate dried eggs in an air- and moistureproof container. At room temperature, they will lose about a third of their vitamin A in six months.

Medical Uses and/or Benefits Protein source. The protein in eggs, like protein from all animal foods, is complete. That is, protein from animal foods provides all the essential amino acids required by human beings. In fact, the protein from eggs is so well absorbed and utilized by the human body that it is considered the standard by which all other dietary protein is measured. On a scale known as biological value, eggs rank 100 ; milk, 93; beef and fish, 75; and poultry, 72. Vision protection. The egg yolk is a rich source of the yellow-orange carotenoid pigments lutein and zeaxanthin. Both appear to play a role in protecting the eyes from damaging ultraviolet light, thus reducing the risk of cataracts and age-related macular degeneration, a leading cause of vision of loss in one-third of all Americans older than 75. Just 1.3 egg yolks a day appear to increase blood levels of lutein and zeaxanthin by up to 128 percent. Perhaps as a result, data released by the National Eye Institute’s 6,000-person Beaver Dam ( Wisconsin) Eye Study in 2003 indicated that egg consumption was inversely associated with cataract risk in study participants who were younger than 65 years of age when the study started. The relative risk of cataracts was 0.4 for people in the highest category of egg consumption, compared to a risk of 1.0 for those in the lowest category. External cosmetic effects. Beaten egg whites can be used as a facial mask to make your skin look smoother temporarily. The mask works because the egg proteins constrict as they dry on your face, pulling at the dried layer of cells on top of your skin. When you wash off the egg white, you also wash off some of these loose cells. Used in a rinse or shampoo, the pro- tein in a beaten raw egg can make your hair look smoother and shinier temporarily by filling in chinks and notches on the hair shaft.

Adverse Effects Associated with This Food Increased risk of cardiovascular disease. Although egg yolks are high in cholesterol, data from several recent studies suggest that eating eggs may not increase the risk of heart disease. In 2003, a report from a 14-year, 177,000-plus person study at the Harvard School of Public Health showed that people who eat one egg a day have exactly the same risk of heart disease as those who eat one egg or fewer per week. A similar report from the Multiple R isk Factor Intervention Trial showed an inverse relationship between egg consumption and cholesterol levels—that is, people who ate more eggs had lower cholesterol levels. Nonetheless, in 2006 the National Heart, Lung, and Blood Institute still recommends no more than four egg yolks a week (including the yolk in baked goods) for a heart-healthy diet. The American Heart Association says consumers can have one whole egg a day if they limit cholesterol from other sources to the amount suggested by the National Cholesterol Education Project following the Step I and Step II diets. (Both groups permit an unlimited number of egg whites.) The Step I diet provides no more than 30 percent of total daily calories from fat, no more than 10 percent of total daily calories from saturated fat, and no more than 300 mg of cholesterol per day. It is designed for healthy people whose cholesterol is in the range of 200 –239 mg/dL. The Step II diet provides 25– 35 percent of total calories from fat, less than 7 percent of total calories from saturated fat, up to 10 percent of total calories from polyunsaturated fat, up to 20 percent of total calories from monounsaturated fat, and less than 300 mg cho- lesterol per day. This stricter regimen is designed for people who have one or more of the following conditions: •  Existing cardiovascular disease •  High levels of low-density lipoproteins (LDLs, or “bad” cholesterol) or low levels of high-density lipoproteins (HDLs, or “good” cholesterol) •  Obesity •  Type 1 diabetes (insulin-dependent diabetes, or diabetes mellitus) •  Metabolic syndrome, a.k.a. insulin resistance syndrome, a cluster of risk fac- tors that includes type 2 diabetes (non-insulin-dependent diabetes) Food poisoning. Raw eggs (see above) and egg-rich foods such as custards and cream pies are excellent media for microorganisms, including the ones that cause food poisoning. To protect yourself against egg-related poisoning, always cook eggs thoroughly: poach them five minutes over boiling water or boil at least seven minutes or fry two to three minutes on each side (no runny center) or scramble until firm. Bread with egg coating, such as French toast, should be cooked crisp. Custards should be firm and, once cooked, served very hot or refrigerated and served very cold. Allergic reaction. According to the Merck Manual, eggs are one of the 12 foods most likely to trigger the classic food allergy symptoms: hives, swelling of the lips and eyes, and upset stomach. The others are berries (blackberries, blueberries, raspberries, strawberries), choco- late, corn, fish, legumes (green peas, lima beans, peanuts, soybeans), milk, nuts, peaches, pork, shellfish, and wheat (see wheat cer ea ls).

Food/Drug Interactions Sensitivity to vaccines. Live-virus measles vaccine, live-virus mumps vaccine, and the vac- cines for influenza are grown in either chick embryo or egg culture. They may all contain minute residual amounts of egg proteins that may provoke a hypersensitivity reaction in people with a history of anaphylactic reactions to eggs (hives, swelling of the mouth and throat, difficulty breathing, a drop in blood pressure, or shock).... eggs

Flour

See also Bread, Corn, Oats, Pasta, Potatoes, R ice, Soybeans, Wheat cereals.

Nutritional Profile Energy value (calories per serving): High Protein: Moderate Fat: Low Saturated fat: Low Cholesterol: None Carbohydrates: High Fiber: Low to high Sodium: Low (except self-rising flour) Major vitamin contribution: B vitamins Major mineral contribution: Iron

About the Nutrients in This Food Flour is the primary source of the carbohydrates (starch and fiber) in bread, pasta, and baked goods. All wheat and rye flours also provide some of the food fibers, including pectins, gums, and cellulose. Flour also contains significant amounts of protein but, like other plant foods, its proteins are “incomplete” because they are deficient in the essential amino acid lysine. The fat in the wheat germ is primarily polyunsaturated; flour contains no cholesterol. Flour is a good source of iron and the B vitamins. Iodine and iodophors used to clean the equipment in grain-processing plants may add iodine to the flour. In 1998, the Food and Drug Administration ordered food manufac- turers to add folates—which protect against birth defects of the spinal cord and against heart disease—to flour, rice, and other grain products. One year later, data from the Framingham Heart Study, which has fol- lowed heart health among residents of a Boston suburb for nearly half a century, showed a dramatic increase in blood levels of folic acid. Before the fortification of foods, 22 percent of the study participants had a folic acid deficiency; after, the number fell to 2 percent. Whole grain flour, like other grain products, contains phytic acid, an antinutrient that binds calcium, iron, and zinc ions into insoluble com- pounds your body cannot absorb. This has no practical effect so long as your diet includes foods that provide these minerals. Whole wheat flours. Whole wheat flours use every part of the kernel: the fiber-rich bran with its B vitamins, the starch- and protein-rich endosperm with its iron and B vitamins, and the oily germ with its vitamin E.* Because they contain bran, whole-grain flours have much more fiber than refined white flours. However, some studies suggest that the size of the fiber particles may have some bearing on their ability to absorb moisture and “bulk up” stool and that the fiber particles found in fine-ground whole wheat flours may be too small to have a bulking effect. Finely ground whole wheat flour is called whole wheat cake flour; coarsely ground whole wheat flour is called graham flour. Cracked wheat is a whole wheat flour that has been cut rather than ground; it has all the nutrients of whole wheat flour, but its processing makes it less likely to yield its starch in cooking. When dried and parboiled, cracked wheat is known as bulgur, a grain used primarily as a cereal, although it can be mixed with other flours and baked. Gluten flour is a low-starch, high-protein product made by drying and grinding hard- wheat flour from which the starch has been removed. Refined (“white”) flours. Refined flours are paler than whole wheat flours because they do not contain the brown bran and germ. They have less fiber and fat and smaller amounts of vitamins and minerals than whole wheat flours, but enriched refined flours are fortified with B vitamins and iron. Refined flour has no phytic acid. Some refined flours are bleached with chlorine dioxide to destroy the xanthophylls (carotenoid pigments) that give white flours a natural cream color. Unlike carotene, the carotenoid pigment that is converted to vitamin A in the body, xanthophylls have no vita- min A activity; bleaching does not lower the vitamin A levels in the flour, but it does destroy vitamin E. There are several kinds of white flours. All-purpose white flour is a mixture of hard and soft wheats, high in protein and rich in gluten.t Cake flour is a finely milled soft-wheat flour; it has less protein than all-purpose flour. Self-rising flour is flour to which baking powder has been added and is very high in sodium. Instant flour is all-purpose flour that has been ground extra-fine so that it will combine quickly with water. Semolina is a pale high-protein, low- gluten flour made from durum wheat and used to make pasta. Rye flours. Rye flour has less gluten than wheat flour and is less elastic, which is why it makes a denser bread.:j Like whole wheat flour, dark rye flour (the flour used for pumpernickel bread) contains the bran and the germ of the rye grain; light rye flour (the flour used for ordinary rye bread) The bran is t he kernel’s hard, brown outer cover, an ext raordinarily rich source of cellulose and lignin. The endosperm is t he kernel’s pale interior, where t he vitamins abound. The germ, a small part icle in t he interior, is t he part of t he kernel t hat sprouts. Hard wheat has less starch and more protein t han soft wheat. It makes a heavier, denser dough. Gluten is t he st icky substance formed when k neading t he dough relaxes t he long-chain molecules in t he proteins gliadin and glutenin so t hat some of t heir intermolecular bonds (bonds bet ween atoms in t he same molecule) break and new int ramolecular bonds (bonds bet ween atoms on different mol- ecules) are formed. Triticale flour is milled from triticale grain, a rye/wheat hybrid. It has more protein and less gluten than all-purpose wheat flour.

The Most Nutritious Way to Serve This Food With beans or a “complete” protein food (meat, fish, poultry, eggs, milk, cheese) to provide the essential amino acid lysine, in which wheat and rye flours are deficient.

Diets That May Restrict or Exclude This Food Low-calcium diet (whole grain and self-rising flours) Low-fiber diet (whole wheat flours) Low-gluten diet (all wheat and rye flour) Sucrose-free diet

Buying This Food Look for: Tightly sealed bags or boxes. Flours in torn packages or in open bins are exposed to air and to insect contamination. Avoid: Stained packages—the liquid that stained the package may have seeped through into the flour.

Storing This Food Store all flours in air- and moistureproof canisters. Whole wheat flours, which contain the germ and bran of the wheat and are higher in fat than white flours, may become rancid if exposed to air; they should be used within a week after you open the package. If you plan to hold the flour for longer than that, store it in the freezer, tightly wrapped to protect it against air and moisture. You do not have to thaw the flour when you are ready to use it; just measure it out and add it directly to the other ingredients. Put a bay leaf in the flour canister to help protect against insect infections. Bay leaves are natural insect repellents.

What Happens When You Cook This Food Protein reactions. The wheat kernel contains several proteins, including gliadin and glute- nin. When you mix flour with water, gliadin and glutenin clump together in a sticky mass. Kneading the dough relaxes the long gliadin and glutenin molecules, breaking internal bonds between individual atoms in each gliadin and glutenin molecule and allowing the molecules to unfold and form new bonds between atoms in different molecules. The result is a network structure made of a new gliadin-glutenin compound called gluten. Gluten is very elastic. The gluten network can stretch to accommodate the gas (carbon dioxide) formed when you add yeast to bread dough or heat a cake batter made with baking powder or baking soda (sodium bicarbonate), trapping the gas and making the bread dough or cake batter rise. When you bake the dough or batter, the gluten network hardens and the bread or cake assumes its finished shape. Starch reactions. Starch consists of molecules of the complex carbohydrates amylose and amylopectin packed into a starch granule. When you heat flour in liquid, the starch gran- ules absorb water molecules, swell, and soften. When the temperature of the liquid reaches approximately 140°F the amylose and amylopectin molecules inside the granules relax and unfold, breaking some of their internal bonds (bonds between atoms on the same molecule) and forming new bonds between atoms on different molecules. The result is a network that traps and holds water molecules. The starch granules then swell, thickening the liquid. If you continue to heat the liquid (or stir it too vigorously), the network will begin to break down, the liquid will leak out of the starch granules, and the sauce will separate.* Combination reaction. Coating food with flour takes advantage of the starch reaction (absorbing liquids) and the protein reaction (baking a hard, crisp protein crust).

Medical Uses and/or Benefits A lower risk of some kinds of cancer. In 1998, scientists at Wayne State University in Detroit conducted a meta-analysis of data from more than 30 well-designed animal studies mea- suring the anti-cancer effects of wheat bran, the part of grain with highest amount of the insoluble dietary fibers cellulose and lignin. They found a 32 percent reduction in the risk of colon cancer among animals fed wheat bran; now they plan to conduct a similar meta- analysis of human studies. Whole wheat flours are a good source of wheat bran. NOTE : The amount of fiber per serving listed on a food package label shows the total amount of fiber (insoluble and soluble). Early in 1999, however, new data from the long-running Nurses Health Study at Brigham Women’s Hospital/Harvard University School of Public Health showed that women who ate a high-fiber diet had a risk of colon cancer similar to that of women who ate a low-fiber diet. * A mylose is a long, unbranched, spiral molecule; amylopect in is a short, compact, branched molecule. A mylose has more room for forming bonds to water. Wheat flours, which have a higher rat io of amy- lose to amylopect in, are superior t hickeners. Because this study contradicts literally hundreds of others conducted over the past 30 years, researchers are awaiting confirming evidence before changing dietary recommendations.

Adverse Effects Associated with This Food Allergic reactions. According to the Merck Manual, wheat is one of the foods most commonly implicated as a cause of allergic upset stomach, hives, and angioedema (swollen lips and eyes). For more information, see under wheat cer ea ls. Gluten intolerance (celiac disease). Celiac disease is an intestinal allergic disorder that makes it impossible to digest gluten and gliadin (proteins found in wheat and some other grains). Corn flour, potato flour, rice flour, and soy flour are all gluten- and gliadin-free. Ergot poisoning. Rye and some kinds of wheat will support ergot, a parasitic fungus related to lysergic acid (LSD). Because commercial flours are routinely checked for ergot contamina- tion, there has not been a major outbreak of ergot poisoning from bread since a 1951 incident in France. Since baking does not destroy ergot toxins, the safest course is to avoid moldy flour altogether.... flour

Grapefruit

(Ugli fruit)

Nutritional Profile Energy value (calories per serving): Low Protein: Low Fat: Low Saturated fat: Low Cholesterol: None Carbohydrates: High Fiber: Moderate Sodium: Low Major vitamin contribution: Vitamin A, vitamin C Major mineral contribution: Potassium

About the Nutrients in This Food Grapefruit and ugli fruit (a cross between the grapefruit and the tangerine) have moderate amounts of dietary fiber and, like all citrus fruits, are most prized for their vitamin C. Pink or red grapefruits have moderate amounts of vitamin A. One-half medium (four-inch diameter) pink grapefruit has 1.4 g dietary fiber, 1,187 IU vitamin A (51 percent of the R DA for a woman, 40 percent of the R DA for a man), and 44 mg vitamin C (59 percent of the R DA for a woman, 49 percent of the R DA for a man). One half medium (3.75-inch diameter) white grapefruit has 1.3 g dietary fiber, 39 IU vitamin A (2 percent of the R DA for a woman, 1 percent of the R DA for a man), and 39 mg vitamin C (52 percent of the R DA for a woman, 43 percent of the R DA for a man). Pink and red grapefruits also contain lycopene, a red carotenoid (plant pigment), a strong antioxidant that appears to lower the risk of cancer of the prostate. The richest source of lycopene is cooked tom atoes.

The Most Nutritious Way to Serve This Food Fresh fruit or fresh-squeezed juice.

Buying This Food Look for: Firm fruit that is heavy for its size, which means that it will be juicy. The skin should be thin, smooth, and fine-grained. Most grapefruit have yellow skin that, depending on the variety, may be tinged with red or green. In fact, a slight greenish tint may mean that the grapefruit is high in sugar. Ugli fruit, which looks like misshapen, splotched grapefruit, is yellow with green patches and bumpy skin. Avoid: Grapefruit or ugli fruit with puff y skin or those that feel light for their size; the flesh inside is probably dry and juiceless.

Storing This Food Store grapefruit either at room temperature (for a few days) or in the refrigerator. Refrigerate grapefruit juice in a tightly closed glass bottle with very little air space at the top. As you use up the juice, transfer it to a smaller bottle, again with very little air space at the top. The aim is to prevent the juice from coming into contact with oxygen, which destroys vitamin C. (Most plastic juice bottles are oxygen-permeable.) Properly stored and protected from oxygen, fresh grapefruit juice can hold its vitamin C for several weeks.

Preparing This Food Grapefruit are most flavorful at room temperature, which liberates the aromatic molecules that give them their characteristic scent and taste. Before cutting into the grapefruit, rinse it under cool running water to flush debris off the peel. To section grapefruit, cut a slice from the top, then cut off the peel in strips—starting at the top and going down—or peel it in a spiral fashion. You can remove the bitter white membrane, but some of the vitamin C will go with it. Finally, slice the sections apart. Or you can simply cut the grapefruit in half and scoop out the sections with a curved, serrated grapefruit knife.

What Happens When You Cook This Food Broiling a half grapefruit or poaching grapefruit sections reduces the fruit’s supply of vitamin C, which is heat-sensitive.

How Other Kinds of Processing Affect This Food Commercially prepared juices. How well a commercially prepared juice retains its vitamin C depends on how it is prepared, stored, and packaged. Commercial flash-freezing preserves as much as 95 percent of the vitamin C in fresh grapefruit juices. Canned juice stored in the refrigerator may lose only 2 percent of its vitamin C in three months. Prepared, pasteurized “fresh” juices lose vitamin C because they are sold in plastic bottles or waxed-paper cartons that let oxygen in. Commercially prepared juices are pasteurized to stop the natural enzyme action that would otherwise turn sugars to alcohols. Pasteurization also protects juices from potentially harmful bacterial and mold contamination. Following several deaths attributed to unpas- teurized apple juices containing E. coli O157:H7, the FDA ruled that all fruit and vegetable juices must carry a warning label telling you whether the juice has been pasteurized. Around the year 2000, all juices must be processed to remove or inactivate harmful bacteria.

Medical Uses and/or Benefits Antiscorbutic. All citrus fruits are superb sources of vitamin C, the vitamin that prevents or cures scurvy, the vitamin C-deficiency disease. Increased absorption of supplemental or dietary iron. If you eat foods rich in vitamin C along with iron supplements or foods rich in iron, the vitamin C will enhance your body’s ability to absorb the iron. Wound healing. Your body needs vitamin C in order to convert the amino acid proline into hydroxyproline, an essential ingredient in collagen, the protein needed to form skin, ten- dons, and bones. As a result people with scurvy do not heal quickly, a condition that can be remedied with vitamin C, which cures the scurvy and speeds healing. Whether taking extra vitamin C speeds healing in healthy people remains to be proved. Possible inhibition of virus that causes chronic hepatitis C infection. In Januar y 2008, research- ers at Massachusetts General Hospital Center for Engineering in Medicine (Boston) published a report in the medical journal Hepatology detailing the effect of naringenin, a compound in grapefruit, on the behavior of hepatitis viruses in liver cells. In laborator y studies, naringenin appeared to inhibit the ability of the virus to multiply and/or pass out from the liver cells. To date, there are no studies detailing the effect of naringenin in human beings with hepatitis C.

Adverse Effects Associated with This Food Contact dermatitis. The essential oils in the peel of citrus fruits may cause skin irritation in sensitive people.

Food/Drug Interactions Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, naproxen and others. Taking aspirin or NSAIDs with acidic foods such as grapefruit may intensif y the drug’s ability to irritate your stomach and cause gastric bleeding. Antihistamines, anticoagulants, benzodiazepines (tranquilizers or sleep medications), calcium channel blockers (blood pressure medication), cyclosporine (immunosuppressant drug used in organ transplants), theophylline (asthma drug). Drinking grapefruit juice with a wide variety of drugs ranging from antihistamines to blood pressure medication appears to reduce the amount of the drug your body metabolizes and eliminates. The “grapefruit effect” was first identified among people taking the antihypertensive drugs felodipine (Plendil) and nifedip- ine (Adalat, Procardia). It is not yet known for certain exactly what the active substance in the juice is. One possibility, however, is bergamottin, a naturally occurring chemical in grapefruit juice known to inactivate cytochrome P450 3A4, a digestive enzyme needed to convert many drugs to water-soluble substances you can flush out of your body. Without an effective supply of cytochrome P450 3A4, the amount of a drug circulating in your body may rise to dangerous levels. Reported side effects include lower blood pressure, increased heart rate, headache, flushing, and lightheadedness. Some Drugs Known to Interact with Grapefruit Juice* Drug Class  Generic (Brand name) Antianxiety drug  Diazepam ( Valium) Antiarrhythmics  Amiodarone (Cordarone) Blood-pressure drugs  Felodipine (Plendil), nicardipine (Cardene), nimodipine (Nimotop), nisoldipine (Sular), verapamil ( Verelan) Cholesterol-lowering drugs  Atorvastatin (Lipitor), lovastatin (Mevacor), simvastatin (Zocor), simvastatin/ezetimibe ( Vytorin) Immune Suppressants  Cyclosporine (Neoral), tacrolimus (Prograf ) Impotence Drug  Sildenafil ( Viagra) Pain Medication Methadone (Dolophine, Methadose) * This list may grow as new research appears.... grapefruit

Humidifier Fever

A form of ALVEOLITIS caused by contamination of the water used to humidify, or moisten, the air in air-conditioning plants. The breathing of the contaminated air results in infection of the lung, which is characterised by fever, cough, shortness of breath and malaise – worse on Monday and tending to improve during the

course of the week. (See also LEGIONNAIRE’S DISEASE.)... humidifier fever

Infection

The entry and development or multiplication of an infectious agent in the body of humans or animals. Infection is not synonymous with infectious disease; the result may be inapparent or manifest. The presence of living infectious agents on exterior surfaces of the body, or upon articles or apparel or soiled articles, is not infection but contamination of such surfaces and articles.... infection

Listeriosis

A rare disease, although the causal organism, Listeria monocytogenes, is widely distributed in soil, silage, water, and various animals, with consequent risk of food contamination – for example, from unpasteurised soft cheese. Neonates are mainly affected – often as a result of a mild or inapparent infection in the pregnant mother. The disease presents in two main forms: MENINGOENCEPHALITIS, or SEPTICAEMIA with enlarged LYMPH glands. Elderly adults occasionally develop the ?rst form, while younger adults are more likely to develop a mild or even inapparent form. The disease is treated with ANTIBIOTICS such as ampicillin (see PENICILLIN) or CHLORAMPHENICOL.... listeriosis

Dysentery

A clinical state arising from invasive colo-rectal disease; it is accompanied by abdominal colic, diarrhoea, and passage of blood/mucus in the stool. Although the two major forms are caused by Shigella spp. (bacillary dysentery) and Entamoeba histolytica (amoebic dysentery), other organisms including entero-haemorrhagic Escherichia coli (serotypes 0157:H7 and 026:H11) and Campylobacter spp. are also relevant. Other causes of dysentery include Balantidium coli and that caused by schistosomiasis (bilharzia) – Schistosoma mansoni and S. japonicum infection.

Shigellosis This form is usually caused by Shigella dysenteriae-1 (Shiga’s bacillus), Shigella ?exneri, Shigella boydii, and Shigella sonnei; the latter is the most benign and occurs in temperate climates also. It is transmitted by food and water contamination, by direct contact, and by ?ies; the organisms thrive in the presence of overcrowding and insanitary conditions. The incubation is between one and seven days, and the severity of the illness depends on the strain responsible. Duration of illness varies from a few days to two weeks and can be particularly severe in young, old, and malnourished individuals. Complications include perforation and haemorrhage from the colo-rectum, the haemolytic uraemic syndrome (which includes renal failure), and REITER’S SYNDROME. Diagnosis is dependent on demonstration of Shigella in (a) faecal sample(s) – before or usually after culture.

If dehydration is present, this should be treated accordingly, usually with an oral rehydration technique. Shigella is eradicated by antibiotics such as trimethoprimsulphamethoxazole, trimethoprim, ampicillin, and amoxycillin. Recently, a widespread resistance to many antibiotics has developed, especially in Asia and southern America, where the agent of choice is now a quinolone compound, for example, cipro?oxacin; nalidixic acid is also e?ective. Prevention depends on improved hygiene and sanitation, careful protection of food from ?ies, ?y destruction, and garbage disposal. A Shigella carrier must not be allowed to handle food.

Entamoeba histolytica infection Most cases occur in the tropics and subtropics. Dysentery may be accompanied by weight loss, anaemia, and occasionally DYSPNOEA. E. histolytica contaminates food (e.g. uncooked vegetables) or drinking water. After ingestion of the cyst-stage, and following the action of digestive enzymes, the motile trophozoite emerges in the colon causing local invasive disease (amoebic colitis). On entering the portal system, these organisms may gain access to the liver, causing invasive hepatic disease (amoebic liver ‘abscess’). Other sites of ‘abscess’ formation include the lungs (usually right) and brain. In the colo-rectum an amoeboma may be di?cult to di?erentiate from a carcinoma. Clinical symptoms usually occur within a week, but can be delayed for months, or even years; onset may be acute – as for Shigella spp. infection. Perforation, colo-rectal haemorrhage, and appendicitis are unusual complications. Diagnosis is by demonstration of E. histolytica trophozoites in a fresh faecal sample; other amoebae affecting humans do not invade tissues. Research techniques can be used to di?erentiate between pathogenic (E. dysenteriae) and non-pathogenic strains (E. dispar). Alternatively, several serological tests are of value in diagnosis, but only in the presence of invasive disease.

Treatment consists of one of the 5nitroimidazole compounds – metronidazole, tinidazole, and ornidazole; alcohol avoidance is important during their administration. A ?ve- to ten-day course should be followed by diloxanide furoate for ten days. Other compounds – emetine, chloroquine, iodoquinol, and paromomycin – are now rarely used. Invasive disease involving the liver or other organ(s) usually responds favourably to a similar regimen; aspiration of a liver ‘abscess’ is now rarely indicated, as controlled trials have indicated a similar resolution rate whether this technique is used or not, provided a 5-nitroimidazole compound is administered.... dysentery

Fucus Vesiculosus

Linn.

Family: Fucaceae. (Laminaria sp.)

Habitat: On the shores of the United Kingdom, North Atlantic Ocean, North Pacific Coast of America; as a weed; found in Indian Ocean on the Manora Rocks. Allied species—F. distichus Linn., and F nodosus Linn. (Included in Glossary of Indian Medicinal Plants, CSIR, also in its second supplement.) F. nodosus is found in India along sea shores.

English: Bladderwrack, Black Tang, Rockweed, Kelp.

Action: Weed—one of the richest source of minerals, chiefly iodine, sodium, manganese, sulphur, silicon, zinc and copper. Effective against obesity, antirheumatic. Stimulates circulation of lymph. Endocrine gland stimulant. Allays onset of arteriosclerosis by maintaining elasticity of walls of blood vessels. Mild diuretic, bulk, laxative, antibiotic. High sodium content may reduce effectiveness of diuretics.

(The herb contains trace metal, particularly iodine from 0.03-1.0%. It may contain waste metals such as cadmium and strontium, when grown in a polluted environment. Variable iodine content and arsenic contamination make the herb unsafe.)

The herb should be used with caution in hyperthyroidism and hypothyroidism. Excess thyroid activity maybe aggravated by the iodine content of the herb; it may disrupt thyroid function. One gram of Bladderwrack might contain as much as 600 mcg iodine (Ingesting more than 150 mcg iodine per day may cause hyperthyroidism or exacerbate existing hyperthyroidism.) (Natural Medicines Comprehensive Database, 2007.)

Due to the antithrombin effects ofits fucan polysaccharides, consumption of the herb in cases of G1 bleeding disorders is contraindicated.

(Included among unapproved herbs by German Commission E.)... fucus vesiculosus

Nappy Rash

A common form of irritant contact DERMATITIS in the nappy area in babies under one year old. Wetting of the skin by urine, abrasion, and chemical changes due to faecal contamination all play a part. Good hygiene and use of disposable absorbent nappies have much reduced its incidence. An ointment containing a barrier, such as titanium dioxide, may help; other medications such as mild CORTICOSTEROIDS or antibiotics should be used very cautiously and only under the guidance of a doctor, as harmful effects may result – especially from overuse.... nappy rash

Obsessive Compulsive Disorder

A mental-health problem which will be experienced at some time by up to 3 per cent of adults. The main feature is the occurrence of spontaneous intrusive thoughts that cause intense anxiety. Many of these thoughts prompt urges, or compulsions, to carry out particular actions in order to reduce the anxiety. One of the commonest obsessions is a fear of dirt and contamination that prompts compulsive cleaning or repeated and unnecessary handwashing. (See MENTAL ILLNESS.)... obsessive compulsive disorder

Occupational Health, Medicine And Diseases

Occupational health The e?ect of work on human health, and the impact of workers’ health on their work. Although the term encompasses the identi?cation and treatment of speci?c occupational diseases, occupational health is also an applied and multidisciplinary subject concerned with the prevention of occupational ill-health caused by chemical, biological, physical and psychosocial factors, and the promotion of a healthy and productive workforce.

Occupational health includes both mental and physical health. It is about compliance with health-and-safety-at-work legislation (and common law duties) and about best practice in providing work environments that reduce risks to health and safety to lowest practicable levels. It includes workers’ ?tness to work, as well as the management of the work environment to accommodate people with disabilities, and procedures to facilitate the return to work of those absent with long-term illness. Occupational health incorporates several professional groups, including occupational physicians, occupational health nurses, occupational hygienists, ergonomists, disability managers, workplace counsellors, health-and-safety practitioners, and workplace physiotherapists.

In the UK, two key statutes provide a framework for occupational health: the Health and Safety at Work, etc. Act 1974 (HSW Act); and the Disability Discrimination Act 1995 (DDA). The HSW Act states that employers have a duty to protect the health, safety and welfare of their employees and to conduct their business in a way that does not expose others to risks to their health and safety. Employees and self-employed people also have duties under the Act. Modern health-and-safety legislation focuses on assessing and controlling risk rather than prescribing speci?c actions in di?erent industrial settings. Various regulations made under the HSW Act, such as the Control of Substances Hazardous to Health Regulations, the Manual Handling Operations Regulations and the Noise at Work Regulations, set out duties with regard to di?erent risks, but apply to all employers and follow the general principles of risk assessment and control. Risks should be controlled principally by removing or reducing the hazard at source (for example, by substituting chemicals with safer alternatives, replacing noisy machinery, or automating tasks to avoid heavy lifting). Personal protective equipment, such as gloves and ear defenders, should be seen as a last line of defence after other control measures have been put in place.

The employment provisions of the DDA require employers to avoid discriminatory practice towards disabled people and to make reasonable adjustments to working arrangements where a disabled person is placed at a substantial disadvantage to a non-disabled person. Although the DDA does not require employers to provide access to rehabilitation services – even for those injured or made ill at work – occupational-health practitioners may become involved in programmes to help people get back to work after injury or long-term illness, and many businesses see the retention of valuable sta? as an attractive alternative to medical retirement or dismissal on health grounds.

Although a major part of occupational-health practice is concerned with statutory compliance, the workplace is also an important venue for health promotion. Many working people rarely see their general practitioner and, even when they do, there is little time to discuss wider health issues. Occupational-health advisers can ?ll in this gap by providing, for example, workplace initiatives on stopping smoking, cardiovascular health, diet and self-examination for breast and testicular cancers. Such initiatives are encouraged because of the perceived bene?ts to sta?, to the employing organisation and to the wider public-health agenda. Occupational psychologists recognise the need for the working population to achieve a ‘work-life balance’ and the promotion of this is an increasing part of occupational health strategies.

The law requires employers to consult with their sta? on health-and-safety matters. However, there is also a growing understanding that successful occupational-health management involves workers directly in the identi?cation of risks and in developing solutions in the workplace. Trade unions play an active role in promoting occupational health through local and national campaigns and by training and advising elected workplace safety representatives.

Occupational medicine The branch of medicine that deals with the control, prevention, diagnosis, treatment and management of ill-health and injuries caused or made worse by work, and with ensuring that workers are ?t for the work they do.

Occupational medicine includes: statutory surveillance of workers’ exposure to hazardous agents; advice to employers and employees on eliminating or reducing risks to health and safety at work; diagnosis and treatment/management of occupational illness; advice on adapting the working environment to suit the worker, particularly those with disabilities or long-term health problems; and advice on the return to work and, if necessary, rehabilitation of workers absent through illness. Occupational physicians may play a wider role in monitoring the health of workplace populations and in advising employers on controlling health hazards where ill-health trends are observed. They may also conduct epidemiological research (see EPIDEMIOLOGY) on workplace diseases.

Because of the occupational physician’s dual role as adviser to both employer and employee, he or she is required to be particularly diligent with regards to the individual worker’s medical CONFIDENTIALITY. Occupational physicians need to recognise in any given situation the context they are working in, and to make sure that all parties are aware of this.

Occupational medicine is a medical discipline and thus is only part of the broader ?eld of occupational health. Although there are some speci?c clinical duties associated with occupational medicine, such as diagnosis of occupational disease and medical screening, occupational physicians are frequently part of a multidisciplinary team that might include, for example, occupational-health nurses, healthand-safety advisers, ergonomists, counsellors and hygienists. Occupational physicians are medical practitioners with a post-registration quali?cation in occupational medicine. They will have completed a period of supervised in-post training. In the UK, the Faculty of Occupational Medicine of the Royal College of Physicians has three categories of membership, depending on quali?cations and experience: associateship (AFOM); membership (MFOM); and fellowship (FFOM).

Occupational diseases Occupational diseases are illnesses that are caused or made worse by work. In their widest sense, they include physical and mental ill-health conditions.

In diagnosing an occupational disease, the clinician will need to examine not just the signs and symptoms of ill-health, but also the occupational history of the patient. This is important not only in discovering the cause, or causes, of the disease (work may be one of a number of factors), but also in making recommendations on how the work should be modi?ed to prevent a recurrence – or, if necessary, in deciding whether or not the worker is able to return to that type of work. The occupational history will help in deciding whether or not other workers are also at risk of developing the condition. It will include information on:

the nature of the work.

how the tasks are performed in practice.

the likelihood of exposure to hazardous agents (physical, chemical, biological and psychosocial).

what control measures are in place and the extent to which these are adhered to.

previous occupational and non-occupational exposures.

whether or not others have reported similar symptoms in relation to the work. Some conditions – certain skin conditions,

for example – may show a close relationship to work, with symptoms appearing directly only after exposure to particular agents or possibly disappearing at weekends or with time away from work. Others, however, may be chronic and can have serious long-term implications for a person’s future health and employment.

Statistical information on the prevalence of occupational disease in the UK comes from a variety of sources, including o?cial ?gures from the Industrial Injuries Scheme (see below) and statutory reporting of occupational disease (also below). Neither of these o?cial schemes provides a representative picture, because the former is restricted to certain prescribed conditions and occupations, and the latter suffers from gross under-reporting. More useful are data from the various schemes that make up the Occupational Diseases Intelligence Network (ODIN) and from the Labour Force Survey (LFS). ODIN data is generated by the systematic reporting of work-related conditions by clinicians and includes several schemes. Under one scheme, more than 80 per cent of all reported diseases by occupational-health physicians fall into just six of the 42 clinical disease categories: upper-limb disorders; anxiety, depression and stress disorders; contact DERMATITIS; lower-back problems; hearing loss (see DEAFNESS); and ASTHMA. Information from the LFS yields a similar pattern in terms of disease frequency. Its most recent survey found that over 2 million people believed that, in the previous 12 months, they had suffered from an illness caused or made worse by work and that

19.5 million working days were lost as a result. The ten most frequently reported disease categories were:

stress and mental ill-health (see MENTAL ILLNESS): 515,000 cases.

back injuries: 508,000.

upper-limb and neck disorders: 375,000.

lower respiratory disease: 202,000.

deafness, TINNITUS or other ear conditions: 170,000.

lower-limb musculoskeletal conditions: 100,000.

skin disease: 66,000.

headache or ‘eyestrain’: 50,000.

traumatic injury (includes wounds and fractures from violent attacks at work): 34,000.

vibration white ?nger (hand-arm vibration syndrome): 36,000. A person who develops a chronic occu

pational disease may be able to sue his or her employer for damages if it can be shown that the employer was negligent in failing to take reasonable care of its employees, or had failed to provide a system of work that would have prevented harmful exposure to a known health hazard. There have been numerous successful claims (either awarded in court, or settled out of court) for damages for back and other musculoskeletal injuries, hand-arm vibration syndrome, noise-induced deafness, asthma, dermatitis, MESOTHELIOMA and ASBESTOSIS. Employers’ liability (workers’ compensation) insurers are predicting that the biggest future rise in damages claims will be for stress-related illness. In a recent study, funded by the Health and Safety Executive, about 20 per cent of all workers – more than 5 million people in the UK – claimed to be ‘very’ or ‘extremely’ stressed at work – a statistic that is likely to have a major impact on the long-term health of the working population.

While victims of occupational disease have the right to sue their employers for damages, many countries also operate a system of no-fault compensation for the victims of prescribed occupational diseases. In the UK, more than 60 diseases are prescribed under the Industrial Injuries Scheme and a person will automatically be entitled to state compensation for disability connected to one of these conditions, provided that he or she works in one of the occupations for which they are prescribed. The following short list gives an indication of the types of diseases and occupations prescribed under the scheme:

CARPAL TUNNEL SYNDROME connected to the use of hand-held vibrating tools.

hearing loss from (amongst others) use of pneumatic percussive tools and chainsaws, working in the vicinity of textile manufacturing or woodworking machines, and work in ships’ engine rooms.

LEPTOSPIROSIS – infection with Leptospira (various listed occupations).

viral HEPATITIS from contact with human blood, blood products or other sources of viral hepatitis.

LEAD POISONING, from any occupation causing exposure to fumes, dust and vapour from lead or lead products.

asthma caused by exposure to, among other listed substances, isocyanates, curing agents, solder ?ux fumes and insects reared for research.

mesothelioma from exposure to asbestos.

In the UK, employers and the self-employed have a duty to report all occupational injuries (if the employee is o? work for three days or more as a result), diseases or dangerous incidents to the relevant enforcing authority (the Health and Safety Executive or local-authority environmental-health department) under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995 (RIDDOR). Despite this statutory duty, comparatively few diseases are reported so that ?gures generated from RIDDOR reports do not give a useful indication of the scale of occupational diseases in the UK. The statutory reporting of injuries is much better, presumably because of the clear and acute relationship between a workplace accident and the resultant injury. More than 160,000 injuries are reported under RIDDOR every year compared with just 2,500 or so occupational diseases, a gross underestimate of the true ?gure.

There are no precise ?gures for the number of people who die prematurely because of work-related ill-health, and it would be impossible to gauge the exact contribution that work has on, for example, cardiovascular disease and cancers where the causes are multifactorial. The toll would, however, dwarf the number of deaths caused by accidents at work. Around 250 people are killed by accidents at work in the UK each year – mesothelioma, from exposure to asbestos at work, alone kills more than 1,300 people annually.

The following is a sample list of occupational diseases, with brief descriptions of their aetiologies.

Inhaled materials

PNEUMOCONIOSIS covers a group of diseases which cause ?brotic lung disease following the inhalation of dust. Around 250–300 new cases receive bene?t each year – mostly due to coal dust with or without silica contamination. SILICOSIS is the more severe disease. The contraction in the size of the coal-mining industry as well as improved dust suppression in the mines have diminished the importance of this disease, whereas asbestos-related diseases now exceed 1,000 per year. Asbestos ?bres cause a restrictive lung disease but also are responsible for certain malignant conditions such as pleural and peritoneal mesothelioma and lung cancer. The lung-cancer risk is exacerbated by cigarette-smoking.

Even though the use of asbestos is virtually banned in the UK, many workers remain at risk of exposure because of the vast quantities present in buildings (much of which is not listed in building plans). Carpenters, electricians, plumbers, builders and demolition workers are all liable to exposure from work that disturbs existing asbestos. OCCUPATIONAL ASTHMA is of increasing importance – not only because of the recognition of new allergic agents (see ALLERGY), but also in the number of reported cases. The following eight substances are most frequently linked to occupational asthma (key occupations in brackets): isocyanates (spray painters, electrical processors); ?our and grain (bakers and farmers); wood dust (wood workers); glutaraldehyde (nurses, darkroom technicians); solder/colophony (welders, electronic assembly workers); laboratory animals (technicians, scientists); resins and glues (metal and electrical workers, construction, chemical processors); and latex (nurses, auxiliaries, laboratory technicians).

The disease develops after a short, symptomless period of exposure; symptoms are temporally related to work exposures and relieved by absences from work. Removal of the worker from exposure does not necessarily lead to complete cessation of symptoms. For many agents, there is no relationship with a previous history of ATOPY. Occupational asthma accounts for about 10 per cent of all asthma cases. DERMATITIS The risk of dermatitis caused by an allergic or irritant reaction to substances used or handled at work is present in a wide variety of jobs. About three-quarters of cases are irritant contact dermatitis due to such agents as acids, alkalis and solvents. Allergic contact dermatitis is a more speci?c response by susceptible individuals to a range of allergens (see ALLERGEN). The main occupational contact allergens include chromates, nickel, epoxy resins, rubber additives, germicidal agents, dyes, topical anaesthetics and antibiotics as well as certain plants and woods. Latex gloves are a particular cause of occupational dermatitis among health-care and laboratory sta? and have resulted in many workers being forced to leave their profession through ill-health. (See also SKIN, DISEASES OF.)

Musculoskeletal disorders Musculoskeletal injuries are by far the most common conditions related to work (see LFS ?gures, above) and the biggest cause of disability. Although not all work-related, musculoskeletal disorders account for 36.5 per cent of all disabilities among working-age people (compared with less than 4 per cent for sight and hearing impairment). Back pain (all causes – see BACKACHE) has been estimated to cause more than 50 million days lost every year in sickness absence and costs the UK economy up to £5 billion annually as a result of incapacity or disability. Back pain is a particular problem in the health-care sector because of the risk of injury from lifting and moving patients. While the emphasis should be on preventing injuries from occurring, it is now well established that the best way to manage most lower-back injuries is to encourage the patient to continue as normally as possible and to remain at work, or to return as soon as possible even if the patient has some residual back pain. Those who remain o? work on long-term sick leave are far less likely ever to return to work.

Aside from back injuries, there are a whole range of conditions affecting the upper limbs, neck and lower limbs. Some have clear aetiologies and clinical signs, while others are less well de?ned and have multiple causation. Some conditions, such as carpal tunnel syndrome, are prescribed diseases in certain occupations; however, they are not always caused by work (pregnant and older women are more likely to report carpal tunnel syndrome irrespective of work) and clinicians need to be careful when assigning work as the cause without ?rst considering the evidence. Other conditions may be revealed or made worse by work – such as OSTEOARTHRITIS in the hand. Much attention has focused on injuries caused by repeated movement, excessive force, and awkward postures and these include tenosynovitis (in?ammation of a tendon) and epicondylitis. The greatest controversy surrounds upper-limb disorders that do not present obvious tissue or nerve damage but nevertheless give signi?cant pain and discomfort to the individual. These are sometimes referred to as ‘repetitive strain injury’ or ‘di?use RSI’. The diagnosis of such conditions is controversial, making it di?cult for sufferers to pursue claims for compensation through the courts. Psychosocial factors, such as high demands of the job, lack of control and poor social support at work, have been implicated in the development of many upper-limb disorders, and in prevention and management it is important to deal with the psychological as well as the physical risk factors. Occupations known to be at particular risk of work-related upper-limb disorders include poultry processors, packers, electronic assembly workers, data processors, supermarket check-out operators and telephonists. These jobs often contain a number of the relevant exposures of dynamic load, static load, a full or excessive range of movements and awkward postures. (See UPPER LIMB DISORDERS.)

Physical agents A number of physical agents cause occupational ill-health of which the most important is occupational deafness. Workplace noise exposures in excess of 85 decibels for a working day are likely to cause damage to hearing which is initially restricted to the vital frequencies associated with speech – around 3–4 kHz. Protection from such noise is imperative as hearing aids do nothing to ameliorate the neural damage once it has occurred.

Hand-arm vibration syndrome is a disorder of the vascular and/or neural endings in the hands leading to episodic blanching (‘white ?nger’) and numbness which is exacerbated by low temperature. The condition, which is caused by vibrating tools such as chain saws and pneumatic hammers, is akin to RAYNAUD’S DISEASE and can be disabling.

Decompression sickness is caused by a rapid change in ambient pressure and is a disease associated with deep-sea divers, tunnel workers and high-?ying aviators. Apart from the direct effects of pressure change such as ruptured tympanic membrane or sinus pain, the more serious damage is indirectly due to nitrogen bubbles appearing in the blood and blocking small vessels. Central and peripheral nervous-system damage and bone necrosis are the most dangerous sequelae.

Radiation Non-ionising radiation from lasers or microwaves can cause severe localised heating leading to tissue damage of which cataracts (see under EYE, DISORDERS OF) are a particular variety. Ionising radiation from radioactive sources can cause similar acute tissue damage to the eyes as well as cell damage to rapidly dividing cells in the gut and bone marrow. Longer-term effects include genetic damage and various malignant disorders of which LEUKAEMIA and aplastic ANAEMIA are notable. Particular radioactive isotopes may destroy or induce malignant change in target organs, for example, 131I (thyroid), 90Sr (bone). Outdoor workers may also be at risk of sunburn and skin cancers. OTHER OCCUPATIONAL CANCERS Occupation is directly responsible for about 5 per cent of all cancers and contributes to a further 5 per cent. Apart from the cancers caused by asbestos and ionising radiation, a number of other occupational exposures can cause human cancer. The International Agency for Research on Cancer regularly reviews the evidence for carcinogenicity of compounds and industrial processes, and its published list of carcinogens is widely accepted as the current state of knowledge. More than 50 agents and processes are listed as class 1 carcinogens. Important occupational carcinogens include asbestos (mesothelioma, lung cancer); polynuclear aromatic hydrocarbons such as mineral oils, soots, tars (skin and lung cancer); the aromatic amines in dyestu?s (bladder cancer); certain hexavalent chromates, arsenic and nickel re?ning (lung cancer); wood and leather dust (nasal sinus cancer); benzene (leukaemia); and vinyl chloride monomer (angiosarcoma of the liver). It has been estimated that elimination of all known occupational carcinogens, if possible, would lead to an annual saving of 5,000 premature deaths in Britain.

Infections Two broad categories of job carry an occupational risk. These are workers in contact with animals (farmers, veterinary surgeons and slaughtermen) and those in contact with human sources of infection (health-care sta? and sewage workers).

Occupational infections include various zoonoses (pathogens transmissible from animals to humans), such as ANTHRAX, Borrelia burgdorferi (LYME DISEASE), bovine TUBERCULOSIS, BRUCELLOSIS, Chlamydia psittaci, leptospirosis, ORF virus, Q fever, RINGWORM and Streptococcus suis. Human pathogens that may be transmissible at work include tuberculosis, and blood-borne pathogens such as viral hepatitis (B and C) and HIV (see AIDS/HIV). Health-care workers at risk of exposure to infected blood and body ?uids should be immunised against hapatitis B.

Poisoning The incidence of occupational poisonings has diminished with the substitution of noxious chemicals with safer alternatives, and with the advent of improved containment. However, poisonings owing to accidents at work are still reported, sometimes with fatal consequences. Workers involved in the application of pesticides are particularly at risk if safe procedures are not followed or if equipment is faulty. Exposure to organophosphate pesticides, for example, can lead to breathing diffculties, vomiting, diarrhoea and abdominal cramps, and to other neurological effects including confusion and dizziness. Severe poisonings can lead to death. Exposure can be through ingestion, inhalation and dermal (skin) contact.

Stress and mental health Stress is an adverse reaction to excessive pressures or demands and, in occupational-health terms, is di?erent from the motivational impact often associated with challenging work (some refer to this as ‘positive stress’). Stress at work is often linked to increasing demands on workers, although coping can often prevent the development of stress. The causes of occupational stress are multivariate and encompass job characteristics (e.g. long or unsocial working hours, high work demands, imbalance between e?ort and reward, poorly managed organisational change, lack of control over work, poor social support at work, fear of redundancy and bullying), as well as individual factors (such as personality type, personal circumstances, coping strategies, and availability of psychosocial support outside work). Stress may in?uence behaviours such as smoking, alcohol consumption, sleep and diet, which may in turn affect people’s health. Stress may also have direct effects on the immune system (see IMMUNITY) and lead to a decline in health. Stress may also alter the course and response to treatment of conditions such as cardiovascular disease. As well as these general effects of stress, speci?c types of disorder may be observed.

Exposure to extremely traumatic incidents at work – such as dealing with a major accident involving multiple loss of life and serious injury

(e.g. paramedics at the scene of an explosion or rail crash) – may result in a chronic condition known as post-traumatic stress disorder (PTSD). PTSD is an abnormal psychological reaction to a traumatic event and is characterised by extreme psychological discomfort, such as anxiety or panic when reminded of the causative event; sufferers may be plagued with uncontrollable memories and can feel as if they are going through the trauma again. PTSD is a clinically de?ned condition in terms of its symptoms and causes and should not be used to include normal short-term reactions to trauma.... occupational health, medicine and diseases

Shigellosis

An acute, self-limiting intestinal infection, with diarrhea, fever, and abdominal pain, caused by one of the Shigella genus of gram-negative bacteria. The infection is contracted through food prepared by infected individuals or by direct contact with them. Raw sewage contamination can also be a source.... shigellosis

Source Of Infection

The person, animal, object or substance from which an infectious agent passes immediately to a host. Source of infection should be clearly distinguished from source of contamination, such as overflow of septic tank contaminating a water supply, or an infected cook contaminating a salad.... source of infection

Tetanus/tetany

Violent spasms, muscle contraction (“lock-jaw”) caused by a spore -forming, Gram positive bacillus penetrating the body though a puncture wound, and usually leading to death. The organism occurs in water and mayoccur after envenomation (eg in stingray spine puncture wounds), as well as the more commonly-known soil contamination (eg in war wounds). It may be prevented by vaccination with tetanus toxoid.... tetanus/tetany

Carcinogens

Substances that bring about a malignant change in body cells. Sources include: pollutants, asbestos, petroleum products, tobacco, Azo food dyes, nickel, X-rays, nitrites in preserved meats, the Pill and hormone replacement therapy. Direct-acting carcinogens may arise in stored food due to contamination by micro-organisms such as aflatoxin in mould-contaminated peanuts. They stimulate chemical change resulting in free-radicals. See: FREE-RADICALS. ... carcinogens

Dressings

Protective coverings for wounds that are used to control bleeding, absorb secretions, prevent contamination, or retain moisture.... dressings

Health

At its simplest, the absence of physical and mental disease. A wider concept promoted by the World Health Organization is that all people should have the opportunity to fulfil their genetic potential. This includes the ability to develop without the impediments of poor nutrition, environmental contamination, or infectious diseases.

(See diet and disease; health hazards.)... health

Hepatitis

In?ammation of the LIVER which damages liver cells and may ultimately kill them. Acute injury of the liver is usually followed by complete recovery, but prolonged in?ammation after injury may result in FIBROSIS and CIRRHOSIS. Excluding trauma, hepatitis has several causes:

Viral infections by any of hepatitis A, B, C, D, or E viruses and also CYTOMEGALOVIRUS (CMV), EPSTEIN BARR VIRUS, and HERPES SIMPLEX.

Autoimmune disorders such as autoimmune chronic hepatitis, toxins, alcohol and certain drugs – ISONIAZID, RIFAMPICIN, HALOTHANE and CHLORPROMAZINE.

WILSON’S DISEASE.

Acute viral hepatitis causes damage throughout the liver and in severe infections may destroy whole lobules (see below).

Chronic hepatitis is typi?ed by an invasion of the portal tract by white blood cells (mild hepatitis). If these mononuclear in?ammatory cells invade the body (parenchyma) of the liver tissue, ?brosis and then chronic disease or cirrhosis can develop. Cirrhosis may develop at any age and commonly results in prolonged ill health. It is an important cause of premature death, with excessive alcohol consumption commonly the triggering factor. Sometimes, cirrhosis may be asymptomatic, but common symptoms are weakness, tiredness, poor appetite, weight loss, nausea, vomiting, abdominal discomfort and production of abnormal amounts of wind. Initially, the liver may enlarge, but later it becomes hard and shrunken, though rarely causing pain. Skin pigmentation may occur along with jaundice, the result of failure to excrete the liver product BILIRUBIN. Routine liver-function tests on blood are used to help diagnose the disease and to monitor its progress. Spider telangiectasia (caused by damage to blood vessels – see TELANGIECTASIS) usually develop, and these are a signi?cant pointer to liver disease. ENDOCRINE changes occur, especially in men, who lose their typical hair distribution and suffer from atrophy of their testicles. Bruising and nosebleeds occur increasingly as the cirrhosis worsens, and portal hypertension (high pressure of venous blood circulation through the liver) develops due to abnormal vascular resistance. ASCITES and HEPATIC ENCEPHALOPATHY are indications of advanced cirrhosis.

Treatment of cirrhosis is to tackle the underlying cause, to maintain the patient’s nutrition (advising him or her to avoid alcohol), and to treat any complications. The disorder can also be treated by liver transplantation; indeed, 75 per cent of liver transplants are done for cirrhosis. The overall prognosis of cirrhosis, however, is not good, especially as many patients attend for medical care late in the course of the disease. Overall, only 25 per cent of patients live for ?ve years after diagnosis, though patients who have a liver transplant and survive for a year (80 per cent do) have a good prognosis.

Autoimmune hepatitis is a type that most commonly occurs in women between 20 and 40 years of age. The cause is unknown and it has been suggested that the disease has several immunological subtypes. Symptoms are similar to other viral hepatitis infections, with painful joints and AMENORRHOEA as additional symptoms. Jaundice and signs of chronic liver disease usually occur. Treatment with CORTICOSTEROIDS is life-saving in autoimmune hepatitis, and maintenance treatment may be needed for two years or more. Remissions and exacerbations are typical, and most patients eventually develop cirrhosis, with 50 per cent of victims dying of liver failure if not treated. This ?gure falls to 10 per cent in treated patients.

Viral hepatitis The ?ve hepatic viruses (A to E) all cause acute primary liver disease, though each belongs to a separate group of viruses.

•Hepatitis A virus (HAV) is an ENTEROVIRUS

which is very infectious, spreading by faecal contamination from patients suffering from (or incubating) the infection; victims excrete viruses into the faeces for around ?ve weeks during incubation and development of the disease. Overcrowding and poor sanitation help to spread hepatitis A, which fortunately usually causes only mild disease.

Hepatitis B (HBV) is caused by a hepadna virus, and humans are the only reservoir of infection, with blood the main agent for transferring it. Transfusions of infected blood or blood products, and injections using contaminated needles (common among habitual drug abusers), are common modes of transfer. Tattooing and ACUPUNCTURE may spread hepatitis B unless high standards of sterilisation are maintained. Sexual intercourse, particularly between male homosexuals, is a signi?cant infection route.

Hepatitis C (HCV) is a ?avivirus whose source of infection is usually via blood contacts. E?ective screening of blood donors and heat treatment of blood factors should prevent the spread of this infection, which becomes chronic in about 75 per cent of those infected, lasting for life. Although most carriers do not suffer an acute illness, they must practise life-long preventive measures.

Hepatitis D (HDV) cannot survive independently, needing HBV to replicate, so its sources and methods of spread are similar to the B virus. HDV can infect people at the same time as HBV, but it is capable of superinfecting those who are already chronic carriers of the B virus. Acute and chronic infection of HDV can occur, depending on individual circumstances, and parenteral drug abuse spreads the infection. The disease occurs worldwide, being endemic in Africa, South America and the Mediterranean littoral.

Hepatitis E virus (HEV) is excreted in the stools, spreading via the faeco-oral route. It causes large epidemics of water-borne hepatitis and ?ourishes wherever there is poor sanitation. It resembles acute HAV infection and the patient usually recovers. HEV does not cause chronic infection. The clinical characteristics of the ?ve hepatic

viruses are broadly similar. The initial symptoms last for up to two weeks (comprising temperature, headache and malaise), and JAUNDICE then develops, with anorexia, nausea, vomiting and diarrhoea common manifestations. Upper abdominal pain and a tender enlarged liver margin, accompanied by enlarged cervical lymph glands, are usual.

As well as blood tests to assess liver function, there are speci?c virological tests to identify the ?ve infective agents, and these are important contributions to diagnosis. However, there is no speci?c treatment of any of these infections. The more seriously ill patients may require hospital care, mainly to enable doctors to spot at an early stage those developing acute liver failure. If vomiting is a problem, intravenous ?uid and glucose can be given. Therapeutic drugs – especially sedatives and hypnotics – should be avoided, and alcohol must not be taken during the acute phase. Interferon is the only licensed drug for the treatment of chronic hepatitis B, but this is used with care.

Otherwise-?t patients under 40 with acute viral hepatitis have a mortality rate of around

0.5 per cent; for those over 60, this ?gure is around 3 per cent. Up to 95 per cent of adults with acute HBV infection recover fully but the rest may develop life-long chronic hepatitis, particularly those who are immunode?cient (see IMMUNODEFICIENCY).

Infection is best prevented by good living conditions. HVA and HVB can be prevented by active immunisation with vaccines. There is no vaccine available for viruses C, D and E, although HDV is e?ectively prevented by immunisation against HBV. At-risk groups who should be vaccinated against HBV include:

Parenteral drug abusers.

Close contacts of infected individuals such as regular sexual partners and infants of infected mothers.

Men who have sex with men.

Patients undergoing regular haemodialysis.

Selected health professionals, including laboratory sta? dealing with blood samples and products.... hepatitis

Organophosphorus

Organophosphorus insecticides act by inhibiting the action of cholinesterase (see ACETYLCHOLINE). For this reason they are also toxic to humans and must therefore be handled with great care. The most widely used are PARATHION and MALATHION. Organophosphorus has also been used to make nerve gases (see BIOLOGICAL WARFARE).

Treatment After contamination with insecticides, decontaminate (remove clothes, wash skin). Those treating should wear gloves, mask, apron and goggles. For symptoms give 2 mg of ATROPINE IV every 30 minutes until full atropinisation (dry mouth, pulse >70). Up to three days’ treatment may be needed. Severe poisoning may require pralidoxine mysalate: available from designated centres, this drug should be given intravenously within 24 hours of exposure.... organophosphorus

Perforation

The perforation of one of the hollow organs of the abdomen or major blood vessels may occur spontaneously in the case of an ulcer or an advanced tumour, or may be secondary to trauma such as a knife wound or penetrating injury from a tra?c or industrial accident. Whatever the cause, perforation is a surgical emergency. The intestinal contents, which contain large numbers of bacteria, pass freely out into the abdominal cavity and cause a severe chemical or bacterial PERITONITIS. This is usually accompanied by severe abdominal pain, collapse or even death. There may also be evidence of free ?uid or gas within the abdominal cavity. Surgical intervention, to repair the leak and wash out the contamination, is often necessary. Perforation or rupture of major blood vessels, whether from disease or injury, is an acute emergency for which urgent surgical repair is usually necessary. Perforation of hollow structures elsewhere than in the abdomen – for example, the heart or oesophagus – may be caused by congenital weaknesses, disease or injury. Treatment is usually surgical but depends on the cause.... perforation

Proteinuria

A condition in which proteins, principally ALBUMINS, are present in the URINE. It is often a symptom of serious heart or kidney disease, although some normal people have mild and transient proteinuria after exercise.

Causes

KIDNEY DISEASE is the most important cause of proteinuria, and in some cases the discovery of proteinuria may be the ?rst evidence of such disease. This is why an examination of the urine for the presence of albumin constitutes an essential part of every medical examination. Almost any form of kidney disease will cause proteinuria, but the most frequent form to do this is glomerulonephritis (see under KIDNEYS, DISEASES OF). In the subacute (or nephrotic) stage of glomerulonephritis, the most marked proteinuria of all may be found. Proteinuria is also found in infections of the kidney (pyelitis) as well as in infections of the bladder (cystitis) and of the urethra (urethritis). PREGNANCY The development of proteinuria in pregnancy requires investigation, as it may be the ?rst sign of one of the most dangerous complications of pregnancy: toxaemia of pregnancy (PRE-ECLAMPSIA and ECLAMPSIA) and glomerulonephritis. Proteinuria may also result from the contamination of urine with vaginal secretions. (See also PREGNANCY AND LABOUR.) CARDIOVASCULAR DISORDERS are commonly accompanied by proteinuria, particularly when the right side of the heart is failing. In severe cases of failure, accompanied by OEDEMA, the proteinuria may be marked. (See also HEART, DISEASES OF.) FEVER often causes proteinuria, even though there is no actual kidney disease. The proteinuria disappears soon after the temperature becomes normal. (See also PYREXIA.) DRUGS AND POISONS These include arsenic, lead, mercury, gold, copaiba, salicylic acid and quinine. ANAEMIA A trace of albumin may be found in the urine in severe anaemia.

POSTURAL OR ORTHOSTATIC ALBUMINURIA

This type is important because, if its true cause is unrecognised, it may be taken as a sign of kidney disease. The signi?cance of postural proteinuria is unclear: it is more common among young people and is absent when the person is recumbent – hence the importance of testing a urine sample that is taken before rising in the morning.

Treatment The treatment is that of the underlying disease. (See KIDNEYS, DISEASES OF.)... proteinuria

Shellfish Poisoning

In the United Kingdom this occurs in two main forms. Shell?sh may be the cause of typhoid fever (see ENTERIC FEVER) as a result of their contamination by sewage containing the causative organism. They may also be responsible for what is known as paralytic shell?sh poisoning. This is caused by a toxin, or poison, known as saxotoxin, which is present in certain planktons which, under unusual conditions, multiply rapidly, giving rise to what are known as ‘red tides’. In these circumstances the toxin accumulates in mussels, cockles and scallops which feed by ?ltering plankton. The manifestations of such poisoning are loss of feeling in the hands, tingling of the tongue, weakness of the arms and legs, and di?culty in breathing. There is also growing evidence that some shell?sh poisoning may be due to a virus infection. (See also FOOD POISONING.)... shellfish poisoning

Msu

The abbreviation for midstream specimen of urine: a specimen of urine to be examined for the presence of microorganisms. The initial part of the stream is not collected, in order to avoid bacterial contamination of the specimen from the skin or the lining of the lower urinary tract.... msu

Pollution

Contamination of the environment by poisons, radioactive substances, microorganisms, or other wastes.... pollution

Compulsion

n. an *obsession that takes the form of a motor act, such as repetitive washing based on a fear of contamination, as seen in *obsessive–compulsive disorder.... compulsion

Dieldrin

n. an insecticide that attacks the central nervous system of insects and has proved useful in the control of various beetles, flies, and larvae that attack crops. Because of its persistence in and contamination of the environment, its use in the UK is now severely restricted.... dieldrin

Flocculent

adj. describing a fluid containing woolly, fluffy, or flaky white particles, usually due to bacterial contamination.... flocculent

Midstream Specimen Of Urine

(MSU) a specimen of urine that is subjected to examination for the presence of microorganisms. In order to obtain a specimen that is free of contamination, the periurethral area is cleansed and the patient is requested to discard the initial flow of urine before collecting the specimen in a sterile container.... midstream specimen of urine

Heavy Metal Toxicity

Pollution of the blood and tissues by environmental poisons and traces of chemicals is a source of chronic disease. The most common toxic metals are lead, aluminium, cadmium, mercury and arsenic in that order. Copper is also toxic but is essential in small amounts.

Lead disrupts neurotransmitters in the brain and disposes to nervous excitability, aggression and hyperactivity. Aluminium is associated with senile dementia and Alzheimer’s disease, accumulating in the brain. Cadmium induces changes in behaviour with reduced mental ability. Mercury is present in the amalgam used in dental surgery as part-filling for teeth. Arsenical poisoning may occur in food contamination or paints.

An internal chelating or cleansing of tissues of the lungs, urinary system, blood and lymph may be assisted by a combination of relative expectorants, diuretics, hepatics and adaptogens among which are: Barberry, Blue Flag root, Chaparral, Burdock, Echinacea, Red Clover, Yellow Dock. To bind with metals and assist their passage through the intestinal canal to the outside of the body: Irish Moss, Iceland Moss or Slippery Elm. Garlic.

The Medicines Control Agency of the Ministry of Health (UK) has given consideration to the content of heavy metal impurities and rules that a limit of 75 micrograms of total heavy metals shall be the acceptable maximum daily intake.

Licence-holders are required to carry out tests on all incoming material. Some seaweeds may be heavily polluted with mercury, arsenic and radioactive particles as a result of micro-biological contamination. The MCA requires Bladderwrack and other seaweeds to contain minimum levels. ... heavy metal toxicity

Herbs, Source Of

Today’s practice: only first grade organically grown herbs (European, British, American, etc) without the aid of pesticides or herbicides are the general rule, but standards vary in different countries. Some herbs are freshly picked and processed on the same day, and it is modern practice to cultivate in a remote location to avoid wind-blown chemical contamination.

Herbs are soft-stemmed plants that die back in winter. No artificial additives; no cruelty to animals; and no damage to the environment is the ideal in the preparation of herbal remedies.

All herbs are subject to natural variations such as weather, climate and constituents of the soil. In herbal pharmacy products are standardised as carefully as possible under strict laboratory conditions. ... herbs, source of

Manufacturing

Criteria for manufacture of herbal preparations are efficacy, safety and purity. To ensure Government requirement, manufacturers test all incoming crude material by first placing it in quarantine, an area specially set aside for quality control. Material is inspected against standard samples by sight, taste, touch and microscopic analysis. Samples are taken for chemical reaction in a laboratory equipped for this purpose.

Herbal preparations are required to meet the same high pharmaceutical standards as conventional medicine.

Today’s exacting standards ensure an absence of sugar, yeast, gluten, milk derivatives, cornstarch, wheat, artificial colours, flavours, and preservatives.

The Department of Health expects manufacturers to standardise active constituents where possible and to ensure purity by eliminating from crude material pesticide residues, aflatoxins and heavy metal contaminants. Chromotography, in one of its forms (thin-layer, gas or high-pressure liquid) are used to assess purity, potency, accurate identity and contamination by lead, cadmium, etc. A Geiger-counter reveals the presence or absence of radio-activity. Each plant has its own signature or ‘fingerprint’ showing density and other important characteristics.

Failure to meet Government requirements empowers a purchaser to return the whole consignment to the supplier. Thus, a high standard of manufacturing practice is maintained.

See: Medicines Act leaflet 39, Revised Guidelines DHSS Nov 1985 ... manufacturing

Creutzfeldt–jakob Disease

A rare, rapidly progressive degenerative condition of the brain. Creutzfeldt–Jakob disease (CJD) is thought to be due to an infection with a prion (slow virus). This is similar to the agent that causes scrapie in sheep and bovine spongiform encephalopathy (BSE) in cattle. One main variant of CJD largely affects middleaged or elderly people and has no obvious cause. A second main variant, occurring in younger people, is associated with contamination during brain surgery or transplants from infected people, or treatment with human growth hormone or gonadotrophin hormones. Recently, a 3rd variant, called new variant (nv) CJD, that attacks people in their teens and 20s has been identified. NvCJD causes pathological changes in the brain similar to those seen in BSEinfected cattle. It is thought to be acquired by eating infected beef.

Symptoms are similar for all variants. Progressive dementia and myoclonus (sudden muscular contractions) occur; muscular coordination diminishes; the intellect and personality deteriorate; and blindness may develop. As the disease progresses, speech is lost and the body becomes rigid. There is no treatment and death usually occurs within 2–3 years.... creutzfeldt–jakob disease

Nosocomial Infection

(hospital infection) an infection that originates in a hospital. It may develop in a hospitalized patient or a member of the hospital staff, or it may be acquired in hospital but only develops after discharge. Such infections include those caused by fungi and opportunist bacteria. They are aggravated by factors favouring the spread of organisms (cross-contamination), such as insufficient hand washing among medical staff, and by reduced resistance of individual patients, as well as by antibiotic-resistant strains of bacteria (see Clostridium; Enterococcus; MRSA).... nosocomial infection

Tularaemia

(rabbit fever) n. a disease of rodents and rabbits, caused by the bacterium Francisella tularensis, that is transmitted to humans by deer flies (see Chrysops), by direct contact with infected animals, by contamination of wounds, or by drinking contaminated water. Symptoms include an ulcer at the site of infection, inflamed and ulcerating lymph nodes, headache, aching pains, loss of weight, and a fever lasting several weeks. Treatment with chloramphenicol, streptomycin, or tetracycline is effective.... tularaemia

Salmonella Infections

Infections due to any of the salmonella group of bacteria. One type of salmonella causes typhoid fever; others commonly result in bacterial food poisoning, most often through contamination of hens’ eggs or chicken. Infants, the elderly, and people who are debilitated are most susceptible.

Symptoms of salmonella food poisoning usually develop suddenly 12–24 hours after infection and include headache, nausea, abdominal pain, diarrhoea, and sometimes fever. The symptoms usually last for only 2 or 3 days, but, in severe cases, dehydration or septicaemia may develop.

Treatment is by rehydration therapy.

In severe cases, fluid replacement by intravenous infusion may be needed.... salmonella infections

Water-borne Infection

A disease caused by infective or parasitic organisms transmitted via water. Infections can be contracted if infected water is drunk, if it contaminates food, or if individuals swim or wade in it. Worldwide, contamination of drinking water is an important mode of transmission for various diseases including hepatitis A, many viral and bacterial causes of diarrhoea, typhoid fever, cholera, amoebiasis, and some types of worm infestation.

Swimming in polluted water should be avoided because, if swallowed, there is a risk of contracting disease. In addition, a form of leptospirosis is caused by contact with water contaminated by rat’s urine. In tropical countries, there is also a risk of contracting schistosomiasis (bilharzia), which is a serious disease caused by a fluke that can burrow through the swimmer’s skin.... water-borne infection

Berylliosis

n. poisoning by beryllium or its compounds, either by inhalation or by skin contamination. Inhalation of fumes from molten beryllium causes an acute *alveolitis and is usually fatal. Subacute and chronic forms can result from extremely low levels of exposure to the powder and can produce granulomata in the skin or lungs very similar to those seen in *sarcoidosis. In the lungs, these lead to fibrosis, which can, however, be prevented by prompt use of oral corticosteroids. Although the incidence of berylliosis has been greatly reduced since the use of beryllium compounds in the manufacture of fluorescent light tubes was discontinued in Britain in 1948, new cases are still occurring.... berylliosis

Clostridium

n. a genus of mostly Gram-positive anaerobic spore-forming rodlike bacteria commonly found in soil and in the intestinal tract of humans and animals. Many species cause disease and produce extremely potent *exotoxins. C. botulinum grows freely in badly preserved canned foods, producing a toxin causing serious food poisoning (*botulism); an extremely dilute form of this toxin is now used to treat muscle spasm (see botulinum toxin). C. histolyticum, C. oedematiens, and C. septicum all cause *gas gangrene when they infect wounds. C. tetani lives as a harmless *commensal in the intestine but causes *tetanus on contamination of wounds (with manured soil). The species C. perfringens – Welch’s bacillus – causes blood poisoning, *food poisoning, and gas gangrene. Overgrowth of Clostridium difficile (often shortened to C. diff), a normal inhabitant of the human large intestine, is not uncommon as a complication of some antibiotic therapy and produces a specific condition – pseudomembranous colitis (see pseudomembrane) – which is life-threatening unless treated promptly and is becoming more common as a hospital-acquired infection.... clostridium

Obsessive–compulsive Disorder

(OCD) a mental illness prevalent in about 1% of the adult population but more common in children. Males are most commonly affected. The affected person has *obsessions or *compulsions he or she recognizes as senseless. Resisting the obsession causes anxiety, which is relieved by giving in to the compulsion. The obsession may, for example, be a vivid image, a fear (e.g. of contamination), or an impulse (e.g. to wash the hands repetitively). In severe cases obsessions and rituals can take over many hours of a person’s life each day. The condition can be treated with behaviour therapy and antidepressant medication, particularly clomipramine and SSRIs. *Psychosurgery is still a rare option in very severe and treatment-resistant cases.... obsessive–compulsive disorder

Peritonitis

n. inflammation of the *peritoneum. Primary peritonitis is caused by bacteria spread via the bloodstream: examples are pneumococcal peritonitis and tuberculous peritonitis. Symptoms are diffuse abdominal pain and swelling, with fever and weight loss. Fluid may accumulate in the peritoneal cavity (see ascites) or the infection may complicate existing ascites (see spontaneous bacterial peritonitis). Secondary peritonitis is due to perforation or rupture of an abdominal organ (for example, a duodenal ulcer, the gall bladder, or the vermiform appendix), allowing access of bacteria and irritant digestive juices to the peritoneum. This produces sudden severe abdominal pain, first at the site of rupture but later becoming generalized. Shock develops, and the abdominal wall becomes rigid; X-ray examination may reveal gas within the peritoneal cavity. Treatment is usually by surgical repair of the perforation, but in some cases conservative treatment using antibiotics and intravenous fluid may be used. *Subphrenic abscess is a possible complication. Meconium peritonitis occurs in newborn infants as a result of a perforated intestine; it is initially a sterile contamination of the peritoneum.... peritonitis

Tetanus

(lockjaw) n. an acute infectious disease, affecting the nervous system, caused by the bacterium Clostridium tetani. Infection occurs by contamination of wounds by bacterial spores. Bacteria multiply at the site of infection and produce a toxin that irritates nerves so that they cause spasmodic contraction of muscles. Symptoms appear 4–25 days after infection and consist of muscle stiffness, spasm, and subsequent rigidity, first in the jaw and neck then in the back, chest, abdomen, and limbs; in severe cases the spasm may affect the whole body, which is arched backwards (see opisthotonos). High fever, convulsions, and extreme pain are common. If respiratory muscles are affected, a *tracheostomy or intubation and ventilation is essential to avoid death from asphyxia. Mortality is high in untreated cases but prompt treatment is effective. An attack does not necessarily confer complete immunity. Immunization against tetanus is effective but temporary. —tetanic adj.... tetanus



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