Doxycycline Health Dictionary

A group of broad-spectrum ANTIBIOTICS which include oxytetracycline, tetracycline, doxycycline, lymecycline, minocycline, and demeclocycline.

All the preparations are virtually identical, being active against both gram-negative and gram-positive bacteria (see GRAM’S STAIN). Derived from cultures of streptomyces bacteria, their value has lessened owing to increasing resistance to the group among bacteria. However, they remain the treatment of choice for BRUCELLOSIS, LYME DISEASE, TRACHOMA, PSITTACOSIS, Q FEVER, SALPINGITIS, URETHRITIS and LYMPHOGRANULOMA INGUINALE, as well as for infections caused by MYCOPLASMA, certain rickettsiae (see RICKETTSIA) and CHLAMYDIA. Additionally they are used in the treatment of ACNE, but are not advised in children under 12 as they may produce permanent discoloration of the teeth. Tetracyclines must not be used if a woman is pregnant as the infant’s deciduous teeth will be stained.... tetracyclines

Nutritional Profile Energy value (calories per serving): Moderate Protein: High Fat: Moderate Saturated fat: High Cholesterol: Moderate Carbohydrates: None Fiber: None Sodium: Low Major vitamin contribution: B vitamins Major mineral contribution: Iron, phosphorus, zinc

About the Nutrients in This Food Like fish, pork, poultry, milk, and eggs, beef has high-quality proteins, with sufficient amounts of all the essential amino acids. Beef fat is slightly more highly saturated than pork fat, but less saturated than lamb fat. All have about the same amount of cholesterol per serving. Beef is an excellent source of B vitamins, including niacin, vitamin B6, and vitamin B12, which is found only in animal foods. Lean beef pro- vides heme iron, the organic iron that is about five times more useful to the body than nonheme iron, the inorganic form of iron found in plant foods. Beef is also an excellent source of zinc. One four-ounce serving of lean broiled sirloin steak has nine grams fat (3.5 g saturated fat), 101 mg cholesterol, 34 g protein, and 3.81 mg iron (21 percent of the R DA for a woman, 46 percent of the R DA for a man). One four-ounce serving of lean roast beef has 16 g fat (6.6 g saturated fat), 92 mg cholesterol, and 2.96 mg iron (16 percent of the R DA for a woman, 37 percent of the R DA for a man).

The Most Nutritious Way to Serve This Food With a food rich in vitamin C. Ascorbic acid increases the absorption of iron from meat. * These values apply to lean cooked beef.

Diets That May Restrict or Exclude This Food Controlled-fat, low-cholesterol diet Low-protein diet (for some forms of kidney disease)

Buying This Food Look for: Fresh, red beef. The fat should be white, not yellow. Choose lean cuts of beef with as little internal marbling (streaks of fat) as possible. The leanest cuts are flank steak and round steak; rib steaks, brisket, and chuck have the most fat. USDA grading, which is determined by the maturity of the animal and marbling in meat, is also a guide to fat content. U.S. prime has more marbling than U.S. choice, which has more marbling than U.S. good. All are equally nutritious; the difference is how tender they are, which depends on how much fat is present. Choose the cut of meat that is right for your recipe. Generally, the cuts from the cen- ter of the animal’s back—the rib, the T-Bone, the porterhouse steaks—are the most tender. They can be cooked by dry heat—broiling, roasting, pan-frying. Cuts from around the legs, the underbelly, and the neck—the shank, the brisket, the round—contain muscles used for movement. They must be tenderized by stewing or boiling, the long, moist cooking methods that break down the connective tissue that makes meat tough.

Storing This Food Refrigerate raw beef immediately, carefully wrapped to prevent its drippings from contami- nating other foods. Refrigeration prolongs the freshness of beef by slowing the natural multi- plication of bacteria on the meat surface. Unchecked, these bacteria will convert proteins and other substances on the surface of the meat to a slimy film and change meat’s sulfur-contain- ing amino acids methionine and cystine into smelly chemicals called mercaptans. When the mercaptans combine with myoglobin, they produce the greenish pigment that gives spoiled meat its characteristic unpleasant appearance. Fresh ground beef, with many surfaces where bacteria can live, should be used within 24 to 48 hours. Other cuts of beef may stay fresh in the refrigerator for three to five days.

Preparing This Food Trim the beef carefully. By judiciously cutting away all visible fat you can significantly reduce the amount of fat and cholesterol in each serving. When you are done, clean all utensils thoroughly with soap and hot water. Wash your cutting board, wood or plastic, with hot water, soap, and a bleach-and-water solution. For ultimate safety in preventing the transfer of microorganisms from the raw meat to other foods, keep one cutting board exclusively for raw meats, fish, and poultry, and a second one for everything else. Finally, don’t forget to wash your hands.

What Happens When You Cook This Food Cooking changes the appearance and flavor of beef, alters nutritional value, makes it safer, and extends its shelf life. Browning meat after you cook it does not “seal in the juices,” but it does change the fla- vor by caramelizing sugars on the surface. Because beef’s only sugars are the small amounts of glycogen in the muscles, we add sugars in marinades or basting liquids that may also con- tain acids (vinegar, lemon juice, wine) to break down muscle fibers and tenderize the meat. (Browning has one minor nutritional drawback. It breaks amino acids on the surface of the meat into smaller compounds that are no longer useful proteins.) When beef is cooked, it loses water and shrinks. Its pigments, which combine with oxygen, are denatured (broken into fragments) by the heat and turn brown, the natural color of well-done meat. At the same time, the fats in the beef are oxidized. Oxidized fats, whether formed in cooking or when the cooked meat is stored in the refrigerator, give cooked meat a character- istic warmed-over flavor. Cooking and storing meat under a blanket of antioxidants—catsup or a gravy made of tomatoes, peppers, and other vitamin C-rich vegetables—reduces the oxidation of fats and the intensity of warmed-over flavor. Meat reheated in a microwave oven also has less warmed-over flavor. An obvious nutritional benefit of cooking is the fact that heat lowers the fat content of beef by liquif ying the fat so it can run off the meat. One concrete example of how well this works comes from a comparison of the fat content in regular and extra-lean ground beef. According to research at the University of Missouri in 1985, both kinds of beef lose mass when cooked, but the lean beef loses water and the regular beef loses fat and cholesterol. Thus, while regular raw ground beef has about three times as much fat (by weight) as raw ground extra-lean beef, their fat varies by only 5 percent after broiling. To reduce the amount of fat in ground beef, heat the beef in a pan until it browns. Then put the beef in a colander, and pour one cup of warm water over the beef. Repeat with a second cup of warm water to rinse away fat melted by heating the beef. Use the ground beef in sauce and other dishes that do not require it to hold together. Finally, cooking makes beef safer by killing Salmonella and other organisms in the meat. As a result, cooking also serves as a natural preservative. According to the USDA, large pieces of fresh beef can be refrigerated for two or three days, then cooked and held safely for another day or two because the heat of cooking has reduced the number of bacteria on the surface of the meat and temporarily interrupted the natural cycle of deterioration.

How Other Kinds of Processing Affect This Food Aging. Hanging fresh meat exposed to the air, in a refrigerated room, reduces the moisture content and shrinks the meat slightly. As the meat ages enzymes break down muscle pro- teins, “tenderizing” the beef. Canning. Canned beef does not develop a warmed-over flavor because the high tempera- tures in canning food and the long cooking process alter proteins in the meat so that they act as antioxidants. Once the can is open, however, the meat should be protected from oxygen that will change the flavor of the beef. Curing. Salt-curing preserves meat through osmosis, the physical reaction in which liquids flow across a membrane, such as the wall of a cell, from a less dense to a more dense solution. The salt or sugar used in curing dissolves in the liquid on the surface of the meat to make a solution that is more dense than the liquid inside the cells of the meat. Water flows out of the meat and out of the cells of any microorganisms living on the meat, killing the microor- ganisms and protecting the meat from bacterial damage. Salt-cured meat is much higher in sodium than fresh meat. Freezing. When you freeze beef, the water inside its cells freezes into sharp ice crystals that can puncture cell membranes. When the beef thaws, moisture (and some of the B vitamins) will leak out through these torn cell walls. The loss of moisture is irreversible, but some of the vitamins can be saved by using the drippings when the meat is cooked. Freezing may also cause freezer burn—dry spots left when moisture evaporates from the surface of the meat. Waxed freezer paper is designed specifically to hold the moisture in meat; plastic wrap and aluminum foil are less effective. NOTE : Commercially prepared beef, which is frozen very quickly at very low temperatures, is less likely to show changes in texture. Irradiation. Irradiation makes meat safer by exposing it to gamma rays, the kind of high- energy ionizing radiation that kills living cells, including bacteria. Irradiation does not change the way meat looks, feels or tastes, or make the food radioactive, but it does alter the structure of some naturally occurring chemicals in beef, breaking molecules apart to form new com- pounds called radiolytic products (R P). About 90 percent of R Ps are also found in nonirradiated foods. The rest, called unique radiolytic products (UR P), are found only in irradiated foods. There is currently no evidence to suggest that UR Ps are harmful; irradiation is an approved technique in more than 37 countries around the world, including the United States. Smoking. Hanging cured or salted meat over an open fire slowly dries the meat, kills micro- organisms on its surface, and gives the meat a rich, “smoky” flavor that varies with the wood used in the fire. Meats smoked over an open fire are exposed to carcinogenic chemicals in the smoke, including a-benzopyrene. Meats treated with “artificial smoke flavoring” are not, since the flavoring is commercially treated to remove tar and a-benzopyrene.

Medical Uses and/or Benefits Treating and/or preventing iron deficiency. Without meat in the diet, it is virtually impossible for an adult woman to meet her iron requirement without supplements. One cooked 3.5- ounce hamburger provides about 2.9 mg iron, 16 percent of the R DA for an adult woman of childbearing age. Possible anti-diabetes activity. CLA may also prevent type 2 diabetes, also called adult-onset diabetes, a non-insulin-dependent form of the disease. At Purdue University, rats bred to develop diabetes spontaneously between eight and 10 weeks of age stayed healthy when given CLA supplements.

Adverse Effects Associated with This Food Increased risk of heart disease. Like other foods from animals, beef contains cholesterol and saturated fats that increase the amount of cholesterol circulating in your blood, raising your risk of heart disease. To reduce the risk of heart disease, the National Cholesterol Education Project recommends following the Step I and Step II diets. 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) Increased risk of some cancers. According the American Institute for Cancer Research, a diet high in red meat (beef, lamb, pork) increases the risk of developing colorectal cancer by 15 percent for every 1.5 ounces over 18 ounces consumed per week. In 2007, the National Can- cer Institute released data from a survey of 500,000 people, ages 50 to 71, who participated in an eight-year A AR P diet and health study identif ying a higher risk of developing cancer of the esophagus, liver, lung, and pancreas among people eating large amounts of red meats and processed meats. Food-borne illness. Improperly cooked meat contaminated with E. coli O157:H7 has been linked to a number of fatalities in several parts of the United States. In addition, meats con- taminated with other bacteria, viruses, or parasites pose special problems for people with a weakened immune system: the very young, the very old, cancer chemotherapy patients, and people with HIV. Cooking meat to an internal temperature of 140°F should destroy Salmo- nella and Campylobacter jejuni; 165°F, the E. coli organism; and 212°F, Listeria monocytogenes. Antibiotic sensitivity. Cattle in the United States are routinely given antibiotics to protect them from infection. By law, the antibiotic treatment must stop three days to several weeks before the animal is slaughtered. Theoretically, the beef should then be free of antibiotic residues, but some people who are sensitive to penicillin or tetracycline may have an allergic reaction to the meat, although this is rare. Antibiotic-resistant Salmonella and toxoplasmosis. Cattle treated with antibiotics may pro- duce meat contaminated with antibiotic-resistant strains of Salmonella, and all raw beef may harbor ordinary Salmonella as well as T. gondii, the parasite that causes toxoplasmosis. Toxoplasmosis is particularly hazardous for pregnant women. It can be passed on to the fetus and may trigger a series of birth defects including blindness and mental retardation. Both Salmonella and the T. gondii can be eliminated by cooking meat thoroughly and washing all utensils, cutting boards, and counters as well as your hands with hot soapy water before touching any other food. Decline in kidney function. Proteins are nitrogen compounds. When metabolized, they yield ammonia, which is excreted through the kidneys. In laborator y animals, a sustained high-protein diet increases the flow of blood through the kidneys, accelerating the natural age-related decline in kidney function. Some experts suggest that this may also occur in human beings.

Food/Drug Interactions Tetracycline antibiotics (demeclocycline [Declomycin], doxycycline [ Vibtamycin], methacycline [Rondomycin], minocycline [Minocin], oxytetracycline [Terramycin], tetracycline [Achromycin V, Panmycin, Sumycin]). Because meat contains iron, which binds tetracyclines into com- pounds the body cannot absorb, it is best to avoid meat for two hours before and after taking one of these antibiotics. Monoamine oxidase (MAO) inhibitors. Meat “tenderized” with papaya or a papain powder can interact with the class of antidepressant drugs known as monoamine oxidase inhibi- tors. Papain meat tenderizers work by breaking up the long chains of protein molecules. One by-product of this process is tyramine, a substance that constructs blood vessels and raises blood pressure. M AO inhibitors inactivate naturally occurring enzymes in your body that metabolize tyramine. If you eat a food such as papain-tenderized meat, which is high in tyramine, while you are taking a M AO inhibitor, you cannot effectively eliminate the tyramine from your body. The result may be a hypertensive crisis. Theophylline. Charcoal-broiled beef appears to reduce the effectiveness of theophylline because the aromatic chemicals produced by burning fat speed up the metabolism of the- ophylline in the liver.... beef

Bacterial infection caused by Vibrio cholerae. The patient suffers profuse watery DIARRHOEA, and resultant dehydration and electrolyte imbalance. Formerly known as the Asiatic cholera, the disease has occurred in epidemics and pandemics for many centuries. When it entered Europe in 1853, Dr John Snow, a London anaesthetist, carried out seminal epidemiological work in Soho, London, which established that the source of infection was contaminated drinking water derived from the Broad Street pump. Several smaller epidemics involved Europe in the latter years of the 19th century, but none has arisen in Britain or the United States for many years. In 1971, the El Tor biotype of V. cholerae emerged, replacing much of the classical infection in Asia and, to a much lesser extent, Europe; parts of Africa were seriously affected. Recently a non-01 strain has arisen and is causing much disease in Asia. Cholera remains a major health problem (this is technically the seventh pandemic) in many countries of Asia, Africa and South America. It is one of three quarantinable infections.

Incubation period varies from a few hours to ?ve days. Watery diarrhoea may be torrential and the resultant dehydration and electrolyte imbalance, complicated by cardiac failure, commonly causes death. The victim’s skin elasticity is lost, the eyes are sunken, and the radial pulse may be barely perceptible. Urine production may be completely suppressed. Diagnosis is by detection of V. cholerae in a faecal sample. Treatment consists of rapid rehydration. Whereas the intravenous route may be required in a severe case, in the vast majority of patients oral rehydration (using an appropriate solution containing sodium chloride, glucose, sodium bicarbonate, and potassium) gives satisfactory results. Proprietary rehydration ?uids do not always contain adequate sodium for rehydration in a severe case. ANTIBIOTICS, for example, tetracycline and doxycycline, reduce the period during which V. cholerae is excreted (in children and pregnant women, furazolidone is safer); in an epidemic, rapid resistance to these, and other antibiotics, has been clearly demonstrated. Prevention consists of improving public health infrastructure – in particular, the quality of drinking water. When supplies of the latter are satisfactory, the infection fails to thrive. Though there have recently been large epidemics of cholera in much of South America and parts of central Africa and the Indian subcontinent, the risk of tourists and travellers contracting the disease is low if they take simple precautions. These include eating safe food (avoid raw or undercooked seafood, and wash vegetables in clean water) and drinking clean water. There is no cholera vaccine at present available in the UK as it provides little protection and cannot control spread of the disease. Those travelling to countries where it exists should pay scrupulous attention to food and water cleanliness and to personal hygiene.... cholera

The disease caused by infection with LEPTOSPIRA. The three most common members of this group in the United Kingdom are L. icterohaemorrhagiae, L. cani-cola, and L. hebdomadis. It is an occupational hazard of farmers, sewage and abattoir workers, ?sh cutters and veterinary surgeons, but the infection can also be acquired from bathing in contaminated water. The disease varies in intensity from a mild in?uenza-like illness to a fatal form of JAUNDICE due to severe liver disease. The kidneys are often involved and there may be MENINGITIS. Penicillin or tetracycline are the usual treatment, but unless they are given early in the disease their e?ect is limited. The tetracycline antibiotic doxycycline (see TETRACYCLINES) given once weekly during periods of exposure prevents infection.... leptospirosis

This infection – also known as bubonic plague

– is caused by the bacterium Yersinis pestis. Plague remains a major infection in many tropical countries.

The reservoir for the bacillus in urban infection lies in the black rat (Rattus rattus), and less importantly the brown (sewer) rat (Rattus norvegicus). It is conveyed to humans by the rat ?ea, usually Xenopsylla cheopis: Y. pestis multiplies in the gastrointestinal tract of the ?ea, which may remain infectious for up to six weeks. In the pneumonic form (see below), human-to-human transmission can occur by droplet infection. Many lower mammals (apart from the rat) can also act as a reservoir in sylvatic transmission which remains a major problem in the US (mostly in the south-western States); ground-squirrels, rock-squirrels, prairie dogs, bobcats, chipmunks, etc. can be affected.

Clinically, symptoms usually begin 2–8 days after infection; disease begins with fever, headache, lassitude, and aching limbs. In over two-thirds of patients, enlarged glands (buboes) appear – usually in the groin, but also in the axillae and cervical neck; this constitutes bubonic plague. Haemorrhages may be present beneath the skin causing gangrenous patches and occasionally ulcers; these lesions led to the epithet ‘Black Death’. In a favourable case, fever abates after about a week, and the buboes discharge foul-smelling pus. In a rapidly fatal form (septicaemic plague), haematogenous transmission produces mortality in a high percentage of cases. Pneumonic plague is associated with pneumonic consolidation (person-to-person transmission) and death often ensues on the fourth or ?fth day. (The nursery rhyme ‘Ringo-ring o’ roses, a pocketful o’ posies, atishoo! atishoo!, we all fall down’ is considered to have originated in the 17th century and refers to this form of the disease.) In addition, meningitic and pharyngeal forms of the disease can occur; these are unusual. Diagnosis consists of demonstration of the causative organism.

Treatment is with tetracycline or doxycycline; a range of other antibiotics is also e?ective. Plague remains (together with CHOLERA and YELLOW FEVER) a quarantinable disease. Contacts should be disinfected with insecticide powder; clothes, skins, soft merchandise, etc. which have been in contact with the infection can remain infectious for several months; suspect items should be destroyed or disinfected with an insecticide. Ships must be carefully checked for presence of rats; the rationale of anchoring a distance from the quay prevents access of vermin. (See also EPIDEMIC; PANDEMIC; NOTIFIABLE DISEASES.)... plague

a sexually transmitted disease caused by Chlamydia trachomatis. It can be transmitted to infants at birth, with the disease clinically apparent 5–13 days after birth. Diagnosis is by cell culture. Treatment in the newborn is with topical erythromycin; adults require oral tetracycline or doxycycline for three weeks.... inclusion conjunctivitis

A parasitic disease caused by four species of PLASMODIUM: P. falciparum, P. vivax, P. ovale, and P. malariae. Clinically, malaria is characterised by recurrent episodes of high fever, sometimes associated with RIGOR; enlargement of the SPLEEN is common. P. falciparum infection can also be associated with several serious – often fatal – complications (see below): although other species cause chronic disease, death is unusual.

During a bite by the female mosquito, one or more sporozoites – a stage in the life-cycle of the parasite – are injected into the human circulation; these are taken up by the hepatocytes (liver cells). Following division, merozoites (minute particles resulting from the division) are liberated into the bloodstream where they invade red blood cells. These in turn divide, releasing further merozoites. As merozoites are periodically liberated into the bloodstream, they cause the characteristic fevers, rigors, etc.

Malaria occurs in many tropical and subtropical countries; P. falciparum is, however, con?ned very largely to Africa, Asia and South America. Malaria is present in increasingly large areas; in addition, the parasites are developing resistance to various preventative and treatment drugs. The disease constitutes a signi?cant problem for travellers, who must obtain sound advice on chemoprophylaxis before embarking on tropical trips – especially to a rural area where intense transmission can occur. Transmission has also been recorded at airports, and following blood transfusion.

The World Health Organisation (WHO) has listed malaria as one of Europe’s top ten infectious diseases. In 1992, 20,000 cases were reported: this had risen to more than 200,000 by the late 1990s. The resurgence of malaria has been worldwide, in part the result of the development of resistant strains of the disease, and in part because many countries have failed (or been unable) to implement environmental measures to eliminate mosquitoes. Nearly 40 years ago the WHO forecast that by 1980 only four million people would be affected worldwide; now, at the beginning of the 21st century, around 500 million people a year are contracting malaria with about 3,000 people a day dying from the infection – as many as 70 per cent of them children under the age of ?ve, according to WHO ?gures. The apparently steady advance of global warming means that countries with temperate climates may well warm up su?ciently to enable malaria to become established as an ENDEMIC disease. In any case, the great increase in international air travel has exposed many more people to the risk of malaria, and infected individuals may not exhibit symptoms until they are back home. Doctors seeing a recent traveller with unexplained pyrexia and illness should consider the possibility of malarial infection.

Diagnosis is by demonstration of trophozoites – a stage in the parasite’s life-cycle that takes place in red blood cells – in thick/thin blood-?lms of peripheral blood. Serological tests are of value in deciding whether an individual has had a past infection, but are of no value in acute disease.

P. vivax and P. ovale infections cause less severe disease than P. falciparum (see below), although overall there are many clinical similarities; acute complications are unusual, but chronic ANAEMIA is often present. Primaquine is necessary to eliminate the exoerythrocytic cycle in the hepatocyte (liver cell).

P. falciparum Complications of P. falciparum infection include cerebral involvement (see BRAIN – Cerebrum), due to adhesion of immature trophozoites on to the cerebral vascular endothelium; these lead to a high death rate when inadequately treated. Renal involvement (frequently resulting from HAEMOGLOBINURIA), PULMONARY OEDEMA, HYPOTENSION, HYPOGLYCAEMIA, and complications in pregnancy are also important. In complicated disease, HAEMODIALYSIS and exchange TRANSFUSION have been used. No adequate controlled trial using the latter regimen has been carried out, however, and possible bene?ts must be weighed against numerous potential side-effects – for instance, the introduction of a wide range of infections, overload of the circulatory system with infused ?uids, and other complications.

P. malariae usually produces a chronic infection, and chronic renal disease (nephrotic syndrome) is an occasional sequel, especially in tropical Africa.

Gross SPLENOMEGALY (hyper-reactive malarious splenomegaly, or tropical splenomegaly syndrome) can complicate all four human Plasmodium spp. infections. The syndrome responds to long-term malarial chemoprophylaxis. BURKITT’S LYMPHOMA is found in geographical areas where malaria infection is endemic; the EPSTEIN BARR VIRUS is aetiologically involved.

Prophylaxis Malaria specialists in the United Kingdom have produced guidance for residents travelling to endemic areas for short stays. Drug choice takes account of:

risk of exposure to malaria;

extent of drug resistance;

e?cacy of recommended drugs and their side-effects;

criteria relevant to the individual (e.g. age, pregnancy, kidney or liver impairment). Personal protection against being bitten by

mosquitoes is essential. Permethrinimpregnated nets are an e?ective barrier, while skin barrier protection and vaporised insecticides are helpful. Lotions, sprays or roll-on applicators all containing diethyltoluamide (DEET) are safe and work when put on the skin. Their e?ect, however, lasts only for a few hours. Long sleeves and trousers should be worn after dark.

Drug prophylaxis should be started at least a week before travelling into countries where malaria is endemic (two or three weeks in the case of me?oquine). Drug treatment should be continued for at least four weeks after leaving endemic areas. Even if all recommended antimalarial programmes are followed, it is possible that malaria may occur any time up to three months afterwards. Medical advice should be sought if any illness develops. Chloroquine can be used as a prophylactic drug where the risk of resistant falciparum malaria is low; otherwise, me?oquine or proguanil hydrochloride should be used. Travellers to malaria-infested areas should seek expert advice on appropriate prophylactic treatment well before departing.

Treatment Various chemoprophylactic regimes are widely used. Those commmonly prescribed include: chloroquine + paludrine, me?oquine, and Maloprim (trimethoprim + dapsone); Fansidar (trimethoprim + sulphamethoxazole) has been shown to have signi?cant side-effects, especially when used in conjunction with chloroquine, and is now rarely used. No chemotherapeutic regimen is totally e?ective, so other preventive measures are again being used. These include people avoiding mosquito bites, covering exposed areas of the body between dusk and dawn, and using mosquito repellents.

Chemotherapy was for many years dominated by the synthetic agent chloroquine. However, with the widespread emergence of chloroquine-resistance, quinine is again being widely used. It is given intravenously in severe infections; the oral route is used subsequently and in minor cases. Other agents currently in use include me?oquine, halofantrine, doxycycline, and the artemesinin alkaloids (‘qinghaosu’).

Researchers are working on vaccines against malaria.... malaria

Formerly known as nonspecific urethritis, inflammation of the urethra due to a cause other than gonorrhoea. Worldwide, nongonococcal urethritis is a very common type of sexually transmitted infection.Almost 50 per cent of cases are known to be caused by chlamydia trachomatis (see chlamydial infections); others are caused by the virus that causes herpes simplex, trichomonas vaginalis infections

(see trichomoniasis), or other microorganisms. In the remainder of cases, the cause remains unknown.

In men, the infection usually causes a clear or a purulent urethral discharge, often accompanied by pain or discomfort on passing urine. The equivalent condition in women, called nonspecific genital infection, may not cause symptoms unless there are complications.

Treatment may be difficult if the cause of symptoms cannot be determined. Antibiotic drugs, such as doxycycline and erythromycin, are given. Follow-up visits may be advised after treatment.

In men, epididymitis, prostatitis and urethral stricture (narrowing of the urethra) can occur as complications of nongonococcal urethritis. Reiter’s syndrome (in which there is arthritis and conjunctivitis as well as urethritis) occurs as a complication in some men who develop nongonococcal urethritis.

In women, pelvic inflammatory disease and cysts of the Bartholin’s glands may occur. Ophthalmia neonatorum, a type of conjunctivitis, sometimes develops in babies born to women with chlamydial cervicitis.... nongonococcal urethritis

a disease caused by a spirochaete, Borrelia burgdorferi, and transmitted by certain ticks of the genus Ixodes. Following a 3–32-day incubation period, a slowly extending red rash develops in approximately 75% of cases; intermittent systemic symptoms include fever, malaise, headache and neck stiffness, and muscle and joint pains. Later, 60% of patients suffer intermittent attacks of arthritis, especially of the knees, each attack lasting months and recurring over several years. The spirochaete has been identified in synovium and synovial fluid. Neurological and cardiac involvement occurs in a smaller percentage of cases. Treatment is with doxycycline or a penicillin.... lyme disease

n. a sexually transmitted disease caused by the bacterium Treponema pallidum, resulting in the formation of lesions throughout the body. Bacteria usually enter the body during sexual intercourse, through the mucous membranes of the vagina or urethra, but they may rarely be transmitted through wounds in the skin or scratches. Bacteria may also pass from an infected pregnant woman across the placenta to the developing fetus, resulting in the disease being present at birth (congenital syphilis).

The primary symptom – a hard painless ulcer (*chancre) at the site of infection – forms 2–4 weeks after exposure. Neighbouring lymph nodes enlarge about 2 weeks later. Secondary stage symptoms appear about two months after infection and include fever, malaise, general enlargement of lymph nodes, and a faint red rash on the chest that persists for 1–2 weeks. After months, or even years, the disease enters its tertiary stage with widespread formation of tumour-like masses (*gummas). Tertiary syphilis may cause serious damage to the heart and blood vessels (cardiovascular syphilis) or to the brain and spinal cord (neurosyphilis), resulting in *tabes dorsalis, blindness, and *general paralysis of the insane.

Treatment is with antibiotics, such as penicillin and doxycycline. Syphilis can be diagnosed by several blood tests. Compare bejel. —syphilitic adj.... syphilis

n. see doxycycline.... vibramycin