Apicomplexan protozoan associated with a watery diarrhoea in children and immunocompromised adults. Zoonotic infection often contracted from contaminated water. Commonest species in humans is Cryptosporidium parvum..
The commonest cause of acute diarrhoea is food poisoning, the organisms involved usually being STAPHYLOCOCCUS, CLOSTRIDIUM bacteria, salmonella, E. coli O157 (see ESCHERICHIA), CAMPYLOBACTER, cryptosporidium, and Norwalk virus. A person may also acquire infective diarrhoea as a result of droplet infections from adenoviruses or echoviruses. Interference with the bacterial ?ora of the intestine may cause acute diarrhoea: this often happens to someone who travels to another country and acquires unfamiliar intestinal bacteria. Other infections include bacillary dysentery, typhoid fever and paratyphoid fevers (see ENTERIC FEVER). Drug toxicity, food allergy, food intolerance and anxiety may also cause acute diarrhoea, and habitual constipation may result in attacks of diarrhoea.
Treatment of diarrhoea in adults depends on the cause. The water and salts (see ELECTROLYTES) lost during a severe attack must be replaced to prevent dehydration. Ready-prepared mixtures of salts can be bought from a pharmacist. Antidiarrhoeal drugs such as codeine phosphate or loperamide should be used in infectious diarrhoea only if the symptoms are disabling. Antibacterial drugs may be used under medical direction. Persistent diarrhoea – longer than a week – or blood-stained diarrhoea must be investigated under medical supervision.
Diarrhoea in infants can be such a serious condition that it requires separate consideration. One of its features is that it is usually accompanied by vomiting; the result can be rapid dehydration as infants have relatively high ?uid requirements. Mostly it is causd by acute gastroenteritis caused by various viruses, most commonly ROTAVIRUSES, but also by many bacteria. In the developed world most children recover rapidly, but diarrhoea is the single greatest cause of infant mortality worldwide. The younger the infant, the higher the mortality rate.
Diarrhoea is much more rare in breast-fed babies, and when it does occur it is usually less severe. The environment of the infant is also important: the condition is highly infectious and, if a case occurs in a maternity home or a children’s hospital, it tends to spread quickly. This is why doctors prefer to treat such children at home but if hospital admission is essential, isolation and infection-control procedures are necessary.
Treatment An infant with diarrhoea should not be fed milk (unless breast-fed, when this should continue) but should be given an electrolyte mixture, available from pharmacists or on prescription, to replace lost water and salts. If the diarrhoea improves within 24 hours, milk can gradually be reintroduced. If diarrhoea continues beyond 36–48 hours, a doctor should be consulted. Any signs of dehydration require urgent medical attention; such signs include drowsiness, lack of response, loose skin, persistent crying, glazed eyes and a dry mouth and tongue.... diarrhoea
does not develop in all people infected with. The interval between infection and the development of is highly variable. Without treatment, around half of those people infected will develop within 8–9 years.
is transmitted in body fluids, including semen, blood, vaginal secretions, and breast milk. The major methods of transmission are sexual contact (vaginal, anal, or oral), blood to blood (via transfusions or needle-sharing in drug users), and mother to fetus. has also been transmitted through blood products given to treat haemophilia, artificial insemination by donated semen, and kidney transplants; but improved screening has greatly reduced these risks. is not spread by everyday contact, such as hugging or sharing crockery. The virus enters the bloodstream and infects cells that have a particular receptor, known as the CD4 receptor, on their surface. These cells include a type of white blood cell (a CD4 lymphocyte) responsible for fighting infection and cells in other tissues such as the brain. The virus reproduces within the infected cells, which then die, releasing more virus particles into the blood. If the infection is left untreated, the number of CD4 lymphocytes falls, resulting in greater susceptibility to certain infections and some types of cancer.
Some people experience a short-lived illness similar to infectious mononucleosis when they are first infected with. Many individuals have no obvious symptoms; some have only vague complaints, such as weight loss, fevers, sweats, or unexplained diarrhoea, described as -related complex.
Minor features of infection include skin disorders such as seborrhoeic dermatitis. More severe features include persistent herpes simplex infections, oral candidiasis (thrush), shingles, tuberculosis, and shigellosis. may also affect the brain, causing a variety of neurological disorders, including dementia.
Certain conditions, known as AIDSdefining illnesses, are characteristic of full-blown. These include cancers (Kaposi’s sarcoma and lymphoma of the brain), and various infections (pneumocystis pneumonia, cytomegalovirus infection, toxoplasmosis, diarrhoea due to CRYPTOSPORIDIUM or ISOSPORA, candidiasis, disseminated strongyloidiasis, and cryptococcosis), many of which are described as opportunistic infections.
Confirmation of infection involves testing a blood sample for the presence of antibodies to. Diagnosis of fullblown is based on a positive test along with the presence of an AIDSdefining illness.
The risk of infection with can be reduced by practising safer sex. Intravenous drug users should not share needles. There is a small risk to health workers handling infected blood products or needles, but this risk can be minimized by safe practices.
Treatment of infection with a combination of antiviral drugs can slow the disease’s progress, and may prevent the development of full-blown. The 2 main types of antiviral drug used are protease inhibitors, such as indinavir, and reverse transcriptase inhibitors such as zidovudine. Treatment is also available for -defining illnesses.... aids
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