Serotype Health Dictionary

Usually a second infection with a different serotype of the dengue virus (see dengue fever). A primary infection at a young age is common finding. Age of patient with DHF is often less than 5 years, but young adults may be affected. Severe illness with abnormal vascular permeability, hypovolaemia and abnormal clotting mechanisms. Bleeding into skin or internally. Dengue shock syndrome may also be a complication.... dengue haemorrhagic fever

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

(LGV) A tropical sexually transmitted disease caused by Chlamydia trachomatis serotypes L1, L2 and L3.... lymphogranuloma venereum

An eye infection causing a purulent conjunctivitis and which can lead to blindness unless treated. Caused by Chlamydia trachomatis serotypes A, B and C.... trachoma

n. a genus of Gram-negative, generally motile, rodlike bacteria that have the ability to ferment carbohydrates, usually with production of gas, and are found in the intestines of humans and many animals. E. coli – a lactose-fermenting species – is usually not harmful but some strains cause gastrointestinal infections. Ingestion of the pathogenic serotype E. coli O157, derived from infected meat, causes colitis with bloody diarrhoea, which may give rise to the complications of *haemolytic uraemic syndrome or thrombocytopenic *purpura (see also food poisoning). E. coli is widely used in laboratory experiments for bacteriological and genetic studies.... escherichia

n. a benign growth on the skin caused by infection with *human papillomavirus (a few of the many serotypes are *oncogenic). Common warts are firm horny papules, 1–10 mm in diameter, found mainly on the hands. Most will clear spontaneously within two years. Plantar warts (or verrucae) occur on the soles and are often tender. Plane warts are flat and skin-coloured – and therefore difficult to see; they are usually found on the face and may be present in very large numbers. Anogenital warts are frequently associated with other genital infections (see condyloma). Treatment of warts is with OTC (over-the-counter) remedies, such as lactic and salicylic acids; *cryotherapy with liquid nitrogen is also effective. Curettage and cautery is very occasionally used, as well as immunotherapy with diphencyclopropenone.... wart