Amoeba Health Dictionary

Colitis is classi?ed as an INFLAMMATORY BOWEL DISEASE (IBD) and ULCERATIVE COLITIS is a particularly troublesome form, the cause of which is not known. CROHN’S DISEASE may also cause colitis and is included in the umbrella designation IBD (see also IRRITABLE BOWEL SYNDROME (IBS)).... colitis

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

The most common cause is an intestinal infection.

Bacteria may spread from areas inflamed by diverticulitis or appendicitis, and amoebae may invade the liver as a result of amoebiasis.

The symptoms are high fever, pain in the upper right abdomen, and (especially in elderly people) mental confusion.

Ultrasound scanning usually reveals the abscess.

It can sometimes be treated by aspiration, but often surgery is needed.... liver abscess

Common bacteria, such as staphylococci, are the usual cause of abscesses, although fungal infections can cause them, and amoebae are an important cause of liver abscesses (see amoebiasis). Infectious organisms usually reach internal organs via the bloodstream, or they penetrate tissues under the skin through a wound.

An abscess may cause pain, depending on where it occurs. Most larger abscesses cause fever, sweating, and malaise. Those that are close to the skin often cause obvious redness and swelling.

Antibiotics, antifungal drugs, or amoebicides are usually prescribed as appropriate.

Most abscesses also need to be drained (see drain, surgical), and in some cases a tube may be left in place to allow continuous drainage.

Some abscesses burst and drain spontaneously.

Occasionally, an abscess within a vital organ damages enough surrounding tissue to cause permanent loss of normal function, or even death.... abscess

Some people carry the amoeba in their intestines and excrete cysts but have no symptoms.

However, some strains invade and ulcerate the intestinal wall, causing diarrhoea and abdominal pain, which may develop into full-blown dysentery.

The amoebae may spread via the bloodstream to the liver, or, rarely, the brain or lung, where they cause abscesses.

Symptoms of an amoebic liver abscess are chills, fever, weight loss, and painful enlargement of the liver.

Treatment of all forms of amoebiasis is with drugs such as metronidazole or diloxanide, which kill the parasite within a few weeks, leading to full recovery.... amoebiasis