Amoebiasis is a worldwide disease, particularly common in tropical countries and places where public hygiene and sanitation are poor. Amoebic infection is caused by an organism, Entamoeba histolytica (EH) which usually spreads through contaminated food and water. Since the causative organism of amoebiasis derives its nutrition from the normal bacterial flora of the large intestine, the latter is the chief site of infection. However, in some cases it may spread to other organs of the body, liver being the most susceptible to infection. Based on the site of the infection, the disease has been divided into intestinal and extra-intestinal amoebiasis.

Intestinal Amoebic Infection: During the acute phase of intestinal amoebiasis the patient may have loose motions, with or without mucus and blood, besides griping pain in the abdomen which may be severe at the time of evacuation. In chronic amoebiasis, a patient may complain of a dull pain in the lower abdomen, alternate constipation and diarrhoea, foul smell in the stools, formation of gases, and loss of appetite. Some people with amoebic infection may remain symptom-free or experience little discomfort but they may pass cysts in their stools (free cyst passers) and are potential carriers of the disease which spread it to others.

Extra-intestinal Infection: This amoebiasis infection is usually associated with a previous history of intestinal amoebiasis. When the liver is involved, the patient 'may have pain in the right upper abdomen, fever, sweating, loss of weight, and anaemia.

Importance of Diet: Successful treatment of amoebiasis depends both on drugs and on proper diet and good hygiene. For quick recovery it is best to eat a protein-rich, low-roughage and low­carbohydrate diet. Use of clean drinking water and avoidance of contamination are important.

Drugs for Intestinal Amoebiasis

The drugs used in treating amoebiasis can be divided into three categories according to their effectiveness.

Metronidazole (Flagyl, Metrogyl, Unimezol)

This is a drug of choice in all forms of amoebiasis except in asymptomatic cyst carriers. Since most of it is absorbed in the intestines, another drug which acts in intestinal amoebiasis should be used along with it to avoid relapse and to eradicate the disease. It is given in a dose of 400 to 800 mg, 3 times a day, for 10 days.

Adverse Effects: The incidence of adverse effects is low and include nausea, an unpleasant metallic taste in the mouth, a furry tongue, ulcers in the mouth, loss of appetite, distress, and pain in the abdomen. Sometimes it may affect nerves and may, in rare cases, cause convulsions. Depression of the bone marrow may lead to a short lasting fall in white blood cell count. A relapse can occur if the full course is not taken.

Precautions

Alcohol consumption should be avoided with this drug as it causes a severe reaction leading to vomiting and flushing. Also avoid its use during initial months of pregnancy.

Those suffering from epilepsy or any other nervous system disorder should avoid it.

It depresses the bone marrow. White blood cell count must be monitored by those taking the drug repeatedly.