Entamoeba Histolytica: Symptoms and Treatment | Parasitology

In this article we will discuss about: 1. Symptoms and Pathogenesis of Amoebic Dysentery or Amoebiasis 2. Prophylaxis (Prevention) and Treat­ment of Amoebic Dysentery.

Symptoms and Pathogenesis of Amoebic Dysentery or Amoebiasis:

Generally E. histolytica lives in the lumen of large intestine of man as harmless minute forms. The trophozoite stage of this parasite penetrate mucosa and submucosa and here they multiply and spread. They form flask shaped lesion or ulcer containing cellular debris, lymphocytes, blood corpuscles and bacteria.

As submucosa is eroded, the ulcers burst and blood capillaries rupture and the blood dysentery may result. Persons suffering from amoebic dysentery has repeated blood mixed, slimy and foul-smelling motions and is confined to the lavatory (Fig. 6.7).

Common complication spread through blood circulation into the brain, liver, spleen, lungs and gonads. Here the trophozoites of E. histolytica invade and destroy the tissues causing amoebic abscesses. Commonest site of E. histolytica in human being is the liver. The affected liver becomes enlarged, congested, and painful to touch. This pathological condition is to as amoebic hepatitis.

Sometimes the trophozoites destroy the tissues and cause formation of abscesses or cavities con­taining pus. Formation of abscesses in lung and brain usually prove fatal. Invasion of the tissue other than the intestinal mucosa is referred to as secondary amoebiasis. Philips et al (1975) opined that in bacteria free guinea-pig, no invasion of the intestinal wall occurs when E. histolytica is intro­duced but amoebic lesions are produced in hosts harbouring a single bacterial symbioant.

Prophylaxis (Prevention) and Treat­ment of Amoebic Dysentery:

Prevention:

Prevention of infection is entirely a matter of hygiene, both personal as well as com­munity prophylaxis.

(a) Personal prophylaxis:

i. Use of boiled drinking water.

ii. Protection of all food and drink from contamination by houseflies, cockroa­ches etc.

iii. Avoidance of consumption of raw vegetables, improperly washed vege­tables and raw salads.

iv. Cutting finger nails regularly, washing hands with soap before taking meals and after using toilet should be practiced.

v. Personal cleanliness and elementary hygienic conditions are to be obser­ved while taking meals.

(b) For community prophylaxis:

i. Purification of drinking water as well as protection of water supplies from pollution.

ii. Effective disposal of sewage.

iii. Avoidance of the use of human faeces as fertiliser.

iv. Proper sanitation of roads, lanes, open-drains etc.

v. Detection and isolation of carriers of Amoebiasis.

vi. Protection of food and water from contamination help in the prevention of amoebiasis.

Treatment:

Treatment of Amoebiasis is not difficult but the permanent cure is hard to achieve:

i. In the intestinal wall, liver and other metastatic lesions—an alkaloid Emetine is effective.

ii. Chloroquine, an anti-malaria drug, is effec­tive against amoebic abscesses in the liver but not elsewhere.

iii. Certain antibiotics like Terramycin, Erythro­mycin, Aureomycin etc. have proved to be effective in the eradication of the parasite.

iv. The use of Metronidazole as an amoebicide is very active against both intestinal and extra-intestinal amoebiasis (Professor M. Sarkar, School of Tropical Medicine).