Amoebiasis (Amoebic Dysentry)

Amoebiasis is caused by Entamoeba histolytica which leads to an intestinal infection causing severe diarrhoea.

Entamoeba histolytica can exist in 2 forms:

• As trophozoites (free amoebae). These are usually easily destroyed by the body when they reach the stomach due to its acidity.
• As infective cysts. These are a group of amoebae enclosed in a protective wall which are then excreted by a carrier either an animal or human. These are less easily destroyed within the stomach due to their protective wall and hence are much more likely to cause the infection.

Mode of Transmission

• Faeco-oral route
• Contamination of food by hands of unhygienic foodhandler
• Fresh vegetables polluted by sewage
• Contaminated water

Incubation period

Incubation period: 2-4 weeks (sometimes months, even years). During this period infected people will still excrete the cysts and can infect the surroundings.

Signs and Symptoms

• Abdominal (stomach) cramps
• Blood-stained stools
• Tenesmus (painful passage of stools)
• Foul smelling stools
• Slimy stools

When amoebae rarely enter blood steam:

• Fever
• Liver cysts
• Unexplained weight loss and/or illness
• Peritonitis (rarely)

Diagnosis

• Stool analysis for ova/cysts.

Treatment

Antibiotic treatment prescribed by doctor (metronidazole).

Control and Prevention

• Educate the general public in personal hygiene - everyone washes hands before preparing/eating food and after defecation.
• It is important that everyone is informed regarding risks involved in eating uncleaned or uncooked fruits/vegetables and in drinking water of questionable purity.
• Known carrierss should be treated.
• Chronic carriers should be taught about personal hygiene.
• Infected food handlers, etc., should stop working until 3 consecutive stool microscopy are negative. Screening of faeces of households and those exposed to the same source of infection is suggested.