Amoebic Dysentery

Causative agent

Amoebic dysentery is an intestinal infection caused by a protozoan parasite called Entamoeba histolytica.

Clinical features

Infection by Entamoeba histolytica are mostly asymptomatic. For patients who develop amoebic dysentery, symptoms include fever, chills, abdominal pain and bloody or mucous diarrhoea. Less commonly, Entamoeba histolytica may invade the liver to form an abscess, or  spread to other parts of the body such as the lungs or brain. Other complications include inflammation of the intestine and in severe cases, intestinal perforation.

Mode of transmission

Transmission of amoebic dysentery occurs mainly through the faecal-oral route, including ingestion of faecal contaminated food or water containing the cyst of Entamoeba histolytica. Transmission can also occur through person-to-person contact such as diaper-changing for an infected child and oral-anal sex.

Risk factors

Amoebic dysentery is more common in developing countries and tropical areas with poor sanitary conditions.  People who live in institutions, travellers to or immigrants from developing countries with poor sanitary condition, and men who have sex with men are at a higher risk of getting the disease.

Incubation period

The incubation period is usually 2 - 4 weeks, but it can range from several days to months or years.

Management

Treatment may include appropriate use of antibiotics.

Prevention

• Perform hand hygiene frequently, especially before handling food or eating, and after using the toilet or handling faecal matter.
• Wash hands with liquid soap and water, and rub for at least 20 seconds; then rinse with water and dry with a disposable paper towel or hand dryer. If hand washing facilities are not available, or when hands are not visibly soiled, hand hygiene with 70 to 80% alcohol-based handrub may be an effective alternative.
• Refrain from work or school, and seek medical advice when suffering from gastrointestinal symptoms such as diarrhoea.

• Adopt the 5 Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases.
• Drink only boiled water from the mains or bottled drinks from reliable sources.
• Avoid drinks with ice of unknown origin.
• Purchase fresh food from hygienic and reliable sources. Do not patronise illegal hawkers. In general, you can eat fruits with skin after thorough washing. However, if you would like to reduce the risk of illness especially when you travel abroad, peel the raw fruits before you eat and do not eat the peelings.
• Cook all food thoroughly before consumption.
• Exclude infected persons and asymptomatic carriers from handling food and from providing care to children, elderly and immunocompromised people.

* Please visit the website of Centre for Food Safety for more information on food safety.