Aetiological agent is Protozoa: Entamoeba histolytica
Epidemiology
The organisms are amoeboid, aero-tolerant anaerobe that survives in the environment in an encysted form. Cysts remain viable and infective in faeces for several days, in soil for at least 8 days at 24-34°C. They are relatively resistant to chlorine (Mensah, et al., 2012).
Symptoms
The incubation period is 2-4 weeks (range several days to several months). Severe bloody diarrhoea, stomach pains, fever and vomiting. Most infections remain symptomless.
Mode of Transmission
Transmission occurs mainly through the ingestion of faecal contaminated food and water containing cysts. Cysts are excreted in large numbers by an infected individual. Illness is spread by faecal-oral route, person-to-person contact or faecal contaminated food and water.
Foods involved include fruits and vegetables and drinking water. The main reservoirs are humans, but also dogs and rats, the organism is also found in sewage used for irrigation.
Occurrence is worldwide particularly in young adults.
Control and Prevention
Filtration and disinfection of water supply; hygiene disposal of sewage water; treatment of irrigation water; thermal processing; good hygiene practices during production and processing.
In food service establishment or household, boiling of water when safe water is not available; thorough washing of fruits and vegetables; thorough cooking of food; thorough handwashing.
References
- Mensah, P., Mwamakamba, L., Mohamed, C., & Nsue-Milang, D. (2012). Public Health and Food Safety in the WHO African Region. African Journal of Food, Agriculture, Nutrition and Development, 12, 3617-35.
