Entamoeba histolytica

Entamoeba histolytica affects millions of people across the world every year, causing dysentery and abscesses in the liver and other organs. There is a significant morbidity and mortality, but infections are relatively uncommon in the western world. This may be due to the high infectious dose of E. histolytica required to cause infection and better sanitation in developed countries. Infections are associated with poverty and rural locations. The World Health Organization considers amebiasis to be one of the major health problems in developing countries and over 50 million people may be affected every year. People are mostly infected through consuming contaminated food or water, or as a result of bad hygiene, in countries where the disease is endemic. Entamoeba histolytica can live in the colon as a commensal without causing symptoms and it is not clear what triggers the switch to cause disease. Most people who are symptomatic get an episode of dysentery and then recover. Not all E. histolytica reported in the literature are invasive and some, now classified as Entamoeba dispar, do not cause disease. The role of E. histolytica in foodborne disease has recently been reviewed. Although amebae are thought to be transmitted through infected food handlers, contaminated raw products, or from contaminated water, infections are usually sporadic and without well-documented outbreaks. This also appears to be related to the high infectious dose.