Entamoeba protozoan parasite Entamoeba histolytica, possibly other Entamoeba spp. Fecal-oral route, either directly by person-to-person contact (such as by diaper-changing or sexual practices) or indirectly by eating or drinking fecally contaminated food or water. Amoebiasis, a disease caused by the intestinal protozoan parasite Entamoeba histolytica, is the third leading parasitic cause of death in humans after malaria and schistosomiasis. A sample of returned travelers who sought health care from 2007 through 2011 at any of 53 international GeoSentinel-associated clinics showed that most people diagnosed with E. histolytica had traveled for tourism to India, Indonesia, Mexico, or Thailand, as opposed to visiting with friends and relatives or traveling for business. Nevertheless, cases of amebiasis are not restricted to these countries and are distributed worldwide, particularly in the tropics, most commonly in areas of poor sanitation. . Similar studies in parts of Africa have recorded infection rates of 14.9% in Equatorial Guinea, Sweden 598,986,4002. Initial estimates were based on microscopy, a method that was insensitive and not species-specific.
Molecular methods using the polymerase chain reaction amplify E. histolytica genes from extracted faecal DNA. Sensitivity and specificity are high (80%–100% and 100%, respectively). For symptomatic intestinal infection and extraintestinal disease, treatment with metronidazole or tinidazole should be followed by treatment with iodoquinol or paromomycin.
Most patients have a gradual illness onset days or weeks after infection. Symptoms include cramps, watery or bloody diarrhea, and weight loss and may last several weeks. Occasionally, the parasite may spread to other organs (extraintestinal amebiasis), most commonly the liver. Amebic liver abscesses may be asymptomatic, but most patients present with fever and right upper quadrant abdominal pain, usually in the absence of diarrhea. Asymptomatic carriers of E. histolytica should be treated with a luminal agent to minimise the spread of disease and the risk of developing invasive disease.