Amoebiasis is the infection of the human gastrointestinal tract by Entamoeba histolytica, a protozoan parasite that is capable of invading the intestinal mucosa and may spread to other organs, mainly the liver. Entamoeba dispar, an ameba morphologically similar to E. histolytica that also colonizes the human gut, has been recognized recently as a separate species with no invasive potential. The acceptance of E. dispar as a distinct but closely related protozoan species has had profound implications for the epidemiology of amoebiasis, since most asymptomatic infections found worldwide are now attributed to this noninvasive ameba.
Invasive amoebiasis due to E. histolytica is more common in developing countries. In areas of endemic infection, a variety of conditions including ignorance, poverty, overcrowding, inadequate and contaminated water supplies, and poor sanitation favor direct fecal-oral transmission of amebas from one person to another. Being responsible for approximately 70 thousand deaths annually, amoebiasis is the fourth leading cause of death due to a protozoan infection after malaria, Chagas’ disease, and leishmaniasis and the third cause of morbidity in this organism group after malaria and trichomoniasis, according to recent World Health Organization estimates.
Patients with dysentery have an average of three to five mucosanguineous evacuations per day, with moderate colic pain preceding discharge, and they have rectal tenesmus. In patients with bloody diarrhea, evacuations are also few but the stools are composed of liquid fecal material stained with blood. While there is moderate colic pain, there is no rectal tenesmus. Fever and systemic manifestations are generally absent.
The Entamoeba MonlabTest® is a rapid chromatographic immunoassay for the qualitative detection of Entamoeba antigens in human feces specimens to aid in the diagnosis of amoebiasis.