Entamoeba histolytica infection in wild lemurs associated with proximity to humans

Amoebiasis, caused by Entamoeba histolytica, affects 50 million people worldwide, and results in 100,000 deaths annually. It is particularly prevalent in developing nations where poverty and poor sanitation contribute to contamination of food and water. E. histolytica is also a zoonotic protozoan parasite with the potential to infect non-human primates. Lemurs, primates endemic to Madagascar, are the most threatened mammalian group in the world due to habitat loss. As forests disappear, humans and lemurs come into more frequent contact, and the potential for E. histolytica to infect lemurs intensifies. Consequently, we screened 176 fecal samples from seven lemur species at eight sites in the rain forests of southeastern Madagascar for E. histolytica to determine if human proximity influenced lemur infection. Of samples examined, 4.0% (from three lemur species) were positive for E. histolytica. Of lemurs infected with E. histolytica, three (43%) exhibited diarrheal feces. Distance to human settlements explained the variation in E. histolytica infection seen in lemurs. These results provide the first evidence of E. histolytica in wild lemurs and highlight the need for additional work to better understand the eco-epidemiology of this potential threat to these species.