Epizootic fatal amebiasis in an outdoor group of Old World monkeys

Background Entamoeba (E.) histolytica is an obligate parasite of humans and non‐human primates. Methods This report describes the pathomorphological, immunohistological, and microbiological findings of fatal E. histolytica infection in two mantled guerezas (Colobus guereza) and one Hanuman langur (Semnopithecus entellus) from an epizootic outbreak of amebiasis in an open‐range recreation park. Results Pathomorphological examination revealed multifocal necrotizing and granulomatous hepatitis with intralesional protozoan trophozoites in all three cases. In addition, necrotizing and ulcerative gastritis was detected in both mantled guerezas. Furthermore, oligofocal acute pulmonary embolization was detected in one of these cases. No extra‐hepatic lesions were observed in the Hanuman langur. Immunohistological examination confirmed the etiologic diagnosis of E. histolytica‐induced lesions. Conclusions Although E. histolytica is a rarely diagnosed pathogen in Western European countries, veterinarians and animal keepers involved in handling and care taking of non‐human primates should be aware of the potential threat caused by this zoonotic parasite.