Entamoeba histolytica infections in wild and semi‐wild orangutans in Sumatra and Kalimantan

Abstract

Key to the success of orangutan conservation management practices is the prevention of the introduction of infectious diseases to the remaining populations. Previous reports of Entamoeba spp. positive orangutans are of concern as Entamoeba spp. infection has been linked to morbidity and mortality in primates. It remains to be determined if the Entamoeba species infecting orangutans is the pathogenic Entamoeba histolytica. Orangutan fecal samples have been collected from orangutans from sites in Sumatra (Bukit Lawang, Ketambe, and Suaq, 241 samples from 64 individuals), and two sites in Kalimantan (Sebangau and Tuanan, 129 samples from 39 individuals). All samples were from wild orangutans except for a proportion from Sumatra which were from semi-wild (108 samples, 10 individuals). E. histolytica-specific nested PCR assays were carried out on the fecal samples. A total of 36 samples from 17 individuals tested positive for E. histolytica. When compared with published sequences using NCBI BLAST the E. histolytica positive samples showed a 98-99% concordance. The majority (76%, n = 36) of the positive isolates came from semi-wild orangutans in Bukit Lawang.This study supports the growing body of evidence that contact with humans is an important risk factor for infection of wild primates with E. histolytica.

Molecular Detection and Characterization of Intestinal and Blood Parasites in Wild Chimpanzees (Pan troglodytes verus) in Senegal

“…infection has been associated with morbidity and even mortality in NHP [ 53 , 54 ], although at present it remains to be fully elucidated if the Entamoeba species carried by NHP include the pathogenic E. histolytica . Indeed, E. histolytica was detected by PCR in wild and semi-wild orangutans in Sumatra, Indonesia [ 6 ]. In that study, contact with humans was considered as an important risk factor for infection of wild primates with this protist parasite.…”

“…Little information is currently available on the epidemiology and potential health impact of zoonotic intestinal and blood protist species in wild chimpanzee populations. These include diarrhoea-causing intestinal protist species such as Cryptosporidium spp., Giardia duodenalis , and Entamoeba histolytica [ 4 , 5 , 6 , 7 ], and the microsporidia Enterocytozoon bieneusi [ 8 ]. Other protist species have uncertain or limited pathogenic significance, such as the stramenopile Blastocystis sp.…”

Primate Selfies and Anthropozoonotic Diseases: Lack of Rule Compliance and Poor Risk Perception Threatens Orangutans

“…It is thought that the lack of recorded mass mortality events from infectious disease in orangutans could be due to their more solitary nature in comparison to the African great apes [Philippa and Dench, 2019]. However, orangutans, especially wild populations, are underrepresented in the literature on great apes and infectious diseases [Mul et al, 2007;Nurcahyo et al, 2017;Philippa and Dench, 2019;Stuart et al, 2020], and the majority of these data is from captive populations in zoos, sanctuaries and rehabilitation centres.…”

“…Semiwild and captive orangutans are more frequently infected by Cryptosporidium sp. than wild orangutans [Mynářová et al, 2016], and 76% of samples from semi-wild Sumatran orangutans (Pongo abelii) in Bukit Lawang, north Sumatra, tested positive for Entamoeba [Stuart et al, 2020]. More recently, concerns have been raised by a plethora of scientists regarding the COVID-19 pandemic, its impacts on biodiversity conservation and specifically its impact on non-human primate species [Corlett et al, 2020;Santos et al, 2020].…”

“…Semi-wild and captive orangutans are more frequently infected by Cryptosporidium sp. than wild orangutans [Mynářová et al, 2016], and 76% of samples from semi-wild Sumatran orangutans (Pongo abelii) in Bukit Lawang, north Sumatra, tested positive for Entamoeba [Stuart et al, 2020].…”