Helminthic parasite infections of endangered western hoolock gibbons (Hoolock hoolock) in degraded habitats of Bangladesh

Abstract

Although habitat degradation and anthropogenic disturbance can increase the risk of parasitic infections for many animals, including primates, little information about parasitism in wild gibbons is available, and almost nothing is known about the prevalence of helminth infection in wild populations. Globally threatened western hoolock gibbons (Hoolock hoolock, Harlan 1834) are exposed to significant anthropogenic disturbances across their range. We examined faecal samples from wild gibbons in three highly degraded and fragmented forests in Bangladesh: Lawachara National Park, Saltila forest, and Sheikh Jamal Inani National Park, for helminths, and identified two helminthic parasites,Bunostomumsp., andEnterobiussp. Overall helminthic parasite prevalence (percentage of samples containing parasites) and intensity (mean number of parasites individuals per sample) in faecal samples from wild gibbons were 82% and 12.1, respectively. This is the first report ofBunostomumsp. andEnterobiussp. infections in wild individuals of western hoolock gibbons or any other small ape. Habitat fragmentation, degradation, human encroachment, and other anthropogenic disturbances in Bangladesh may contribute to higher infection risk and transmission of zoonotic diseases in this highly arboreal gibbon species, with unknown consequences for their health and long-term survival. As parasitic infections can be transmitted within and across species, affecting humans, other primates, and other wild and domesticated animals, habitat protection and restoration and public awareness campaigns applying the One Health approach should be used to mitigate the spread of zoonotic disease in shared landscapes.HIGHLIGHTSFirst reported helminthic parasite infections withBunostomumsp. andEnterobiussp. in wild gibbonsOut of 50 collected fecal samples from the endangered Western hoolock gibbon in three degraded forests in Bangladesh, 41 (82%) tested positive for helminthic infectionsParasite intensity ranged from 1 to 45 individuals per gram, with a median intensity of 9Lower parasite intensity (≤5) was more common in winter than in the monsoon season indicating seasonal variationsGRAPHICAL ABSTRACT