Fecal parasite risk in the endangered proboscis monkey is higher in an anthropogenically managed forest environment compared to a riparian rain forest in Sabah, Borneo

Abstract

Understanding determinants shaping infection risk of endangered wildlife is a major topic in conservation medicine. The proboscis monkey, Nasalis larvatus, an endemic primate flagship species for conservation in Borneo, is endangered through habitat loss, but can still be found in riparian lowland and mangrove forests, and in some protected areas. To assess socioecological and anthropogenic influence on intestinal helminth infections in N. larvatus, 724 fecal samples of harem and bachelor groups, varying in size and the number of juveniles, were collected between June and October 2012 from two study sites in Malaysian Borneo: 634 samples were obtained from groups inhabiting the Lower Kinabatangan Wildlife Sanctuary (LKWS), 90 samples were collected from groups of the Labuk Bay Proboscis Monkey Sanctuary (LBPMS), where monkeys are fed on stationary feeding platforms. Parasite risk was quantified by intestinal helminth prevalence, host parasite species richness (PSR), and eggs per gram feces (epg). Generalized linear mixed effect models were applied to explore whether study site, group type, group size, the number of juveniles per group, and sampling month predict parasite risk. At the LBPMS, prevalence and epg of Trichuris spp., strongylids, and Strongyloides spp. but not Ascaris spp., as well as host PSR were significantly elevated. Only for Strongyloides spp., prevalence showed significant changes between months; at both sites, the beginning rainy season with increased precipitation was linked to higher prevalence, suggesting the external life cycle of Strongyloides spp. to benefit from humidity. Higher prevalence, epgs, and PSR within the LBPMS suggest that anthropogenic factors shape host infection risk more than socioecological factors, most likely via higher re-infection rates and chronic stress. Noninvasive measurement of fecal parasite stages is an important tool for assessing transmission dynamics and infection risks for endangered tropical wildlife. Findings will contribute to healthcare management in nature and in anthropogenically managed environments.

A Review of Strongyloides spp. Environmental Sources Worldwide

“…Tourist sanctuaries provide an ideal environment for contact between primates and humans. Environmental controls such as fecal contamination removal can decrease helminthic infection in both primates and humans without interfering with natural behaviors [62]. Strongyloides spp.…”

GASTROINTESTINAL PARASITES IN Macaca fascicularis LIVING IN TWO URBAN AREAS OF MALAYSIA

“…Trichuris spp., Entamoeba spp., and Strongyloides spp. are the most prevalent gastrointestinal parasites discovered in primates (Hahn et al, 2003;Trejo-Macias & Estrada, 2012;Mafuyai et al, 2013;Klaus et al, 2018). According to Valenta et al, (2017), macaques in human-occupied areas have a greater frequency of Cryptosporidium spp.…”

Understanding foraging flexibility in urban vervet monkeys, Chlorocebus pygerythrus, for the benefit of human-wildlife coexistence

“…A further management strategy could be to create supplementary foraging patches, providing preferred food items away from human residences. However, supplementary food patches are known to increase aggression and are likely to be dominated by higher ranked individuals leading to rank dependent reproductive costs (King et al 2008;Strum 2010;Kaplan et al 2011), as well as increasing proximity and likelihood of disease transmission (Klaus et al 2018). Thus, if supplementary foraging patches are implemented effort should be made to disperse such foraging patches as much as possible to reduce intragroup competition.…”