Gastrointestinal Parasites of Free-Ranging Rhesus Macaques (Macaca mulatta) in Kathmandu: A One Health Perspective on Shared Environmental Risks.

BACKGROUND

The increasing interface between human and non-human primate populations in urban centres presents a shared environmental health risk. This risk is particularly prominent at religious sites where close interactions are culturally motivated.

OBJECTIVES

This study aimed to determine the prevalence and diversity of gastrointestinal (GI) parasites in free-ranging rhesus macaques (Macaca mulatta) at two UNESCO World Heritage sites in Kathmandu, Nepal.

METHODS

An opportunistic, non-invasive cross-sectional study was conducted in July and August 2024. Freshly voided faecal samples (N = 105) were collected from macaques at Pashupatinath Temple (n = 45) and Swayambhunath Stupa (n = 60). The samples were processed using standard coprological techniques, including zinc sulphate flotation and sedimentation, for microscopic examination.

RESULTS

The overall prevalence of GI parasites was 77.1% (81/105). Nine genera were identified, comprising four protozoans and five helminths, eight of which contain species with recognized zoonotic potential. The most prevalent parasites were Entamoeba sp. (37.1%), Strongyle-type eggs (25.7%), and Strongyloides sp. (20.0%). Double infections were the most frequent pattern (41.0%).

CONCLUSIONS

The high burden of potentially zoonotic parasite genera in macaques at these popular international sites highlights substantial environmental contamination and a shared exposure risk at the human-macaque interface. These findings underscore the urgent need for integrated sanitation, public awareness, and management strategies guided by a One Health framework.