Gastro-intestinal parasites in two subspecies of toque macaque (Macaca sinica) in Sri Lanka and their zoonotic potential.

Gastro-intestinal (GI) parasites of primates have a greater potential of becoming zoonotic. This potential may vary in different primates based on multiple factors such as proximity to human settlements and the climate of their habitat. We examined the GI parasites in two subspecies of toque macaque: Macaca sinica sinica (confined to the dry zone) and Macaca sinica aurifrons (confined to the wet zone) of Sri Lanka. Fresh faecal samples were collected and analysed following a modified Sheather's sucrose floatation method. A total of 90.8% (89/98) macaques were infected with one or more parasite species. There was no difference in the overall prevalence of GI parasites between the two subspecies, M. s. aurifrons (95.9%) and M. s. sinica (85.7%; χ2;χ = 3.059, p = 0.080). Sixteen parasite species were recorded including, 15 species in the M. s. sinica and 12 species in the M. s. aurifrons. Among the helminths identified, Anatrichosoma sp., Ancylostoma spp., Capillaria spp., Oesophagostomum /Bunostomum spp. and Physaloptera spp. are known to be zoonotic while Ascaris spp., Enterobius sp., Strongyloides spp. and Trichuris spp. have both zoonotic and anthroponotic potential. Among the protozoans, Balantidium coli and Buxtonella sp. are known to be zoonotic, while Entamoeba spp. and Cryptosporidium spp. have both anthroponotic and zoonotic potential. This study provides the first record of Anatrichosoma sp. and Buxtonella sp. in Sri Lanka and the first record of Cryptosporidium spp. in M. s. aurifrons. The molecular data allowed further identification and differentiation of Entamoeba nuttalli and E. coli that are known to be zoonotic and anthroponotic, respectively. The two subspecies of macaques have close interactions with humans; hence, in-depth epidemiological studies are required to understand the potential public-health risks to humans and conservation implications for macaque populations.