Molecular detection and prevalence of Giardia duodenalis and Cryptosporidium spp. among long-tailed macaques (Macaca fascicularis) in Thailand.

Giardia duodenalis and Cryptosporidium spp. are divergent protozoal intestinal parasites that infect human beings and other animals, including non-human primates. Although long-tailed macaques (Macaca fascicularis) reside in human communities in Thailand, the prevalence of Giardia spp. and Cryptosporidium spp. in these primates has not been previously investigated. The objective of this study was to evaluate long-tailed macaques living near human communities as possible hosts of these intestinal parasites. In 2014, 200 fecal samples were randomly collected from long-tailed macaques living in different areas of Lopburi province, Thailand, and tested with a panel of PCR assays for Giardia spp. and Cryptosporidium spp. G. duodenalis assemblage B was most frequently detected (6%), while assemblage A and an inconclusive assemblage were detected in single samples, for a total G. duodenalis infection rate of 7%. Two samples (1%) tested positive for Cryptosporidium spp., which were both classified as monkey genotypes. No significant associations were found between G. duodenalis infection and sex or location of macaques. This study indicates that long-tailed macaques can carry G. duodenalis and, to a lesser extent, Cryptosporidium spp. monkey genotype. These results warrant education of residents and tourists to limit contact with long-tailed macaques and to take hygienic precautions to mitigate risk of zoonotic and anthroponotic transmission of these parasites between people and macaques.