Prevalence of gastrointestinal parasites in lion-tailed macaque Macaca silenus in central Western Ghats, India.

This study examines gastrointestinal parasites in the endangered lion-tailed macaque, which is sympatric with the bonnet macaque that has relocated from nearby towns or agriculture landscapes dominated by humans and livestock. One hundred and ninety-four fresh fecal samples from lion-tailed macaques were collected from a group located at Chiksuli in the central Western Ghats. Of these, 48.5% had at least one endoparasite taxon. The prevalence of endoparasites varied from 0 to 75.0%, and observed endoparasite taxa varied between 0 and 10 across different months. The prevalence of endoparasites decreased with increasing rainfall and with increasing average maximum temperature across months. Of the 17 endoparasite taxa, 11 were nematodes, two were cestodes, and four were protozoans. The prevalence of Ascaris sp. and Entamoeba coli was higher than the other taxa. The overall load, helminth load, and protozoan load did not differ between months. The overall endoparasite load was greater in immature macaques in all seasons. Helminth load was higher in adult males, especially in the summer. Comparing our findings with those from sympatric relocated bonnet macaques of Chiksuli (Kumar et al. in PLoS ONE 13(11):e0207495, 2018) and lion-tailed macaques of Anamalai Hills (Hussain et al. in PLoS ONE 8(5):e63685, 2013) revealed: (a) a much higher prevalence of endoparasites in lion-tailed macaques from fragments of Anamalai Hills than in lion-tailed and bonnet macaques of Chiksuli; (b) higher richness of endoparasites in both macaque species of Chiksuli than in Anamalai lion-tailed macaques; and (c) more similar composition of endoparasite taxa between the Chiksuli lion-tailed and bonnet macaques than with the Anamalai Hills lion-tailed macaques. We suggest a complete cessation of relocation of commensal animals to the wild habitat. If relocation is necessary, then individuals to be relocated should be thoroughly screened and treated to prevent transferring endoparasite infections to wild populations.