Prevalence of gastrointestinal helminth parasites in rhesus macaques and local residents in the central mid-hills of Nepal

Rhesus macaques (Macaca mulatta) are distributed across Nepal in close association with humans and with a high probability of sharing of soil-transmitted intestinal helminth parasites. This study was carried out to determine the prevalence, richness and risk factors of gastrointestinal (GI) helminth parasites among rhesus macaques and humans in the Daunne Forest area, a community managed forest in the central mid-hills of Nepal. A total of 190 fecal samples, including 120 samples from rhesus macaques residing around the Daunne Devi Temple and in the surrounding forest, and 70 from local people, were microscopically examined by direct wet mount, floatation and sedimentation methods. Seasonal and age-sex based variations in helminth parasite prevalence were analyzed. Among the rhesus macaques, the total parasite prevalence was 39.2 %. Strongyloides sp. accounted for the highest prevalence (19.17 %) followed by Ascaris sp. (13.33 %), hookworm (10.83 %) and Trichuris sp. (4.17 %). Among the humans, Ascaris lumbricoides (11.3 %) was the only parasite detected. The Sorenson's coefficient of similarity of GI parasites between the macaques and local people at the generic level was 0.4. Mean parasite richness for the macaques was 1.21 ± 0.41 (SD) per infected sample. Parasite prevalence in the summer season (41.4 %) was higher than in the winter season (36 %). Adult macaques (41.67 %) had higher GI parasite prevalence than the young (30.77 %) and infants (27.27 %). Among the adult macaques, the prevalence rate was significantly higher (P=0.005) in females (52.46 %) than in males (22.86 %). Our results indicate that the temple rhesus macaques have a high prevalence of GI helminth parasites and could pose a potential zoonotic risk. As such, the need for routine monitoring and an effective management strategy is essential.