Gastrointestinal helminth and protozoan infections of wild mammals in four major national parks in Sri Lanka

Abstract

A cross-sectional, coprological survey of gastrointestinal (GI) parasites of wild mammals in four major National Parks in Sri Lanka: Wilpattu, Udawalawe, Wasgamuwa, and Horton Plains was carried out during November 2016 to August 2017. Fresh fecal samples were collected and analyzed using sedimentation technique, iodine & saline smears, and Sheather’s sucrose flotation for morphological identification parasite eggs, cysts, and larvae. A modified salt flotation was carried out for egg counts. Seventy samples from 10 mammal species: Asian Elephant, Spotted Deer, Water Buffalo, Sambar, Indian Hare, Asian Palm Civet, Sloth Bear, Wild Boar, Grey Langur, Leopard, and four unknown mammals (two carnivores, one herbivore and one omnivore) were analyzed. Most were infected (94.3%) with more than one GI parasites. The highest prevalence of infection was recorded in Horton Plains (100%), followed by Wasgamuwa (92.8%), Wilpattu (90.4%) and Udawalawe (75.0%) with a significant difference among four parks (Chi square test; χ2=35.435; df=3; p<0.001). Nineteen species of GI parasites were recorded, of which Entamoeba, Isospora, Balantidium, Fasciola, Moniezia, Dipylidium, strongyles, Toxocara, Trichiurus and hookworms were the most common. Strongyles (62.1%) and Entamoeba (80.3%) were the most prevalent helminth and protozoan infections, respectively. Overall, there was no difference in the prevalence of protozoans (84.3%) and helminths (87.1%; χ2=1.0; df=1; p=0.317). In carnivores, Entamoeba, Balantidium, Moniezia, strongyles and Strongyloides were common and in herbivores, Entamoeba, strongyles, Strongyloides and Toxocara were common. The quantitative analysis showed strongyles (17.639 EPG) and Isospora (18,743 OPG) having the highest infection intensity among helminthes and protozoans, respectively. This study provides baseline information of GI parasites and their distribution in wild mammals in the four national parks. Although the prevalence of GI infections was high, their intensity shows that they could be incidental infections. When the prevalence of an infection is high but the intensity is low, it is unlikely to be a major health problem leading to the endangerment of a species. Parasitic diseases can not only affect conservation efforts, but they are also natural selection agents and drive biological diversification, through influencing host reproductive isolation and speciation.