Diversity of gastrointestinal parasites in Blue Monkeys and Grey-cheeked Mangabeys at Ngogo Research Site, Kibale National Park

Abstract

Gastrointestinal parasites are a well-known threat to non-human primates‟ health and conservation. These parasites affect non-human primates‟ ecology and evolution, population growth and regulation, and community biodiversity. Faecal samples (n = 241) from two Blue Monkey (Cercopithecus mitis) groups (“Blue Monkey Group 1”, n = 68 and “Blue Monkey Group 2”, n = 53) and two Grey-cheeked Mangabey (Lophocebus albigena) groups (“Mangabey east”, n = 64 and “Mangabey north west”, n = 56) were collected during the period from March to August 2016 at Ngogo Research Site, Kibale National Park to determine gastrointestinal parasites diversity, incidence, prevalence, intensity and effect of season on parasites relative abundance. All the samples were examined for protozoa cysts and helminthes eggs using sodium nitrate floatation, formol-ether sedimentation and direct smear methods before identification under the microscope. Twenty two different parasites were revealed including four protozoa (Cryptosporidium sp., Eimeria sp., Entamoeba coli and Entamoeba histolytica/dispar). Other parasites included trematodes (Fasciolopsis sp., Unidentified trematode sp.1 and sp. 2), and cestodes (Taenia sp.) These parasites were shared among the four non-human primate groups. On the other hand, trematodes (Paragonimus sp., two Schistosoma spp.), cestodes (Hymenolepis sp.) and nematodes (two Anatrichosoma spp., Ancylostoma sp., Chitwoodspirura sp., Strongyloides sp., Trichostrongylus sp., two Trichuris spp., Unidentified nematode sp.1 and sp. 2) were only found in specific non-human primate groups. Ninety four percent (n = 227) of the non-human primates were found infected with at least one parasite species. Three protozoa (Cryptosporidium sp., Eimeria sp., and Entamoeba histolytica/dispar) and fourteen helminthes including two cestodes (Hymenolepis sp., Taenia sp.,) four trematodes (Fasciolopsis sp., two Schistosoma spp., Paragonimus sp.) and eight nematodes (two Anatrichosoma spp., Ancylostoma sp., Chitwoodspirura sp. Strongyloides sp., Trichostrongylus sp., and two Trichuris spp.) present are known to infect humans. All the four primate groups had a significant difference in monthly incidence of parasites (Kruskal-Wallis Test, df = 5, P = 2.08 E -5) and parasites mean intensity (Kruskal-Wallis Test, df = 21, P = 0.000066). However, there was no significant difference in parasites prevalence among the four primate groups (Kruskal-Wallis Test, df = 3, P = 0.131). There was a significant difference in the relative abundance of parasites between wet and dry seasons (Mann-Whitney U-test, Z = -3.485, P = 4.93 E -4). This study generated a baseline data on gastrointestinal parasites in Blue Monkeys and Grey-cheeked Mangabeys at Ngogo Research Site where there is least amount of human influence. The presence in monkeys of parasites that are morphologically indistinguishable from human-infective ones suggests several situations including contamination of the environment by humans, and natural occurrence in these monkeys of parasites cross infective to humans at Ngogo Research Site. This calls for proper design and implementation of effective control measures like good sanitation policies in and around Ngogo Research Site to avoid importation of gastrointestinal parasites from outside the park and park periphery to Ngogo Research Site. There is also a need to carry out research to establish the full extent of these primates‟ home ranges, otherwise there is a possibility that the Ngogo non-human primates freely interact with those ones at the park periphery and hence share parasite populations. This will provide safety to non-human primates, more so the Blue Monkeys whose population is currently low compared to other non-human primate species at Ngogo Research Site.