Gastrointestinal parasites of blue monkeys (Cercopithecus mitis) and grey-cheeked mangabeys (Lophocebus albigena) at the Ngogo Research Site in Kibale National Park, Uganda

There has been persistent decline in blue monkey (Cercopithecus mitis) population at Ngogo research site in the past 40 years for no clear reasons. In contrast, the populations of other nonhuman primates like the grey-cheeked mangabeys (Lophocebus albigena) which share identical home ranges with blue monkeys have not been obviously affected. However, stakeholders attribute this decline to gastrointestinal parasitic diseases, hence the need to determine the profile of parasitic infections in blue monkeys and compare them to that of grey-cheeked mangabeys within a shared home range. Faecal samples (n = 241) were subjected to diagnostic tests, namely sodium nitrate floatation and formol-ether sedimentation before microscopic examination. 227 (94%) samples were parasite positive; six protozoa and 21 helminths were present. This implies that Ngogo hosts a high diversity of parasites which poses health risks to nonhuman primates. There was no significant statistical difference in the prevalence of the overall main pathogenic parasites between the two studied nonhuman primate species. Therefore, gastrointestinal parasites may not be the obvious cause of the proclaimed blue monkey population decline at Ngogo research site.