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.

中文翻译：

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乌干达基巴莱国家公园Ngogo研究中心的蓝猴（Cercopithecus mitis）和灰颊man（Lophocebus albigena）的胃肠道寄生虫

过去40年中，在Ngogo研究地点，蓝猴（Cercopithecus mitis）种群持续下降，原因不明。相比之下，其他非人类灵长类动物（如灰颊man（Lophocebus albigena））与蓝猴具有相同的居所，它们的种群并未受到明显影响。但是，利益相关者将这种下降归因于胃肠道寄生虫病，因此需要确定蓝猴中寄生虫感染的情况，并将其与共用住所范围内的灰颊man进行比较。粪便样本（ñ = 241）进行了诊断测试，即在显微镜检查之前进行了硝酸钠浮选和甲醚-醚沉淀。227（94％）个样本为寄生虫阳性；存在六个原生动物和21个蠕虫。这意味着Ngogo拥有大量的寄生虫，这对非人类灵长类动物构成了健康风险。在两个研究的非人类灵长类物种之间，总体主要致病性寄生虫的患病率没有统计学差异。因此，在Ngogo研究现场，胃肠道寄生虫可能不是造成蓝猴数量下降的明显原因。