The Dian Fossey Gorilla Fund International, 800 Cherokee Ave SE, Atlanta, GA, 30315, USA.
The University of Rwanda, Butare, Huye, Rwanda.
Primates. 2021 Mar;62(2):311-320. doi: 10.1007/s10329-020-00874-7. Epub 2020 Nov 22.
Increasing population density can increase infectious disease risk and thus reduce population growth and size. Host-parasite interactions of threatened animals that remain in small protected forest fragments therefore need to be monitored carefully. Due to extreme conservation efforts, the mountain gorilla (Gorilla beringei beringei) population in the 450-km Virunga Massif has more than doubled since 1973, reaching 604 individuals in 2016. To better understand changes in the transmission risks of soil-borne and other enteric pathogens for mountain gorillas, we determined defecation outputs of different age-sex classes and the diurnal variation in feces deposition. We weighed 399 wet fecal samples deposited at nest sites and on trails between nest sites by gorillas of varying age and sex, determined by lobe diameter, from five social groups (n = 58 gorillas) that range in the Volcanoes National Park, Rwanda. We found increasing daily average defecation outputs with increasing age-sex class (infants, 435 g; juveniles, 1346 g; medium-sized gorillas, 2446 g; silverbacks, 3609 g). Gorillas deposited two- to threefold the amount of feces at nest sites compared to on trails, suggesting that nest sites may function as hotspots for enteric pathogen infections through direct contact or when gorillas ingest foods contaminated with infectious larvae during site revisits in intervals matching the maturation period of environmentally transmitted gastrointestinal parasites. In combination with ranging and demographic data, these findings will enable the modeling of spatiotemporal variation in soil contamination and infectious disease risk for Virunga gorillas as their population density continues to increase.
人口密度的增加会增加传染病的风险，从而降低人口的增长和规模。因此，需要仔细监测留在小的受保护森林碎片中的受威胁动物的宿主-寄生虫相互作用。由于极端的保护努力，自 1973 年以来，维龙加山脉（Virunga Massif）的山地大猩猩（Gorilla beringei beringei）数量增加了一倍多，2016 年达到 604 只。为了更好地了解土壤传播和其他肠道病原体对山地大猩猩传播风险的变化，我们确定了不同年龄-性别类别的粪便排放量和粪便沉积的昼夜变化。我们通过耳垂直径确定了五个社会群体（n=58 只大猩猩）中不同年龄和性别的粪便沉积量，这些粪便沉积在巢穴和巢穴之间的小径上。这五个社会群体的范围是卢旺达的火山国家公园。我们发现，随着年龄-性别类别的增加，每日平均粪便排放量也在增加（婴儿，435 克；青少年，1346 克；中等体型的大猩猩，2446 克；银背大猩猩，3609 克）。与在小径上相比，大猩猩在巢穴地点沉积的粪便量是其两倍到三倍，这表明巢穴地点可能通过直接接触或当大猩猩在与环境传播的胃肠道寄生虫成熟周期相匹配的时间间隔内返回巢穴时摄入受传染性幼虫污染的食物而成为肠道病原体感染的热点。结合分布范围和人口统计数据，这些发现将使我们能够对维龙加大猩猩的土壤污染和传染病风险的时空变化进行建模，因为它们的人口密度继续增加。
