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-km2 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.

中文翻译：

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卢旺达火山国家公园山地大猩猩 (Gorilla beringei beringei) 的每日排便量

增加人口密度会增加传染病风险，从而减少人口增长和规模。因此，需要仔细监测留在小型受保护森林碎片中的受威胁动物的宿主-寄生虫相互作用。由于采取极端的保护措施，维龙加地块 450 平方公里的山地大猩猩 (Gorilla beringei beringei) 数量自 1973 年以来增加了一倍多，2016 年达到 604 只。 为了更好地了解土壤传播和其他肠道传播风险的变化山地大猩猩的病原体，我们确定了不同年龄性别类别的排便量和粪便沉积的昼夜变化。我们称重了 399 个不同年龄和性别的大猩猩在巢址和巢址之间的小径上沉积的湿粪便样本，这些样本由叶直径决定，来自分布在卢旺达火山国家公园的五个社会群体（n = 58 只大猩猩）。我们发现日均排便量随着年龄性别等级的增加而增加（婴儿，435 克；青少年，1346 克；中型大猩猩，2446 克；银背大猩猩，3609 克）。与在小径上相比，大猩猩在筑巢地点沉积的粪便量是在小径上的两到三倍，这表明筑巢地点可能通过直接接触或当大猩猩在与成熟时间相匹配的时间间隔重新访问期间摄入被传染性幼虫污染的食物时成为肠道病原体感染的热点环境传播的胃肠道寄生虫时期。结合测距和人口统计数据，