Department of Biology, Georgetown University, Washington, DC, USA.
Center for Global Health Science and Security, Georgetown University Medical Center, Washington, DC, USA.
Nat Ecol Evol. 2022 Jun;6(6):794-801. doi: 10.1038/s41559-022-01723-0. Epub 2022 May 2.
The world is rapidly urbanizing, inviting mounting concern that urban environments will experience increased zoonotic disease risk. Urban animals could have more frequent contact with humans, therefore transmitting more zoonotic parasites; however, this relationship is complicated by sampling bias and phenotypic confounders. Here we test whether urban mammal species host more zoonotic parasites, investigating the underlying drivers alongside a suite of phenotypic, taxonomic and geographic predictors. We found that urban-adapted mammals have more documented parasites and more zoonotic parasites: despite comprising only 6% of investigated species, urban mammals provided 39% of known host-parasite combinations. However, contrary to predictions, much of the observed effect was attributable to parasite discovery and research effort rather than to urban adaptation status, and urban-adapted species in fact hosted fewer zoonotic parasites than expected on the basis of their total parasite richness. We conclude that extended historical contact with humans has had a limited impact on zoonotic parasite richness in urban-adapted mammals; instead, their greater observed zoonotic richness probably reflects sampling bias arising from proximity to humans, supporting a near-universal conflation between zoonotic risk, research effort and synanthropy. These findings underscore the need to resolve the mechanisms linking anthropogenic change, sampling bias and observed wildlife disease dynamics.
世界正在快速城市化，人们越来越担心城市环境将面临更高的人畜共患病风险。城市中的动物可能会与人类有更频繁的接触，从而传播更多的人畜共患寄生虫；然而，这种关系受到采样偏差和表型混杂因素的影响而变得复杂。在这里，我们测试了城市哺乳动物是否携带更多的人畜共患寄生虫，同时调查了一系列表型、分类和地理预测因子，以探究其潜在驱动因素。我们发现，适应城市生活的哺乳动物携带更多的寄生虫和更多的人畜共患寄生虫：尽管只占调查物种的 6%，但城市哺乳动物提供了 39%的已知宿主-寄生虫组合。然而，与预测相反，观察到的大部分影响归因于寄生虫的发现和研究工作，而不是城市适应状态，事实上，适应城市生活的物种携带的人畜共患寄生虫比根据其总寄生虫丰富度预期的要少。我们的结论是，与人类的长期接触对适应城市生活的哺乳动物的人畜共患病寄生虫丰富度的影响有限；相反，它们更多的人畜共患寄生虫丰富度可能反映了由于接近人类而产生的采样偏差，这支持了将人畜共患风险、研究工作和与人类共生混为一谈的普遍现象。这些发现强调了需要解决将人为变化、采样偏差和观察到的野生动物疾病动态联系起来的机制。
