Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA.
Environmental Studies Program, University of Colorado at Boulder, Boulder, Colorado, USA.
Integr Zool. 2021 Nov;16(6):834-851. doi: 10.1111/1749-4877.12546. Epub 2021 May 31.
Yersinia pestis, causative agent of plague, occurs throughout the western United States in rodent populations and periodically causes epizootics in susceptible species, including black-tailed prairie dogs (Cynomys ludovicianus). How Y. pestis persists long-term in the environment between these epizootics is poorly understood but multiple mechanisms have been proposed, including, among others, a separate enzootic transmission cycle that maintains Y. pestis without involvement of epizootic hosts and persistence of Y. pestis within epizootic host populations without causing high mortality within those populations. We live-trapped and collected fleas from black-tailed prairie dogs and other mammal species from sites with and without black-tailed prairie dogs in 2004 and 2005 and tested all fleas for presence of Y. pestis. Y. pestis was not detected in 2126 fleas collected in 2004 but was detected in 294 fleas collected from multiple sites in 2005, before and during a widespread epizootic that drastically reduced black-tailed prairie dog populations in the affected colonies. Temporal and spatial patterns of Y. pestis occurrence in fleas and genotyping of Y. pestis present in some infected fleas suggest Y. pestis was introduced multiple times from sources outside the study area and once introduced, was dispersed between several sites. We conclude Y. pestis likely was not present in these black-tailed prairie dog colonies prior to epizootic activity in these colonies. Although we did not identify likely enzootic hosts, we found evidence that deer mice (Peromyscus maniculatus) may serve as bridging hosts for Y. pestis between unknown enzootic hosts and black-tailed prairie dogs.
鼠疫耶尔森菌是鼠疫的病原体，存在于美国西部的啮齿动物种群中，并定期在易感物种中引起动物疫情，包括黑尾草原犬鼠（Cynomys ludovicianus）。在这些动物疫情之间，鼠疫耶尔森菌如何在环境中长期存在尚不清楚，但已经提出了多种机制，包括独立的地方性传播循环，即在不涉及动物疫情宿主的情况下维持鼠疫耶尔森菌的存在，以及在不导致这些宿主种群高死亡率的情况下，鼠疫耶尔森菌在动物疫情宿主种群中的持续存在。我们于 2004 年和 2005 年在有和没有黑尾草原犬鼠的地点，使用活体陷阱捕获黑尾草原犬鼠和其他哺乳动物物种的跳蚤，并对所有跳蚤进行鼠疫耶尔森菌检测。2004 年采集的 2126 只跳蚤中未检测到鼠疫耶尔森菌，但在 2005 年从多个地点采集的 294 只跳蚤中检测到了鼠疫耶尔森菌，当时正值广泛的动物疫情，受影响的殖民地中黑尾草原犬鼠的数量急剧减少。跳蚤中鼠疫耶尔森菌的出现的时间和空间模式以及一些感染跳蚤中的鼠疫耶尔森菌的基因分型表明，鼠疫耶尔森菌是从研究区域以外的多个来源多次传入的，一旦传入，就会在几个地点之间传播。我们得出结论，在这些黑尾草原犬鼠殖民地发生动物疫情之前，鼠疫耶尔森菌可能不在这些黑尾草原犬鼠中存在。虽然我们没有确定可能的地方性宿主，但我们发现了证据表明，鹿鼠（Peromyscus maniculatus）可能在未知的地方性宿主和黑尾草原犬鼠之间充当了鼠疫耶尔森菌的桥梁宿主。
