Wilder Aryn P, Eisen Rebecca J, Bearden Scott W, Montenieri John A, Gage Kenneth L, Antolin Michael F
Bacterial Diseases Branch, Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80522, USA.
Vector Borne Zoonotic Dis. 2008 Jun;8(3):359-67. doi: 10.1089/vbz.2007.0181.
Plague, caused by the bacterium Yersinia pestis, often leads to rapid decimation of black-tailed prairie dog colonies. Flea-borne transmission of Y. pestis has been thought to occur primarily via blocked fleas, and therefore studies of vector efficiency have focused on the period when blockage is expected to occur (> or =5 days post-infection [p.i.]). Oropsylla hirsuta, a prairie dog flea, rarely blocks and transmission is inefficient > or =5 days p.i.; thus, this flea has been considered incapable of explaining rapid dissemination of Y. pestis among prairie dogs. By infecting wild-caught fleas with Y. pestis and exposing naïve mice to groups of fleas at 24, 48, 72, and 96 h p.i., we examined the early-phase (1-4 days p.i.) efficiency of O. hirsuta to transmit Y. pestis to hosts and showed that O. hirsuta is a considerably more efficient vector at this largely overlooked stage (5.19% of fleas transmit Y. pestis at 24 h p.i.) than at later stages. Using a model of vectorial capacity, we suggest that this level of transmission can support plague at an enzootic level in a population when flea loads are within the average observed for black-tailed prairie dogs in nature. Shared burrows and sociality of prairie dogs could lead to accumulation of fleas when host population is reduced as a result of the disease, enabling epizootic spread of plague among prairie dogs.
由鼠疫耶尔森菌引起的鼠疫，常常导致黑尾土拨鼠群落迅速大量死亡。鼠疫耶尔森菌通过跳蚤传播一直被认为主要是通过堵塞的跳蚤发生的，因此对媒介效率的研究主要集中在预计堵塞发生的时期（感染后≥5天）。毛多山蚤，一种土拨鼠跳蚤，很少堵塞，且在感染后≥5天传播效率低下；因此，这种跳蚤一直被认为无法解释鼠疫耶尔森菌在土拨鼠中的快速传播。通过用鼠疫耶尔森菌感染野生捕获的跳蚤，并在感染后24、48、72和96小时将未感染的小鼠暴露于跳蚤群体中，我们研究了毛多山蚤在感染早期（感染后1 - 4天）将鼠疫耶尔森菌传播给宿主的效率，并表明毛多山蚤在这个很大程度上被忽视的阶段（感染后24小时有5.19%的跳蚤传播鼠疫耶尔森菌）比后期阶段是一种效率高得多的媒介。使用媒介能力模型，我们认为当跳蚤数量在自然界中黑尾土拨鼠观察到的平均范围内时，这种传播水平可以在种群中维持地方病水平的鼠疫。土拨鼠共有的洞穴和群居性可能导致当宿主种群因疾病而减少时跳蚤的聚集，从而使鼠疫在土拨鼠中发生流行传播。
