PDF(Pubmed)
Abstract：
Yersinia pestis, the causative agent of plague, is a highly lethal vector-borne pathogen responsible for killing large portions of Europe\'s population during the Black Death of the Middle Ages. In the wild, Y. pestis cycles between fleas and rodents; occasionally spilling over into humans bitten by infectious fleas. For this reason, fleas and the rats harboring them have been considered the main epidemiological drivers of previous plague pandemics. Human ectoparasites, such as the body louse (Pediculus humanus humanus), have largely been discounted due to their reputation as inefficient vectors of plague bacilli. Using a membrane-feeder adapted strain of body lice, we show that the digestive tract of some body lice become chronically infected with Y. pestis at bacteremia as low as 1 × 105 CFU/ml, and these lice routinely defecate Y. pestis. At higher bacteremia (≥1 × 107 CFU/ml), a subset of the lice develop an infection within the Pawlowsky glands (PGs), a pair of putative accessory salivary glands in the louse head. Lice that developed PG infection transmitted Y. pestis more consistently than those with bacteria only in the digestive tract. These glands are thought to secrete lubricant onto the mouthparts, and we hypothesize that when infected, their secretions contaminate the mouthparts prior to feeding, resulting in bite-based transmission of Y. pestis. The body louse\'s high level of susceptibility to infection by gram-negative bacteria and their potential to transmit plague bacilli by multiple mechanisms supports the hypothesis that they may have played a role in previous human plague pandemics and local outbreaks.
摘要：
鼠疫耶尔森氏菌,鼠疫的病原体，是一种高度致命的媒介传播的病原体，在中世纪的黑死病期间杀死了大部分欧洲人口。在野外,鼠疫菌在跳蚤和啮齿动物之间循环；偶尔会被传染性跳蚤咬伤。出于这个原因,跳蚤和携带跳蚤的老鼠被认为是以前鼠疫大流行的主要流行病学驱动因素。人类外寄生虫,例如体虱（Pediculushumanushumanus），由于其作为鼠疫杆菌的低效媒介的声誉，在很大程度上被打折。使用适应体虱的膜喂食器，我们显示一些体虱的消化道在菌血症低至1×105CFU/ml时慢性感染鼠疫菌，这些虱子经常排便鼠疫杆菌。在较高的菌血症（≥1×107CFU/ml），一部分虱子在Pawlowsky腺体（PG）内发生感染，在虱子头中的一对推定的副唾液腺。发展为PG感染的虱子比仅在消化道中具有细菌的虱子更一致地传播鼠疫杆菌。这些腺体被认为向口腔分泌润滑剂，我们假设当感染时，它们的分泌物在进食前污染了口腔，导致鼠疫杆菌的咬伤传播。体虱对革兰氏阴性菌感染的高度敏感性及其通过多种机制传播鼠疫杆菌的潜力支持了这一假设，即它们可能在先前的人类鼠疫大流行和局部暴发中发挥了作用。
