Sanford School of Medicine, Division of Basic Biomedical Sciences, University of South Dakota, Vermillion, SD, United States.
Pathog Dis. 2022 Aug 17;80(1). doi: 10.1093/femspd/ftac028.
Bartonella quintana is a re-emerging louse-borne pathogen. Horizontal transmission from the body louse vector (Pediculus humanus humanus) to a human host occurs through contact with infectious louse feces containing a high concentration of the bacteria. However, questions have remained about whether vertical transmission from infected vectors to their progeny, which could significantly influence the dynamics of transmission to humans, occurs in body lice. To address this subject, we performed a series of controlled laboratory experiments that examined the presence of B. quintana on the surface of and within eggs produced by female body lice that were provisioned multiple infectious blood meals to recapitulate the natural pathogen acquisition process. Our results demonstrate that B. quintana DNA can be detected from the surface of eggs by qPCR due to vertical transfer of infectious feces to the egg sheath during or after oviposition. However, viable B. quintana could not be cultured from the hemolymph of adult female lice or from within eggs that were surface sterilized, indicating a lack of true transovarial transmission. Based on this evidence, vertical transfer of B. quintana from infected adult lice to their eggs probably has a limited impact on the dynamics of transmission to humans.
巴尔通体(Bartonella quintana)是一种重新出现的虱传病原体。体虱(Pediculus humanus humanus)媒介从身体上通过接触含有高浓度细菌的传染性虱子粪便向人类宿主发生水平传播。然而，关于感染媒介是否会垂直传播给它们的后代，从而显著影响向人类传播的动力学，这在体虱中仍然存在疑问。为了解决这个问题，我们进行了一系列的对照实验室实验，检查了在被多次感染性血液喂养的雌性体虱所产的卵的表面和内部是否存在巴尔通体。我们的结果表明，由于在产卵期间或之后，传染性粪便垂直转移到卵鞘，B. quintana 的 DNA 可以通过 qPCR 从卵的表面检测到。然而，从成年雌性虱子的血淋巴或经过表面消毒的卵内，无法培养出存活的 B. quintana，这表明不存在真正的经卵传播。基于这一证据，从感染的成年虱子向其卵的巴尔通体垂直传播可能对向人类传播的动力学影响有限。
