Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States.
Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States.
Epidemics. 2017 Sep;20:56-66. doi: 10.1016/j.epidem.2017.03.004. Epub 2017 Mar 16.
Bartonella spp. are erythrocytic bacteria transmitted via arthropod vectors, which infect a broad range of vertebrate hosts, including humans. We investigated transmission dynamics and host-parasite-vector relationships for potentially zoonotic Bartonella spp. in invasive Rattus rattus hosts and associated arthropod ectoparasites in Madagascar. We identified five distinct species of Bartonella (B. elizabethae 1, B. elizabethae 2, B. phoceensis 1, B. rattimassiliensis 1, and B. tribocorum 1) infecting R. rattus rodents and their ectoparasites. We fit standard epidemiological models to species-specific age-prevalence data for the four Bartonella spp. with sufficient data, thus quantifying age-structured force of infection. Known zoonotic agents, B. elizabethae 1 and 2, were best described by models exhibiting high forces of infection in early age class individuals and allowing for recovery from infection, while B. phoceensis 1 and B. rattimassiliensis 1 were best fit by models of lifelong infection without recovery and substantially lower forces of infection. Nested sequences of B. elizabethae 1 and 2 were recovered from rodent hosts and their Synopsyllus fonquerniei and Xenopsylla cheopsis fleas, with a particularly high prevalence in the outdoor-dwelling, highland-endemic S. fonquerniei. These findings expand on force of infection analyses to elucidate the ecological niche of the zoonotic Bartonella elizabethae complex in Madagascar, hinting at a potential vector role for S. fonquerniei. Our analyses underscore the uniqueness of such ecologies for Bartonella species, which pose a variable range of potential zoonotic threats.
巴尔通体属细菌通过节肢动物媒介传播，感染范围广泛的脊椎动物宿主，包括人类。我们调查了马达加斯加入侵的拉氏巨鼠宿主和相关节肢动物外寄生虫中潜在的人畜共患巴尔通体属细菌的传播动态和宿主-寄生虫-媒介关系。我们鉴定出感染拉氏巨鼠啮齿动物及其外寄生虫的五种不同的巴尔通体属细菌（Bartonella elizabethae 1、Bartonella elizabethae 2、Bartonella phoceensis 1、Bartonella rattimassiliensis 1 和 Bartonella tribocorum 1）。我们对具有足够数据的四种巴尔通体属细菌的物种特异性年龄流行率数据拟合了标准的流行病学模型，从而量化了年龄结构的感染力。已知的人畜共患病原体 B. elizabethae 1 和 2 被描述为在早期年龄组个体中具有高感染力且允许从感染中恢复的模型，而 B. phoceensis 1 和 B. rattimassiliensis 1 则被描述为终生感染且没有恢复和感染力显著降低的模型。从啮齿动物宿主及其 Synopsyllus fonquerniei 和 Xenopsylla cheopsis 跳蚤中回收了 B. elizabethae 1 和 2 的嵌套序列，其中在户外居住、高地特有的 S. fonquerniei 中，其流行率特别高。这些发现扩展了感染力分析，以阐明人畜共患的巴尔通体属伊丽莎白菌复合体在马达加斯加的生态位，暗示 S. fonquerniei 可能具有潜在的媒介作用。我们的分析强调了这些生态系统对巴尔通体属物种的独特性，这些物种构成了一系列不同的潜在人畜共患病威胁。
