Reservoir dynamics of rabies in Southeast Tanzania and the roles of cross-species transmission and domestic dog vaccination

Understanding the role of different species in the transmission of multi-host pathogens, such as rabies virus, is vital for effective control strategies. Across most of sub-Saharan Africa domestic dogs (Canis familiaris) are considered the reservoir for rabies, but the role of wildlife has been long debated. Here we explore the multi-host transmission dynamics of rabies across southeast Tanzania.

Between January 2011 and July 2019 data on probable rabies cases were collected in the regions of Lindi and Mtwara. Hospital records of animal-bite patients presenting to healthcare facilities were used as sentinels for animal contact tracing. The timing, location and species of probable rabid animals was used to reconstruct transmission trees to infer who infected whom and the relative frequencies of within- and between-species transmission.

During the study, 688 probable human rabies exposures were identified, resulting in 47 deaths. Of these exposures, 389 were from domestic dogs (56.5%) and 262 from jackals (38.1%). Over the same period 549 probable animal rabies cases were traced: 303 in domestic dogs (55.2%) and 221 in jackals (40.3%).

Although dog-to-dog transmission was most commonly inferred (40.5% of transmission events), a third of inferred events involved wildlife-to-wildlife transmission (32.6%) and evidence suggested some sustained transmission chains within jackal populations.

A steady decline in probable rabies cases in both humans and animals coincided with the implementation of widespread domestic dog vaccination during the first six years of the study. Following the lapse of this programme dog rabies cases began to increase in one of the northernmost districts.

Synthesis and applications: In southeast Tanzania, despite a relatively high incidence of rabies in wildlife and evidence of wildlife-to-wildlife transmission, domestic dogs remain essential to the reservoir of infection. Continued dog vaccination alongside improved surveillance would allow a fuller understanding of the role of wildlife in maintaining transmission in this area. Nonetheless, dog vaccination clearly suppressed rabies in both domestic dog and wildlife populations, reducing both public health and conservation risks and, if sustained, has potential to eliminate rabies from this region.

Methods
This dataset contains code and data to reproduce the analyses in the paper, however sensitive data (GPS locations and other identifiers) have been removed. Full methods are detailed in the paper.

明确不同物种在多宿主病原体（multi-host pathogens），如狂犬病病毒传播中的作用，对于制定高效防控策略至关重要。在撒哈拉以南非洲大部分地区，家犬（Canis familiaris）被认为是狂犬病的储存宿主，但野生动物在其中的作用长期存在争议。本研究聚焦坦桑尼亚东南部地区的狂犬病多宿主传播动态。

2011年1月至2019年7月期间，研究团队在林迪（Lindi）和姆特瓦拉（Mtwara）两地区收集疑似狂犬病病例数据。以就诊于医疗机构的动物咬伤患者的医院记录作为动物接触追踪的哨兵监测数据。通过疑似狂犬病动物的发病时间、感染地点及宿主物种信息，重建传播树以推断感染传播链，并计算种内与种间传播的相对频率。

研究期间共确认688起人类疑似狂犬病暴露事件，其中47例死亡。在这些暴露事件中，389起（56.5%）由家犬导致，262起（38.1%）由胡狼导致。同期共追踪到549起动物疑似狂犬病病例：家犬病例303例（55.2%），胡狼病例221例（40.3%）。

尽管研究推断的传播事件中以家犬间传播最为常见（占40.5%），但仍有三分之一的推断传播事件（32.6%）涉及野生动物间传播，且有证据显示胡狼种群内部存在持续的传播链。

研究前六年期间，随着大范围家犬疫苗接种计划的推行，人类与动物的疑似狂犬病病例数均持续下降。该计划终止后，最北部的一个地区家犬狂犬病病例数开始回升。

综合分析与应用启示：在坦桑尼亚东南部地区，尽管野生动物狂犬病发病率相对较高，且存在野生动物间传播的证据，但家犬仍是狂犬病感染储存宿主的核心组成部分。持续推进家犬疫苗接种并完善监测体系，将有助于更全面地阐明野生动物在维持该地区狂犬病传播中的作用。尽管如此，家犬疫苗接种已明确抑制了家犬与野生动物种群中的狂犬病疫情，同时降低了公共卫生与生物保护风险；若该措施得以持续推行，则有望在该地区根除狂犬病。

研究方法：本数据集包含可复现论文中分析过程的代码与原始数据，但已移除敏感数据（GPS定位信息及其他身份标识）。完整研究方法详见论文原文。