Ramasindrazana Beza, Harimalala Mireille, Rasoamalala Fanohinjanaharinirina, Martin Cynthia Haingotiana, Maminirina Lanto Andrianarijaona, Raritahiry Sylvie Claudia, Michaux Johan, Rajerison Minoarisoa, Linchant Julie, Walter Pierre, Kassié Daouda, Guis Hélène, Keatts Lucy, Jori Ferran
Plague Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar.
Ecole Doctorale Sciences de la Vie et de l'Environnement, Université d'Antananarivo, Antananarivo, Madagascar.
PLoS Negl Trop Dis. 2025 Nov 17;19(11):e0013710. doi: 10.1371/journal.pntd.0013710. eCollection 2025 Nov.
Plague, a zoonosis caused by Yersinia pestis, is endemic in Madagascar but knowledge on the epidemiological situation in the northern focus remains unclear. The aim of this study was to investigate the circulation of Y. pestis in terrestrial small mammals in north eastern Madagascar, where suspected plague outbreaks have been reported.
Sampling of terrestrial small mammals and their fleas was carried out in 22 trapping sites within 9 localities of the two sectors (1 and 3) of Makira Natural Park (MNP) and surroundings, from 2020 to 2022. Yersinia pestis was investigated in terrestrial small mammal spleen samples and their fleas using bacteriological, serological and molecular methods.
A total of 614 terrestrial small mammals composed of eight species and 1,754 individual fleas were collected following 4,880 trap-nights. The black rat (Rattus rattus) represented the majority (87.8%) of the small mammal species caught. Flea infestation rate was higher in sector 3 compared to sector 1. In sector 3, Xenopsylla brasiliensis, a plague vector, represented 66.4% of fleas identified. Further, one plague seropositive R. rattus individual, captured inside a house, and one Ctenocephalides felis specimen, collected on another R. rattus, was positive on PCR in this sector.
Despite low detection rates, we confirmed the circulation of Y. pestis in our study area (one rat seropositive and one flea PCR positive) and highlight the risk of potential human transmission. Our results also suggest that R. rattus contributes to the maintenance and transmission of plague in MNP, as described for other areas in Madagascar. Further, these findings contribute to documentation of the known geographic distribution of the endemic plague vector S. fonquerniei and X. brasiliensis.
The confirmation of the circulation of the Y. pestis through serological and molecular diagnostics in small mammals and fleas underscores the urgent need to assess awareness levels of risk factors and symptoms to monitor among local communities and health workers and ensure that trained rapid response teams are prepared to intervene promptly upon suspect case detection. The risk and epidemiology of plague circulation in remote rural areas of Madagascar remains insufficiently studied. Addressing this gap is crucial, as a more comprehensive understanding of the distribution and dynamics of the wild animal hosts, their vectors and host-vector interactions will enhance risk assessment and prevention for plague emergence and improve mitigation and early control of potential outbreaks.
鼠疫是由鼠疫耶尔森菌引起的一种人畜共患病，在马达加斯加呈地方性流行，但北部疫源地的流行病学情况仍不清楚。本研究的目的是调查在马达加斯加东北部有疑似鼠疫疫情报告的地区，鼠疫耶尔森菌在陆生小型哺乳动物中的传播情况。
2020年至2022年期间，在马基拉自然公园（MNP）两个区（1区和3区）及其周边9个地点的22个诱捕点对陆生小型哺乳动物及其跳蚤进行采样。采用细菌学、血清学和分子方法对陆生小型哺乳动物脾脏样本及其跳蚤中的鼠疫耶尔森菌进行调查。
经过4880个诱捕夜，共收集到614只由8个物种组成的陆生小型哺乳动物和1754只个体跳蚤。黑家鼠（Rattus rattus）占捕获的小型哺乳动物物种的大多数（87.8%）。3区的跳蚤感染率高于1区。在3区，鼠疫传播媒介巴西客蚤（Xenopsylla brasiliensis）占已鉴定跳蚤的66.4%。此外，在该区域内，在一所房屋内捕获的一只鼠疫血清阳性的黑家鼠个体，以及在另一只黑家鼠身上采集的一只猫栉首蚤（Ctenocephalides felis）标本，经PCR检测呈阳性。
尽管检出率较低，但我们在研究区域内证实了鼠疫耶尔森菌的传播（一只大鼠血清阳性和一只跳蚤PCR阳性），并强调了潜在人际传播的风险。我们的结果还表明，如马达加斯加其他地区所述，黑家鼠在马基拉自然公园鼠疫的维持和传播中发挥了作用。此外，这些发现有助于记录地方鼠疫传播媒介方氏沙鼠鼠疫杆菌（S. fonquerniei）和巴西客蚤已知的地理分布。
通过血清学和分子诊断在小型哺乳动物和跳蚤中证实鼠疫耶尔森菌的传播，突出了迫切需要评估当地社区和卫生工作者对风险因素和症状的认知水平，以进行监测，并确保训练有素的快速反应团队随时准备在发现疑似病例时迅速进行干预。马达加斯加偏远农村地区鼠疫传播的风险和流行病学仍研究不足。弥补这一差距至关重要，因为更全面地了解野生动物宿主、其传播媒介以及宿主-媒介相互作用的分布和动态，将加强对鼠疫出现的风险评估和预防，并改善对潜在疫情的缓解和早期控制。
