Exposure to Yersinia pestis increases resistance to plague in black rats and modulates transmission in Madagascar

• Published in: BMC Research Notes
• Main Authors: Andrianaivoarimanana, Voahangy, Rajerison, Minoarisoa, Jambou, Ronan
• Other Authors: Unité Peste - Plague Unit Antananarivo, Madagascar, Institut Pasteur de Madagascar, Réseau International des Instituts Pasteur (RIIP)-Réseau International des Instituts Pasteur (RIIP), Unité d'immunologie des maladies infectieuses Antananarivo, Madagascar (IPM), Département Parasites et Insectes vecteurs - Department of Parasites and Insect Vectors, Institut Pasteur Paris, This work was funded by an internal grant from the Institut Pasteur de Madagascar. The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: Madagascar; Outbreak; F1 antigen; Plague; Rattus rattus; [SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases
• Online Access: https://hal-riip.archives-ouvertes.fr/pasteur-01968317; https://hal-riip.archives-ouvertes.fr/pasteur-01968317/document; https://hal-riip.archives-ouvertes.fr/pasteur-01968317/file/Exposure%20to%20Yersinia%20pestis%20increases%20resistance%20to%20plague%20in%20black%20rats_Andrianaivoarimanana%20et%20al_2018.pdf; https://doi.org/10.1186/s13104-018-3984-3

International audience OBJECTIVES:In Madagascar, plague (Yersinia pestis infection) is endemic in the central highlands, maintained by the couple Rattus rattus/flea. The rat is assumed to die shortly after infection inducing migration of the fleas. However we previously reported that black rats from endemic areas can survive the infection whereas those from non-endemic areas remained susceptible. We investigate the hypothesis that lineages of rats can acquire resistance to plague and that previous contacts with the bacteria will affect their survival, allowing maintenance of infected fleas. For this purpose, laboratory-born rats were obtained from wild black rats originating either from plague-endemic or plague-free zones, and were challenged with Y. pestis. Survival rate and antibody immune responses were analyzed.RESULTS:Inoculation of low doses of Y. pestis greatly increase survival of rats to subsequent challenge with a lethal dose. During challenge, cytokine profiles support activation of specific immune response associated with the bacteria control. In addition, F1 rats from endemic areas exhibited higher survival rates than those from non-endemic ones, suggesting a selection of a resistant lineage. In Madagascar, these results support the role of black rat as long term reservoir of infected fleas supporting maintenance of plague transmission.