Background
Plague is still a major public health concern in Madagascar despite the effort to reduce human cases and understand its epidemiology. In several localities known as plague foci, human cases are reported but the origin of the infection is most on the time unknown. In the present study, we report the presence of different genotypes of Yersinia pestis co-occurring in the same locality.
Methods
Human case was sampled in October 2016 and sent to the Central Laboratory for Plague for confirmation. Further, we undertook small mammal sampling to identify the circulation of plague in reservoirs. Isolated strains from human case, rodents as well as some archived strains from the same locality were combined with previously published strains to document the genotype of circulating strains. Further, blood sample from rodents were collected for seroprevalence analysis.
Results
In 2016, two different strains of Y. pestis from a human case and a reservoir circulated concurrently in the Ambohitromby commune (Ankazobe District) based on plague investigation. One type had been persisting there for more than 10 years but at least one other type may have been recently introduced. Seroprevalence of plague in rodents indicates that portion of the local murine population may resist to plague. These findings have implications for plague public health investigations and surveillance in Madagascar. Multiple distinct types of Y. pestis were circulating concurrently in the Ambohitromby commune (Ankazobe District) in Madagascar. Three strains genotype are now documented in Ambohitromby with the strain isolated in rats being a new genotype which is probably new to this locality or unobserved in previous years.