Bubonic Plague Outbreak Investigation in the Endemic District of Tsiroanomandidy - Madagascar, October 2014

Background: Plague remains a major public health problem in Madagascar. Faced with reports of plague cases and deaths in Tsiroanomandidy district, we performed an investigation in October 2014. Our aim was to describe the plague outbreak and to improve the national plague control strategies. Methods: We used the National plague control program case definition. We identified cases from outpatient registers and collected socio-demographic and clinical information. Plague circulation was determined through a retrospective environmental survey of rodents and vectors. Results: From August 1st to October 12th 2014, we identified 30 cases of which 13 deaths in 7 out of 17 municipalities; 18 were confirmed, 6 probable, and 6 suspected cases. The sex ratio (M/F) was 4:1. Yersinia pestis was isolated from Rattus rattus in one municipality. Flea index was 2.3. We collected 45 fleas through a trap set in a house 6 hours after insecticide spraying. Conclusion: The presence of infected flea and rodent maintain the persistence of plague in the municipalities investigated. There is a high risk of plague transmission to humans. This study showed that rodent and flea information are important for plague control strategies.