Potential mammalian reservoirs in a bubonic plague outbreak focus in Mbulu District, northern Tanzania, in 2007

Abstract

This study investigated mammalian involvement in an outbreak of bubonic plague in Mbulu District, northern Tanzania, in March 2007. Plague is a rodent-borne zoonotic disease that spreads to humans through fleas infected with Yersinia pestis. Live trapping of rodents and shrews was conducted in fallow and crop fields, peri-domestic areas, houses and the neighboring forest reserve. Serum was separated from blood of captured animals. A rapid diagnostic test (RDT) was used for diagnosis of plague infection. An ELISA technique was used to detect antibodies against Yersinia pestis fraction 1 antigen. Wild and commensal rodents tested positive by RDT, indicating current infection in clinically healthy animals. The ELISA showed that wild rodents (Lophuromys flavopunctatus, Praomys delectorum, Graphiurus murinus, Lemniscomys striatus) and commensal rats (Rattus rattus, Mastomys natalensis, Mus minutoides) were Y. pestis-positive. Two potential vectors, Xenopsylla brasiliensis and Dinopsyllus lypusus, were found on wild and commensal rodents with a flea index of 1.8. We conclude that diverse potential mammalian reservoirs and efficient vectors of Y. pestis are present in abundance in Dongobesh and could lead to persistence and future plague outbreaks.