Metapopulation dynamics of bubonic plague

Bubonic plague is widely regarded as a disease of mainly historical importa nce; however, with increasing reports of incidence(1-3) and the discovery o f antibiotic-resistant strains of the plague bacterium Yersinia pestis(4), it is re-emerging as a significant health concern(5,6). Here we bypass the conventional human-disease models, and propose that bubonic plague is drive n by the dynamics of the disease in the rat population. Using a stochastic, spatial metapopulation model, we show that bubonic plague can persist in r elatively small rodent populations from which occasional human epidemics ar ise, without the need for external imports. This explains why historically the plague persisted despite long disease-free periods, and how the disease re-occurred in cities with tight quarantine control. In a contemporary set ting, we show that human vaccination cannot eradicate the plague, and that culling of rats may prevent or exacerbate human epidemics, depending on the timing of the cull. The existence of plague reservoirs in wild rodent popu lations has important public-health implications for the transmission to ur ban rats and the subsequent risk of human outbreaks.