Nils Chr. Stenseth

Centre for Ecological and Evolutionary Synthesis (CEES)               
Department of Biology               
University of Oslo               
P.O. Box 1066 Blindern
N-0316 Oslo
Norway

The bacterium Yersinia pestis causes bubonic plague. In Central Asia, where human plague is still reported regularly, the bacterium is common in natural populations of great gerbils. By way of introduction, I will summarize the ecology of the plague system in Central Asia. I will then summarize finding based upon analysis of field data from 1949-1995, showing that Y. pestis prevalence in gerbils increases with warmer springs and wetter summers: a 1ºC increase in spring is predicted to lead to more than a 50% increase in prevalence. Climatic conditions favouring plague apparently existed in this region at the onset of the Black Death as well as when the most recent plague pandemic arose in the same region, and are expected to continue or become more favourable as a result of climate change.