Environmental Sciences-Biological Sciences
Plague dynamics are driven by climate variation
( Generalized Threshold Mixed Model | historic and recent climatic conditions | time-series data | Yersinia pestis )

Nils Chr. Stenseth *, Noelle I. Samia , Hildegunn Viljugrein *, Kyrre Linné Kausrud *, Mike Begon ¶, Stephen Davis ||, Herwig Leirs ||**, V. M. Dubyanskiy , Jan Esper , Vladimir S. Ageyev , Nikolay L. Klassovskiy , Sergey B. Pole , and Kung-Sik Chan 
*Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, Norway; Department of Statistics and Actuarial Science, University of Iowa, Iowa City, IA 52242; ¶School of Biological Sciences, Biosciences Building, University of Liverpool, Liverpool L69 7ZB, United Kingdom; ||Evolutionary Biology Group, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium; **Danish Pest Infestation Laboratory, Department of Integrated Pest Management, Danish Institute of Agricultural Sciences, Skovbrynet 14, DK-2800 Kongens Lyngby, Denmark; Kazakh Scientific Centre for Quarantine and Zoonotic Diseases, Almaty, Kazakhstan; and Swiss Federal Research Institute (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland

Edited by James H. Brown, University of New Mexico, Albuquerque, NM, and approved June 28, 2006 (received for review March 26, 2006)

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 using field data from 1949-1995 and previously undescribed statistical techniques, we show that Y. pestis prevalence in gerbils increases with warmer springs and wetter summers: A 1°C increase in spring is predicted to lead to a >50% increase in prevalence. Climatic conditions favoring 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 they are expected to continue or become more favorable as a result of climate change. Threats of outbreaks may thus be increasing where humans live in close contact with rodents and fleas (or other wildlife) harboring endemic plague.