Modeling the epidemiological history of plague in Central Asia: Palaeoclimatic forcing on a disease system over the past millennium
1 Centre for Ecological and Evolutionary Synthesis (CEES), Dept. of Biology, University of Oslo, P.O. Box 1066, N-0316 Oslo, Norway
2 School of Biological Sciences, University of Liverpool, Liverpool L69 7ZB, UK
3 Department of Geography, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
4 Dendro Sciences Unit, Swiss Federal Research Institute WSL, Switzerland
5 Dept. of Biology, University of Antwerp, Groenenborgerlaan 171 B-2020, Antwerp, Belgium
6 Danish Pest Infestation Laboratory, University of Aarhus, Dept. of Integrated Pest Management, Skovbrynet 14, DK-2800 Kongens Lyngby, Denmark
7 Key Laboratory of Desert and Desertification, Cold and Arid Regions, Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, Gansu Province, China
8 State Key Laboratory of Cryspheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
9 State Key Laboratory of Integrated Management on Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
BMC Biology 2010, 8:112 doi:10.1186/1741-7007-8-112Published: 27 August 2010
Human cases of plague (Yersinia pestis) infection originate, ultimately, in the bacterium's wildlife host populations. The epidemiological dynamics of the wildlife reservoir therefore determine the abundance, distribution and evolution of the pathogen, which in turn shape the frequency, distribution and virulence of human cases. Earlier studies have shown clear evidence of climatic forcing on contemporary plague abundance in rodents and humans.
We find that high-resolution palaeoclimatic indices correlate with plague prevalence and population density in a major plague host species, the great gerbil (Rhombomys opimus), over 1949-1995. Climate-driven models trained on these data predict independent data on human plague cases in early 20th-century Kazakhstan from 1904-1948, suggesting a consistent impact of climate on large-scale wildlife reservoir dynamics influencing human epidemics. Extending the models further back in time, we also find correspondence between their predictions and qualitative records of plague epidemics over the past 1500 years.
Central Asian climate fluctuations appear to have had significant influences on regional human plague frequency in the first part of the 20th century, and probably over the past 1500 years. This first attempt at ecoepidemiological reconstruction of historical disease activity may shed some light on how long-term plague epidemiology interacts with human activity. As plague activity in Central Asia seems to have followed climate fluctuations over the past centuries, we may expect global warming to have an impact upon future plague epidemiology, probably sustaining or increasing plague activity in the region, at least in the rodent reservoirs, in the coming decades.