The threat of plague in Central Asia may be increasing owing to climate change.

Professor Nils Christian Stenseth and colleagues, including Wellcome Trust-funded researcher Vladimir Ageyev, have found that warmer spring temperatures and wetter summers in Central Asia affect the prevalence of Yersinia pestis, the bacterium that causes plague, in the great gerbil population. Most strikingly, an increase of 1°C in spring temperatures increases prevalence by more than 50 per cent.

The combination of higher temperature and humidity during these seasons causes flea generations to overlap, making it easier for Y. pestis to be spread between animals. In addition, the numbers of great gerbils, the primary host of plague in the desert regions of Central Asia, are also known to be influenced by climate changes. This combination of effects leads to the threshold density condition for plague being reached more often, increasing the likelihood of an outbreak of plague in humans.

These insights may also shed light on the emergence of the Black Death in Europe and the plague’s Third Pandemic, which affected Eastern countries in the mid-19th century. They may have spread from Central Asia during warmer and wetter periods.

Image: Rhombomys opimus, the great gerbil. © D Evans/Courtesy of the International Health Image Collection.

External links

• Stenseth NC et al. Plague dynamics are driven by climate variation. Proc Natl Acad Sci USA 2006;103(35):13110–5