This article is from the WSSF 2015 AFRMA Rat & Mouse Tales news-magazine.

For centuries, rats and their fleas have been the blame for the Black Death which first happened in the 14th century medieval Europe. This was widely believed to have been caused by bacterium transported by fleas attached to black rats. Warm weather was thought to be connected to the outbreaks. In a new study though, researchers didn’t find a relationship between the climate changes and the outbreaks in Europe. Instead, they found evidence that the weather in Central Asia—ideal conditions for gerbils—where the plague originated, matched the outbreaks. Plague among gerbils is affected by the weather and correlates with the population density of the gerbils and fleas themselves.

Study published in PNAS (Proceedings of the National Academy of Sciences), 2015 Mar 10; 112(10): 3020–3025, Climate-driven introduction of the Black Death and successive plague reintroductions into Europe.

One article A Promising Moment for Rat-Human Relations by Emily Epstein in The Atlantic (many other articles done as well on this study). Thanks to Emily for letting us know about this.