Climate change to spur bat expansion, rabies virus spillover in US

Vampire bats may soon take up residence in the US and bring with them an ancient pathogen -- rabies virus.

Vampire bats are known carriers of rabies, a disease known for its high mortality rates and often considered the oldest pathogen known by humans, dating back 3,000 years.

The bats -- currently only found in Mexico and Central and South America -- are on the move, with the US being a viable home in 27 years.

"What we found was that the distribution of vampire bats has moved northward across time due to past climate change, which has corresponded with an increase in rabies cases in many Latin American countries," said lead author Paige Van de Vuurst, doctoral student in Virginia Tech's Translational Biology, Medicine, and Health Graduate Programme.

The findings, published in the journal Ecography, concluded that with shifting seasonality -- the differences in temperature between the coldest and warmest seasons -- vampire bats have expanded their locations in search of more stable, temperate climates.

The researchers also found this expanded reach could be linked to a spillover of rabies.

To identify and track the bats, the team travelled all across Colombia to collect more than 70 samples of bat species.

They focused on the impacts of climate change on the distributional ecology of the common vampire bat Desmodus rotundus across the last century.

The retrospective analysis revealed a positive relationship between changes in climate and the northern expansion of the distribution of D. rotundus in North America.

Furthermore, the researchers also found a reduction in the standard deviation of temperatures at D. rotundus capture locations during the last century, expressed as a more consistent, less-seasonal climate in recent years.

“These results elucidate an association between D. rotundus range expansion and a continental-level rise in rabies virus spillover transmission from D. rotundus to cattle in the last 50 years of the 120-year study period,” they wrote in the paper.

“We conclude that the D. rotundus rabies system exemplifies the consequences of climate change augmentation at the wildlife-livestock-human interface, demonstrating how global change acts upon these complex and interconnected systems to drive increased disease emergence,” they said.