Culling vampire bat colonies to stem the transmission of rabies in Latin America does little to slow the spread of the virus and could even have the reverse effect, according to Professor Pej Rohani and his colleagues.

Vampire bats transmit rabies virus throughout Latin America, causing thousands of livestock deaths each year, as well as occasional human fatalities. Poison and even explosives have been used since the 1960s in attempts to control vampire bat populations, but those culling efforts have generally failed.

Last year, a team of U-M researchers and their University of Georgia colleagues reported the results of a long-term vampire bat field study in Peru. Now, the same team has combined the field findings with new computer models of rabies transmission and data from infection studies using captive vampire bats to show that culling has minimal effect on containing the virus, and can, in some cases, actually increase its spread by driving infected bats into neighboring colonies.

The findings suggest that geographic coordination of vampire bat control efforts in Latin America—taking into account the interconnectedness of seemingly isolated colonies—might reduce transmission to humans and domestic animals. The team's new paper, published online Dec. 2, 2013 in the Proceedings of the National Academy of Sciences, also establishes that rabies is usually not lethal among vampire bats.

"In the paper last year, we demonstrated that bat colony size wasn't a predictor of rabies prevalence, which indicated that culling hadn't reduced transmission," said U-M population ecologist and epidemiologist Rohani, senior author of the PNAS paper.

The first author is Julie Blackwood, a former postdoctoral fellow in Rohani's lab who is now at Williams College. Coauthors of the PNAS paper are Daniel Streicker and Sonia Altizer of the University of Georgia.

Michigan News press release