Rabies is likely to appear on the Pacific coast of Peru, an area where it currently does not occur, within four years, according to a report by an international team of researchers just published in the Proceedings of the National Academy of Sciences.
The authors, led by Daniel Streicker of the University of Glasgow and UGA, combined genetic analysis of vampire bats and rabies virus strains from across Peru to gain insights into how the virus spreads. They found that it is most likely carried from one area to another by infected male vampire bats that leave their original colonies upon reaching maturity.
Because tracking infected vampire bats in real time is logistically impractical at best, Streicker and his colleagues collected molecular genetic data from bats and the rabies virus to explore historical patterns of the virus’ spread.
To analyze vampire bat genetics, they used tissue samples from 468 bats collected from across Peru between 2008 and 2013. They looked at two kinds of DNA: nuclear DNA, which is inherited from both parents, and mitochondrial DNA, inherited only from the mother.
The researchers found that bats with the same nuclear DNA signature were clustered into just three separate geographic regions. The spatial distribution of these three lineages was strikingly similar to the three genetic groups of rabies virus.
“In a nutshell, this shows that male vampire bats are likely responsible for dispersing rabies across the landscape at the continent level,” said study co-author Sonia Altizer of the UGA Odum School of Ecology.
By taking into account the collection dates of rabies virus samples, Streicker and his colleagues were able to reconstruct the velocity of the historical spread of the virus across the country. Using these estimates combined with detailed maps of Peru’s landscape features, they developed a forecast for likely future rabies invasions. Based on the historic rate of spread, the researchers calculated that rabies virus could reach Peru’s Pacific coast by June 2020.