Abortive vampire bat rabies infections in Peruvian peridomestic livestock

Author summary Rabies virus is the deadliest virus affecting mammals. In Latin America, rabies transmitted by vampire bats is one of the most recognized zoonoses affecting humans and livestock. For unknown reasons, species such as bats and cattle can produce antibodies against rabies that clear viral infection prior to the development of deadly clinical signs. However, the extend of this phenomenon in naturally exposed populations remains unknows. In this study, we detected anti-rabies antibodies among cattle and, for the first time, goats and sheep bitten by vampire bats across as large geographic area endemic of vampire bat rabies in South Peru. We also showed that the presence of antibodies in livestock can indicate the past and future levels of cattle mortality due to rabies in the area. Future research should resolve the within-host biology underlying clearance of rabies infections and evaluate if antibody detection of healthy animals can be used for monitoring vampire bat rabies risk. Rabies virus infections normally cause universally lethal encephalitis across mammals. However, 'abortive infections' which are resolved prior to the onset of lethal disease have been described in bats and a variety of non-reservoir species. Here, we surveyed rabies virus neutralizing antibody titers in 332 unvaccinated livestock of 5 species from a vampire bat rabies endemic region of southern Peru where livestock are the main food source for bats. We detected rabies virus neutralizing antibody titers in 11, 5 and 3.6% of cows, goats and sheep respectively and seropositive animals did not die from rabies within two years after sampling. Seroprevalence was correlated with the number of local livestock rabies mortalities reported one year prior but also one year after sample collection. This suggests that serological status of livestock can indicate the past and future levels of rabies risk to non-reservoir hosts. To our knowledge, this is the first report of anti-rabies antibodies among goats and sheep, suggesting widespread abortive infections among livestock in vampire bat rabies endemic areas. Future research should resolve the within-host biology underlying clearance of rabies infections. Cost-effectiveness analyses are also needed to evaluate whether serological monitoring of livestock can be a viable complement to current monitoring of vampire bat rabies risk based on animal mortalities alone.