Ecological and anthropogenic drivers of rabies exposure in vampire bats: Implications for transmission and control

Background/Question/Methods

Despite extensive culling of common vampire bats (Desmodus rotundus) in Latin America, lethal human rabies outbreaks transmitted by this species are increasingly recognized and livestock rabies cases occur with striking frequency. Longitudinal studies of rabies dynamics within vampire bat populations have never been conducted, imposing serious limitations on understanding of natural viral maintenance and development of improved disease control strategies. To identify the individual and population level factors driving rabies virus transmission in vampire bats, we conducted a 4-year, capture-recapture study in 20 vampire bat colonies spanning 4 regions of Peru. Serological data and population estimates from mark-recapture studies were then used to inform mathematical models of rabies dynamics using a panel data approach. 

Results/Conclusions

Serology demonstrated the circulation of rabies virus in all regions in all years. Seroprevalence ranged from 3 to 28% and was highest in juvenile and sub-adult bats. Rabies virus exposure was independent of bat colony size, consistent with an absence of population density dependent thresholds for viral invasion and extinction. Culling campaigns implemented during our study failed to reduce seroprevalence and were perhaps counterproductive for disease control due to the targeted removal of adults, but greater importance of young bats for transmission. Preliminary results from mathematical models parameterized from our field data indicated a high sensitivity of transmission dynamics to immigration, suggesting that metapopulation dynamics might be crucial for long-term viral maintenance. These findings provide new insights into the mechanisms of rabies virus maintenance in vampire bats and highlight the need for ecologically informed approaches to rabies prevention in Latin America.