Fluorescent biomarkers demonstrate prospects for spreadable vaccines to control disease transmission in wild bats

Vaccines that autonomously transfer among individuals have been proposed
as a strategy to control infectious diseases within wildlife populations.
However, understanding rates of spread and epidemiological efficacy in
real world systems remain elusive. Here, we investigated whether topical
vaccines that transfer among bats through social contacts can control
vampire bat rabies, a medically and economically important zoonosis in
Latin America. Field experiments in 3 Peruvian bat colonies which used
fluorescent biomarkers as a proxy for the bat-to-bat transfer and
ingestion of an oral vaccine revealed that vaccine transfer would increase
population-level immunity up to 2.6 times beyond the same effort using
conventional, non-spreadable vaccines. Mathematical models demonstrated
that observed levels of vaccine transfer would reduce the probability,
size, and duration of rabies outbreaks, even at low, but realistically
achievable levels of vaccine application. Models further predicted that
existing vaccines provide substantial advantages over culling bats, the
policy currently implemented in North, Central, and South America. Linking
field studies with biomarkers to mathematical models can inform how
spreadable vaccines may combat pathogens of health and conservation
concern prior to costly investments in vaccine design and testing.