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

Abstract

Vaccines that autonomously transfer among individuals have been proposed as a strategy to control infectious diseases within inaccessible wildlife populations. However, rates of vaccine spread and epidemiological efficacy in real world systems remain elusive. Here, we investigated whether topical vaccines that transfer among individuals 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.