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Desmodus; zoonotic disease; forecasting; sex bias; spatial dynamics
Abstract:
Anticipating how epidemics will spread across landscapes requires
understanding host dispersal events that are notoriously difficult to
measure. Here, we contrast host and virus genetic signatures to
resolve the spatiotemporal dynamics underlying geographic expansions
of vampire bat rabies virus (VBRV) in Peru. Phylogenetic
analysis revealed recent viral spread between populations that,
according to extreme geographic structure in maternally inherited
host mitochondrial DNA, appeared completely isolated. In contrast,
greater population connectivity in biparentally inherited nuclear
microsatellites explained the historical limits of invasions, suggesting
that dispersing male bats spread VBRV between genetically
isolated female populations. Host nuclear DNA further indicated
unanticipated gene flow through the Andes mountains connecting
the VBRV-free Pacific coast to the VBRV-endemic Amazon rainforest.
By combining Bayesian phylogeography with landscape resistance
models, we projected invasion routes through northern Peru that
were validated by real-time livestock rabies mortality data. The first
outbreaks of VBRV on the Pacific coast of South America could occur
by June 2020,which would have serious implications for agriculture,
wildlife conservation, and human health. Our results show that
combining host and pathogen genetic data can identify sex biases
in pathogen spatial spread, which may be a widespread but underappreciated
phenomenon, and demonstrate that genetic forecasting
can aid preparedness for impending viral invasions.