West Nile Virus Prevalence across Landscapes Is Mediated by Local Effects of Agriculture on Vector and Host Communities

Abstract

Arthropod-borne viruses (arboviruses) threaten the health of humans, livestock, and wildlife. West Nile virus (WNV), the world’s most widespread arbovirus, invaded the United States in 1999 and rapidly spread across the county. Although the ecology of vectors and hosts are key determinants of WNV prevalence across landscapes, the factors shaping local vector and host populations remain unclear. Here, we used spatially-explicit models to evaluate how three land-use types (orchards, vegetable/forage crops, natural) and two climatic variables (temperature, precipitation) influence the prevalence of WNV infections and vector/host distributions at landscape and local spatial scales. Across landscapes, we show that orchard habitats were associated with greater prevalence of WNV infections in reservoirs (birds) and incidental hosts (horses), while increased precipitation was associated with fewer infections. At local scales, orchard habitats increased the prevalence of WNV infections in vectors (mosquitoes) and the abundance of mosquitoes and two key reservoir species, the American robin and the house sparrow. Thus, orchard habitats benefitted WNV vectors and reservoir hosts locally, creating focal points for the transmission of WNV at landscape scales in the presence of suitable climatic conditions.

Impacts of Migratory Sandhill Cranes (Grus canadensis) on Microbial Water Quality in the Central Platte River, Nebraska, USA

“…In general, however, avian diseases such as psittacosis are considered more likely than legionellosis following exposures to birds (Gacouin et al 2012). In addition, emerging avian zoonoses such as West Nile virus appear largely associated with corvids, the American robin, and the house sparrows, not waterfowl (Dridi et al 2013;Crowder et al 2013;Reisen et al 2013;Valiakos et al 2012). Lastly, despite the concern over avian influenza virus zoonosis, in the current study, the lack of avian influenza virus detection could have resulted from insufficient sample volumes being examined and that this virus does not persist in the Platte River environment.…”

Landscape, demographic and climatic associations with human West Nile virus occurrence regionally in 2012 in the United States of America

“…WNV is an arbovirus maintained primarily in a bird-mosquito-bird transmission cycle with larger mammals, such as humans, being considered incidental, or dead-end hosts as they do not sufficiently amplify the virus for further transmission (Gould and Fikrig, 2004). Although the virus has been detected in up to 65 different mosquito species (Peterson et al, 2013), a much smaller number of mosquito species are considered the primary vectors responsible for transmission to humans. The distributions of these vectors vary across the country due to biotic and abiotic requirements of the species.…”

Global Climate Change and Children’s Health

“…120 120 Precipitation has also been shown to affect mosquito populations and prevalence of West Nile infections, although results have been conflicting. [121][122][123][124] Additional research on West Nile ecology in the setting of climate change is needed.…”