Patterns of mosquito and arbovirus community composition and ecological indexes of arboviral risk in the northeast United States

Background: In the northeast United States (U.S.), mosquitoes transmit a
number of arboviruses, including eastern equine encephalitis, Jamestown
Canyon, and West Nile that pose an annual threat to human and animal
health. Local transmission of each virus may be driven by the involvement
of multiple mosquito species; however, the specificity of these
vector-virus associations has not been fully quantified. Methodology: We
used long-term surveillance data consistently collected over 18 years to
evaluate mosquito and arbovirus community composition in the State of
Connecticut (CT) based on land cover classifications and mosquito
species-specific natural histories using community ecology approaches
available in the R package vegan. We then used binomial-error generalized
linear mixed effects models (GLMMs) to quantify species-specific trends in
arbovirus detections. Primary Results: The composition of
mosquito communities throughout CT varied more among sites than among
years, with variation in mosquito community composition among sites
explained mostly by a forested-to-developed-land-cover gradient. Arboviral
communities varied equally among sites and years, and only developed and
forested wetland land cover classifications were associated with the
composition of arbovirus detections among sites. Overall, the avian host
arboviruses, mainly West Nile and eastern equine encephalitis viruses,
displayed the most specific associations among species and sites, while in
contrast, the mammalian host arboviruses (including Cache Valley,
Jamestown Canyon, and Potosi viruses) associated with a more diverse mix
of mosquito species and were widely distributed throughout CT.
Conclusions: We find that avian arboviruses act as vector specialists
infecting a few key mosquito species that associate with discrete
habitats, while mammalian arboviruses are largely vector generalists
infecting a wide diversity of mosquito species and habitats in the
region. These distinctions have important implications for the
design and implementation of mosquito and arbovirus surveillance programs
as well as mosquito control efforts.