Avian roosting behavior influences vector-host interactions for West Nile virus hosts.

William M Janousek,Peter P Marra,A Kilpatrick

doi:10.1186/1756-3305-7-399

Abstract

BackgroundExtensive work has shown that vectors almost never feed at random. Often, a subset of individual hosts and host species are fed on much more frequently than expected from their abundance and this can amplify pathogen transmission. However, the drivers of variation in contact patterns between vectors and their hosts are not well understood, even in relatively well-studied systems such as West Nile virus (WNV).MethodsWe compared roosting height and roost aggregation size of seven avian host species of WNV with patterns of host-seeking mosquito (Culex pipiens) abundance at communal and non-communal roost sites.ResultsFirst, host-seeking mosquito abundance increased with height and paralleled increased mosquito feeding preferences on species roosting higher in the tree canopy. Second, there were several hundred-fold fewer mosquitoes per bird trapped at American robin (Turdus migratorius) communal roosts compared to non-communal roost sites, which could reduce transmission from and to this key amplifying host species. Third, seasonal changes in communal roost formation may partly explain observed seasonal changes in mosquito feeding patterns, including a decrease in feeding on communal roosting robins.ConclusionsThese results illustrate how variation in habitat use by hosts and vectors and social aggregation by hosts influence vector-host interactions and link the behavioral ecology of birds and the transmission of vector-borne diseases to humans.

Highlights

Extensive work has shown that vectors almost never feed at random
Avian roosting and mosquito host-seeking behavior We deployed 213 radio transmitters nearly four-fold more than previous studies on West Nile virus (WNV) host behavior [40,41,55], and quantified roosting behavior of 91 individuals of six species from July-September
Cx. pipiens host-seeking mosquito abundance increased with trap height (Figure 1b, generalized linear mixed-effects model with Poisson distribution and log-link, χ2 = 24.51, df = 2, P < 0.001)

Summary

Introduction

Extensive work has shown that vectors almost never feed at random. Often, a subset of individual hosts and host species are fed on much more frequently than expected from their abundance and this can amplify pathogen transmission. The behavioral ecology of hosts can play a significant role in determining pathogen transmission dynamics. For diseases where transmission is direct, host foraging ecology, habitat preference, and social interactions, including mating strategy, can influence the probability of contact with an infected host or environment and create hotspots for transmission [1,2,3,4]. Most studies exploring the influence of host behavior on vector contact rates have examined how human behavior influences the transmission of pathogens causing malaria, dengue fever, and Chagas disease [7,8,9]. The importance of these factors, as well as host habitat use and aggregation in determining the extent to which vectors successfully move across the landscape to maximize feeding success is unknown

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Conclusion