Vector host-feeding preferences drive transmission of multi-host pathogens: West Nile virus as a model system

Abstract

Seasonal epizootics of vector-borne pathogens infecting multiple species are ecologically complex and difficult to forecast. Pathogen transmission potential within the host community is determined by the relative abilities of host species to maintain and transmit the pathogen and by ecological factors influencing contact rates between hosts and vectors. Increasing evidence of strong feeding preferences by a number of vectors suggests that the host community experienced by the pathogen may be very different from the local host community. We developed an empirically informed transmission model for West Nile virus (WNV) in four sites using one vector species (Culex pipiens) and preferred and non-preferred avian hosts. We measured strong feeding preferences for American robins (Turdus migratorius) by Cx. pipiens, quantified as the proportion of Cx. pipiens blood meals from robins in relation to their abundance (feeding index). The model accurately predicted WNV prevalence in Cx. pipiens at three of four sites. Sensitivity analysis revealed feeding preference was the most influential parameter on intensity and timing of peak WNV infection in Cx. pipiens and a threshold feeding index for transmission was identified. Our findings indicate host preferenceinduced contact heterogeneity is a key mediator of vector-borne pathogen epizootics in multi-species host communities, and should be incorporated into multi-host transmission models.

Supersuppression: Reservoir Competency and Timing of Mosquito Host Shifts Combine to Reduce Spillover of West Nile Virus

“…In addition, the Park: Water microhabitat type, which had the highest probability of seropositive birds, also had the highest WNV amplification fraction (80%) from American robins, with less than 6% of amplification from northern cardinals and song sparrows combined. Taken together, these results suggest that the absence of American robins, which have been considered "superspreaders" of WNV elsewhere, 13,14,37,45 combined with WNV amplification arising predominantly from northern cardinals and song sparrows, may be responsible for diminished WNV transmission in the urban forest patch microhabitats.…”

Estimating biologically relevant parameters under uncertainty for experimental within-host murine West Nile virus infection

“…Other related flaviviruses such as dengue virus, Zika virus and HCV are also human pathogens of public health relevance. While the transmission of WNV between hosts has been modelled [54][55][56][57], little attention has been paid to modelling the within-host dynamics of WNV. Here we have modified a within-host model first developed for influenza A infection [30] in order to describe WNV infection in mice.…”

Host compatibility rather than vector–host-encounter rate determines the host range of avian Plasmodium parasites

“…However, numerous studies have revealed an important interplay between host compatibility and the encounter rate in driving pathogen transmission dynamics over time [3], space [5] and between ecological communities that differ in structure [4,67]. Indeed, host range expansions also depend on the compatibility of novel hosts toward those parasites, and will not proceed if new host-parasite combinations are incompatible.…”

“…Mosquitoes, which are important vectors for a diversity of pathogens, are known to feed heterogeneously across hosts by using some species disproportionately, relative to their abundance [13][14][15]. This heterogeneity in mosquito-feeding patterns can strongly influence disease transmission dynamics [3,4,13,16]. Mosquito-feeding networks may also be compartmentalized [17], with certain vector species using a distinct subset of available host species [14,[18][19][20][21].…”

“…Assessing the relative strength of these filters is a fundamental step in determining mechanisms that govern the distribution of a parasite across hosts. Understanding factors that modulate host range is important because changes in these factors alter transmission dynamics [3][4][5] and introduce novel parasites to naive hosts, sometimes with devastating consequences [6].…”