Host-Feeding Patterns of Suspected West Nile Virus Mosquito Vectors in Delaware, 2001–2002

Abstract

Paucity of data on host-feeding patterns and behavior of 43 mosquito species that are reported as suspected West Nile virus (WN) vectors has limited full evaluation of their vectorial capacity. Recent studies addressing this issue need additional confirmation and should also be expanded to include collections of species or subpopulations attracted to humans. We used 4 types of collection methods to collect mosquitoes, including omnidirectional Fay-Prince traps, Centers for Disease Control-type light traps, gravid traps, and human-landing collections. Mosquitoes were collected during 2 full WN transmission seasons in 2001 and 2002, at 9 different sites across Delaware. We collected from various habitats, including salt marshes, brackish water areas, woodlands, a tire dump, a racetrack, and a mushroom farm. Blood-meal analyses were performed on parous mosquitoes by using a sandwich-type enzyme-linked immunosorbent assay. We tested primarily for 5 common host species, including rabbits, dogs, deer, horses, and chickens. We obtained substantial host-feeding data from 8 mosquito species. The most mammalophilic species were Anopheles quadrimaculatus, Coquillettidia perturbans, and Aedes albopictus, whereas the most ornithophilic species was Culex pipiens. Aedes albopictus was the most anthropophilic species, whereas Ae. vexans and Cq. perturbans exhibited relatively low attraction to humans. Culex salinarius was the species with the most diverse host-feeding activity. Based on feeding behavior, Cx. pipiens and Cx. salinarius appear to be the most likely bridge vectors. Other species may have opportunities to be bridge vectors under special circumstances, as discussed in the paper.

Host Feeding Patterns ofCulexMosquitoes and West Nile Virus Transmission, Northeastern United States

“…These findings were consistent with prior host preference studies ( 8 , 9 , 16 , 20 ) and strongly support the view that this predominant "early season" species is most likely involved in initiation and amplification of WNV transmission among wild birds and rarely, if ever, feeds on humans in this region. This finding differs from a recent blood-meal analysis by Gingrich and Williams ( 19 ), who found that a limited number (n = 9) of Cx. restuans from Delaware were highly mammalophilic (9:1 mammal-to-bird ratio).…”

“…pipiens collected from suburban locales in nearby Westchester County, New York ( 9 ), but contrasts sharply with a recent study conducted in Delaware, where 69% of the blood meals taken by Cx. pipiens were from large mammals ( 19 ), which suggests a difference in host preference from more southern regions of its range.…”

Host-feeding pattern of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in heterogeneous landscapes of South Andaman, Andaman and Nicobar Islands, India

“…Affinity for mammalian hosts, excluding humans in invasive Ae. albopictus has been reported from Hawaii (Tempelis et al 1970), temperate regions of North America (Savage et al 1993), United States (Niebylski et al 1994;Gingrich and Williams 2005;Richards et al 2006), and Spain (Munoz et al 2011). The results from the present study are at variance from these observations because only 34 % of the blood-fed Ae.…”

Host Choice and West Nile Virus Infection Rates in Blood-Fed Mosquitoes, Including Members of theCulex pipiensComplex, from Memphis and Shelby County, Tennessee, 2002–2003

“…Similarly, Cx. restuans fed upon avian hosts 62% of the time in this study, while it was reported to be exclusively ornithophilic in Connecticut (Molaei et al 2006) and highly mammalophilic in Delaware (Gingrich and Williams 2005). This level of variation may in part reflect the limited number of specimens analyzed in some of the previous studies (Apperson et al 2004, Gingrich andWilliams 2005).…”

“…restuans fed upon avian hosts 62% of the time in this study, while it was reported to be exclusively ornithophilic in Connecticut (Molaei et al 2006) and highly mammalophilic in Delaware (Gingrich and Williams 2005). This level of variation may in part reflect the limited number of specimens analyzed in some of the previous studies (Apperson et al 2004, Gingrich andWilliams 2005). However it is also possible that these data reflect the fact that host feeding choice may vary widely within a single species from location to location, which may in turn affect the role that each species plays both as an enzootic and as a bridge vector in different regions.…”