Host Feeding Patterns of <I>Culex</I> Mosquitoes (Diptera: Culicidae) in East Baton Rouge Parish, Louisiana

Abstract

Host feeding patterns were examined for four species of Culex mosquitoes collected from 18 sites in or adjacent to East Baton Rouge Parish, LA, from November 2002 to October 2004. Host DNA from 37 bloodfed Culex coronator Dyar and Knab, 67 bloodfed Cx. salinarius Coquillett, 112 bloodfed Cx. nigripalpus Theobald, and 684 bloodfed Cx. quinquefasciatus Say were identified. The percentages of bloodmeals containing mammalian DNA were 94.6% for Cx. coronator, 82.1% for Cx. salinarius, 66.1% for Cx. nigripalpus, and 40.1% for Cx. quinquefasciatus. Human DNA was detected in 7% of the bloodmeals from Cx. quinquefasciatus and 2.7% of the bloodmeals from Cx. nigripalpus. The northern cardinal was the most frequent avian host of Cx. quinquefasciatus and Cx. nigripalpus. In 2003 and 2004, there was no significant relationship from May through October between the proportion of Cx. quinquefasciatus feeding on mammalian hosts and the date of collection. Of the six avian species most frequently fed on by Cx. quinquefasciatus, the northern cardinal, northern mockingbird, common grackle, and brown thrasher were fed on more frequently than expected based on their abundance. House sparrows were fed on less frequently than expected based on their abundance. These data support the conclusions of previous studies that Cx. quinquefasciatus is the most important vector for both the enzootic amplification and transmission of West Nile virus to humans in southern Louisiana.

Ecology of Potential West Nile Virus Vectors in Southeastern Louisiana: Enzootic Transmission in the Relative Absence of Culex quinquefasciatus

“…nigripalpus in enzootic amplification of WNV may be limited by its seasonality of host-seeking and the high percentage of mammalian blood meals taken by this species. 40 In this study, Cx. nigripalpus was not seen in light traps before July, and 66% of identified blood meals were from mammalian sources (2.7% from humans).…”

“…quinquefasciatus blood meals, but this result, combined with a high percentage of blood meals taken on known avian amplifier hosts, indicated a primary role for this species as an enzootic and epidemic vector. 40 Because Cx. quinquefasciatus was not commonly collected, our results may be most pertinent to understanding enzootic transmission of WNV in rural areas with a paucity of primary vectors such as Cx.…”

“…36 The likely explanation for this result is that~50% of avian blood meals identified in engorged Cx. salinarius were from passerine species, 40 two of which, the northern cardinal (Cardinalis cardinalis) and the northern mockingbird (Mimus polyglottos), are competent WNV amplifier hosts. 51 Among the potential mechanisms advanced to explain WNV overwintering is continued low-level transmission between mosquitoes and birds.…”

Entomologic Investigations during an Outbreak of West Nile Virus Disease in Maricopa County, Arizona, 2010

“…quinquefasciatus blood-feeding behavior in other parts of the United States have found that 52.5% of feeds were mammalian (0.4% human) in Harris County, TX, 20 11.6% mammalian (1.9% human) in southern California, 14 and 40.1% mammalian (7% human) in East Baton Rouge, LA. 29 However, our data on blood meal host preferences need to be interpreted cautiously because they represent a snapshot of host preferences taken during a brief period approximately mid-way through the outbreak. Also, we did not conduct bird or mammal censuses in our study areas to quantify availability of various host species.…”

A Multi-Year Study of Mosquito Feeding Patterns on Avian Hosts in a Southeastern Focus of Eastern Equine Encephalitis Virus

“…1 Recent research has emphasized that some bird species are overused relative to their local availability by vector mosquitoes as blood-meal sources [2][3][4][5][6][7] and that overuse of certain avian species could influence the transmission of pathogens. 8 For example, temporal and spatial patterns of American robin ( Turdus migratorius ) abundance have been associated with variability of the rate of human cases of West Nile virus (WNV) and prevalence of WNV in mosquito populations.…”