TO
BITE OR NOT TO BITE - DISCERNING BLOOD FEEDERS AND THEIR CATHOLIC COUNTERPARTS:
VECTOR-HOST INTERACTIONS GOVERNING EPIDEMIOLOGY OF WEST NILE VIRUS IN
G. Molaei and T. G.
Andreadis
Center for Vector Biology & Zoonotic Diseases
The
ABSTRACT
Eco-epidemiological studies of vectors-hosts interactions
are of vital importance to better understand the transmission dynamics of
mosquito-borne viruses. We investigated
host-feeding patterns of several mosquito species representing six genera, Aedes, Anopheles, Culex, Coquillettidia, Psorophora, and Uranotaenia,
and their potential involvement in enzootic and/or epidemic transmission of
West Nile virus in northeastern US, by taking advantage of a polymerase chain
reaction-based assay and sequencing portions of mitochondrial cytochrome b
gene. We found that Culex pipiens and Cx. restuans
predominantly feed on avian hosts (93% and 100%, respectively). Culex
salinarius fed frequently on both
mammals (53%) and birds (36%).
Mixed-blood meals were detected in 11% and 4% of Cx. salinarius and Cx. pipiens,
respectively. Culiseta melanura fed
predominantly on avian species (89.6%) but exhibited some inclination for
mammalian blood (4.2%) including humans.
American robin was the most common source of avian blood, followed by
grey catbird, mourning dove, house sparrow and a few other mostly Passeriformes
birds. Analyses of engorged Aedes vexans revealed that 92.4% of individuals acquired blood solely
from mammalian and 2.5% from avian hosts.
Mixed bloodmeals from both avian and mammalian hosts were detected in 5%
of individuals of this species.
Examination of engorged An. quadrimaculatus and An. punctipennis revealed
a mammalophilic nature (96%-100%) in these Anopheline
mosquitoes with little or no inclination for avian hosts. Other relatively common mosquito species in
the region acquired blood meals predominately from mammals with the exception
of Cx. territans, which obtained bloodmeals from all four classes of
vertebrates including birds, reptiles, amphibians, and mammals. White-tailed deer was the most common source
of blood meal for the mammalophilic mosquitoes.
Human-derived bloodmeals were also identified from some mosquito
species. Epidemiological significance of
spatio-temporal variations in host feeding patterns of these mosquitoes, and relative
contribution of vertebrate hosts to WNV maintenance and amplification will be
discussed.
Key words. Mosquito, host-feeding pattern, mitochondrial
cytochrome b gene, West Nile virus,