Abstract
After the acute infection period, birds persistently infected with West Nile virus (family Flaviviridae, genus Flavivirus, WNV) occasionally shed virus into the bloodstream, but these virions normally are inactivated by neutralizing antibody. The current work tested the hypothesis that these host neutralizing antibodies protect mosquito vectors from WNV infection and reevaluated the minimum WNV infectious dose necessary to infect Culex tarsalis Coquillett. To determine whether host antibodies protect mosquitoes from infection, Cx. tarsalis and Culex stigmatosoma Dyar were fed bloodmeals containing avian blood, WNV, and sera with or without WNV-specific neutralizing antibodies. When viral particles were completely bound by antibody, mosquitoes were protected from infection; however, when incompletely bound, WNV titers as low as 10 2.3 plaque-forming units (pfu)/ml resulted in 5% infection. These data indicated that avian antibodies were protective to mosquito vectors and were not dissociated during digestion. Because recrudescent viremias may not attain the same magnitude as initial acute viremias, Cx. tarsalis vector competence was reevaluated focusing on the fate of low-titered bloodmeals. Females were evaluated for vector competence after ingesting bloodmeals containing 102.2, 103.4, 104.5,10 5.5, or 106.5 WNV pfu/ml. Infection increased with bloodmeal titer, with 1% of the mosquitoes ingesting 103.4 pfu/ml and 45% of the mosquitoes ingesting 106.5 pfu/ml developing disseminated infections. The incomplete neutralization of recrudescent virus may be sufficient to infect a low proportion of competent blood-feeding Culex mosquitoes and perhaps allow persistently infected birds to provide a mechanism for arbovirus overwintering.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 895-902 |
| Number of pages | 8 |
| Journal | Journal of Medical Entomology |
| Volume | 49 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jul 1 2012 |
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Keywords
- antibody
- Culex
- recrudescence
- vector competence
- West Nile virus
ASJC Scopus subject areas
- Insect Science
- veterinary(all)
- Infectious Diseases
- Parasitology
Cite this
Importance of recrudescent avian infection in west nile virus overwintering : Incomplete antibody neutralization of virus allows infrequent vector infection. / Wheeler, Sarah S.; Vineyard, Meighan P.; Barker, Chris; Reisen, William.
In: Journal of Medical Entomology, Vol. 49, No. 4, 01.07.2012, p. 895-902.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Importance of recrudescent avian infection in west nile virus overwintering
T2 - Incomplete antibody neutralization of virus allows infrequent vector infection
AU - Wheeler, Sarah S.
AU - Vineyard, Meighan P.
AU - Barker, Chris
AU - Reisen, William
PY - 2012/7/1
Y1 - 2012/7/1
N2 - After the acute infection period, birds persistently infected with West Nile virus (family Flaviviridae, genus Flavivirus, WNV) occasionally shed virus into the bloodstream, but these virions normally are inactivated by neutralizing antibody. The current work tested the hypothesis that these host neutralizing antibodies protect mosquito vectors from WNV infection and reevaluated the minimum WNV infectious dose necessary to infect Culex tarsalis Coquillett. To determine whether host antibodies protect mosquitoes from infection, Cx. tarsalis and Culex stigmatosoma Dyar were fed bloodmeals containing avian blood, WNV, and sera with or without WNV-specific neutralizing antibodies. When viral particles were completely bound by antibody, mosquitoes were protected from infection; however, when incompletely bound, WNV titers as low as 10 2.3 plaque-forming units (pfu)/ml resulted in 5% infection. These data indicated that avian antibodies were protective to mosquito vectors and were not dissociated during digestion. Because recrudescent viremias may not attain the same magnitude as initial acute viremias, Cx. tarsalis vector competence was reevaluated focusing on the fate of low-titered bloodmeals. Females were evaluated for vector competence after ingesting bloodmeals containing 102.2, 103.4, 104.5,10 5.5, or 106.5 WNV pfu/ml. Infection increased with bloodmeal titer, with 1% of the mosquitoes ingesting 103.4 pfu/ml and 45% of the mosquitoes ingesting 106.5 pfu/ml developing disseminated infections. The incomplete neutralization of recrudescent virus may be sufficient to infect a low proportion of competent blood-feeding Culex mosquitoes and perhaps allow persistently infected birds to provide a mechanism for arbovirus overwintering.
AB - After the acute infection period, birds persistently infected with West Nile virus (family Flaviviridae, genus Flavivirus, WNV) occasionally shed virus into the bloodstream, but these virions normally are inactivated by neutralizing antibody. The current work tested the hypothesis that these host neutralizing antibodies protect mosquito vectors from WNV infection and reevaluated the minimum WNV infectious dose necessary to infect Culex tarsalis Coquillett. To determine whether host antibodies protect mosquitoes from infection, Cx. tarsalis and Culex stigmatosoma Dyar were fed bloodmeals containing avian blood, WNV, and sera with or without WNV-specific neutralizing antibodies. When viral particles were completely bound by antibody, mosquitoes were protected from infection; however, when incompletely bound, WNV titers as low as 10 2.3 plaque-forming units (pfu)/ml resulted in 5% infection. These data indicated that avian antibodies were protective to mosquito vectors and were not dissociated during digestion. Because recrudescent viremias may not attain the same magnitude as initial acute viremias, Cx. tarsalis vector competence was reevaluated focusing on the fate of low-titered bloodmeals. Females were evaluated for vector competence after ingesting bloodmeals containing 102.2, 103.4, 104.5,10 5.5, or 106.5 WNV pfu/ml. Infection increased with bloodmeal titer, with 1% of the mosquitoes ingesting 103.4 pfu/ml and 45% of the mosquitoes ingesting 106.5 pfu/ml developing disseminated infections. The incomplete neutralization of recrudescent virus may be sufficient to infect a low proportion of competent blood-feeding Culex mosquitoes and perhaps allow persistently infected birds to provide a mechanism for arbovirus overwintering.
KW - antibody
KW - Culex
KW - recrudescence
KW - vector competence
KW - West Nile virus
UR - http://www.scopus.com/inward/record.url?scp=84863762578&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84863762578&partnerID=8YFLogxK
U2 - 10.1603/ME11286
DO - 10.1603/ME11286
M3 - Article
C2 - 22897050
AN - SCOPUS:84863762578
VL - 49
SP - 895
EP - 902
JO - Journal of Medical Entomology
JF - Journal of Medical Entomology
SN - 0022-2585
IS - 4
ER -