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Vector competence of Culex pipiens quinquefasciatus (Diptera: Culicidae) for West Nile virus isolates from Florida
Author(s) -
Richards Stephanie L.,
Anderson Sheri L.,
Lord Cynthia C.
Publication year - 2014
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/tmi.12277
Subject(s) - biology , culex quinquefasciatus , titer , virology , vector (molecular biology) , veterinary medicine , virus , west nile virus , genotype , larva , medicine , ecology , gene , aedes aegypti , genetics , recombinant dna
Objectives To assess vector competence (infection, dissemination and transmission) of Culex pipiens quinquefasciatus for Florida (FL) West Nile virus (WNV) isolates. Methods West Nile virus isolates (WN‐FL‐03: NY99 genotype; WN‐FL‐05‐558, WN‐FL‐05‐2186, WN‐FL‐05‐510: WN02 genotype) collected from different regions of FL were used for vector competence experiments in Cx. p. quinquefasciatus from Alachua County and Indian River County in FL. Mosquitoes from both colonies were fed blood containing 7.9 ± 0.2 log 10 plaque‐forming units WNV/ml ± SE and incubated at 28 °C for 14 days. Vector competence, including rates of infection, dissemination, and transmission, was compared between colonies for WN‐FL‐03 using chi‐squared . Virus titres in bodies, legs and saliva were compared using anova . Daily measurements of in vitro replication of WNV isolates were evaluated in Vero cells so that a standardised virus dose for each isolate could be delivered to mosquitoes. Results Infection and dissemination rates were high (≥95%) and not affected by isolate or colony (infection, P = 0.679; dissemination, P = 0.799). Transmission rates were low (≤20%), detected in one colony and affected by isolate ( P = 0.008). Body and leg titres differed between isolates (body titre, P = 0.031; leg titre, P = 0.044) and colonies (body titre, P = 0.001; leg titre, P = 0.013) while saliva titre did not differ between isolates ( P = 0.462). Conclusions Variation in vector competence of mosquito populations may be attributed, in part, to exposures to WNV with genetic differences leading to different rates of replication in mosquitoes. Evaluation of vector competence for different WNV isolates may help us understand vector–virus interactions and, hence, the role of vectors in complex virus transmission cycles in nature.