Goddard Laura B, Roth Amy E, Reisen William K, Scott Thomas W
Department of Entomology, Davis Arbovirus Research Unit, University of California, Davis, One Shields Ave., Davis, CA 95616, USA.
J Med Entomol. 2003 Nov;40(6):743-6. doi: 10.1603/0022-2585-40.6.743.
Three California Culex species previously identified as efficient laboratory vectors of West Nile (WN) virus were tested for their capability to vertically transmit WN virus. Wild-caught Culex pipiens pipiens L., Culex pipiens quinquefasciatus Say, and two populations of Culex tarsalis Coquillett females were inoculated intrathoracically with 10(2.7 +/- 0.1) plaque-forming units of WN virus. F1 progeny were reared at 18 degrees C and subsequently tested as adults for infectious virus on Vero cell culture. Virus was not detected in 197 pools comprising 4,884 Cx. p. pipiens. The minimum filial infection rate (MFIR) for Cx. p. quinquefasciatus was approximately 3.0/1,000 for 665 progeny tested in 28 pools. There was no virus detected in 102 pools of 2,453 progeny from Cx. tarsalis collected in Riverside County. The MFIR for Cx. tarsalis collected in Yolo County was approximately 6.9/1,000 for 2,165 progeny tested in 86 pools. Mosquito progeny infected vertically during the fall could potentially serve as a mechanism for WN virus to overwinter and initiate horizontal transmission the following spring.
对先前被鉴定为西尼罗河（WN）病毒高效实验室传播媒介的三种加利福尼亚库蚊进行了垂直传播WN病毒能力的测试。用10(2.7±0.1)个噬斑形成单位的WN病毒对野外捕获的致倦库蚊、淡色库蚊以及两个群体的塔尔西斯库蚊雌性进行胸腔内接种。F1代子代在18摄氏度下饲养，随后作为成虫在Vero细胞培养物上检测是否存在感染性病毒。在由4884只淡色库蚊组成的197个样本池中未检测到病毒。对28个样本池中检测的665只子代致倦库蚊而言，其最小子代感染率（MFIR）约为3.0/1000。在里弗赛德县采集的2453只塔尔西斯库蚊子代的102个样本池中未检测到病毒。对在约洛县采集的塔尔西斯库蚊而言，在86个样本池中检测的2165只子代的MFIR约为6.9/1000。秋季垂直感染的蚊子子代可能是WN病毒越冬并在次年春季引发水平传播的一种机制。
