Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Vector Borne Zoonotic Dis. 2011 Aug;11(8):1099-105. doi: 10.1089/vbz.2010.0144. Epub 2011 Jan 22.
Culex flavivirus (CxFV) is an insect-specific flavivirus globally distributed in mosquitoes of the genus Culex. CxFV was positively associated with West Nile virus (WNV) infection in a case-control study of 268 mosquito pools from an endemic focus of WNV transmission in Chicago, United States. Specifically, WNV-positive Culex mosquito pools were four times more likely also to be infected with CxFV than were spatiotemporally matched WNV-negative pools. In addition, mosquito pools from residential sites characterized by dense housing and impermeable surfaces were more likely to be infected with CxFV than were pools from nearby urban green spaces. Further, 6/15 (40%) WNV-positive individual mosquitoes were also CxFV positive, demonstrating that both viruses can coinfect mosquitoes in nature. Phylogenetic analysis of CxFV from Chicago demonstrated a pattern similar to WNV, consisting of low global viral diversity and lack of geographic clustering. These results illustrate a positive ecological association between CxFV and WNV, and that coinfection of individual mosquitoes can occur naturally in areas of high flaviviral transmission. These conclusions represent a challenge to the hypothesis of super-infection exclusion in the CxFV/WNV system, whereby an established infection with one virus may interfere with secondary viral infection with a similar virus. This study suggests that infection with insect-specific flaviviruses such as CxFV may not exclude secondary infection with genetically distinct flaviviruses such as WNV, and that both viruses can naturally coinfect mosquitoes that are epidemic bridge vectors of WNV to humans.
库蚊黄病毒（CxFV）是一种在全球范围内分布于库蚊属蚊子中的昆虫特异性黄病毒。在美国西尼罗河病毒（WNV）传播的地方性流行地区，对 268 个蚊子池进行的病例对照研究表明，CxFV 与 WNV 感染呈正相关。具体而言，WNV 阳性的库蚊蚊子池感染 CxFV 的可能性是空间和时间匹配的 WNV 阴性池的四倍。此外，人口稠密且表面不渗透的住宅蚊子池比附近的城市绿地蚊子池更有可能感染 CxFV。此外，在 15 只（60%）WNV 阳性的个体蚊子中，有 6 只（60%）也呈 CxFV 阳性，这表明这两种病毒都可以在自然界中共同感染蚊子。来自芝加哥的 CxFV 的系统发育分析表明，与 WNV 相似的模式，即全球病毒多样性低且没有地理聚类。这些结果说明了 CxFV 和 WNV 之间存在积极的生态关联，并且个体蚊子的共同感染可能会在高黄病毒传播地区自然发生。这些结论对 CxFV/WNV 系统中的超级感染排斥假说提出了挑战，即一种病毒的既定感染可能会干扰类似病毒的二次病毒感染。本研究表明，感染昆虫特异性黄病毒（如 CxFV）可能不会排除与遗传上不同的黄病毒（如 WNV）的二次感染，并且这两种病毒都可以自然地共同感染蚊子，这些蚊子是 WNV 向人类传播的流行桥梁媒介。
