ICMR-Vector Control Research Centre (Field Station), Kottayam, Kerala, 686 003, India.
ICMR- Vector Control Research Centre, Puducherry, 605 006, India.
Trans R Soc Trop Med Hyg. 2023 Dec 4;117(12):839-843. doi: 10.1093/trstmh/trad048.
Culex quinquefasciatus is a notorious vector known to transmit pathogens such as Wuchereria bancrofti (causing Lymphatic filariasis) and flaviviruses such as West Nile virus in India and St. Louis Encephalitis virus in the USA. It is the vector of the Rift Valley Fever virus, also on the African continent. Mosquitoes also harbor other non-pathogenic insect-specific flaviviruses (ISFs), such as Culex flavivirus (CxFV) and Aedes flavivirus. Recent studies have implicated ISFs interfering with the vectorial efficiency of the pathogenic arbo-viruses.
One hundred specimens of the Cx. quinquefasciatus population in two urban areas in Kerala State, India, were screened to have an understanding of the prevalence of these flaviviruses in this vector species. Viral RNA was extracted from individual specimens and was subjected to RT-PCR towards amplification of the CxFV non-structural protein 5 (NS5) gene.
Among the 100 specimens, 7.0% were found to be harboring CxFV infection. The phylogenetic analysis of the gene sequences showed that the virus isolates were genetically related to Kenya, with 98-99% sequence similarities.
This is the first report on the occurrence of CxFV from Cx. quinquefasciatus from India. The occurrence of these viruses in mosquitoes could play a critical role in disease vector management.
库蚊是一种臭名昭著的传播媒介，已知可传播丝虫病病原体（引起淋巴丝虫病）和黄病毒，如在印度的西尼罗河病毒和在美国的圣路易斯脑炎病毒。它是裂谷热病毒的媒介，裂谷热病毒也存在于非洲大陆。蚊子还携带其他非致病性昆虫特异性黄病毒（ISFs），如库蚊黄病毒（CxFV）和埃及伊蚊黄病毒。最近的研究表明，ISFs 会干扰致病性虫媒病毒的传播效率。
在印度喀拉拉邦的两个城市地区，对 100 只库蚊种群进行了筛查，以了解这种媒介物种中这些黄病毒的流行情况。从单个标本中提取病毒 RNA，并进行 RT-PCR 扩增 CxFV 非结构蛋白 5（NS5）基因。
在 100 个标本中，发现有 7.0%的标本携带 CxFV 感染。基因序列的系统发育分析表明，这些病毒分离株与肯尼亚的病毒具有遗传关系，序列相似度为 98-99%。
这是首次从印度的库蚊中报告 CxFV 的发生。这些病毒在蚊子中的存在可能在病媒管理中发挥关键作用。
