Paramasivan R, Mishra A C, Mourya D T
Microbial Containment Complex, National Institute of Virology (ICMR), Pune, India.
Indian J Med Res. 2003 Sep;118:101-8.
West Nile virus (WNV) is an important arthropod borne flavivirus; usually causes a mild infection called West Nile fever (WNF) in human and horses. Mosquitoes are the principal vectors of WNV. Various Culex species are found to act as vectors in different geographical regions. The virus is maintained in a bird-mosquito cycle in nature. In India, Culex mosquitoes are tentatively incriminated as vectors of WNV. Experimental studies have shown that Culex tritaeniorhynchus, Cx. vishnui, Cx. bitaeniorhynchus and Cx. univittatus, Culex pipiens fatigans and Aedes albopictus could act as potential vectors of WNV. Transovarial transmission of WNV has been experimentally demonstrated in Culex mosquitoes. Apart from mosquitoes, the role of other arthropods is also considered in the maintenance of WNV during inter-enzootic periods. The possible role of ardeid birds in the maintenance of WNV has been described in India. Though very few clinically overt cases of human encephalitis due to WNV are observed, Japanese encephalitis virus (JEV) is found to dominate in southern India. WNF in horses has not been documented in India. JEV immunized monkeys were protected from WNV challenge and the WNV immunization was found to reduce the disease severity due to JEV. Based on the limited genome sequence analysis, the Indian isolates are grouped together under the genetic lineage-I. WNV infection is diagnosed by IgM antibody capture enzyme linked immunosorbant assay, haemagglutination inhibition test, neutralization test and reverse transcriptase-polymerase chain reaction (RT-PCR). For the effective control of Culex mosquitoes, integrated vector control strategies are recommended. Specific methods are not available for the treatment of WNV infection. However, in patients with encephalitis supportive therapy is recommended. Though a few candidate vaccines are under laboratory trial, no vaccine has been available commercially for the control of WNV infection in human and animals. In view of the global interest on WNV, this paper describes the present status of WNV in India.
西尼罗河病毒（WNV）是一种重要的节肢动物传播的黄病毒；通常会在人类和马匹中引发一种名为西尼罗河热（WNF）的轻度感染。蚊子是WNV的主要传播媒介。在不同地理区域发现多种库蚊属物种可充当传播媒介。该病毒在自然界中通过鸟类 - 蚊子循环得以维持。在印度，库蚊属蚊子被初步认定为WNV的传播媒介。实验研究表明，三带喙库蚊、致倦库蚊、双喙库蚊、单带库蚊、致乏库蚊和白纹伊蚊都可能是WNV的潜在传播媒介。WNV在库蚊属蚊子中已通过实验证明可经卵传播。除蚊子外，其他节肢动物在病毒非流行期间对WNV维持传播所起的作用也受到关注。在印度，已描述了鹭科鸟类在WNV维持传播中可能发挥的作用。尽管由WNV引起的人类脑炎临床显性病例极少，但在印度南部，日本脑炎病毒（JEV）占主导地位。在印度尚未记录到马匹感染西尼罗河热的情况。接种JEV疫苗的猴子可免受WNV攻击，且发现接种WNV疫苗可降低因JEV感染导致的疾病严重程度。基于有限的基因组序列分析，印度分离株在遗传谱系 - I下归为一组。WNV感染通过IgM抗体捕获酶联免疫吸附测定、血凝抑制试验、中和试验和逆转录聚合酶链反应（RT-PCR）进行诊断。为有效控制库蚊，建议采用综合媒介控制策略。目前尚无针对WNV感染的特效治疗方法。然而，对于脑炎患者，建议采取支持性治疗。尽管有几种候选疫苗正在进行实验室试验，但尚无用于控制人类和动物WNV感染的商业疫苗。鉴于全球对WNV的关注，本文描述了WNV在印度的现状。
