Role of Natural Killer and Gamma-Delta T cells in West Nile Virus Infection

Wang, Tian; Welte, Thomas

West Nile virus (WNV), a plus-sense, single-stranded neurotropic flavivirus, has been a public health concern in North America for more than a decade [1, 2] . The virus is maintained in an enzootic cycle that involves mosquitoes and birds, with humans and horses as incidental hosts. Infection in humans results from mosquito bites, blood transfusion, organ transplantation, breast feeding, and in utero or occupational exposure [2] [3] [4] [5] [6] . WNV infection of the central nervous system (CNS, neuroinvasive disease) commonly OPEN ACCESS presents as encephalitis, meningitis, or acute flaccid paralysis. The overall mortality rate in persons who develop WNV neuroinvasive disease is about 10%, although the mortality rate increases significantly in the elderly and immunocompromised. Recently, some WNV convalescent patients were reported to have significant long-term morbidity years after their acute illness; symptoms include muscle weakness and pain, fatigue, memory loss, and ataxia [7] [8] [9] [10] [11] . At present, there is no specific therapeutic agent for treatment of the infection. No approved human vaccines are available for its prevention.