West Nile Virus

West Nile Virus (WNV) is a mosquito-borne viral infection caused by a flavivirus that infects birds, humans, and other mammals. It is primarily transmitted to humans through the bite of an infected Culex species mosquito. Human infection can range from asymptomatic to severe neuroinvasive disease. Most infected individuals (approximately 80%) do not exhibit symptoms, while some develop a self-limiting febrile illness known as West Nile Fever, characterized by fever, headache, body aches, skin rash, and swollen lymph glands.

In a minority of cases (∼1%), WNV can progress to severe neurological illness, including encephalitis (inflammation of the brain), meningitis (inflammation of the membranes surrounding the brain and spinal cord), or an acute flaccid paralysis known as West Nile poliomyelitis. Such neuroinvasive diseases can lead to long-term neurological deficits or death, particularly in the elderly and those with compromised immune systems. There is no specific antiviral treatment for WNV; thus, care is supportive, focusing on the alleviation of symptoms and, in severe cases, intensive medical care. Prevention strategies center on mosquito control programs and individual protective measures to avoid mosquito bites, as there is no commercially available vaccine for human use.