West Nile is a virus that is transmitted by mosquitoes. It was first identified in Uganda in 1937 and later spread to other parts of Africa, Europe, and Asia. The virus is named after the West Nile region of Uganda.
The majority of people who are infected with West Nile virus will not develop any symptoms. For those who do become ill, the most common symptom is fever. Other symptoms may include headache, body aches, joint pain, vomiting, diarrhea, or rash. In rare cases, more serious illness can occur including encephalitis (inflammation of the brain) or meningitis (inflammation of the spinal cord).
There is no specific treatment for West Nile virus infection. Most people recover on their own within a few weeks. Those with more severe illness may require hospitalization and supportive care. There is no vaccine available to prevent West Nile virus infection.
Mosquitoes become infected with West Nile virus when they bite an infected bird or animal. They can then transmit the virus to humans through their bites. People can also be infected if they come into contact with infected mosquito saliva or blood – for example, through a cut or scratch on the skin or mucous membranes such as those in the eyes or nose. Once a person has been infected with West Nile virus, they cannot pass it on to others through mosquito bites or contact with bodily fluids; however, they can infect mosquitoes that bite them during the first few days of illness when the viral load in their blood is highest.
Most cases of West Nile virus infection occur between June and September when mosquitoes are most active; however, infections have been reported year-round in some areas of the world where mosquitoes are present year-round (such as Florida). People of all ages can be infected with West Nile virus but those over 50 years old and those with certain medical conditions such as cancer, diabetes mellitus, hypertension are at greater risk for developing more severe illness if they become infected