People become infected with West Nile virus from the bite of an infected mosquito. Mosquitoes become infected by biting birds which are infected with the virus. Some birds may die of the disease, but they are not known to transmit the disease to humans. Not all humans infected with the disease will become ill. Most infections are mild and symptoms may include fever, headache, body aches, skin rashes and swollen lymph glands.
Most people recover from the disease.
When more severe symptoms occur, they can range from fever, rash and headache to meningitis, encephalitis, coma and death. People who live or work in areas where active cases have been identified are at risk of getting West Nile virus if bitten by an infected mosquito. However, people over the age of 50 and those with weak immune systems are at greater risk for more serious illness. There is no specific treatment for West Nile virus, nor is there a vaccine. Most people recover completely within two weeks.