Most people bitten by WNV-infected mosquitoes do not get sick. However, the elderly and people with weakened immune systems are more prone to infections. Symptoms begin 3 - 15 days after the bite from an infected mosquito. Symptoms may include fever, headache, nausea, rash, stiff neck, muscle weakness, and disorientation. The natural cycle of WNV involves birds and mosquitoes.
Mosquitoes acquire the virus from biting an infected bird.
There is no evidence that humans can contract WNV directly from birds. Some bird species display no symptoms, while other species exhibit symptoms ranging from encephalitis to death. These include crows, chickens, ducks, gulls, and pigeons. WNV can also cause encephalitis in horses. Several species of mosquitoes in Rhode Island can transmit WNV from birds to humans.