West Nile virus is an arthropod-borne virus (arbovirus) most commonly spread by infected mosquitoes.  West Nile virus can cause febrile illness, encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord).

Most people who get the West Nile virus are infected by the bite of an infected mosquito.  Mosquitoes become infected when they feed on infected birds.  Infected mosquitoes can then spread the virus to humans and other animals.

Typically people get infected with the West Nile virus from June through September.

West Nile virus disease cases have been reported from all 48 lower states.  The only states that have not reported cases are Alaska and Hawaii.  The weather, numbers of birds that maintain the virus, numbers of mosquitoes that spread the virus, and human behavior are all factors that influence when and where outbreaks occur.

Avoiding exposure to mosquitoes is the best way to avoid getting the West Nile virus.  The CDC also recommends doing the following to reduce your risk of mosquito bites:

  • Use repellents with Deet, Picardin, IR3535 or oil of lemon eucalyptus
  • Take extra care during peak mosquito biting hours.  Use repellent and wear protective clothing from dusk to dawn.
  • Install or repair screens on windows and doors to keep mosquitoes outside.
  • Help reduce the number of mosquitoes around your home by emptying standing water from flowerpots, gutters, buckets, pool covers, pet water dishes, discarded tires, and birdbaths on a regular basis.