Ask the Doctor: West Nile Virus
Dr. Marie McCormack is the medical director of Renown Medical Group. She's taking calls in tonight's Ask the Doctor segment about West Nile Virus from 5 p.m. to 6 p.m. tonight. Just call 858-2222.
What is West Nile virus?
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).
West Nile virus transmission has been documented in Europe and the Middle East, Africa, India, parts of Asia, and Australia. It was first detected in North America in 1999, and has since spread across the continental United States and Canada.
How do people get infected with West Nile virus?
Most people get infected with West Nile virus 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.
In a very small number of cases, West Nile virus has been spread through blood transfusions, organ transplants, and from mother to baby during pregnancy, delivery, or breastfeeding.
Who is at risk for infection with West Nile virus?
Anyone living in an area where West Nile virus is present in mosquitoes can get infected. West Nile virus has been detected in all lower 48 states (not in Hawaii or Alaska). Outbreaks have been occurring every summer since 1999. The risk of infection is highest for people who work outside or participate in outdoor activities because of greater exposure to mosquitoes.
Is there a vaccine available to protect people from West Nile virus?
No. Currently there is no West Nile virus vaccine available for people. Many scientists are working on this issue, and there is hope that a vaccine will become available in the future.
How soon do people get sick after getting bitten by an infected mosquito?
The incubation period is usually 2 to 6 days but ranges from 2 to 14 days. This period can be longer in people with certain medical conditions that affect the immune system.