West Nile Virus (WNV) is a mosquito-borne disease that is closely related to St. Louis encephalitis virus and can cause encephalitis, or a brain infection. Mosquitoes spread this virus after they feed on infected birds and then bite people, other birds and animals. It is not spread by person-to-person contact and there is no evidence that people can get the virus by handling infected animals.
West Nile Virus cases occur primarily in the late summer or early Fall, although the mosquito season is April through October.
What are the symptoms of West Nile Virus?
Serious Symptoms in a Few People. About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.
Milder Symptoms in Some People. Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.
No Symptoms in Most People. Approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.
Who is at risk for contracting West Nile Virus?
Being outside means you're at risk. The more time you're outdoors, the more time you are exposed to the risk of being bitten by an infected mosquito. Pay attention to avoiding mosquito bites if you spend a lot of time outside, either working or playing. Wear insect repellant and avoid staying outdoors at dawn or after dark when mosquitoes are most active.
People over 50 at higher risk to get severe illness. People over the age of 50 are more likely to develop serious symptoms of WNV if they are infected and should take special care to avoid mosquito bites
How soon do infected people get sick?
People typically develop symptoms between 3 to 14 days after they have been bitten by the infected mosquito.
Is there treatment or a vaccine for West Nile Virus?
There is no specific treatment for WNV infection. Milder WNV illness improves on its own, and people do not necessarily need to seek medical attention for this infection though they may choose to do so. If you develop symptoms of severe WNV illness, such as unusually severe headaches or confusion, seek medical attention immediately. Severe WNV illness usually requires hospitalization. Pregnant women and nursing mothers are encouraged to talk to their doctor if they develop symptoms that could be WNV. In more severe cases, people usually need to go to the hospital where they can receive supportive treatment including intravenous fluids, help with breathing and nursing care.
Currently there is no WNV vaccine available for humans. Many scientists are working on this issue, and there is hope that a vaccine will become available in the next few years. However, there is a very effective vaccine against WNV in horses. Horse owners should consult their veterinarians for vaccine information.
IMPORTANT! The vaccine developed for horses SHOULD NOT be used on humans. It has not been studied in humans and could be harmful. The effectiveness of this vaccine in preventing West Nile virus infections in horses has yet to be fully evaluated, and its effectiveness in humans is completely unknown.
What else should I know?
If you find a dead bird: don't handle the body with your bare hands. Contact the Board of Health at 985-447-0916 for instructions on reporting and disposing of the dead bird. They may tell you to dispose of the bird after they log your report.