What is West Nile Virus?

West Nile Virus (WNV) is a mosquito-borne virus that can cause encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord).

How is West Nile Virus spread?

WNV is spread to humans by the bite of an infected mosquito. A mosquito becomes infected by biting a bird that carries the virus. You or your child cannot get WNV from a person who has the disease. WNV is not spread by person-to-person contact such as touching, kissing, or caring for someone who is infected.

Are older adults more at risk for West Nile Viral disease?

Yes. While the chances of anyone becoming infected with WNV is very low, most cases have occurred in people older than 50. People in this age group, especially the elderly, are also more likely to develop severe diseases, such as encephalitis or meningitis, if they become infected.

Where did West Nile Virus come from?

Outbreaks of WNV disease have occurred in Africa, Egypt, Israel, Asia, Romania, Russia, and France. Before 1999, however, WNV had never before been found in the Americas. The most likely explanation for its appearance here is that the virus was introduced by an infected bird that was imported or an infected person returning from a country where the virus is common.

Can you get WNV directly from birds?

There is currently no evidence that WNV can be spread directly from birds to people. However, dead birds carry a variety of diseases and therefore should never be handled with bare hands. Use gloves to carefully place dead birds in double-plastic bags and then place in the outdoor trash. Dead crows and blue jays that are found should be reported to the Macomb County Health Department for possible testing.

Besides mosquitoes, can you get West Nile Virus from other insects or ticks?

Infected mosquitoes are the primary source of WNV. There is no evidence to suggest that ticks or other insects transmit WNV.

What are the symptoms of West Nile viral infection?

Most people who are infected with WNV either have no symptoms or experience mild illness such as fever, headache and body aches before fully recovering. Some persons may develop a mild rash or swollen lymph glands. In some individuals, particularly the elderly, WNV can cause serious disease that affects the brain tissue. At its most serious, it can cause permanent neurological damage and can be fatal. Symptoms of encephalitis (inflammation of the brain) include the rapid onset of severe headache, high fever, stiff neck, confusion, loss of consciousness (coma), or muscle weakness, and may be fatal.

How is West Nile encephalitis treated?

There is no specific therapy. In more severe cases, intensive supportive therapy is indicated, i.e. hospitalization, intravenous (IV) fluids and nutrition, airway management, ventilator support if needed, prevention of secondary infections (pneumonia, urinary tract, etc.), and good nursing care.

Is there a vaccine against West Nile Virus?

No. A vaccine for WNV does not currently exist.

How long does it take to get sick if bitten by an infected mosquito?

Being bitten by an infected mosquito will not necessarily make you sick. Most people who are infected with WNV have no symptoms or experience only mild illness. If illness were to occur, it would occur within 3-15 days of being bitten by an infected mosquito.

What should I do if I think I have West Nile encephalitis?

If you develop signs of encephalitis, with fever, muscle weakness, and confusion, you should seek medical care immediately.

What can I do to reduce my risk of becoming infected with West Nile Virus?

From April to October, when mosquitoes are most active, take the following precautions:

• Avoid being outdoors around dawn and dusk when mosquitoes are most active.
• Avoid areas where mosquitoes live: tall grass or weeds, bushes, wooded areas
• Wear protective clothing such as long sleeve shirts, long pants, loose-fitting clothing and socks
• Use insect repellent containing DEET according to the manufacturer's directions on the label

What can I do around my home to help reduce exposure to mosquitoes?

Eliminate mosquito breeding and harborage areas. Mosquitoes lay their eggs in standing or slow moving water. Weeds, tall grass, and bushes provide an outdoor home for mosquitoes. Mosquitoes can also enter homes through unscreened windows/doors or through screens that are broken or torn. Follow the links to the right for more information.

Questions?

If you have any questions, call us at 586-469-5236, Monday-Friday,
8:30 a.m. - 5:00 p.m. or E-mail us now.

Other Resources

Michigan Department of Environmental Quality
http://www.michigan.gov/emergingdiseases/0,1607,7-186-25805-75950---,00.html