WEST NILE VIRUS

West Nile virus is a potentially serious illness transmitted by mosquitoes. It was first discovered in the United States in 1999 in New York.  Since then, the virus has spread throughout the United States.

Experts believe the West Nile virus is a seasonal epidemic in North America that flares up in the summer and continues into the fall. The risk of disease decreases as the weather become colder and mosquitoes die off.

SYMPTOMS:
Most people infected with the West Nile virus have no signs or symptoms but there is no way to know in advance if you will develop an illness or not.

MILD INFECTION SIGNS AND SYMPTOMS:
Up to 20 percent of the people who have become infected will display symptoms which can include: fever, headache, body aches, nausea, fatigue, vomiting, and sometimes skin rash, swollen lymph glands and eye pain.

SERIOUS INFECTION SIGNS AND SYMPTOMS:
About one in 150 people infected by the West Nile virus will develop severe illness.  The severe symptoms can include: high fever, severe headache, stiff neck, disorentation or confusion, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis.  These symptoms may last several weeks, and neurological effects may be permanent.  If you experience any of these symptoms after being bitten by a mosquito, you should seek medical attention immediately.  People typically develop symptoms between 3 and 14 days after they are bitten by the infected mosquito.

HOW DOES THE WEST NILE VIRUS SPREAD?
Most often the West Nile virus is spread by the bite of an infected mosquito.  Mosquitoes become infected when they feed on infected birds.  Infected mosquitos can then spread the virus to humans and other animals when they bite.  The virus is not spread through casual contact such as touching or kissing a person with the virus.

RISK FACTORS:

• People over the age of 50 are at higher risk of infection
• If you work or spend time outdoors, you have a greater chance of being bitten by an infected mosquito
• People who have a weakened immune system are most likely to develop a severe or fatal infection

• Avoid unnecessary outdoor activity when mosquitoes are most prevalent, such as dawn, dusk and early evening
• Be sure to use insect repellants containing an EPA-registered insect repellant (follow the directions on the package) and wear shoes, long sleeved shirts and long pants when outdoors.  Don't allow children to apply insect repellants themselves.
  
• Eliminate standing water in your yard.  Mosquitoes breed in pools of standing water
• Make sure you have good screens on your windows and doors to keep mosquitoes out
• Empty unused swimming pools
• Keep roof gutters clear and draining properly
• Monitor the news for information about current insect conditions and community effors to control insects
• Be aware that increased sightings of dead birds in your area can be a sign that West Nile virus might be present.  If you see multiple dead birds in your area, you should immediately contact your health department.

RESOURCES:

• Centers for Disease Control and Prevention: http://www.cdc.gov/ncidod/dvbid/westnile/index.htm
• U.S. National Library of Medicine: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004457/
• MedlinePlus: http://www.nlm.nih.gov/medlineplus/westnilevirus.html
• Alliance for Consumer Education: http://stopgerms.org/documents/mosquitoes.html?gclid=CP-H95ul7LECFWFgTAodVC4AbA
  

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SOURCE: Centers for Disease Control and Prevention
PREPARED BY: 211/lb
CONTENT LAST REVIEWED: August2012