Frequently Asked Questions about the West Nile Virus
What is West Nile virus?
West Nile virus is a viral infection that is spread by the bite of an infected mosquito. Mosquitoes get infected with the West Nile virus by feeding on infected birds. The infected mosquitoes then spread the virus by biting humans and other animals, such as horses. Identified in the United States in 1999, West Nile virus is seen most often during the summer and early fall months.
Who gets West Nile virus?
Anyone can get infected with the West Nile virus. The virus can affect anyone bitten by an infected mosquito. People over the age of 50 and people with weak immune systems are at greater risk of developing severe illness.
How do people get West Nile virus?
The virus is spread by the bite of a mosquito infected with the West Nile virus.
What are the symptoms of West Nile virus?
Many people infected with West Nile virus do not become ill and may not develop symptoms. About 20% of infected people will develop West Nile fever. When symptoms do occur, they may be mild or severe and show up 3 to 15 days after being bitten by an infected mosquito.
• Mild symptoms include flu-like illness with fever, headache, body aches, nausea and sometimes swollen lymph glands or a skin rash on the chest, stomach and back.
• Severe symptoms include high fever, neck stiffness and swelling of the brain (encephalitis) which can lead to coma, convulsions and death. Less than 1% of infected people will develop severe symptoms.
How is West Nile virus diagnosed?
If a health care provider suspects West Nile virus, samples of the patient’s blood or spinal fluid will be examined.
What is the treatment for West Nile virus?
There is no specific treatment for West Nile virus. Most people with West Nile fever will recover in approximately seven days. Antibiotics are not effective against viral illnesses and anti-viral drugs have not shown to be effective for treating West Nile virus. Most treatment focuses on supportive therapy to lower fever and ease pressure on the brain and spinal cord. In severe cases, hospitalization may be needed. There is no vaccine for humans.
Can people with West Nile virus pass the illness to others?
The virus that causes West Nile virus is spread only by mosquitoes. West Nile virus is not spread from person to person.
In rare cases, the virus has been spread through blood transfusions, organ transplants, breastfeeding and during pregnancy from mother to baby.
How can West Nile virus be prevented?
The best way to protect yourself from getting West Nile virus is to prevent mosquito bites.
Follow these steps to reduce your risk of being bitten by mosquitoes:
• Wear shoes and socks, long pants and a long-sleeved shirt when outdoors at dusk or dawn when mosquitoes are most active.
• Use an EPA-registered insect repellent such as those with DEET, picaridin, or oil of lemon eucalyptus. These products can be used on skin or clothing. Choose a product that provides protection for the amount of time spent outdoors. Permethrin is another type of insect repellent. It can only be used on clothing. ALWAYS follow the directions on the product label.
Mosquitoes begin to breed in any puddle or standing water that lasts for more than four days. Get rid of mosquito breeding sites around the home.
• Clean out gutters and drains
• Dispose of old tires
• Drain standing water from pool covers. Keep pools chlorinated. Flip over plastic children’s pools when not in use.
• Remove all containers that hold water
• Change birdbath water every several days
• Make sure all windows and doors have screens and that all screens are in good condition.
Where can I get more information on West Nile virus?
• Your health care provider
• Your local health department
• Centers for Disease Control and Prevention http://www.cdc.gov/westnile
This information is intended for educational purposes only and is not intended to replace consultation with a health care professional. Adapted from Centers for Disease Control and Prevention