Specific Disease Frequently Asked Questions | West Nile Virus

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	What are West Nile virus, West Nile fever, and West Nile encephalitis?
	What can I do to reduce my risk of becoming infected with West Nile virus?
	How do people get infected with West Nile virus (WNV)?
	How is West Nile encephalitis treated?

What are West Nile virus, West Nile fever, and West Nile encephalitis?
West Nile Virus is a flavivirus that can infect humans, birds, mosquitoes, horses and some other mammals.

West Nile fever is a case of mild disease in people, characterized by flu-like symptoms. West Nile fever typically lasts only a few days and does not appear to cause any long-term health effects.

More severe disease due to a person being infected with this virus can be West Nile encephalitis, West Nile meningitis or West Nile meningoencephalitis. Encephalitis refers to an inflammation of the brain, meningitis is an inflammation of the membrane around the brain and the spinal cord, and meningoencephalitis refers to inflammation of the brain and the membrane surrounding it.

What can I do to reduce my risk of becoming infected with West Nile virus?
Here are preventive measures that you and your family can take:

Protect yourself from mosquito bites:

• Apply insect repellent sparingly to exposed skin. The more DEET a repellent contains the longer time it can protect you from mosquito bites. A higher percentage of DEET in a repellent does not mean that your protection is better-just that it will last longer. DEET concentrations higher than 50% do not increase the length of protection. Choose a repellent that provides protection for the amount of time that you will be outdoors.
  
  • Repellents may irritate the eyes and mouth, so avoid applying repellent to the hands of children.
    
  • Whenever you use an insecticide or insect repellent, be sure to read and follow the manufacturer's DIRECTIONS FOR USE, as printed on the product.
    
• Spray clothing with repellents containing permethrin or DEET since mosquitoes may bite through thin clothing. Do not apply repellents containing permethrin directly to exposed skin. If you spray your clothing, there is no need to spray repellent containing DEET on the skin under your clothing.
  
• When possible, wear long-sleeved shirts and long pants whenever you are outdoors.
  
• Place mosquito netting over infant carriers when you are outdoors with infants.
  
• Consider staying indoors at dawn, dusk, and in the early evening, which are peak mosquito biting times.
  
• Install or repair window and door screens so that mosquitoes cannot get indoors.

Help reduce the number of mosquitoes in areas outdoors where you work or play, by draining sources of standing water. In this way, you reduce the number of places mosquitoes can lay their eggs and breed.

• At least once or twice a week, empty water from flower pots, pet food and water dishes, birdbaths, swimming pool covers, buckets, barrels, and cans.
  
• Check for clogged rain gutters and clean them out.
  
• Remove discarded tires, and other items that could collect water.
  
• Be sure to check for containers or trash in places that may be hard to see, such as under bushes or under your home.
  

Note: Vitamin B and "ultrasonic" devices are NOT effective in preventing mosquito bites.

How do people get infected with West Nile Virus (WNV)?
The main route of human infection with West Nile virus is through the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds, which may circulate the virus in their blood for a few days. The virus eventually gets into the mosquito's salivary glands. During later blood meals (when mosquitoes bite), the virus may be injected into humans and animals, where it can multiply and possibly cause illness.

Additional routes of human infection became apparent during the 2002 West Nile epidemic. It is important to note that these other methods of transmission represent a very small proportion of cases. Investigations have identified WNV transmission through transplanted organs and through blood transfusions.

There is one reported case of transplacental (mother-to-child) WNV transmission. There is also one reported case of transmission of WNV through breast-milk.

Although transmission of WNV and similar viruses to laboratory workers is not a new phenomenon, two recent cases of WNV infection of laboratory workers have been reported.

How is West Nile encephalitis treated?
There is no specific treatment for West Nile virus infection. In more severe cases, intensive supportive therapy is indicated, often involving hospitalization, intravenous fluids, airway management, respiratory support (ventilator), prevention of secondary infections (pneumonia, urinary tract, etc.), and good nursing care.
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