Has West Nile Virus been detected in our area?
Yes. In August 2002 a blue jay tested positive for the virus.

What is West Nile encephalitis?
Encephalitis is an inflammation of the brain. It can be caused by viruses and bacteria, including viruses transmitted by mosquitoes. West Nile encephalitis is an infection of the brain caused by West Nile Virus.

How is West Nile Virus spread?
West Nile Virus is transmitted when mosquitoes become infected by feeding on infected birds. Infected mosquitoes can then transmit West Nile Virus to humans and animals. West Nile Virus can also be transmitted through blood transfusions, organ donations and breast milk. There is no evidence that a person can get the virus from handling infected birds, however, individuals should avoid bare-hand contact with infected animals and should wear gloves when handling any dead animal.

Where is West Nile Virus found?
West Nile Virus has been commonly found in humans, birds and other vertebrates in Africa, Eastern Europe, West Asia, and the Middle East. It was not documented in the Western Hemisphere until 1999. The continued expansion of West Nile Virus in the United States indicates that it is now permanently established in the Western Hemisphere. West Nile encephalitis cases occur primarily in the late summer or early fall. In the southern climates where temperatures are milder, West Nile Virus can be transmitted year round.

Who gets West Nile encephalitis?
People who live in or travel to areas where West Nile Virus activity has been identified are at risk of getting West Nile encephalitis. Individuals who are 50 or older are at highest risk of developing severe West Nile Virus disease.

What is my risk?
Even in areas where mosquitoes do carry the virus, less than 1% of them are actually infected. If the mosquito is infected, less than 1% of people who get bitten and become infected will get severely ill. The chances of an individual becoming severely ill from any one mosquito bite are extremely small.

What are the symptoms of West Nile encephalitis?
Most infections are mild. Symptoms include fever, headache, and body aches, and occasionally skin rash and swollen lymph glands. More severe infection may be marked by headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, paralysis, and, rarely, death. Individuals with these symptoms should contact their health care provider.

How is West Nile encephalitis diagnosed?
People who live in or travel to areas where West Nile Virus activity has been identified are at risk of getting West Nile encephalitis. Individuals who are determined to be at high risk and who have symptoms of West Nile encephalitis, may be asked by their health care provider for a blood sample. The sample will likely be sent to a commercial or public health laboratory for testing and confirmation.

How is West Nile encephalitis treated?
There is no specific therapy. 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.

Is a woman's pregnancy at risk if she gets West Nile encephalitis?
There is no documented evidence that a pregnancy is at risk due to infection with West Nile Virus.

What proportion of people with severe illness due to West Nile Virus die?
Less than 1% of people who get bitten by an infected mosquito become infected and get severely ill. Case-fatality rates range from 3% to 15% among those with severe illness due to West Nile Virus, and are highest among the elderly.

Is there a vaccine against West Nile encephalitis?
There is no vaccine to prevent the virus in people, however several companies are working towards developing a vaccine. A vaccine does exist for horses.

What can I do to reduce my risk of becoming infected with West Nile Virus?
To avoid mosquito bites:

• Stay indoors at dawn and dusk when mosquitoes are most active.
• Wear long sleeved shirts and long pants when spending time outdoors.
• Use an approved insect repellent, and follow the instructions on the product label.

• Eliminate mosquito habitat in yards by removing standing water.
• Dispose of old tires, cans, wading pools or any other items that collect water.
• Make sure roof gutters are draining properly.
• Change the water in birdbaths and pet dishes daily.
• Use mosquito eliminating products according to product labels in standing water like ponds.

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Springfield-Greene County Health Department 227 East Chestnut Expressway Springfield, MO 65802 (417) 864-1658 * (417) 864-1099 fax Email questions or comments to the Webmaster.