Minnesota Department of Health

News Release

July 14, 2005

Contact information

State reports season’s first human West Nile virus case

The Minnesota Department of Health (MDH) today announced the first human case of West Nile virus disease in a Minnesota resident for 2005.

An adult Wadena County woman tested positive for West Nile virus at the MDH Public Health Laboratory. The woman became ill in late June with symptoms including high fever and severe headache. She has been hospitalized with encephalitis and is improving slowly.

“This case reminds us that we are entering the peak season for West Nile virus in humans, from mid-July through mid-September, so we all need to take steps to prevent mosquito bites,” said David Neitzel, an MDH epidemiologist specializing in tick and mosquito-borne diseases. “This is the time of year when we typically see our greatest number of illnesses from West Nile virus because this is the time of year when you’re most likely to be bitten by an infected mosquito.”

While WNV can occur anywhere in the state, western and central Minnesota are at highest risk for the disease. Also, the older you are, the higher your risk of developing serious forms of illness from the virus.

West Nile virus is transmitted through the bite of a mosquito. It cannot be spread by contact with an infected person. While usually not serious in humans, it can sometimes lead to encephalitis, which is an inflammation of the brain.

To reduce your risk of being bitten:

• While outside among mosquitoes, use a good mosquito repellent, such as those containing no more than 30 percent of the active ingredient DEET. Products containing the active ingredient picaridin are also now commercially available.
• Minimize outdoor activities at dusk or dawn, when mosquitoes are most actively feeding.
• Wear long-sleeve shirts and long pants if you have to spend time in an area where mosquitoes are biting.
• Eliminate mosquito breeding sites on and around your property – including items such as old tires, buckets, clogged rain gutters, cans, other containers and anything else that can hold a small amount of water. Change the water in birdbaths and horse troughs at least weekly.

Of those who become infected with West Nile virus, most people will have no symptoms at all or display only mild symptoms. Approximately one out of 150 people who become infected will develop encephalitis or other severe forms of the disease. Symptoms usually show up three to 15 days after being bitten. They can include headache, high fever, muscle weakness, stiff neck, disorientation, tremors, convulsions, paralysis and coma. Severe cases tend to occur more often in the elderly.

So far in 2005, West Nile virus has also been found in one bird and four horses in Minnesota. A map showing updated West Nile findings in Minnesota can be found on the MDH Web site.

West Nile virus is widespread in Africa, the Middle East, and much of Europe. The virus first appeared in North America (New York City) during 1999 and has since been found in 48 states and the District of Columbia. In 2004, 34 human cases of West Nile virus infection were reported in Minnesota, with two deaths. Nationwide in 2004, there were 2,539 human cases reported with 100 deaths. So far in 2005, 25 other cases of West Nile disease have been reported from 11 states, with one death.

More information on West Nile and other forms of mosquito-borne encephalitis, and a form to report dead birds to help with West Nile virus monitoring, are available on the MDH Web site. Information is also available at the Centers for Disease Control and Prevention site. People who have questions about West Nile Virus can call MDH at 612-676-5414 or 1-877-676-5414 (outstate) between 8 a.m. and 4:30 p.m. Monday through Friday.

-MDH-

NOTE: DAVID NEITZEL, WNV SURVEILLANCE COORDINATOR, WILL BE AVAILABLE TO MEET WITH MEDIA ABOUT WEST NILE VIRUS FROM 11 A.M.-3 P.M. TODAY AT 717 DELAWARE IN MINNEAPOLIS.

For more information, contact:

Doug Schultz
MDH Communications
(651) 215-1303

David Neitzel
Insect-borne disease specialist
(612) 676-5414

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