West Nile virus is most commonly spread by infected mosquitoes that have fed on infected birds. The disease was first detected in North America in 1999 and has spread across the continental U.S. and Canada. While all mosquitoes may look alike to the lay person, species of the genusCulexare the primary vectors for West Nile virus in the U.S.

Once a person is bitten by an infected mosquito, the incubation period for the virus ranges from 3 to 15 days. However, about 80 percent of persons infected by West Nile virus do not develop any symptoms. The remainder may develop a fever and other symptoms such as head and body aches, joint pains, vomiting, diarrhea or rash. Most people recover completely, although fatigue and weakness may persist for weeks or months. Less than one percent of infected patients develop a serious neurological illness such as encephalitis or meningitis. Approximately 10 percent of people with such neurological complications succumb to the infection. People who have had West Nile virus are considered immune.

The Kansas Department of Health and Environment (KDHE) began surveillance for West Nile virus in 2001, and the first human case was reported in Kansas in 2003. There were 54 cases reported in Kansas in 2014. KDHE conducts targeted mosquito surveillance in Sedgwick County and uses the information to assess the potential for West Nile virus transmission statewide.

KDHE recommends the following precautions to protect against West Nile virus:

• When outdoors, use insect repellent containing an EPA-registered active ingredient on skin and clothing, including DEET, picaridin, oil of lemon eucalyptus, or IR3535. Follow the directions on the package.
• Many mosquitoes are most active at dusk and dawn. Use insect repellent and wear long sleeves and pants at these times or consider staying indoors during these hours.
• Make sure doors and windows have tight-fitting screens. Repair or replace screens that have tears. Try to keep doors and windows shut, especially at night.
• Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets and barrels. Change the water in outdoor pet dishes and replace the water in bird baths twice weekly. Drill holes in tire swings so water drains out. Keep children's wading pools empty and on their sides when they aren't being used.

Additional information about West Nile virus and preventing mosquito bites is available at www.kdheks.gov/westnilevirus