The Fresno County Department of Public Health has issued a warning regarding a virus found in Fresno area mosquitoes.

According to a press release issued by the department, the Fresno Mosquito and Vector Control District has discovered the Saint Louis encephalitis (SLE) virus in the local Culex mosquito population in the area of Bullard and Polk avenues.

SLE virus can cause swelling of the brain and is transferred by mosquito bite. Most infected persons will not show any signs of illness, but symptoms including fever, headache, dizziness, nausea and fatigue are possible for upwards of a week. Severe symptoms include fever, headache, stiff neck, confusion and an altered state of consciousness.

In extreme cases, coma, convulsions, paralysis and even death are possible, and SLE virus carries a 5 to 15 percent mortality rate.

Residents are advised by the department to use insect repellent and wear long-sleeved shirts, pants and socks when weather permits. Avoiding the peak biting hours between dusk and dawn, and removing any standing water (where mosquitoes lay eggs) from flower pots, buckets, barrels and tires is also recommended.

For further advice, Fresno area residents are encouraged to contact Fresno Mosquito and Vector Control District Manager Tim Phillips at 559-268-6565, or visit fresnomosquito.org