Two Dane County residents have tested positive for the first local cases of West Nile virus this season.

Nasia Safdar, the medical director of infection control at UW Hospital and Clinic, said the virus is fairly common, but most cases don’t show symptoms so people don’t report them.

Those who become ill may develop a fever, headache, rash, muscle or joint aches, nausea, vomiting and fatigue that could last a couple days.

Safdar said there are only few cases that need to seek medical attention.

Zika virus case identified in Dane CountyPublic health officials have identified the first instance of Zika virus in Dane County.  Public Health Madison and Dane County announced Read…

The virus is spread through an infected mosquito’s bite, not person-to-person. People could notice symptoms three to 15 days after being bitten by an infected mosquito.

John Hausbeck, the environmental health supervisor for the Public Health Madison and Dane County, said in a statement people should take steps to minimize exposure even though it is late in the mosquito season.

“With the warm, wet weather this late summer and fall, our mosquito season has extended longer than in past years,” Hausbeck said.

Safdar said the virus can be life-threatening to a small proportion of people. People older than 65 and kids who don’t have well-developed immune systems are often more prone to severe cases. She said for most people, the virus is not life-threatening or severe.

Safdar said to prevent contracting the virus, it is important to use mosquito repellant and wear long-sleeve shirts or pants — anything to prevent the mosquito from making contact with your skin.