A patient has the first probable case this season of West Nile virus in Rock County, according to a release from the Rock County Health Department.

West Nile virus is spread to people through the bite of an infected mosquito and is not transmitted person to person, according to the release. Although few mosquitoes carry the virus, it is important to take steps to minimize your exposure even in October, which is late in the mosquito season.

The likelihood of contracting a West Nile virus infection is low and most people infected with the virus will not have symptoms. Those who do become ill may develop a fever, headache, rash, muscle and joint aches, nausea, vomiting and fatigue that can last a few days.

Symptoms may begin three to 15 days after a person is bitten by an infected mosquito. In rare cases, severe diseases including encephalitis and meningitis, can develop from a West Nile virus infection. Older adults and people with compromised immune systems are at an increased risk of severe disease caused by the virus.

There is no specific treatment for West Nile virus infection other than treating its symptoms.

Mosquito activity will persist until there is frost or a hard freeze. Until then, PHMDC advised that residents minimize exposure to mosquito bites by:

• Limiting time spent outside at dawn and dusk, when mosquitoes are most active
• Applying insect repellent to clothing as well as exposed skin because mosquitoes may bite through clothing
• Making sure window and door screens are in good repair to prevent mosquito entry
• Disposing of items that hold water, such as tin cans, plastic containers, ceramic pots or discarded tires to prevent mosquito breeding and turning over wheelbarrows, wading pools, boats and canoes when not in use
• Cleaning roof gutters and downspouts for proper drainage.
• Changing the water in birdbaths and pet dishes at least every three days
• Cleaning and chlorinating swimming pools, outdoor saunas and hot tubs and draining water from pool covers
• Trimming tall grass, weeds and vines, because mosquitoes use these areas to rest during hot daylight hours
• Landscaping to prevent water from pooling in low-lying areas