West Nile virus is spreading in Salt Lake County

West Nile virus has been detected in multiple mosquito groups in Salt Lake County, health officials announced Wednesday.

Why it matters: Although most human cases are asymptomatic, some infections can cause serious illness, including debilitating, long-term complications or death.

Driving the news: The virus was found in mosquito traps in western Salt Lake City and along the Draper-Riverton border, per the county health department.

Threat level: Health officials expect it to be detected in more parts of the county in the coming days and weeks.

• "Because mosquitoes can travel several miles, everyone in the region—regardless of their exact location—should take precautions against mosquito bites to avoid exposure to the virus," county health officials wrote in a statement.

How it works: Mosquitos are most active from dusk to dawn.

• Health officials recommend an EPA-registered mosquito repellent with DEET, permethrin, picaridin, IR3535 or oil of lemon eucalyptus.
• Wear long sleeves and pants after dusk.
• Keep weeds and tall grass trimmed short, and drain standing water from yards and other spots like old tires and plant container trays.
• Clear roof gutters.
• Keep garden ponds clean and stocked with mosquito-eating fish or mosquito "dunks" — chemical pellets that dissolve and kill larvae.
• Repair door and window screens to keep mosquitos out of your home.

Zoom in: Symptoms develop within two to 14 days of a mosquito bite and can include fever and aches. Serious infections may cause high fever, disorientation, tremors, muscle weakness, disorientation and neck stiffness.

• There is no cure for the virus, apart from treating symptoms. Call your doctor if you think you're infected.
• People older than 50 and those with weakened immune systems face the highest risk.

Catch up quick: Eight human West Nile infections were confirmed in Utah last year, five of which resulted in the dangerous, neuroinvasive form of the disease.

• One Utahn died from the virus.