West Nile Virus discovered in Salt Lake County mosquito pools

SALT LAKE CITY, Utah– The Salt Lake County Health Department (SLCoHD) is urging residents to take precautionary measures to avoid exposure to the West Nile Virus (WNV) after it was detected in multiple mosquito pools within Salt Lake County. 

It’s important to note that “mosquito pools” refer to a group of mosquitoes caught and tested out of a single trap. The term has no relation to swimming pools or other bodies of water. 

Throughout the county, Local Mosquito Abatement Districts (MADs) have been collecting mosquito samples around numerous locations, the department said in a statement Monday. 

“We currently do not have any confirmed human cases of West Nile virus reported in Salt Lake County,” explained Dr. Dagmar Vitek, SLCoHD medical director. “But this is a good reminder that it is now especially important that residents protect themselves from mosquito bites, particularly in the hours from dusk to dawn.” 

Effects of West Nile Virus 

The virus is known to cause mild to severe illness and many people may be unaware they’re infected.

It typically takes two to 14 days from exposure of WNV for symptoms to appear. Symptoms include fever, headache and body aches. More severe infections may include high fever, neck stiffness, disorientation, coma, tremors and muscle weakness or convulsions.

“It is estimated that less than 1% of people infected with WNV will develop neuroinvasive disease, which can result in debilitating long-term complications or death,” SLCoHD said. 

Individuals over age 50 and those immunocompromised are at the highest risk of illness due to WNV. But anyone who has been bit by an infected mosquito can become sick. 

Public health officials say only 20-30% of infected people will experience WNV symptoms and most cases will be minor flu-like symptoms. 

The WNV was detected in the U.S. in 1999. In 2003, Utah diagnosed its first case. Last year, public health officials reported 21 people in Utah contracted the virus; 12 of those people developed a neuroinvasive disease and one passed away.

Unlike the coronavirus, WNV is not transmissible from person to person. However, there’s no way to determine which mosquito may be infected. 

Protecting yourself from West Nile Virus 

Here’s what public health officials recommend to minimize exposure opportunities during mosquito season:

• Use an EPA-registered mosquito repellent with DEET, permethrin, picaridin, IR3535 or oil of lemon eucalyptus; follow package directions about application.
• Drain standing water in yards (old tires, potted plant trays, pet dishes, toys, buckets, etc.).
• Wear long sleeves and pants after dusk.
• Keep roof gutters clear of debris.
• Clean swimming pools often or drain them.
• Clean and stock garden ponds with mosquito-eating fish or mosquito dunks.
• Make sure doors and window screens are in good condition so that mosquitoes cannot get indoors.
• Keep weeds and tall grass cut short; adult mosquitoes look for these shady places to rest during the hot daylight hours.

If you think you have WNV infection, contact your health care provider.