First human case of West Nile virus confirmed in Mesa County

For the first time this season, a person has tested positive for West Nile virus in Mesa County. Mesa County Public Health tracks the human cases of West Nile virus, while the Grand River Mosquito Control District monitors and treats mosquito populations. Both organizations work closely to keep our community safe. The only other positive human case in Colorado so far this season is in Arapahoe County.

“We are right in the middle of mosquito season, and prevention continues to be crucial to avoid West Nile virus,” said Kathleen Satterfield, Epidemiologist for Mesa County Public Health. “If you’re planning to spend time outside, do what you can to protect yourself and your family from mosquito bites.”

PREVENTION

West Nile virus is spread to people by the bite of an infected mosquito. There are simple, effective things you can do to lower your risk for mosquito bites:

• Use an EPA-approved insect repellent effective against mosquitoes. Look for one that contains DEET, Picaridin, IR3535, 2-undecanone, or oil of lemon eucalyptus.
• Dress in long sleeves and pants when in areas where mosquitoes are active.
• Avoid being outdoors at dusk and dawn; this is when mosquitoes are most active.
• Drain and remove sources of standing water on your property.

Talk to a health care provider if you develop a fever with severe headaches or confusion.

WEST NILE VIRUS BACKGROUND

The West Nile virus season runs from May through October with case counts typically peaking in September. Most people who are infected with West Nile virus do not get sick. In fact, about 75-80% of cases are asymptomatic. For those who do experience symptoms, they can range from mild illness to severe encephalitis, which is inflammation of the brain. People who are over the age of 50 are at the highest risk for severe illness.  

LOCAL AND STATE CASES IN 2023

Last year was a severe year for West Nile Virus in Colorado. There were 18 cases in Mesa County, and 13 of those people were hospitalized. According to the Colorado Department of Public Health and Environment (CDPHE), 634 cases of West Nile virus were reported across Colorado in 2023. Statewide, 386 people were hospitalized and 51 people died.