First Positive West Nile Virus Mosquitoes Found in Larimer County

The first positive West Nile virus mosquitoes of the year in Larimer County have been detected. The positive mosquito pools were found in the southeast and southwest areas of Fort Collins. So far this year, no human cases of West Nile virus have been reported.

West Nile disease is a viral infection that is spread to people through bites from infected Culex mosquitoes. The symptoms of West Nile disease can vary widely, from no symptoms to severe illness, and generally appear between 3-14 days after infection. The most common symptoms include fever, nausea and vomiting, muscle weakness and aches, rash, and headaches.

Dr. Paul Mayer, Medical Officer with the Larimer County Department of Health and Environment cautions residents, “If you believe you are experiencing symptoms of West Nile Virus, contact your healthcare provider right away for a diagnosis. Although rare, 1% of individuals infected may go on to develop a serious, neuroinvasive form of the disease.”

Mosquito sampling to monitor for West Nile virus risk began the first week in June in Larimer County. With peak West Nile season generally lasting from July through August, the Larimer County Department of Health and Environment continues to closely monitor West Nile prevalence in the community through partnerships with our cities, a mosquito abatement company (Vector Disease Control International, formerly called Colorado Mosquito Control), and Colorado State University to monitor and assess the risk to Larimer County residents.

West Nile virus is preventable. In addition to community mitigation efforts, individuals can practice the 4 D’s to help prevent West Nile virus disease:

• Defend – Use DEET or another effective mosquito repellent – Use an EPA-registered mosquito repellent that has been proven to be effective against West Nile virus-carrying mosquitoes. DEET, Picaridin, Oil of Lemon Eucalyptus (also called p-menthane-3,8-diol or PMD), and IR3535 are effective choices.
• Dusk to Dawn – Avoid exposure during peak Culex mosquito feeding times, from dusk through dawn.
• Dress – Wear long sleeves and pants to keep mosquitoes from biting.
• Drain – Remove standing water in your yard or garden to minimize mosquito breeding areas.

For more tips on what you can do to prevent the West Nile virus, visit Larimer.gov/westnile.