First Positive West Nile Virus Mosquitoes Found in Larimer County

Larimer County, Colorado –  The first positive West Nile virus mosquitoes of the year in Larimer County have been detected. They were found in the southwest area of Loveland. So far this year, no human cases of West Nile virus have been reported in Larimer County.

West Nile disease is a viral infection which 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. Although rare, some 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 and towns, a mosquito abatement company (Vector Disease Control International), and Colorado State University to monitor and assess the risk to Larimer County residents.

“As we enter mosquito season, it’s critical for everyone to take steps to protect themselves and their families from mosquito bites, which can transmit West Nile virus. Adopting simple safety measures, such as applying insect repellent, wearing long sleeves and pants during dusk and dawn, and eliminating standing water around your home can significantly reduce your risk,” says Tom Gonzales, Larimer County Public Health Director.

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 an EPA-registered mosquito repellent that has been proven to be effective against West Nile virus-carrying mosquitoes.  DEET, Picaridin, Oil of Lemon Eucalyptus, 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 West Nile virus, visit

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