By Jennifer McRae

WELD COUNTY, Colo. (CBS4)– For the first time this season, West Nile Virus has been detected in mosquitoes in Weld County. County officials say that Culex mosquitoes, the ones that carry West Nile Virus, are more prevalent than in previous years.

They say this year, compared to the five-year average, the Culex mosquito count is over three times higher this mosquito season.

A culex tarsalis mosquito (credit:

“The increasing hot weather and afternoon thundershowers have created favorable conditions for the Culex mosquito that carries West Nile virus,” said Mark Lawley, Executive Director of the Weld County Health Department, in a statement.

There are no West Nile Virus cases in humans in Weld County so far this season.

“The public needs to be vigilant because West Nile virus has a permanent summer presence in Colorado,” Lawley said in a statement.

According to Weld County health officials, West Nile virus symptoms can appear 3-14 days after infection. Initial symptoms can include fever, headache, nausea and vomiting, muscle aches and weakness, and rash, but most infected people don’t show any symptoms. If a person develops symptoms, they should see a health care professional immediately. There are no medications to treat or vaccines to prevent WNV infection. Less than 1% of infected people develop a serious, sometimes fatal, neuroinvasive illness. Health officials recommend following the four “D’s” to prevent mosquito bites:

  • DRAIN standing water around your house weekly. Remember to drain water from tires, cans, flowerpots, clogged rain gutters, rain barrels, toys, and puddles.
  • DUSK and DAWN are when mosquitoes are most active. Limit outdoor activities and take precautions to prevent mosquito bites during these times.
  • DEET is an effective ingredient to look for in insect repellents. Other repellents containing picaridin, IR3535, oil of lemon eucalyptus, or para-menthane-diol are also effective against mosquitoes. Always follow the product label instructions carefully.
  • DRESS in long sleeves and pants, and a hat, in areas where mosquitoes are active.

Jennifer McRae