NewsCovering Colorado


West Nile virus found in Arapahoe County mosquitoes, bringing number of affected Colorado counties up to 5

State health officials warn residents to protect themselves as state expects active mosquito season due to recent rainy weather
Mosquitoes in Longmont test positive for West Nile Virus
Posted at 8:15 AM, Jul 10, 2023
and last updated 2023-07-10 10:15:05-04

ARAPAHOE COUNTY, Colo. – Arapahoe County on Friday became the latest in a growing list of counties across the state to report mosquitoes in their area had tested positive for West Nile virus.

No human cases have so far been reported, but nevertheless, state health officials and other experts are warning residents to protect themselves against the flying insects as the wet and cool spring and early summer we are experiencing is leading to a boom in mosquito populations due more standing water and most soil from our recent downpours.

In a news release Friday, Arapahoe County government officials said mosquitoes were found to be carrying the virus near the Arapahoe County Fairgrounds, adding that due to the wet weather in recent weeks, officials had already begun treating the fairgrounds with insecticide prior to the positive result for West Nile.

After Friday’s news, Arapahoe now joins Boulder, Delta, Larimer, and Weld counties with mosquitoes confirmed to be carrying the virus, officials said.

Most people infected with West Nile Virus don’t experience symptoms, but some can become seriously ill and even die.

Symptoms generally appear 2 to 14 days after exposure, with 1 in 5 people developing fever, body aches, headache and occasionally skin rashes and swollen nymph nodes.

The Colorado Department of Public Health and Environment (CDPHE) says most human cases of West Nile virus are reported in August and September. To protect yourself, the agency recommends:

  • Limiting activities outdoors at dusk and dawn, when mosquitoes are most active
  • Wearing long pants, long-sleeved shirts, and socks in areas where mosquitoes are active
  • Using an insect repellent containing DEET, picaridin, oil of lemon eucalyptus, or para-menthane-diol

Experts also recommend eliminating sources of standing water near your home, which can become a breeding ground for the mosquitoes that carry West Nile virus.