City and County of Denver, CO

08/02/2024 | Press release | Distributed by Public on 08/02/2024 10:16

Mosquito Sample in Denver Tests Positive for West Nile Virus

Mosquito Sample in Denver Tests Positive for West Nile Virus

Published on August 02, 2024

The Denver Department of Public Health & Environment (DDPHE), in collaboration with the Colorado Department of Public Health (CDPHE), has confirmed that mosquitoes collected in Denver have tested positive for West Nile Virus.

Denver conducts routine testing of adult mosquitoes for West Nile Virus from mid-June through mid-September. The testing involves weekly trappings from five locations across the city. Alongside virus surveillance, DDPHE takes proactive measures to mitigate mosquito populations by reducing breeding sites and applying larvicide to decrease larval mosquito survival.

West Nile Virus season in the adult mosquito population typically runs from mid-July through September, ending with the first freeze of the fall. CDPHE has confirmed seven human cases of West Nile Virus this year in Colorado, with four requiring hospitalization. No human cases have been reported in the City and County of Denver.

While everyone is at risk of contracting West Nile Virus, individuals over 50 years old or with weakened immune systems are at higher risk of developing serious illness. Common symptoms include fever, extreme fatigue, headache, and body aches. In some cases, symptoms may also include skin rashes and swollen lymph nodes. These symptoms generally appear three to 14 days after being bitten by an infected mosquito. While most infections are mild, severe cases can lead to encephalitis (inflammation of the brain) or meningitis (inflammation of the brain's lining), which can cause loss of vision, paralysis, coma, tremors, convulsions, and even death.

Anyone experiencing these symptoms should consult a doctor. There is currently no treatment, cure, or vaccine for West Nile Virus, but medical professionals can provide supportive care to alleviate symptoms and aid recovery.

DDPHE encourages residents to remember the 4Ds to avoid getting infected with the virus:

  • Use insect repellent with DEET.
  • DRESS in long sleeves and pants when in areas with higher mosquito populations, like the mountains or garden.
  • Avoid the outdoors from DUSK until DAWN.
  • DRAIN standing water outside your home.

For more information about West Nile Virus in Colorado or mosquito activity data visit the CDPHE website. Learn more about Denver's mosquito management program in the DDPHE Environmental What If podcast.