2 Human Cases of West Nile Virus Diagnosed in Weld County

Published on August 13, 2021

Culex Mosquito

Weld County, Colorado — Two individuals in Weld County have been diagnosed with West Nile virus (WNV). Both individuals are adult females, one of whom is currently hospitalized with serious neuroinvasive disease. The other is recovering at home from febrile illness. Although these are the first human cases of WNV in Weld County in 2021, there have been three positive raptors and three equine cases in the county since July 18, 2021. Compared to a five-year average, the number of Culex mosquitoes, which carry WNV, has been higher throughout the summer. The onset date of this year’s first human case, however, is in line with the onset date of the first human case in previous years.

Most people infected with WNV will not show any symptoms, and only one in five will develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. People who have WNV fever typically recover on their own, but fatigue and weakness can last for weeks or months. Only about 1% of people infected with WNV will develop a serious neurologic illness, such as meningitis or encephalitis, which require hospitalization. Individuals with the more serious form of the disease can die from the illness or have debilitating symptoms for the rest of their life.

WNV is carried by birds and transmitted by mosquitoes that bite the infected birds. Infected mosquitoes can then transmit the virus to humans, horses, and other birds. WNV symptoms usually appear 3-14 days after being bitten by an infected mosquito. Although serious illness can occur in anyone, those residents who are over 60 years old or who have certain medical conditions that may weaken the immune system are at a greater risk for serious illness. There are no medications to treat WNV or vaccines to prevent infection. County health officials recommend the four D’s to prevent mosquito bites and to reduce breeding areas:

  • 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. Always follow label instructions carefully.
  • DRESS in long sleeves and pants in areas where mosquitoes are active.
Tagged as: