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4 Human West Nile Virus Cases Confirmed In Colorado After Additional Weld County Residents Diagnosed

WELD COUNTY, Colo (CBS4) -- Weld County health authorities confirmed on Friday afternoon that two residents have been diagnosed with West Nile virus. One person is hospitalized with serious neuroinvasive disease, or an increased white blood cell count in the cerebrospinal fluid, the Weld County Department of Public Health and Environment stated in a press release.

The second person is recovering at home with a fever, the agency added.

The Colorado Department of Pubic Health and Environment earlier Friday announced the state's first positive tests for West Nile Virus this year came from one person each in Larimer and Delta counties.

West Nile Virus is most often transmitted by mosquitoes. Health officials believe mosquitoes acquire the virus by biting birds, and pass it along to animals and, in some cases, humans.

CDPHE indicated West Nile-positive mosquitoes have been found in Adams, Boulder, Delta, Denver, Larimer, and Weld counties this year. Weld County has seen three raptors and three horses test positive for the virus since July 18.

"Compared to a five-year average, the number of Culex mosquitoes, which carry WNV, has been higher throughout the summer," CDPHE stated. "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 West Nile Virus will not show any symptoms, health official say, and only one in five will develop a fever with other symptoms such as headache or body aches. Only about 1% of people infected with the virus will develop a serious neurologic illness, such as meningitis or encephalitis, which requires hospitalization.

There are currently no medications to treat West Nile virus 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.

For more information about West Nile Virus, visit

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