West Nile virus confirmed in Fort Collins mosquitos

Haley Candelario

A member of the mosquito species Culex quinquefasciatus sucks blood from a finger. There are two species out of 40 in Colorado that can transfer the West Nile virus. (Photo courtesy Wikimedia Commons)

Mosquitos in Fort Collins were confirmed to be carrying West Nile virus for the first time this season.

According to a press release from the City of Fort Collins, Culex mosquitos in the northeast and southeast sections of Fort Collins tested positive for West Nile virus, which is transmitted to humans by mosquitos.


The vector index — the amount of infected mosquitos in an area — is currently 0.203 in the northeast section of Fort Collins and 0.004 in the southeast section, according to the press release.

The City currently has no plans to spray pesticides to prevent the spread of West Nile due to its high standards for spraying. The City considers adult mosquito spraying when the vector index is 0.75 or higher in any of the four zones of the City, and when there are two confirmed human cases of West Nile virus during one week.

The City may consider spraying pesticides earlier at the reccomendation of the Health and Environment Department’s director, according to the press release.

When the vector index in Fort Collins reached 0.93 in August 2016, the City sprayed pesticides to prevent the threat of West Nile virus from growing.

The City urges residents to protect themselves from mosquitos by following the four D’s.

  1. Drain
    • Drain standing water near homes, since mosquitos breed near water.
  2. Dress
    • Wear long, lightweight clothing while outdoors to make it more difficult for mosquitos to bite the skin.
  3. Defend
    • Spray insect repellent on clothes and exposed skin.
  4. Dusk/Dawn
    • Spend less time outside during the early evening and early morning, since mosquitoes are most active during those times.

In 2016, there were 19 confirmed human cases of West Nile virus in Larimer County. So far this season, there have been no human cases of West Nile wirus in Fort Collins or in Larimer County. Only one human case of the disease in Colorado this year has been confirmed, according to the Coloradoan.

According to the Centers for Disease Control and Prevention, about 70 to 80 percent of people who contract West Nile virus do not experience any symptoms and less than 1 percent of people develop a serious illness from West Nile virus. At least 10 percent of cases concerning serious illness from West Nile virus result in fatalities. There is currently no cure for the disease.

Collegian news director Haley Candelario can be reached at hcandelario@collegian.com or on Twitter @H_Candelario98.