First West Nile virus death confirmed in Larimer County

Jenn Yingling

A Fort Collins resident has died after contracting a form of West Nile virus, marking the first fatal case in Colorado this year.

West Nile disease is an infection which spreads to people through bites from infected Culex mosquitoes.


According to a press release sent out by the Larimer County Department of Health and Environment, the resident contracted a neuroinvasive form of the virus. Neuroinvasive West Nile infections can include meningitis, encephalitis, and paralysis.

West Nile was confirmed in Fort Collins mosquitos earlier this year. Four cases of West Nile virus were reported in Larimer County this year, of which two were neuroinvasive cases. 

According to the release, 75 percent of people who are infected with the virus are asymptomatic, while around 25 percent develop West Nile fever. An average of 1 percent of people develop the neuroinvasive form, which can lead to critical illness, disability, or death.

“We see cases every year,” said Katie O’Donnell, the Larimer County Department of Health and Environment Public Information Officer. “(The cases) vary depending on the year we have.”

According to the press release, infection rates can be high even while mosquito numbers are often lower in September.

“This is about the time of year we see infection reports increase,” O’Donnell said. “Protect (yourself) until the first frost. We aren’t done with the season quite yet.”

The prevention of West Nile virus is encouraged via:

  1. The use of an EPA-registered mosquito repellent.
  2. Avoiding exposure from dusk through dawn, peak Culex mosquito feeding times.
  3. Wearing long sleeves and pants to prevent bites.
  4. Removal of standing water to minimize mosquito breeding areas.

Collegian news reporter Jenn Yingling can be reached at or on Twitter @jenn_yingling.