Windsor man hospitalized with severe strain of West Nile virus

A Windsor man has been hospitalized with a neuro-invasive strain of West Nile virus, according to the Weld County Department of Public Health and Environment.

The neuro-invasive strain is the most serious form of infection, and it can lead to hospitalization, critical illness, chronic disability or death.

A Greeley woman is also recovering from the mosquito-transmitted virus. The two cases are the first confirmed human cases this year in Weld County. Two other potential cases are under investigation.

In Larimer County year to date, there have been three confirmed cases of West Nile. There was also one case in an asymptomatic blood donor and two cases currently under review, according to Katie O'Donnell, a spokeswoman for the Larimer County Department of Health and Environment.

Blood donations are screened prior to distribution to ensure recipient safety. Blood donations that test positive for West Nile are discarded and not used for transfusions, county health officials said.

Last year, there were 32 confirmed human cases of the virus in Larimer County.

Larimer County is among counties in the nation with the largest number of human West Nile cases, according to U.S. Geological Survey data. Various Northern Colorado municipalities have different policies regarding spraying for mosquitoes. 

Before the city of Fort Collins will consider spraying, the vector index — a measurement of infected mosquitoes — has to reach 0.75 in one of the city's four zones. The city also won't spray unless two human cases of West Nile virus are confirmed in city limits within one week. Some other Northern Colorado municipalities spray based on lower vector indices or on the sheer number of mosquitoes.

Weld County officials said they'll end mosquito trapping and testing Aug. 31, but people are at risk of infection until the first hard frost later this fall. Last year, there were 27 confirmed human cases in Weld County. 

The first Larimer County, West Nile virus-infected mosquito of the season was trapped in Berthoud in late June. Fort Collins and Loveland will test through the end of August.

West Nile symptoms can appear three to 14 days after an infection, with initial symptoms such as fever, headache, nausea, vomiting, muscle aches, weakness and rash. However, most infected people don't exhibit symptoms.

Reporter Cassa Niedringhaus covers breaking news for the Coloradoan. Follow her on Twitter: @CassaMN.

How to prevent West Nile

To avoid infection, follow the 4 D's:

• Use DEET or other effective mosquito repellent — Use an EPA-registered mosquito repellent that has been proven to be effective against West Nile virus-carrying mosquitoes.  DEET, Picaridin, Oil of Lemon Eucalyptus (also called p-menthane-3,8-diol or PMD) and IR3535 are good choices.
• Dusk to dawn — Avoid exposure during peak Culex mosquito feeding times, from dusk through dawn. 
• Dress — Wear long sleeves and pants to keep mosquitoes from biting.
• Drain — Remove standing water in your yard or garden to minimize mosquito breeding areas.

​​​​​​​Source: Weld County Department of Health and Environment