Discovery of horse with virus means West Nile definitely here

The Daily Inter Lake

Flathead County Health Officer Joe Russell said a horse diagnosed with West Nile virus means a reservoir of the disease exists here.

"Is it a large reservoir? I don't know," he said.

Russell said he was skeptical last year when a horse was found infected with West Nile because the animal had come from another area.

But the local case confirmed last week involved a native horse that had not traveled.

"This is definite," he said.

The Flathead horse brings the total to nine horses infected statewide with West Nile virus.

There were 20 human cases in Montana as of Sept. 16.

No human cases have cropped up in Flathead County. Custer County in eastern Montana had the largest number with seven people infected in 2005, followed by three in Yellowstone and two in Valley County.

No one has died of the virus this year. However, 11 people developed a fever while eight developed the severe symptoms of encephalitis or meningitis, inflammation of the brain and spinal cord.

Montanans infected with the disease since 2002 have ranged in age from 3 to 91. However, fatalities occurred with victims between the ages of 65 and 84.

Russell said the discovery of West Nile virus in the horse population means that county's bird population undoubtedly carries the virus.

This is significant because mosquitoes transmit the virus to humans and horses after feeding on birds. In Montana, crows, ravens, magpies and jays commonly carry West Nile virus.

Russell said the onset of fall and cold weather should soon eliminate mosquitoes and mitigate the spread of West Nile virus this year.

"All we know is we'll possibly have a reservoir [of virus] make it through the winter," Russell said.

With the formation of a countywide mosquito control district this fall, Russell said the district's board will have the winter to get a control plan together.

"It's going to be science-based," he said. "It's very timely."