Health Officials Warn Montanans As West Nile Virus Resurfaces

Aug 16, 2019


The West Nile virus, the leading mosquito-borne disease in the U.S., has just been detected for the first time this year in mosquitoes in three counties in south-central, central and northeast Montana. And public health officials are urging everyone to take precautions.

The detections were in Yellowstone, Cascade and Sheridan Counties.

There are no vaccines or treatments for the disease so prevention is the key says Erika Baldry, communicable disease epidemiologist with Montana’s Department of Public Health and Human Services.

“So the best way we can prevent from being infected with West Nile Virus is to actually prevent a mosquito bite,” says Baldry.

Baldry says we should think of preventions as the four D’s of DEET: drain, dusk and dawn and dress. Use DEET or other insect repellent. Drain standing water around the house. Stay indoors during dusk and dawn or use other precautions. When possible, dress in long sleeves and pants.

Most people who become infected with West Nile have no symptoms. One in five will have mild symptoms such as headache, body ache, vomiting or rash. But Baldry says one out of 150 may become severely ill.

“This is where we could have inflammation of the brain or the individual may experience other neuro-invasive signs and symptoms,” she says.

This could include encephalitis or meningitis.

She urges anyone experiencing signs or symptoms to see a healthcare provider.

Baldry says last year there were 47 symptomatic human cases of West Nile virus in Montana. That’s the third highest number of cases since 2003, the year when West Nile virus was first detected in Montana.

Editor's Note: This story was updated Monday, August 19 to include the three counties where West Nile virus has been detected this year.