West Nile virus detected on the Hi-Line

The state government has confirmed that West Nile season has hit the state, with the virus found in six counties, including Blaine County, although no human infections have yet been detected.

Hill County Mosquito District Coordinator Terry Turner said today that the virus has not been found in Hill County yet, but with confirmed cases so close, people need to be cautious.

“So far so good. … So far we have tested negative, so no positive cases so far, but we’re pretty much surrounded,” Turner said. “I caution everybody to make sure that they use the DEET (insect repellent) in the late evening hours and early morning hours and all night long.”

The disease, most commonly spread by mosquitoes, has no symptoms in most people affected but about 1 in 5 will will develop symptoms that can cause problems for weeks or months, and some — about 1 percent of people infected — will develop severe illness that could cause permanent damage or death.

Officials urge people to reduce the amount of standing water on their property and to protect themselves with the proper clothing and insect repellents to reduce the chance of infection.

This year has been a banner year for mosquitoes on the Hi-Line, with the high amount of water that both brought flood disaster declarations and abundant water for crops also bringing good breeding conditions for the insect. The warmer weather in recent weeks also speeds up the development of the insect, bringing about more mosquitoes and a chance of more bites and infections.

Montana Department of Health and Human Services, Carroll College and Montana State University said Thursday that mosquitoes with the virus have been confirmed in Cascade, Blaine, Prairie, Sheridan, Phillips and Teton counties.

A pelican also tested positive near Medicine Lake National Wildlife Refuge in Sheridan County, the press release said.

Health and Human Services said 174 human cases have been reported across the nation this year, with the highest rates in North Dakota and South Dakota.

Last year, six human cases of West Nile virus were reported in Montana, including one death.

While most people infected with West Nile will develop no symptoms and likely never know they were infected, the Centers for Disease Control reports, about 20 percent will suffer a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea or rash. Most people with this type of West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months.

A small amount of people infected — fewer than 1 percent — will develop serious neurological illness, with symptoms including headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis. Recovery from severe disease could take several weeks or months, and some of the effects could be permanent. About 10 percent of people who develop these neurologic infections due to West Nile virus will die.

People with certain medical conditions, such as cancer, diabetes, hypertension and kidney disease are also at greater risk for serious illness.

There is no vaccine, and there is no treatment for the virus, only the symptoms. The most effective way to avoid being infected is to avoid mosquito bites.

Health officials recommend people who are outside wear long-sleeved shirts and long pants to avoid being bitten by the insect, especially during the evening when the mosquito that bears West Nile virus, the culex mosquito, is most likely to be out.

Using insect repellent, such as those containing DEET, picaridin, IR3535, some oil of lemon eucalyptus and para-menthane-diol, also is recommended.

And a main way to avoid being bitten is to reduce the number of mosquitoes in the area.

While the Hill and Blaine county mosquito district personnel spray to kill adult mosquitoes whenever the weather allows — the night must be almost windless, and with no rain — people draining water from their property reduces the breeding grounds for the insects.

Pellets also are available from the districts to put in standing water which prevents the larvae from metamorphosing into adult mosquitoes.

People can reduce the amount of standing water in which mosquitoes breed by changing the water in containers such as dog drinking dishes or bird baths at least once a week, and emptying any containers that have collected water and making sure rain gutters and tarps or covers such as for a swimming pool are emptied and dry.

One cup of water can breed 250 mosquitoes, while a 5-gallon can half-full of water can breed 10,000 of the insects.

A particular problem is water in old tires. The combination of standing water and the heat generated in the tires speeds up the life cycle, with thousands of mosquitoes potentially hatching out in just a few days.

Online: Centers for Disease Control and Prevention: http://www.cdc.gov/westnile/index.html

American Mosquito Control Association: http://www.mosquito.org/