West Nile cases are turning up earlier than ever

West Nile virus is showing up earlier this year in Idaho.

This year’s first case in a human was diagnosed in late June, about a month earlier than in 2005, according to Department of Health and Welfare officials. And while there have been no infections yet in North Idaho, eight southern counties have documented infections – compared to 13 for all of 2005.

“Every year we think this is going to be the year” for North Idaho, said Susan Cuff, a spokeswoman for Panhandle Health District. “So far we’ve dodged a bullet.”

Washington has never had a reported human case, and so far this year the state has no documented cases of infected animals.

In 2002, a dead raven was found to have been infected with West Nile in Washington’s Pend Oreille County, which borders Bonner and Boundary counties in North Idaho.

Bonner County officials are especially concerned this year, because flooding has left widespread puddles where mosquitoes could breed, said David Hylsky, an epidemiologist with the Panhandle Health District.

Hylsky said determining the size of the mosquito population is difficult because Panhandle Health stopped setting surveillance traps last year. Judging from the number of phone calls about the pests – not counting a surge of recent calls from the flooded areas – the population seems about average.

More than 80 percent of West Nile virus cases in humans result in no symptoms, said Dr. Leslie Tengelsen, an Idaho Department of Health and Welfare epidemiologist. The other 20 percent generally involve mild flu-like symptoms like headaches, body aches and fever. Less than 1 percent of infections are fatal. Adults 50 or older are more likely to suffer a severe case of the virus, she said.

Tengelsen said the Owyhee County woman who suffered this year’s first case survived. The woman, who was not identified, is in her 40s, Tengelsen said.

Washington and Idaho have education campaigns on mosquito control and the West Nile virus. Officials tout these efforts as having sufficiently helped prevent its spread.

“Every year conditions change,” said Jeff Smith, a Washington State Department of Health spokesman. “Every year (infection is) a possibility.”

After detecting no West Nile in the state for two years, Washington officials in 2005 found the virus in two mosquitoes, a bird and a horse – all in Yakima County. Six cases in six counties had been documented in 2002 – the most documented infections in state history.

There are several types of West Nile vaccines for horses, and they have reduced the number of cases, Smith said. There is no West Nile vaccine for humans, however.

Tengelsen said she doesn’t want people to be overly concerned about West Nile.

“Go outside,” she said, “but wear bug spray.”