Valley Fever: Hidden threat in wind

Monday, Aug. 11, 2003 | 11:07 a.m.

A fungus that blows along with dust particles in Southern Nevada's dry winds has produced 21 cases of the respiratory illness known as Valley Fever so far this year.

Although the disease is not contagious, it can be a serious illness, health experts said. Anyone working or playing outside when winds kick up dust can inhale spores of the fungus, doctors said.

Michelle Bossler is one of those who contracted the infection, also called coccidioidomycosis.

The infection can be deadly.

In early June, while conducting an environmental survey about 30 miles south of Las Vegas, Bossler started having headaches, chills and a fever.

"I went home in the afternoon and went to bed," Bossler said. "It was like the flu. It hurt so bad, I felt like someone was sitting on my chest."

Her doctor suspected viral pneumonia, but then her fever rose and she broke out in a rash.

A visit to Valley Hospital Medical Center's emergency room brought a tentative diagnosis of Valley Fever. A series of tests proved inconclusive, but Bossler was so sick by then that she was hospitalized for 13 days.

The Mayo Clinic in Scottsdale, Ariz., on July 2 confirmed she had Valley Fever, after she had been released from the hospital, Bossler said.

"The physicians suspected it from the beginning and began three kinds of drugs," Bossler said. "I don't want this to happen to anybody else; people should be aware of it."

Darren Paulson, a University of Nevada, Las Vegas science student who assisted Bossler on the environmental study, also felt ill about a week later.

"I got it about a week after her and it was not as bad," Paulson said. He was not hospitalized and improved on his own, he said.

Dr. Eugene Speck, a Las Vegas infectious disease expert, said the illness is difficult to diagnose. A blood test or culture is used to detect it.

"The incubation period after coming in contact with the spores is roughly two weeks," Speck said.

This spring's rains provided a good breeding ground for the fungus, and the hot, dry, windy summer has effectively spread it, he said.

About 95 percent of the population exposed to the windborne fungus handle it without becoming severely ill like Bossler did, Speck said.

"It's very difficult to treat, but we're getting better and better drugs," Speck said.

Medicines used to treat the fungus include ketoconazole, itraconazole and fluconazole for mild to moderate levels of the disease and amphotericin B., given intravenously for severe cases, according to the Valley Fever Center for Excellence in Tucson.

The drugs work by inhibiting the fungus and allowing the body's immune system to fight it.

"In some instances, the fungus may never leave the body," Speck said.

Those living in a desert environment for long periods of time tend to build antibodies against the fungus, Speck said. Some people may develop a mild form of the disease, which builds resistance.

The fungus, Coccidioides immitis, produces spores that are inhaled when airborne. The spores are hardy and can live for a long time in the harsh desert environments of California, Arizona and Nevada, state epidemiologist Dr. Randall Todd said.

The Las Vegas Valley has reported 21 cases of the disease this year, Todd said. Washoe County has had 11.

Of the 368 cases of Valley Fever confirmed in Nevada from 1992 to the present, 336, or 90 percent of them, occurred in Clark County, Todd said.

The number of cases is increasing because more people are moving into the areas where the disease is common, both Todd and Speck said.

Cases in Clark County have ranged from a low of 20 in 1995 to a high of 57 in 1993.

The weather could have caused the fluctuations.

During dry years, such as 1993, there is probably more dust airborne, Todd said. Wetter years, such as 1995, don't produce as much blowing particles and reduces exposure risks.

Natural disasters can trigger a rise in Valley Fever cases. Southern California had a four-year epidemic of the fungus in the early 1990s after a severe drought. There was also an increase after the 1994 earthquake in Northridge, Calif., Todd said.

Todd, who grew up in the San Joaquin Valley of California, said he almost certainly was exposed to the fungus.

"If you live all your life in one place, you'll probably show some antibodies to it," he said.

Most people have no symptoms from exposure to the fungus. Those who fall ill develop flu-like symptoms that can last for a month. Fatigue can last for longer than a few weeks.

Less than 1 percent of infected people develop the disease outside the lungs, in which case it is called disseminated disease. That means the fungus can spread to internal organs, joints or other parts of the body besides the lungs.

"Sometimes it can reactivate, but that's kind of rare," Speck said.

Without proper treatment, the federal Centers for Disease Control and Prevention said, Valley Fever can lead to severe pneumonia, meningitis or even death.

Farmers, construction workers, military personnel and archaeologists, who all work with soil, are most likely to contract Valley Fever.

People with weakened immune systems are at increased risk for developing the disease. The elderly, blacks, Asians and women in the third trimester of pregnancy are also more susceptible.

An estimated 50,000 to 100,000 people develop symptoms of Valley Fever each year in the United States, with 35,000 new infections a year in California alone.