Lack of rain leads to drop in Valley fever cases

PHOENIX — A dry winter may be contributing to an increase in Arizona’s fire danger, but it’s also causing a drop in a common fungal infection.

The Phoenix area has had about an inch of rain all year and what seems like day after day of wind and dust. John Calgiani, head of the University of Arizona’s Valley Fever Center at St. Joseph’s Hospital and Medical Center in Phoenix, said the real driver for Valley fever cases is rainfall.

“The lack of rainfall may not have supported the fungus in the soil,” he said. “With there being so little rain this past winter there could be fewer cases to fall.”

Calgiani said, even though there’s a lot of dust blowing around, the Valley fever spores aren’t along for the ride. Valley fever is caused by a fungus that lives in soil in the southwestern United States. Inhaling the airborne fungal spores causes the infection. Most people who are exposed to the fungus do not get sick, but some people develop flu-like symptoms that may last for weeks or months.

There were 16,000 Valley fever cases in Arizona in 2011. This year, Calgiani expects to see about half of that number. About 60 percent of all cases happens in three Arizona counties — Pima, Pinal and Maricopa.

Calgiani said doctors are much more aware of what to look for now when it comes to diagnosing Valley fever.