A Fungus Causes More Unexpected Illnesses In Montana

By Nancy Shute

Published May 14, 2015 at 12:50 PM EDT

Cough? Check. Fever? Check. But bet you didn't think that this common fungus, <em>Histoplasma capsulatum</em>, could be making you sick. — Cough? Check. Fever? Check. But bet you didn't think that this common fungus, *Histoplasma capsulatum*, could be making you sick.

If you go to the doctor with a cough and fever, odds are you're not thinking you could have an unusual fungal infection — and neither is the doctor.

That's why the Centers for Disease Control and Prevention wants to get the word out that they found more people sick with histoplasmosis in Montana and Idaho.

When we first heard about people out West getting histoplasmosis back in 2013, it was one of those gee-whiz infectious disease stories. The Histoplasma fungus is common in the Mississippi and Ohio River valleys, but infectious disease doctors hadn't seen it causing illness in Montana before. It could have been a fluke, they figured. Maybe people had gotten infected while traveling out of state.

But now they're reporting two more cases, bringing the total to five in Montana and one in Idaho. Three people were sick enough to be hospitalized; one died. The cases were reported Thursday in Emerging Infectious Diseases.

If you happen to be living in the Intermountain West there's no need to freak out, says Dr. Randall Nett, a medical officer for the CDC in Helena, Mont., and lead author of the report. There are medications that work on histoplasmosis, but doctors need to realize it can be the cause of pneumonia-like symptoms. "It's a very difficult disease to diagnose because it kind of mimics many other things," he tells Shots.

Half of these people had been sick for more than six months before they were correctly diagnosed, Nett says. A urine test detects it.

The Histoplasma fungus likes to hang out in soil, especially with bird or bat droppings. Four of the six people who fell ill had been doing things that increased their risk of infection, including working with potting soil, exploring caves and cleaning pigeon cages.

Most people who breathe in spores never get sick, the CDC says. But having other health issues ups the risk of life-threatening illness. Five of the six people had other health problems, including Type 2 diabetes, hepatitis C and active mononucleosis.

"We would ask folks in the community to be aware if they have a compromised immune system," Nett says. "They should avoid high-risk activities." That includes spelunking, demolishing buildings or other activities that kick up a lot of dust.