Cases of an unusual fungal infection, called histoplasmosis, have shown up in Montana and Idaho. The Histoplasma capsulatum fungus is something commonly found in the Ohio River and Mississippi valleys, but it has not previously appeared in Montana.
Not just a fluke
According to a report by the U.S. Centers for Disease Control and Prevention (CDC), it was first thought that its appearance might be a fluke where someone traveled out of state and was infected before returning home.
That is clearly not the case as a total of five people have been infected in Montana and one in Idaho. Of those infected people, three needed to be hospitalized, and another has died. None of the people had been involved in any recent travel.
While it is not immediately a cause for alarm, as the fungus is treatable, the problem is the diagnosis. Doctors who are evaluating patients need to be aware that histoplasmosis can cause people to develop pneumonia-like symptoms.
Knowing what to test for is crucial
“It’s a very difficult disease to diagnose because it kind of mimics many other things,” explained Dr. Randall Nett, a medical officer for the CDC in Helena, Montana, who was also the lead author of the report. “Half of these people had been sick for more than six months before they were correctly diagnosed.”
The time these patients first visited a doctor until their official diagnosis ranged from one week up to 20 months. Four of the people had even undergone surgery before receiving their diagnosis.
According to Nett, three of the patients who were not diagnosed for more than six months was, “probably because they had reported no recent travel to H. capsulatum-endemic areas. Among these three patients, none had urine [enzyme immunoassay] testing for the presence of H. capsulatum antigen.”
Specific activities increased risk of infection
The source of these infections, the H. capsulatum fungus, is most often found in soil, particularly if there are bat or bird droppings in it. The spores of H. capsulatum are released into the air when the soil is disturbed.
In looking at the people who were infected, four of the six became sick after performing activities that raised their risk for contracting the fungus. These types of activities included cleaning bird cages, exploring caves, and working with potting soil that contained bat guano.
“The exposure to potting soil occurred in California; the other three exposures occurred in Montana,” said Nett.
Compromised health is also a risk factor
The physical activities were not the only thing that put these people at higher risk. While a normal, healthy person can inhale spores and not become ill, people with compromised health are definitely at an increased risk.
Five of the six people who became sick with the fungus already had compromised health from problems such as previous history of breast cancer, previous history of colon cancer, hepatitis C, active mononucleosis, and type 2 diabetes.
“We would ask folks in the community to be aware if they have a compromised immune system,” said Nett. “They should avoid high-risk activities.”
Use some caution
If you have a compromised immune system, try to avoid activities that involve disturbing soil that might be contaminated, or use protective gear. If you suspect an illness you have contracted could be histoplasmosis, you should consider asking your doctor to perform a noninvasive urine test called enzyme immunoassay.