NBC NEWS
A rare fungal infection thought to mainly occur in the northern Midwest and parts of the Southeast is more common in other parts of the U.S. than expected, new research published Wednesday finds.
The illness, called blastomycosis, can be difficult to diagnose, in part because it can resemble other respiratory infections. And the longer it goes undiagnosed, the more difficult it is to treat.
The infection is caused by a fungus called Blastomyces dermatitidis, which thrives in wet soil and decaying logs and leaves. Blastomycosis is considered an “endemic mycosis” — a type of fungal disease that only occurs in a particular geographic area.
While it’s well known in areas around the Great Lakes, the Ohio River valley and the Mississippi River valley, it’s a bit more surprising for the infection to pop up in Vermont, but that’s exactly what was found in the new study, published in the Centers for Disease Control and Prevention’s Emerging Infectious Diseases journal.
“Vermont is not generally an area you think of when you talk about blastomycosis,” said Dr. Arturo Casadevall, chair of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health. But “there have been several papers recently suggesting that fungal infections are on the move across the country and this is one of them.”
Dr. Brian Borah, medical director for Vaccine-Preventable Diseases Surveillance at the Chicago Department of Public Health, who led the study, said, “It’s a big question whether we were able to detect cases that were unknown to us previously, or if we are detecting an increase in cases.”
The epidemiology of other fungal diseases nationwide has been changing, however, Borah said, adding, “I don’t think blastomycosis would be immune from those patterns.”
Blastomycosis is rare, and can cause respiratory symptoms, fever and body aches in about half of the people who are infected from inhaling the Blastomyces spores. Most cases are mild, but if left untreated, blastomycosis can cause serious illness or death.
“One of the great problems with fungal diseases is that they are unreportable,” meaning public health departments don’t require doctors to report cases of the illness they see to the state, said Casadevall, who was not involved with the new study.
Only five states — Arkansas, Louisiana, Michigan, Minnesota and Wisconsin — have public health surveillance for blastomycosis. That means the prevalence of the disease outside these states is unknown.
Borah, who was previously a CDC epidemic intelligence service officer assigned to the Vermont Department of Health, said that there had been some reports of blastomycosis cases in the Northeast, including from a couple of studies as well as anecdotal reports from doctors and veterinarians in Vermont.
Without public surveillance, Borah and his team turned to health insurance claims to determine how many patients were treated for blastomycosis in Vermont from 2011 through 2020.
The data included all claims from Medicare and Medicaid recipients in the state and about 75% of Vermont residents who had other health insurance. They identified 114 cases during the 10-year period, and 30% required hospitalization. With an average rate of 1.8 cases per 100,000 people every year, Vermont…
