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Climate change enables spread of fungal diseases in U.S., experts warn

Fungal infections are spreading outside their geographic niches due to climate change, and can be mistaken easily for more common viral and bacterial lung infections, experts warn. Photo by MCSA Joshua Adam Nuzzo/U.S. Navy
Fungal infections are spreading outside their geographic niches due to climate change, and can be mistaken easily for more common viral and bacterial lung infections, experts warn. Photo by MCSA Joshua Adam Nuzzo/U.S. Navy

Nov. 21 (UPI) -- Climate changes in temperature and rainfall are enabling the spread of certain fungal lung diseases beyond their traditional geographic hot spots in the United States, and doctors commonly miss the diagnosis.

That's according to two experts -- including Dr. Tom M. Chiller, chief of the Centers for Disease Control and Prevention's Mycotic Diseases Branch, which targets fungal diseases -- whose commentary was published Monday in the Annals of Internal Medicine.

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Chiller and Dr. George R. Thompson III, the commentary's lead author, who specializes in caring for patients with invasive fungal infections, said their aim is to heighten clinicians' awareness because such fungal infections, known as mycoses, can inflame the lungs and easily be mistaken for more common viral and bacterial lung infections.

And this is causing delays in proper treatment and the use of unneeded, ineffective antibiotics in the latter instance, they said. They urged national surveillance, better reporting of fungal diseases and a push to find a vaccine to prevent infection.

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The experts' commentary focused on the geographic spread and risk from the three endemic fungal diseases that are most prevalent in North America: histoplasmosis, blastomycosis and coccidioidomycosis, known as Valley fever.

Symptoms of all three diseases may include fever, chills, cough, night sweats and fatigue, and cause lung infections that mimic pneumonia, Thompson and Chiller said.

While these three fungal diseases usually inhabit specific U.S. regions that are conducive to their survival, recently more cases are being found "outside their known areas, taking clinicians and patients by surprise," Thompson said in a news release.

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Valley fever, for example, has been found in Nebraska, as well as Washington state, well beyond its traditional hot spots in California and Arizona, according to the commentary.

This fungal infection, caused by coccidioides organisms, can cause symptoms such as a fever, cough and tiredness, according to the Mayo Clinic. The fungi are commonly found in the soil, and their spores can be stirred into the air by anything that disrupts the soil, such as farming, construction or even wind -- and then inhaled.

"The organisms are probably much more widespread than we originally thought. There is an increasing likelihood that clinicians who are not familiar with these organisms will encounter them during their daily practice," said Thompson, a professor of clinical medicine at the University of California, Davis, School of Medicine.

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He has a joint appointment in the departments of internal medicine and medical microbiology and immunology, and the division of infectious diseases.

Although fungal infections are "increasing in geographic reach and frequency," the commentators said guidelines on pneumonia from the American Thoracic Society and the Infectious Diseases Society of America don't offer specific testing or treatment recommendations -- and most practitioners may have little experience recognizing and treating them.

Also, the test panels typically used to diagnose respiratory infections don't include the fungal infections; and the serum antibody and urinary antigen tests used to spot them are typically available only from certain laboratories, the release said.

Even in traditional geographic areas for these fungal infections, underdiagnosis is common, the experts said in their commentary.

Roughly 20% of pneumonia cases in some parts of California and Arizona are caused by Valley fever, they said, and yet it typically takes more than three weeks after symptoms start to get the right diagnosis -- and antibiotics are inappropriately prescribed to more than 70% of these patients.

It might take even longer to diagnose histoplasmosis and blastomycosis, the commentators added.

In the United States, Histoplasma, the fungus that causes histoplasmosis, mainly lives in soil in the Central and Eastern states, particularly in areas around the Ohio and Mississippi River Valleys. the CDC says.

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Yet, the experts said it's now been found farther north, in Michigan, Minnesota and Wisconsin, as well as Alberta, Canada.

In October, the World Health Organization published its first global "fungal priority pathogens list," trying to prioritize infection-causing fungi of concern because of resistance to drugs or other challenges in order to develop effective strategies.

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