Fungal infections are becoming more common as their range expands

Fungal infections are more common than doctors or patients realize, research shows. And they are expected to grow even more in the years to come.

“We are definitely seeing disease in places that we haven’t seen before,” said Dr. George Thompson, an infectious disease specialist at the University of California, Davis. “And it’s worrying, because if we recognize these places, where are the places where this is happening that just hasn’t been recognized yet?”

Thompson co-authored a paper published Monday in the journal Annals of Internal Medicine, which suggests that more than 10% of fungal infections are diagnosed outside regions where the pathogens are known to be endemic. In addition, according to the document, misdiagnoses and lack of data make it difficult to know the true prevalence of cases.

This is becoming a more pressing issue, as research shows that climate change is making these infections more diffuse. For example, coccidioides, the fungus that causes valley fever, thrives in desert climates, so increased heat and drought has created more hospitable areas for its growth.

Sedona, Arizona, 2009. Carol M. Highsmith/Getty Images File

Meanwhile, the histoplasma fungus, which can cause an illness characterized by fever, cough and fatigue, tends to survive longer in high humidity – a condition that also becomes more common as temperatures rise. increase. Additionally, histoplasm is found in soil that contains large amounts of bird and bat droppings, and climate change is altering the migration patterns of some of these species.

People usually get fungal infections after inhaling spores. Often the immune system fights off these invaders or the infections lead to mild flu-like symptoms that go away on their own. But some people – usually those with weakened immune systems – can develop life-threatening illnesses such as pneumonia or meningitis.

“The vast majority of people who get valley fever will tell you that they have a cough that lasts a few weeks and goes away,” said Dr. Arturo Casadevall, a microbiologist and immunologist at Johns Hopkins University School of Medicine. “But when people are immunocompromised or when they’re just unlucky because they’ve had a very high dose, these diseases can spread or come out of the lungs.”

Typically, different fungal infections are associated with specific regions: Valley fever is most common in the southwest, for example, while histoplasmosis is mostly identified in central and eastern states. . But the coccidioides fungus was found in Washington soil in 2014.

Thompson’s article came just weeks after another study found high rates of diagnoses of fungal diseases far outside their traditionally understood geographies. The researchers found that 94% of US states had at least one county with a significant number of histoplasmosis cases and 69% had at least one county with a significant number of Valley fever cases.

“Over the past few years, I’ve started getting a lot of requests for help with these illnesses,” said Andrej Spec, a co-author of this paper and an infectious disease specialist at Washington University School of Medicine in St. Louis. . “Frequently I would get a request that started, ‘Interestingly enough, we don’t have this disease in Massachusetts. But here’s a patient who’s never traveled from Massachusetts and he’s got it, it’s funny. But I’m like, ‘You got it; it’s just that the maps are outdated.

The last study that updated geographic distributions of pathogenic fungi in the United States based on patient data was in 1969, according to the study by Spec.

Globally, a 2019 analysis determined that fungal infections were increasing and suggested that fungi may often be overlooked as sources of infection. A World Health Organization report in October also found that serious fungal infections have become more prevalent in people with pre-existing health conditions during the Covid pandemic.

Climate change isn’t the only factor likely to fuel this trend, Casadevall said. Increased travel to places where fungal infections are more prevalent could play a role, and doctors could better diagnose infections in places where they had previously gone undetected.

But Casadevall said many U.S. hospitals don’t report fungal infections to the CDC, and the agency has historically not prioritized collecting that data because fungi don’t typically cause outbreaks. The CDC received more than 20,000 reports of valley fever and approximately 1,100 reports of confirmed or probable histoplasmosis in 2019.

Thompson and other infectious disease experts are calling for national surveillance of fungal infections and urging doctors to test them more often.

Fungal infections aren’t easily detected during routine tests, so if doctors don’t know it could be a risk, they may not order the appropriate tests. The later a diagnosis, the longer it takes to treat a patient, which can lead to higher medical costs and an increased risk of serious illness or death. In some cases, fungal infections can take months of treatment to clear up and can become chronic.

Dr David Denning, chief executive of Global Action for Fungal Infections, an advocacy and research group, said some rapid tests allow doctors to diagnose fungal infections within hours or minutes, but they are not widely available. available in the United States (the standard way of is to send a urine or blood sample to a lab and then wait several days for the result.)

“There are very few FDA-approved molecular tests for mushrooms,” Denning said. “The FDA rules are quite strict, which is a good thing, but it’s also a bad thing because all of Europe uses these tests and in the United States there are too many obstacles for these tests be routinely adopted.”

Many people go undiagnosed at all, Thompson said: “There’s probably a significant number of patients who were never directly diagnosed and really had a lot more morbidity from their disease.”

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