A severe lung infection can develop when someone inhales the fungal spores of the three types of dimorphic fungi. Once thought to be confined to some areas of the United States, the risk of fungi-induced medical problems has become an alarmingly widespread concern. Historically, cases of lung infections caused by these specific fungi were mainly found in the Midwest and East, along with parts of the Southwest. However, new analyses from 2007 through 2016 indicate that the fungi have spread, causing increasing infection rates in over 35 states.
Although these three types of fungi traditionally have had “distinct geographic distributions,” climate change greatly contributes to the expansion of these endemic fungi beyond their natural habitats. According to UC Davis Health, changes in climate, temperature, and rain “are affecting where these fungi thrive.” Physicians relying on data from the 1950s and ’60s may fail to diagnose infections in patients outside the fungi’s historical borders. Subsequently, “missed or delayed diagnoses can have deadly consequences,” says Andrej Spec, an infectious diseases doctor and mycologist at Washington University School of Medicine in St. Louis.
The expanding geographic range of Histoplasma, Coccidioides, and Blastomyces fungi is causing the rise of serious lung infections. Named after the fungi that cause them, the conditions such as Histoplasmosis, Blastomycosis, and Coccidioidomycosis – also known as “Valley Fever” or “desert rheumatism” – vastly spread throughout the nation. These soil fungi grow particularly well in dirt that contains large amounts of organic matter (i.e., decomposing wood and leaves, bird or bat droppings, etc.). People generally get infected by breathing in the microscopic fungal spores released during the fungi’s normal life cycle by disturbing the fungi’s soil through farming, gardening, construction, road work, or archaeology.
Although most people that inhale these spores do not contract these fungal infections, in some, the fungi can transform into a rapidly-growing yeast that spreads through the lungs and cause a flu-like illness, pneumonia, or chronic disease. In a small percentage of cases, the fungi can spread to other parts of the body and cause more severe infections.
For example, Blastomyces can spread to bones and joints and could spread to the brain, where it can cause an abscess. It is possible for the fungi to start an infection in the skin through a cut, scrape, or wound, but such cases are extremely rare. Moreover, people generally can’t transmit the infection to one another, except on rare occasions when an infected person donates organs or other bodily tissue. Some people may develop symptoms like fever and cough.
In contrast, immunocompromised individuals with weakened immune systems can become severely infected, especially if it spreads from the lungs into other organs. Coccidioides spreads similarly to Blastomyces, targeting the bones, joints, skin, and the brain; however, instead of creating a brain abscess, it can cause meningitis which inflames the brain and spinal cord.
Adults and children with healthy immune systems who contract Valley Fever or other fungal infections may develop mild flu-like symptoms or no symptoms at all. Most people can fend off and recover on their own within a few weeks or months. Certain groups of people, such as older adults, infants, and individuals with immune-compromised symptoms, will be at a higher risk for developing severe forms of the infection and thus need antifungal medication and treatment. Symptoms of all three fungal diseases caused by Histoplasma, Coccidioides, and Blastomyces fungi are similar and can resemble the flu or other lung infections. Warning signs of a fungal lung infection may include:
Once airborne, Science News reports that “fungal infections and severe disease occur more often in men than women.” Researchers found no differences in the infection rates in those up to the age of nineteen, though, beyond that, the infection rate for males remained steady, while female infection rates dropped. Additionally, people of Filipino or African descent may be at an increased risk of developing more severe forms of Valley Fever, though the reason for this disparity is uncertain.
Those who are pregnant, have diabetes, HIV/AIDS, or have weakened immune systems from other causes are also at a higher risk of developing more severe illnesses from all three fungi.
Because symptoms of these fungal infections closely resemble other illnesses, such as Covid-19, tuberculosis, or bacterial pneumonia, it can be hard to diagnose the fungal disease. Though these infections are “more common than patients, doctors, and public health officials realize,” they are still relatively rare. The medical community needs to recognize the symptoms of these soil-dwelling fungi due to their quick spread throughout the U.S.
People with concerns about contracting a fungal lung infection can visit mycoses.org to view interactive maps where the fungi are found. According to Andrej Spec, “Any doctor can order a test, but infectious diseases specialists may have more expertise with the fungal diseases.” Spec encourages that “wearing a mask can also help limit exposure,” especially for those who are immunosuppressed or work in fields with a higher risk of potential exposure, such as landscapers, constructionists, and other environmental laborers.