Readers ask about fungal lung infections

Fungi Q&A

Three types of fungi — Histoplasma, Coccidioides and Blastomyces — that cause serious lung infections were thought to be confined to certain regions of the United States. But now they are widespread in the country, Tina Hesman Saey reported in “Where fungal lung infections have spread” (SN: 1/14/23, p. 32).

The story prompted so many questions from readers about the symptoms, treatments and testing for these fungal infections that Saey answered them in a follow-up article online. An abridged version appears below.

How do you get infected?

People generally get infected by inhaling fungal spores. Human activities such as farming, gardening and construction can disturb the soil where these fungi live, stirring up spores. Bird droppings and bat guano can also be sources of Histoplasma. Sweeping dried droppings increases the risk that spores will get kicked into the air and inhaled.

When cleaning up bird and bat droppings, it’s best to first wet them with a hose. Wearing a mask can also help limit exposure.

What are the symptoms and treatments?

People with healthy immune systems may show no symptoms or may develop mild flulike symptoms, including fever, cough, fatigue, chills and body aches. Other symptoms may include chest pain or discomfort, weight loss, headache, muscle or joint pain, shortness of breath or night sweats.

People with coccidioidomycosis, also known as valley fever — the disease caused by Coccidioides — may also get a rash on their legs or upper body.

Symptoms can take time to appear. Those of histoplasmosis, the disease caused by Histoplasma, can develop between three and 17 days after exposure. Valley fever symptoms can appear between one and three weeks after exposure. For blastomycosis, the disease caused by Blastomyces, symptom onset can take anywhere from three weeks to three months.

Mild cases of all three infections usually clear up on their own in a few weeks to a few months. But some people may have lingering symptoms, especially if the infection becomes severe. Some people may develop severe or chronic pneumonia. And in a small number of people, the infections may spread to other parts of the body. For instance, Histoplasma tends to spread to the liver, spleen, bone marrow, adrenal glands and intestines. Blastomyces and Coccidioides often target joints. All three fungi can spread to the brain, where they may cause abscesses or meningitis — an inflammation of the membranes surrounding the brain and spinal cord.

Doctors can order blood or urine tests, chest X-rays or CT scans to help diagnose fungal infections. In some cases, doctors may need to test a small amount of body tissue or fluid from the spine or lungs.

Antifungal drugs and other medications can help treat infections and manage symptoms. If caught early, most people fully recover.

Who’s at risk?

Infections and severe disease from all three fungi occur more often in men than in women, but the reason is unclear. People who are pregnant, living with HIV/AIDS or have weakened immune systems for other reasons are at higher risk of severe disease. So are older people and those with diabetes.

Visit to assess your risk for fungal disease based on where you live.

Editor’s note

The study featured in “A newfound dinosaur had a flashy look” (SN: 1/16/21, p. 11) was withdrawn by Cretaceous Research in September 2021. In an email to Science News, journal publisher Lantice Brett stated that the withdrawal was due to ethical and legal concerns “regarding permissions for specimen export [which] remained unresolved nine months after [the study’s] initial publication.”