September 01, 2021

Fungal lung infections

Persistent pneumonia is a clue

There are multitudes of different fungi on Earth — mostly found in soil, trees, air and water. Most of these fungi typically don't cause problems for healthy people. Still, fungal lung infections, which are often misdiagnosed, can cause serious illness for those with weakened immune systems. They are also on the rise, in part due to increased travel and environmental changes.

Two main categories of fungi infect the lungs: opportunistic and endemic. Opportunistic fungi are those that are able to cause infection only under certain health circumstances. For example, the opportunistic fungus aspergillus — found in soil, plants and house dust — can cause the lung infection aspergillosis in people with weakened immune systems. This fungus is also turning up in people with acute respiratory distress syndrome (ARDS), including those infected with the COVID-19 virus.

Endemic fungi are continually present in certain regions and are able to produce infection in a healthy host. Several types of endemic fungi are discussed below.

Valley fever

Valley fever (coccidioidomycosis) is caused by the fungus coccidioides, which lives in the soil and is endemic to the southwestern U.S. and parts of Mexico, Central America and South America. It was also recently found in south-central Washington state. In fact, the incidence of valley fever has risen significantly in the last 20 years, and some scientists predict that the disease's range will more than double this century. Climate change, which is producing more dust storms, may be contributing to this increase.

Rates of valley fever are typically highest among people age 60 and...