Where Aspergillosis Comes From

Aspergillus up close

Microscopic image of Aspergillus fumigatus

Aspergillus lives in the environment

Aspergillus, the mold (a type of fungus) that causes aspergillosis, is very common both indoors and outdoors, so most people breathe in fungal spores every day. It’s probably impossible to completely avoid breathing in some Aspergillus spores. For people with healthy immune systems, breathing in Aspergillus isn’t harmful. However, for people who have weakened immune systems, breathing in Aspergillus spores can cause an infection in the lungs or sinuses which can spread to other parts of the body.

I’m worried that the mold in my home is Aspergillus. Should someone test the mold to find out what it is?

No. Generally, it’s not necessary to identify the species of mold growing in a home, and CDC doesn’t recommend routine sampling for molds. For more information about indoor mold, including cleanup and remediation recommendations, please visit CDC’s Basic Facts abBasic Facts about Moldout Mold web page.

Types of Aspergillus

There are approximately 180 species of Aspergillus, but fewer than 40 of them are known to cause infections in humans. Aspergillus fumigatus is the most common cause of human Aspergillus infections. Other common species include A. flavus, A. terreus, and A. niger.