Aspergillus is a common type of fungus (mould).

It can be found in many places including heating or air conditioning systems and rotting material such as hay or compost. Find out more about how to stop aspergillus growing in your home.

Small particles (spores) of aspergillus which float in the air can be breathed into your lungs. This normally doesn’t cause any problems as the particles are destroyed by your body’s immune system.

But if they’re inhaled by someone with a weakened immune system or lung condition such as asthma or cystic fibrosis it can cause a range of problems. These include chest infections caused by growth of aspergillus or symptoms related to an allergic reaction to the aspergillus.

Because this condition is rare, it may take some time to get a diagnosis. Your doctor will need to consider other possible causes of your symptoms. You may need to have a few tests and you might need to see a specialist.

You can’t catch aspergillus from another person.

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Last medically reviewed: December 2016. Due for review: December 2019

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.