Causes of aspergillosis 

Aspergillosis is caused by breathing in small particles of a mould called aspergillus.

In most healthy people, the immune system is able to quickly destroy the mould before it causes any problems. However, symptoms can develop in people with a pre-existing lung condition or a weak immune system.

Aspergillosis isn't contagious, so it can't be passed from person to person.

Aspergillus mould

Aspergillus mould is found in all countries and in many different environments. This makes it difficult to avoid.

Aspergillus mould can be found in:

  • rotting leaves and compost
  • plants, trees and crops
  • air conditioning and heating systems
  • insulation material
  • carpets
  • pillows and bedding 
  • dust
  • ground pepper and spices

Who's most at risk?

Aspergillus can cause aspergillosis if you have a health problem affecting your lungs, or your immune system is weak.

You may be at risk of aspergillosis if you have:

  • asthma – a common long-term condition that can cause coughing, wheezing, chest tightness and breathlessness
  • cystic fibrosis – a condition in which the lungs and digestive system become clogged with thick, sticky mucus
  • chronic obstructive pulmonary disease (COPD) – a group of lung conditions that affect breathing
  • tuberculosis (TB) – a bacterial infection that mainly affects the lungs
  • sarcoidosis – where small patches of swollen tissue develop in the lungs
  • HIV or AIDS – conditions in which the immune system is weakened
  • current or recent cancer treatment – including radiotherapy and chemotherapy
  • an organ transplant – as you'll need to take medication that weakens your immune system

If you're at risk, you may need to take extra precautions to prevent aspergillosis – for example, by wearing a face mask near dusty environments, avoiding activities such as gardening, or taking long-term antifungal medication.

Read more about preventing aspergillosis.

Page last reviewed: 30/09/2015

Next review due: 28/02/2018