A University of Manchester team found up to 16 types of fungi in pillows they analysed, the Allergy journal reported.

Researchers said feather pillows had fewer species than synthetic versions, particularly in the case of a fungus which exacerbates asthma.

Experts advise disinfecting pillows but say fungi occur in most environments.

The researchers took samples from 10 pillows - five feather and five synthetic - which had been used for between 18 months and 20 years.

The fungal spores found in the pillows fed off human skins scales and dust mite faeces.