• Guest speakers Professor Darius Armstrong-James and Dr Iain Page

Aspergillus spp.

• Aspergillus is a ubiquitous environmental, saprophytic mould and the most common genus of mould to cause disease in humans
• Aspergillosis refers to the wide spectrum of disease caused by Aspergillus, ranging from allergic disease to acute invasive aspergillosis
• Exposure to Aspergillus spores is common, but disease only occurs in a minority of individuals, usually with specific risk factors
• The clinical presentation of aspergillosis depends on the host immune reaction to the fungus
• Aspergillus is a very large genus containing about 250 species
  • All may cause allergic disease
  • Over 20 are reported to cause invasive disease in human - of these the most common disease-causing species are: Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus and Aspergillus niger
• Aspergillus fumigatus accounts for the majority of infections and is a WHO critical priority fungal pathogen
• Rise in azole-resistant Aspergillus fumigatus infections, linked to the widespread use of azole fungicides in agriculture, is of particular concern

Taxonomy

The Aspergillus genus containing about 250 species which are classified into 7 subgenera, that are in turn subdivided into several ‘complexes’

Many species have overlapping morphological characteristics - species that cannot clearly be distinguished morphologically are clustered into ‘species complexes’ which include:

• Aspergillus fumigatus complex - include A. fumigatus sensu stricto and A. fumigatus-like species eg. A. lentulus
• Aspergillus flavus complex
• Aspergillus terreus complex
• Aspergillus niger complex
• Aspergillus nidulans complex

Epidemiology