Professor Malcolm Richardson, Clinical Mycologist

1. The life and times of
Aspergillus in the home
Prof Malcolm Richardson
Mycology Reference Centre
National Aspergillosis Centre
UHSM and University of Manchester

2. Our first encounter with Aspergillus

3. Aw < 0.80, ERH <80%
Aw < 0.80-0.90, ERH <80-90%
Aw >0.90, ERH >90%
water
Aw: Minimum water activity level at 25°C
ERH: Equilibrium relative humidity

4. WHO Dampness and Mould
 Occupants of damp or mouldy buildings are at increased risk of
respiratory symptoms, respiratory infections and exacerbation of
asthma
 Remediation of dampness can reduce adverse health outcomes
 There is clinical evidence that exposure to mould increases the risk of
allergic alveolitis, chronic rhinosinusitis and allergic fungal sinusitis
 Allergic people are particularly susceptible to biological and chemical
agents in damp building
 The increasing prevalence of asthma and allergies increases the
number of people susceptible to the effects of dampness and mould.

5. Mouldy houses in the UK
RICS Report :
‘ Mould in the Indoor Environment of
Dwellings in England’.
- Visible mould growth in 5.4% of properties
tested (65/~1200).
- Stachybotrys chartarum found in 12 homes.
- Aspergillus fumigatus found in 2 homes.
CONDENSATION/PENETRATING DAMPNESS.

6. Aspergillus fumigatus

7. Aspergillus fumigatus

8. Aspergillus fumigatus
 Ubiquitous organism.
 Most commonly reported
opportunistic
hyphomycete.
 Important in compost
cycle.
 How did this grass
eater become an
opportunistic pathogen?

9. A. fumigatus: Compost to Man
 Life is very competitive in a compost pile.
 What are some of the growth characteristics that enable
A. fumigatus to be successful in the environment that
may also allow it to be an opportunistic pathogen?

10. Nutritional Versatility: Compost to Man
 A. fumigatus plays a key role in recycling C and N in compost.
 Carbon sensing and utilization: pkaR and sakA.
 Nitrogen sensing and utilization: rhbA, areA, cpcA, & sakA.
 Auxotrophies: pabaA, pyrG, lysF.

11. Sources of Aspergillus
 Soil
 Air; spores may be inhaled: (100-200 spores daily)
 Water / storage tanks in hospitals
 Food
 Compost and decaying vegetation
 Fire proofing materials
 Bedding, pillows
 Ventilation and air conditioning systems
 Computer fans

12. Members of the family
 Genus of around 200 fungi (moulds) worlwide
 Filamentous fungus (opposed to single celled
 fungus), reproduction by spores
 A. fumigatus, A. flavus, A. terreus, A. niger,
A. clavatus

15. People live in mouldy houses: exposure to
Aspergillus and more

16. Mould and contents

17. Dust: a perfect home for Aspergillus!

18. More dust

19. Aspergillus is in the air!

20. What’s growing in the wall?

21. What’s growing in the wall?

22. In need of repair and clean up

23. Patient’s house

24. Patient’s house

25. How can we detect Aspergillus in
the home?

26. Aspergillus in dust

27. Air sampling

28. Air sampling: >1300 cfu/m3!

29. Aspergillus is found in A/C units

30. Patient’s house

31. Aspergillus is everywhere!

32. Aspergillus in the nursery

33. No home is spared!

34. Aspergillus in the garden