Aw < 0.80, ERH <80% Aw < 0.80-0.90, ERH <80-90% Aw >0.90, ERH >90% waterAw: Minimum water activity level at 25°CERH: Equilibrium relative humidity
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.
Mouldy houses in the UKRICS 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.
Aspergillus fumigatus Ubiquitous organism. Most commonly reported opportunistic hyphomycete. Important in compost cycle. How did this grass eater become an opportunistic pathogen?
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?
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.
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
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
People live in mouldy houses: exposure to Aspergillus and more