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Prevalence and residential determinants of fungi within homes in Melbourne, Australia
S Dharmage1, M Bailey, J Raven
1Department of Epidemiology and Preventive Medicine, Monash Medical School and The Alfred Hospital, Prahran, Victoria, Australia.
Background:
Recent epidemiological studies suggest that the adverse respiratory health effects caused by the inhalation of fungal propagules are substantial. Knowledge of the prevalence and environmental determinants of indoor fungal levels is essential in designing effective avoidance measures.
Aim:
To investigate the prevalence of fungi and the influence of residential characteristics on levels of fungi within homes in Melbourne, Australia.
Methods:
Floor dust and air samples were collected from bedrooms in 485 houses over 1 year. The dust was analysed for ergosterol, a marker of cumulative fungal biomass exposure. Total and genera-specific fungal propagules were identified in air samples. Details of the relevant residential characteristics were documented using a questionnaire. Independent predictors (P < 0.05) of ergosterol and total fungal propagules were identified by multiple linear regression.
Results:
Fifty-five percent of the houses had viable fungal propagules exceeding 500 CFU/m3. Cladosporium and Penicillium were identified as the most prevalent and abundant fungal genera in indoor air. The median ergosterol level in bedroom floor was 3.8 microg/g of dust. Multivariate analysis showed that total fungal propagules in indoor air were lower in bedrooms with a ceiling fan, without visible mould, and those that were more frequently vacuumed, had a solid fuel fire, had windows closed at the time of the sampling or lacked pets. The presence of more than one cat had the greatest effect on total fungal propagules. Ergosterol levels were significantly lower in homes without old fitted carpets, visible mould or pets and those with frequent airing and regular use of an extractor fan in the kitchen. Old wall-to-wall carpets had the greatest effect on ergosterol.
Conclusions:
High indoor fungal exposures were associated with infrequent ventilation or vacuuming, presence of pets, visible mould and old carpets.
Insights
High indoor fungal exposures, linked to respiratory issues, are common in homes. Reducing exposure involves better ventilation, regular vacuuming, and avoiding pets and old carpets.
Area of Science:
- Environmental Health
- Mycology
- Epidemiology
Background:
- Inhalation of fungal propagules poses significant respiratory health risks.
- Understanding indoor fungal prevalence and determinants is crucial for effective avoidance strategies.
Purpose of the Study:
- To determine the prevalence of indoor fungi in Melbourne homes.
- To investigate how residential characteristics influence indoor fungal levels.
Main Methods:
- Collected floor dust and air samples from 485 homes over one year.
- Analyzed dust for ergosterol (fungal biomass marker) and air for fungal propagules.
- Used multiple linear regression to identify predictors of fungal levels.
Main Results:
- 55% of homes exceeded 500 CFU/m3 of viable fungal propagules.
- Cladosporium and Penicillium were the most common airborne fungi.
- Lower fungal propagules associated with ceiling fans, no visible mold, frequent vacuuming, and closed windows.
- Higher ergosterol levels linked to old carpets, visible mold, and pets.
Conclusions:
- Infrequent ventilation or vacuuming, pets, visible mold, and old carpets correlate with high indoor fungal exposure.
- These factors are key targets for reducing indoor fungal contamination and associated health risks.