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Health Problems Associated with Indoor Moulds

Exposure to indoor mould has been associated with the following health problems:

  • respiratory symptoms such as coughing, wheezing
  • respiratory infections such as aspergilloses
  • allergic diseases, including allergic asthma and bronchitis
  • unspecific symptoms, e.g., eye and skin irritation, fatigue, headache, nausea, and vomiting.

The moulds most frequently encountered in indoor environment are Penicillium, Aspergillus, Chaetomium, Ulocladium, Stachybotrys, Cladosporium, Acremonium, Mucor, Paecilomyces, Alternaria, and Trichoderma. These moulds are all known to cause different types of inhalation allergy. Some moulds such as Chaetomium, Stachybotrys and Ulocladium thrive under very wet conditions. Their presence in indoor environment is an indication of water problem.

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Dampness, Mould, Mites and Allergy

Dampness in buildings is believed to increase asthma and allergy risks. Studies have shown that the risk of asthma, allergic rhinitis, and atopic dermatitis is higher in damp homes. This is partly because dampness encourages proliferation of micro-organisms such as moulds, bacteria and mites, some of which are well established and documented toxin producers or allergens. Dampness in homes and workplaces should therefore be controlled in order to reduce the risk of occupants developing respiratory problems.

The Mould Ulocladium

Ulocladium is a widely distributed mould commonly found in soil and decaying plants. It has also been isolated from paper, textiles, dung, emulsion paint, grasses, fibres and wood. In indoor environment, Ulocladium has been found on painted surfaces, damp wall finished with wallpaper or water based emulsion paint; floor and mattress dust.

Conidiophores and spores of Ulocladium spUlocladium has two known species; Ulocladium chartarum and Ulocladium botrytis. Ulocladium chartarum is the species most commonly found in indoor environment. Presence of Ulocladium in indoor environment together with other moulds such as Stachybotrys, Fusarium and Chaetomium is an indication of water damage.

Ulocladium has been reported to cause Type I (hay fever) allergy. There have been cases of Ulocladium chartarum causing skin surface and deep skin infections in immuno-suppressed patients. Ulocladium botrytis has no proven pathogenicity.

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The Mould Wallemia sebi

Wallemia sebi is one of the so called xerophilic moulds, meaning that it can grow under relatively dry conditions (i.e., low water activity). Wallemia sebi has a world-wide distribution. It is common in indoor environment and has been isolated from jams, dates, bread, cakes, salted beans and fish, bacon, fruits, soil, hay, and textiles. It is also common in agricultural environments where it is suspected to be one of the causes of farmer’s lung disease and other human allergies.

Wallemia sebi also produces a mycotoxin called walleminol A. Not much is know about the health effects of this toxin to humans in indoor environment.

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Mould Allergies

Moulds have a protein and polysaccharide components that make them potentially allergenic to sensitized individuals. Due to their small size, mould spores are able to penetrate deep into the respiratory tract where they can elicit allergic reactions. There are 2 types of respiratory allergy, the type I allergy (immediate hay-fever or asthma) and the type III (delayed farmer’s lung). Type I allergy occurs only in atopic (allergic) individuals.

Type I allergy may be caused by plant pathogens such as Tilletia caries, Fulvia fulva, and Leptosphaeria nodorum. Saprophytic moulds such as Cladosporium herbarum and Alternaria spp occurring in indoor environment or from rotting vegetation can also cause type 1 allergy. Mouldy straw, hay and decaying leaves are important sources of allergenic moulds such as Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, and Penicillium spp.

There are occupational pulmonary and epidermal allergies. The former occur in the cheese industry (Penicillium roquefortii), the breweries (Aspergillus clavatus), mushroom farms (Doratomyces sp) and compositing sites (various moulds). An example of epidermal or skin allergies is the cane harvesters allergy caused by Arthrinium sp.

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Salmonella food poisoning and symptoms

Salmonella food poisoning has been a growing concern in recent news. It has frequently lead to recalls of beef, salads and organic products and, even peanut butter products. Salmonella food poisoning occurs when one eats raw or undercooked foods such meat, poultry, eggs or egg products. Properly cooked food can get contaminated with Salmonella if […]

Legionella pneumophila – Guidelines for Laboratory Interpretation

Legionella pneumophila is a Gram negative, aerobic bacteria that is characterized as an opportunistic pathogen. It is the cause of Legionnaires’ Disease, a severe form of pneumonia and, it is the cause of Pontiac fever, a non-pneumonic form of L. pneumophila infection. Legionella spp.’s mode of transmission is through aerosols or aspiration of contaminated water. The Public Health […]

The Indoor Mold Is An Early Warning Device

The mold (or mould, in the Queen’s English) has been the victim of a bad press. Mention the word and it conjures up an image of something rotting or in the process of decomposition. And yet, were it not for the mold that inspired the discovery of penicillin millions of lives would have been lost. […]