Relationship Between Indoor Moulds and Health

1
Relationship Between Indoor Moulds and Health

• Michael R. McGinnis, Ph.D.
• Professor
• Department of Pathology
• University of Texas Medical Branch
• Galveston, TX 77555-0609
• michael.mcginnis_at_utmb.edu

2
Health Problem

• Establishing the cause-effect
• relationship between indoor
• fungi and the health problem
• of the building resident.

3
Indoor Bioaerosols

• Pollen
• Algae
• Bacteria
• Viruses
• Protozoa
• Mites

• Insects and feces
• Dander
• Dried pet saliva
• Yeasts
• Moulds

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Risk Of Developing Disease Following Mould
Exposure

• 1. Weakened immune systems (HIV
• infection, cancer chemotherapy)
• 2. Infants and young children
• 3. Elderly
• 4. Respiratory diseases

5
Diseases Caused by Fungi Indoors

• Infectious diseases
• a. exceptionally rare
• b. solid organ transplant patients
• c. aspergillosis
• d. invasive sinusitis
• Noninfectious diseases
• a. aspergillosis

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Diseases Caused by Fungi Indoors (continued)

• b. asthma activation
• c. allergic rhinitis
• d. allergic alveolitis
• e. organic dust toxic
• syndrome
• f. allergic sinusitis

7
Diseases Caused by Fungi Indoors (continued)

• 3. Toxic diseases
• a. fungal volatile organic compounds
• b. mycotoxins and other secondary
• metabolites
• 1). inhalation
• 2). ingestion
• 3). skin contact

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Allergic Symptoms

• runny nose
• eye irritation
• cough
• congestion
• aggravation of asthma

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Asthma Symptoms

• difficult to breathe
• wheezing
• shortness of breath
• coughing
• constriction of air passages
• Inflammation of air passages

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Mycotoxin Symptoms

• fatigue
• nausea
• headaches
• respiratory irritation
• eye irritation
• discomfort
• inability to concentrate
• dermatitis

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Diagnostic Approaches

• 1. Serology
• IgE antibodies
• IgG antibodies
• 2. Skin test
• Type I immediate sensitivity
• Type IV delayed hypersensitivity
• 3. Clinical signs and symptoms

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Water Sources

• 1. Damp basement or crawl space
• 2. Steam from shower or cooking
• 3. Humidifiers
• 4. Wet clothes drying indoors or
• clothes dryers exhausting indoors

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Water Sources (continued)

• 5. Flooding
• 6. Leaky roofs
• 7. Sprinkler spray hitting the
• house
• 8. Plumbing leaks
• 9. Overflow from sinks or sewers

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Water Activity (aw)

• Amount of free or available water in a
  substrate. It is equivalent to 1/100th of the
  relative humidity of the air in equilibrium with
  the material (equilibrium relative humidity or
  ERH).

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Aw lt 0.80, ERH lt80
Aw lt 0.80-0.90, ERH lt80-90
Aw gt0.90, ERH gt90
Aw Minimum water activity level at 25C ERH
Equilibrium relative humidity Aw gt0.90, ERH gt90
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Aspergillus versicolor Aw 0.74-0.79
Ulocladium chartarum Aw 0.89
Stachybotrys chartarum Aw 0.94
Aw Minimum water activity level at 25C Aw
gt0.90, ERH gt90
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Order of Occurrence of Moulds Growing Indoors

• Chaetomium globosum
• Stachybotrys chartarum
• Stachybotrys new species
• Alternaria alternata
• Aspergillus versicolor
• Cladosporium sphaerospermum

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Order of Occurrence of Moulds Growing Indoors

• 3. Aureobasidium pullulans
• Cladosporium cladosporioides
• Penicillium brevicompactum
• Penicillium chrysogenum
• Ulocladium chartarum
• Acremonium strictum
• Aspergillus niger

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Order of Occurrence of Moulds Growing Indoors

• Epicoccum nigrum
• Eurotium amstelodami
• Penicillium aurantiogriseum
• Trichoderma harzianum
•  

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Regional Variability of Moulds
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Collection of Fungi

• 1. Air spora
• a. indoor
• b. outdoor
• 2. Tape preparations
• 3. Swab samples
• 4. Bulk samples
• 5. Dust and filters

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Air Spora

• 1. Called nonviable count when not cultured
• a. spores/ m3 of air
• b. does not distinguish between dead
• and alive spores
• 2. Called viable count when cultured
• a. recovers some viable spores and
• hyphal fragments
• b. media selection critical

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Air Spora (continued)

• c. CFU/unit of surface area
• d. identification of fungi to species
• 3. Measures
• a. dispersal efficiency
• b. sporulation efficiency
• c. diversity of types of spores in air
• d. numbers of spores in air

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Air Spora (continued)

• 4. Uses
• a. determine if amplification of fungus
• has occurred
• b. determine exposure risk leading to
• potential or actual disease
• c. determine distribution indoors
• d. comparison of indoor and outdoor
• species

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Air Spora (continued)

• 5. Limitations
• a. data varies depending upon when
• and where it is collected
• b. prone to misidentification of fungi
• c. prone to not detecting all fungi
• present

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Air Spora (continued)

• 6. Popularity
• a. easy to collect spore count data
• b. provides numbers for reports
• c. easy to interpretate by comparing
• numbers
• d. difficult to interpretate health
• significance by itself

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Air Spora (continued)

• 7. Easy to use for developing number-
• based standards
• 8. Exceptionally limited usefulness.
• 9. Key reference
• Rao, CY et al. Review of quantitative standards
  and guidelines for fungi in indoor air. J. Air
  Waste Man. Assoc. 46899-908, 1996.

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Tape Preparation

• 1. Purpose
• a. directly identify fungus growing on
• surface of a building material
• b. portion can be inoculated onto
• isolation medium for species level
• identification

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Tape Preparation (continued)

• 2. Benefit
• a. documents what is growing and
• being amplified within the structure
• b. used to determine potential health
• risk
• 1). potential for presence of
• mycotoxins
• 2). potential as allergen

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Tape Preparation (continued)

• 3). evaluate sporulation capability
• 4). evaluate spore dispersal
• capability
• 3. Limitation
• a. requires mycologist capable to identify
• fungi to the species level

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Swab Sample

• Purpose
• a. collect surface growth
• 1). isolate fungus
• 2). quantitate fungal growth
• 3). moist to wet sites
• b. measure density of growth for area
• sampled

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Swab Sample (continued)

• c. isolation of fungi allows for
• identification to the species level
• 2. Benefit
• a. same as tape preparation
• b. good for moist or wet surfaces
• 3. Limitation
• a. same as tape preparation
• b. quantitation data is meaningless

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Bulk Sample

• 1. Purpose
• a. collect growth within, on surface,
• or both of building material
• b. isolate fungus so that it can be
• identified to the species level
• 2. Benefit
• a. same as tape preparation
• b. detection of fungi within building
• material

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Dust

• Benefit
• a. reflects a historical summary of
• what was in the house
• b. same as other types of samples
• 2. Limitations
• a. do not know events occurred
• b. do know know where the fungus
• came from

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Mycotoxins Detected in Crude Building Materials

• Acetyl-T-2 toxin Satratoxin G
• Citrinine
  Sterigmatocystin
• DAS
  T-2 toxin
• DON
  T-2 tetraol
• HT-2 toxin
  T-2 triol
• Nivalenol
  Verrucarine A
• Ochratoxin A
  Verrucarol
• RDRA
• ____________ 
• Tuomi et al. Appl. Environ. Microbiol. 2000,
  661899-1904

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Ecology of Mycotoxins

• Not all strains of a known mycotoxin producing
  species may produce particular mycotoxins.
• a. two chemotypes of Stachybotrys
• chartarum
• 2. The strain that produced the mycotoxin may
  not be present at sampling.

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Things to Consider

• Investigator
• a. written protocol for specimen
• collection procedures and transport
• of specimens to the laboratory
• b. quality control data for instruments
• used
• c. quality assurance plan to detect
• errors

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Things to Consider (continued)

• d. interpretation of data specifically for
• site being investigated
• 2. Laboratory.
• a. laboratory procedure manual for all
• assays and reporting procedures
• b. evaluate all data and methods
• used against the written laboratory
• procedure manual

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Things to Consider (continued)

• b. evaluate capability to identify fungi to
• species level
• c. evaluate reference laboratories used
• for specialize testing such as
• mycotoxin detection and measurement
• 3. Clinicians
• a. board certified
• b. specialty in allergic diseases

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Things to Consider (continued)

• c. certified laboratory (CLIA, CAP)
• used for patient specimen testing
• 4. Pathologist
• a. board certified
• b. specialty in pulmonary pathology or
• surgical pathology

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Things to Consider (continued)

• 5. Microbiologist.
• a. board certified
• b. specialty in medical mycology