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Biogenics Research Institute
Other Respiratory Tract Disorders
Hypersensitivity Pneumonitis
Idiopathic Intersitial Lung Disease

Environmental Antigens, Allergens and Irritants


Alternaria species: Alternaria species are some of the most common molds worldwide. It is found on composting vegetation and is parasitic on grasses and grains. It is one of the most commonly found molds in dwellings in the USA and Europe. It grows well in soil, inside plants, on foodstuffs, sheetrock, wood, and fabrics. It may be identified in air conditioning systems and other areas of dampness within a dwelling. It has been shown to be the most common mold to cause allergic symptoms in humans. It has been demonstrated to cause an ABPA-like illness, fungal sinusitis, and hypersensitivity pneumonias.

Aspergillus species: A. nidulans, A. glaucus, A. terreus, and A. niger are the more common species of the Aspergillus genus after A. fumigatus. These organisms are found world wide, may grow at a wide temperature range, and may cause a variety of medical problems for humans. Decomposing organic matter serves as the main source for the growth of A. species including potting soil, mulches, freshly cut grass, stored hay, and many dried foods that may have contact with soil. Certain species are more commonly identified in drier climates.

Fusarium species: Fusarium species may be found worldwide in soil and parasitic on plants in the grass family. It may also be found on peas, beans, cotton, tomatoes, and the seeds of cereals, particularly corn and barley. It has been identified in massive amounts in water damaged carpets in schools and homes. It has been recently reported to cause hypersensitivity pneumonia of several types in Texas.

Cladosporium species: Cladosporium herbarum and C. cladosporioides are the dominant airborne mold spores in temperate North America. They thrive on composting vegetation (dead grass and leaves) and are parasitic on certain living plants. They are the most common mold identified in home contaminations. They are commonly found in air conditioning systems, dirty refrigerators, moist window frames, wet carpeting, wet sheetrock, inside plants, and damp basements.

Penicillium species: Penicillium species are very commonly found in contaminated homes. It is worldwide in distribution and grows well at a wide range of temperatures. The major sources for the growth of Penicillium include soil, composts, paper, foodstuffs, and materials and fabrics undergoing degradation. Penicillium may be frequently cultured from contaminated air conditioning systems and water damaged carpets. It is known to cause respiratory allergic disease and hypersensitivity pneumonias.

Stachybotrys species: Stachybotrys chartarum (atra) is rarely found in outdoor or indoor air sampling at any significant level. When there has been extensive water damage and visible mold growth on surfaces, particularly wet sheetrock, Stachybotrys may be cultured by direct swabs very commonly. For air samples to show Stachybotrys, the source usually must be disturbed. There has not been any good evidence that indoor inhalation of Stachybotrys has caused any disease in man.

Additional information can be found at:

There are 4 species of cockroach that commonly infest homes including the German, American, Oriental, and Brown-banded. The allergens are located primarily in the gastrointestinal tract and placed into the environment through feces and saliva. Reactivity to these allergens may often be identified by prick skin testing. Their role in causation of symptoms are more difficult to discern in individuals not living in heavily infested dwellings.

These insects is the most common indoor allergen in temperate regions of the world. They are not parasites, however, do ingest human skin scales as their major food source. They are in highest concentration in mattresses and pillows but may be found in other fabrics including carpets, curtains, stuffed animals, and covered furniture.

Allergens from animals are found in dander and secretions including saliva, sebum, perianal glands, and urine. These particles are easily airborne and become widely distributed throughout the home. The only proven method to reduce these allergens is to remove the animal from the home. Six months may be required to adequately clean the allergen from the dwelling.
more on Cats...
more on Dogs...


All birds lose serum protein in their fecal material. This protein, when inhaled in high concentration over time, has the capability of stimulating the immune system becoming one of the most common causes of hypersensitivity pneumonia of several types. Birds require significant attention in keeping the cage clean by the owner. Exposure to a single bird that is not well cared for may lead to enough exposure to sensitize and cause HP.
more on birds...


Endotoxin is a component present in the outer membrane of gram-negative bacteria. Airborne endotoxin is known to cause respiratory tract disease in several occupational situations. When detected in the dust of homes has been associated with severity of asthma in children and adults. Excessive levels of bacteria have been shown to be present in microbial contaminations of homes that has been associated with several types of respiratory tract disease including interstitial lung disease, chronic cough, asthma, and upper respiratory tract symptoms. Many of these organisms are gram-negative bacteria and would produce endotoxin which easily becomes airborne. Factors recognized to be associated with high levels of airborne endotoxin include moisture sources, presence of dogs, and increased amounts of settled dust.



Other Respiratory Tract Irritants

Environmental Tobacco Smoke (ETS)
Volatile Organic Compounds(VOCs)
Combustion Products