Stachybotrys spp.

Aw - 0.94 , optimum Aw - >0.98 (22). Several strains of this fungus (S. atra, S. chartarum and S. alternans are synonymous) (1) may produce a trichothecene mycotoxin- Satratoxin H - which is a poisonous by inhalation. The toxins are present on the fungal spores. This is a slow growing fungus on media. It does not compete well with other rapidly growing fungi. The dark colored fungi grows on building material with a high cellulose content and a low nitrogen content. Areas with relative humidities above 55% and are subject to temperature fluctuations are ideal for toxin production (29).

Individuals with chronic exposure to the toxin produced by this fungus reported cold and flu symptoms, sore throats, diarrhea, headaches, fatigue, dermatitis, intermittent local hair loss (28) and generalized malaise. The toxins produced by this fungus will suppress the immune system affecting the lymphoid tissue and the bone marrow (1). Animals injected with the toxin from this fungus exhibited the following symptoms, necrosis and hemorrhage within the brain, thymus, spleen, intestine, lung, heart, lymph node, liver, and kidney. (29) Affects by absorption of the toxin in the human lung are known as pneumomycosis (1).

This organism is rarely found in outdoor samples. It is usually difficult to find in indoor air samples unless it is physically disturbed or if there is (speculation- a drop in the relative humidity). The spores are in a gelatinous mass. Appropriate media for the growth of this organism will have a high cellulose content and a low nitrogen content. It is easy to visually see the spore on a particle trace sample. The spores will die readily after release. The dead spores are still allergenic and toxigenic. Percutaneous absorption has caused mild symptoms (6).

There is controversy about toxigenic effects through inhalation of spores or mycelia. The following websites cover both sides: