What can you tell me about the toxic mold Chaetomium?  I have read on websites (such as mold-help.org) that it can cause autoimmune diseases, cancer, etc.  Also, if one cleans up such a mold incorrectly before realizing that it is toxic, how do you know if your house and possessions are contaminated with spores and how can you get rid of them?-Karen , Massachusetts

            Chaetomium is a fungal genus that includes approximately 80 different species.  The species that is reported to be growing in building interiors and present in air samples is C. globosum.   It is found outdoors growing on soil and plant debris.  It does produce a variety of mycotoxins called chaetoglobsins whose health effects in humans is for the most part unknown. Because it is a toxigenic fungus, it is one of species sometimes identified as requiring special precautions in its remediation.

            The website (www.mold-help.org) describes C.globosum as allergenic and an agent of onychomycoses (nasal infection), peritonitis, cutaneous lesions and potential agent in fatal systemic mycoses.  It is also says “No toxic diseases have been documented to date”.  In another website (www.mold-survivor.com) this is what is written “unlike most other mold pathogens, there is medical evidence to suggest that people who are exposed to Chaetomium may have neurological damage…..  Therefore, a noticeably high incidence of autoimmune diseases have been linked to exposure to this mold, such as Multiple Sclerosis, Lupus, etc.  It has also been linked to certain forms of cancer”

            Note the contrasts between these different websites.  The former is scientifically correct; the latter is highly speculative at best.

            A variety of mycotoxins cause immunosuppression in laboratory tests and some are carcinogenic.  Such findings, however, do not mean that the presence of mold species that produce mycotoxins that have these toxic capabilities in fact cause significant health effects in humans.

            Chaetomium globosum like Stachybotrys chartaium are demataceous, that is they produce dark spores.  Because they can both use cellulose directly as a nutrient source, they can be found on the wetted facing of gypsumboard.  Indeed when one looks at a Chaetomium infestations the spores are so dark that it appears that Stachybotrys is present.  An infestation of Chaetomium on gypsumboard can be seen in the following image.

            Chaetomium like Stachybotrys produces relatively large spores.  They differ in that Chaetomium spores are produced by sexual processes while Stachybotrys primarily produces spores asexually.  The spores of Chaetomium are large and ovoid and do not have the ornamentation characteristics of Stachybotrys.

            Because both Chaetomium and Stachybotrys spores are relatively large, they have relatively high setting velocities.  Thus, they settle out relatively quickly and do not remain airborne for more than a few minutes.  As a consequence, airborne mold levels are usually low even in infested environments.  Due to this fact, exposure levels are likely to be low as well.  Toxicity does matter.  However, it may not be that important if one is exposed to such low doses that such exposures are not biologically significant.

            One can sample house dust to identify whether Chaetomium is present or not.  However, I doubt the average homeowner that has Chaetomium reported in an air sample has much if anything to worry about.

 

October 8, 2004