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One of the questions commonly asked by people who have been exposed to mould is whether they should dispose of all their belongings inside the mouldy house including clothes. I will reserve my opinion on this for today. However, I would be interested to learn from other people what they think about disposing of household items including clothes because of mould.
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As usual, if you have a question concerning mould, send it to as at My Question.
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Myth #1: Mould that come back after treatment with bleach is is mould that is more than one year old.
The Truth: Bleach may not be 100% effective against all moulds. Mould will grow as long as there is moisture, nutrients and suitable temperature for growth. Growth may start from just a few spores or hyphal fragments that escaped bleach or were not killed by bleach. To control mould, one needs to keep the house or building dry. This means the moisture source or causes need to be identified and fixed. The other truth about mould is that there is currently no way of telling how old the mould is and whether it was there one year or two years ago. Spores of some moulds can remain viable on surfaces of building material for several years until they get the right conditions for growth.
Myth #2: Black mould is deadly.
The Truth: All moulds are potentially harmful regardless of their colour. However, not all black moulds are known to cause health problems. Some black moulds that could be of health concern are Aspergillus niger and Stachybotrys chartarum (greenish black). Aspergillus flavus is not black and it is the most well known producer of the potent mycotoxins called aflatoxins. Aspergillus fumigatus is also not black and is one of the biggest concerns in hospitals because it can infect people particularly those with low immunity.
Memnoniella echinata is an indoor mould very similar to Stachybotrys chartarum. The only obvious difference between the two moulds is that Memnoniella echinata produces spores in chains while Stachybotrys chartarum produces its spores in a mass. Memnoniella echinata was previously named Stachybotrys echinata.
Memnoniella echinata has a world-wide distribution and is mainly isolated from soil. Similar to Stachybotrys, it is isolated from cellulose containing materials such as paper, wallpaper, textiles and dead plant material. Sometimes both Memnoniella echinata and Stachybotrys chartarum occur on the same water damaged building material.
Memnoniella echinata produces toxic metabolites similar to those of Stachybotrys chartarum.
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Mold & Bacteria Consulting Laboratories (MBL) Inc. is now offering full-day training seminars on how to recognize indoor mould, how to develop effective sampling strategies and how to interpret laboratory results. If you have been considering attending a similar course, don’t delay to register as we have limited spaces left!
Three Reasons Why You Should Attend
MBL, Inc. has become one of the premier providers of quality laboratory testing services for mould and bacteria in Canada. MBL offers convenient, rapid turnaround time, competitive pricing and value-added services unavailable at other laboratories, such as free technical information, consulting with the client on the most appropriate test samples and test methods, provide help with the interpretation of results, provide services after working hours if required and provide free unlimited after sales consultation.
Please call (905)290-9101 or visit our website at http://www.moldbacteria.com/ for details of our services.
Stachybotrys chartarum, also known by an old name as Stachybotrys atra, is a cellulose degrading fungus commonly found in soil and on materials rich in cellulose such as hay, straw, cereal grains, plant debris, wood pulp, paper, and cotton. It produces a mass of wet spores sticking together giving the appearance of black pin-heads. The spores (referred to as conidia) are single-celled and ornamented. In indoor environment Stachybotrys thrives on wet cellulose containing material such as drywall and wallpaper. It is thus common in buildings with mechanical or structural defects that result to moisture damage or dampness. It has been isolated from very wet gypsum board/walls and wallpaper; asbestos building substitute; HVAC humidifier water and fans. Although Stachybotrys chartarum mainly survives as a saprophyte (i.e., by feeding on dead organic material), it has also been reported to cause root lesions on soybeans.
Why is Stachybotrys chartarum so feared?
The health effects attributed to Stachybotrys chartarum are controversial. It is generally agreed that Stachybotrys chartarum can potentially cause allergic reactions from inhaled spores and also poses the threat of mycotoxin poisoning. However, there is still a lot of debate as to whether this mould is the sole cause of various illnesses as reported in the literature. One of the recent disputed claims is the idiopathic pulmonary haemorrhage that resulted in deaths of infants in Cleveland, Ohio, USA in 1993-1994. The publicity of this incidence and that of mould related legal cases where Stachybotrys was mentioned has fuelled the public fear for this mould. The mould has been given various names such as “deadly toxic mould” and “deadly black mould”.
What is known about Stachybotrys chartarum and ill-health?
The first reports associating Stachybotrys chartarum with ill-health dates back to the 1930s. Horses and other animals fed with straw and grains in Ukraine and other parts of eastern Europe developed disease symptoms such as irritation of the mouth, throat, and nose; shock; dermal necrosis; a decrease in leukocytes; haemorrhage; nervous disorder; and death. Russian scientists, in 1938, conducted intensive studies and demonstrated that these symptoms were due to mycotoxins produced by Stachybotrys chartarum that had grown on the cellulose rich straw. The disorders were subsequently named stachybotryotoxicosis. There are reports of stachybotryotoxicosis in farm workers who handled contaminated straw. Recent studies have shown spores of Stachybotrys chartarum to contain high concentrations of highly toxic mycotoxins. As mentioned earlier, in 1993-1994, an outbreak of pulmonary haemorrhage in infants in Cleveland, Ohio,USA, was initially attributed to Stachybotrys chartarum. Although studies associating the outbreak with this mould were later reviewed and the reviewers found little evidence to associate the disease with Stachybotrys chartarum, there are still no studies to date to prove or disapprove this association.
Current knowledge about Stachybotrys chartarum
Recent studies seem to suggest Stachybotrys chartarum consist of closely related individuals in which case it is a species complex. What exactly constitutes Stachybotrys chartarum still remains uncertain. Strains of moulds currently referred to as Stachybotrys chartarum are morphologically and biochemically highly variable. Recently what used to be referred to as Stachybotrys chartarum has been separated into one other distinct species and 2 other strains that were only different from each other by secondary metabolites profiles. The distinct species was named Stachybotrys chlorohalonata. Stachybotrys chartarum and Stachybotrys chlorohalonata require an experienced mycologist to differentiate. The uncertainty of what strains constitutes Stachybotrys chartarum may explain in part the current confusion concerning the health effects attributed to this mould.
Stachybotrys chartarum produces a number of potent mycotoxins including trichothecenes Roridin E, Verrucarin J, and Satratoxin H. Trichothecenes are capable of inhibiting the synthesis of DNA, RNA, and protein. These toxins are present on the spore surface, and therefore can be inhaled into the lungs. Studies have also shown that Stachybotrys chartarum trichothecenes can become airborne not only in association with intact spores but also with particles smaller than spores such as fungal fragments. It is, however, not known what level of mycotoxin must be present in the air to affect human health. There is still insufficient evidence supporting a causal relationship between symptoms or illness among building occupants and exposure to mycotoxins.
References
D. -W. Li, C. S. Yang (2005). Taxonomic history and current status of Stachybotrys chartarum and related species. Indoor Air, Volume 15 Issue s9 Page 5 – June 2005
B. Andersen, K. F. Nielsen, U. Thrane, M. Cruse, J. Taylor, and B. B. Jarvis(2003). Stachybotrys chlorohalonata, a new species from water-damaged buildings,” Mycologia 95, 1228-1237.
D. M. Kuhn and M. A. Ghannoum (2003). Indoor Mold, Toxigenic Fungi, and Stachybotrys chartarum: Infectious Disease Perspective. Clinical Microbiology Reviews, Jan. 2003, p. 144–172S. Li, G. L. Hartman, B. B. Jarvis, and H. Tak, A (2001). Stachybotrys chartarum Isolate from Soybean.” Mycopathologia, 154, 41-49.
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