What, if anything, does black mould have to do with human disease?

‘Hot off the press’, my Nutritional Therapist wrote. ‘Results have just come through. Did you know that Seren has antibodies to black mould?’


I stared at the email bleary-eyed with my morning coffee trying to figure out what she was on about. We had just had some blood samples taken that were sent to a world-renowned laboratory specialising in functional immunology and autoimmunity. I knew I’d found someone who spoke my language when I first met our Nutritional Therapist. Unlike dieticians and nutritionists, Nutritional Therapists are interested in answering the question why someone has fallen victim to a chronic disease. To this end, a test was ordered to look at antibodies to pathogens that Seren might have. By doing this, it might give us an insight into the root cause and then we could fix it, right? If only things were as simple as that.

Anyway. There it was. Antibodies to something I’d never even heard of: Stachybotrys chartarum, and as the main picture for this blog shows, it is a green/black indoor mould. It has a fondness for cellulose[1] (the main component of paper, cardboard and textiles). Therefore, it is typically found on fibreboard, gypsum board, aluminium foil and wallpaper. It grows there when the material has become water damaged and it requires constant moisture to grow (ibid.). The toxin-bearing spores are made within the slimy mass and later become airborne when dry or when they become attached to other particles such as dust[2]. But before I get into the research on the effects of Stachybotrys chartarum on human health, I wanted to know more about the significance of this latest blood test. I went to town on looking at the available research and I even conversed with a specialist researcher in autoimmune disease. Antibodies to black mould may not be that uncommon because so many people likely become exposed to it, and it has traditionally been observed that no correlation exists between antibodies to black mould and ill health. More recently though, a study[3] observed antibody levels in participants (40 of whom had not been exposed to various moulds (known as a ‘control group’) and 40 who had been exposed). The IgG antibody levels against all seven moulds and two mycotoxins were significantly greater in those participants exposed compared to the control group. Therefore, Seren’s latest blood results may be important in identifying part of the journey to healing.

So, what is known about Stachybotrys chartarum and its potential impact on human health?

Well, in recent years, Stachybotrys chartarum has attracted a lot of attention because of suspicions of harm to human health. Historically though, the effect of Stachybotrys genus on human health has been poorly described in the research. However, some research indicates the fatal effects of Stachybotrus chartarum[4],[5],[6],[7]. For example, in the 1990s, 37 cases of pulmonary haemorrhage (the presentation being coughing with blood), were identified in 37 infants in Cleveland, Ohio. 12 of those cases were fatal and all the infants (ranging from 1-8 months in age), lived in water damaged or flooded buildings in which Stachybotrys chartarum was found in abundance[8],[9]. However, the CDC (Center for Disease and Control) conducted a study that did not prove that Stachybotrys chartarum was unequivocally responsible for the cases of pulmonary haemorrhage[10]. That said, later studies ‘strongly suggest that this species was the etiological agent of acute pulmonary haemorrhage in the infants’ [11].

The most up-to-date research on the clinical significance of Stachybotrys charatrum remains extremely controversial. On the one hand, there have been many case studies revealing relationships between mould-infested buildings and poor health (for a review, see [12]). On the other hand, there remains no consensus on the specific symptoms associated with ‘long-term low-level exposure’[13] to Stachybotrys chartarum. Part of the problem is, Stachybotrys chartarum rarely infests buildings in isolation and instead, is usually identified along with other toxigenic mould species[14]. This might explain why the findings of an earlier review on this topic revealed a confusing picture. The authors of the review suggest that the studies ‘nearly uniformly suffer from significant methodological flaws, making their findings inconclusive’[15]. In other words, conducting studies whereby participants are asked to complete a questionnaire about their health symptoms is not quite the same as a double blind, randomised control trial in which measures could be taken of air exchange rate, moisture levels and proper identification of organisms and mycotoxins. Of course, this would produce more objective and significant findings. Understanding the mechanism of any potential harm that Stachybotrys chartarum may have on human health is extremely difficult because it is a highly complex species. For a start, it produces several different types of toxins and consists of two separate toxin chemotypes: one that produces satratoxins and another than produces the less toxic atranones. These are known as secondary metabolite toxins[16]and is these that are thought to be potentially harmful to human health rather than the Stachybotrys chartarum itself. Because of the variation in toxins, levels of symptoms experienced may vary. Additionally, some people may be more sensitive to mould and like Seren, genes may also play a role in the onset of disease. On top of that, although Stachybotrys chartarum can produce very toxic trichothecenes, the presence of it doesn’t necessarily mean the presence of a toxin, and additionally, levels of environmental samples tend to be low[17]. Furthermore, whether the Stachybotrys chartarum produces toxins may depend on the material it sits on, whether it has sufficient nutrient levels to feed from, and the degree of moisture and temperature[18],[19]. This again, makes research on this phenomenon a real challenge.

Notwithstanding these difficulties, in their 2022 review on the research relating to black mould as potentially pathogenic to humans, Dylag et al. listed some of the effects of exposure to Stachybotrys chartarum on humans and they highlight several research papers[20],[21],[22],[23],[24],[25],[26],[27],[28],[29],[30],[31]. Those effects include but are not limited to: pulmonary haemorrhage, gastrointestinal haemorrhage, sick building syndrome, lymphadenopathy, headache, fatigue, cough, asthma, allergies, nasal bleeding, hypertension, irritation and necrotic changes to the skin and/or mucous membranes, burning of the nasal passages and muscle and stomach aches.

An interesting study in Finland[32] examined the health effects of both a house and a school proven to be infested with mould. The exposed individuals reported experiencing a myriad of ailments including mucosal irritation, neurological, skin, and allergic symptoms and even more interestingly, there was a greatly elevated prevalence of autoimmune conditions and malignancies. This particular study caught my attention because the prevalence of thyroid disorder was elevated by 3.4-fold. The two buildings had been confirmed as mould-infested by certified professional bodies and medical data were collected by evaluation of medical records. But methodological problems are an issue for this study too. For example, it suffers a small sample (n=89) of only two cohorts and the measures taken to identify the moulds are not described in any detail. Regardless, such a study may well be signposting us to some important markers for future research.

In the 2022 review I just mentioned, Dylag et al. point out that despite the evidence of the ‘extremely harmful properties’ of Stachybotrys chartarum, it has not been included in the list of dangerous species in the 1996 European Confederation of Medical Mycology. However, at the same time, the American Industrial Hygiene Association ranked Stachybotrys chartarum first among the moulds producing mycotoxins that are harmful to human health. All of that said, the authors of the review caveat the findings to date by pointing out that health-related effects could also be because of other building-associated moulds. To this end, the clinical significance of Stachybotrys chartarum remains contested and more research is required. It is argued that future studies need to use objective markers of illness with better methodological techniques. That said, Kuhn and Ghannoum (2003)[33] conclude that ‘Valid concerns exist regarding the relationship between indoor air, mold exposure, mycotoxins, and human disease’.

So, for a while I sat quietly doing this research. It was imperative given the picture that was beginning to emerge: Seren continued to be suffering with acute nausea, sometimes vomiting and stomach pain – despite the thyroid levels now being regarded as normal. I also had reason to believe that she had been exposed to indoor black mould. If I was going to take this latest blood test seriously, I needed to know how to interpret the results against the backdrop of the available evidence on these kinds of tests and whether the results made any significance sense to me. And they did. So, it meant changes needed to be made and of course, we were willing to do anything that might mean Seren had a chance of proper healing.

Do I think that Stachybotrys chartarum played any role in the onset of Seren’s Hashimoto’s? I don’t know. Certainly, the available research evidence isn’t strong enough to make any such claim. As with anything, there are probably a variety of factors and that is what has made this journey so challenging. There have been consistent small wins and then big defeats along the way. That is, Seren will seemingly begin to improve and then she gets knocked back again. Last month I wrote about the impact it was having on my own well-being and certainly, it was beginning to hurt all of us in different ways. I have always loved my rewarding career but the ability to have the energy to confront and master problems is only sustained when work remains the biggest challenge in my life. Things had menacingly started to disrupt my flow and the burnout was becoming more and more evident. A combination of working too hard while never feeling good enough, a long-standing disharmony with extended family that gnawed into me while leaving permanent damage, and then a child, who, overnight became ill – was layer by layer building the brick wall that I would inevitably run in to, knocking me down and seeing me struggle to get back up again.

And the latest Stachybotrys chartarum discovery wasn’t to be the last. As it turned out, it wasn’t the only environmental toxin we needed to be concerned about…

[1] Kuhn, D. M. and Ghannoum, M. A. (2003) ‘Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective’, Clin Microbiol Rev. 16(1): 144-72. 

[2] Hintikka, E. L. and Nikulin, M. (1998) ‘Airborne mycotoxins in agricultural and indoor environments’, Indoor Air Suppl. 4:66-70.

[3] Vojdani, A., Campbell, A. W. Kashanian, A. and Vojdani, E. (2003) ‘Antibodies against molds and mycotoxins following exposure to toxigenic fungi in a water-damaged building’, Arch Environ Health. 58(6): 324-36. 

[4] Dearborn, D. G., Yike, I., Sorenson, W. G., Miller, M. J. and Etzel,  R. A. (1999) ‘Overview of Investigations into Pulmonary Hemorrhage among Infants in Cleveland, Ohio’, Environ. Health Perspect. 107((Suppl. 3)): 495–499.

[5] Ochiai, E., Kamei, K., Hiroshima, K., Watanabe, A., Hashimoto, Y., Sato A. and Ando, A. (2005) ‘The Pathogenicity of Stachybotrys chartarum’, Nihon Ishinkin Gakkai Zasshi. 46:109–117.

[6] Miller, J. D., Rand, T. G. and Jarvis, B. B. (2003) ‘Stachybotrys chartarum: Cause of Human Disease or Media Darling?’ Med. Mycol. 41:271–291. 

[7] Sudakin, D. L. (2000) ‘Stachybotrys chartarum: Current Knowledge of Its Role in Disease’, MedGenMed. 2:E11.

[8] Dearborn, D. G., Yike, I., Sorenson, W. G., Miller, M. J. and Etzel,  R. A. (1999) ‘Overview of Investigations into Pulmonary Hemorrhage among Infants in Cleveland, Ohio’, Environ. Health Perspect. 107((Suppl. 3)): 495–499.

[9] Jarvis, B. B., Sorenson, W. G., Hintikka, E.-L., Nikulin, M., Zhou, Y., Jiang, J., Wang, S., Hinkley S., Etzel, R. A. and Dearborn, D. (1998) ‘Study of toxin production by isolates of Stachybotrys chartarum and Memnoniella echinata isolated during a study of pulmonary hemosiderosis in infants’,  Appl. Environ. Microbiol. 64:3620–3625.

[10] Acute Pulmonary Hemorrhage/Hemosiderosis among Infants—Cleveland, January 1993–November 1994. MMWR Morb. Mortal. Wkly. Rep. 1994; 43:881–883.

[11] Dyląg, M., Spychała, K., Zielinski, J., Łagowski, D. and Gnat, S. (2022) ‘Update on Stachybotrys chartarum-Black Mold Perceived as Toxigenic and Potentially Pathogenic to Humans’, Biology (Basel). Feb 23;11(3):352. 

[12] Kuhn DM, Ghannoum MA. Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective. Clin Microbiol Rev. 2003;16:144–172. doi: 10.1128/CMR.16.1.144-172.2003.

[13] Semeiks, J., Borek, D., Otwinowski, Z. and Grishin, N. V. (2014) ‘Comparative genome sequencing reveals chemotype-specific gene clusters in the toxigenic black mold Stachybotrys’, BMC Genomics. Jul 12;15(1):590.

[14] Kuhn, D. M. and Ghannoum, M. A. (2003) ‘Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective’, Clin Microbiol Rev. 16(1): 144-72. 

[15] Kuhn, D. M. and Ghannoum, M. A. (2003) ‘Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective’, Clin Microbiol Rev. 16(1): 144-72. 

[16] Semeiks, J., Borek, D., Otwinowski, Z. and Grishin, N. V. (2014) ‘Comparative genome sequencing reveals chemotype-specific gene clusters in the toxigenic black mold Stachybotrys’, BMC Genomics. Jul 12;15(1):590.

[17]  Jarvis., B. B., Eppley, R. M. and Mazzolla, E. P. (1983) ‘Chemistry and bioproduction of macrocyclic trichothecenes’ p. 20-38. In Y. Ueno (ed.), Trichothecenes—chemical, biological, and toxicological aspects, vol. 4. Elsevier, New York, N.Y.

[18] Hintikka, E.-L., and M. Nikulin. (1998) ‘Airborne mycotoxins in agricultural and indoor environments’, Indoor Air Suppl. 4:66-70.

[19] Murtoniemi, T.,  Nevalainen, A., Suutari, M., Toivola, M., Komulainen, H. and Hirvonen, M. R. (2001) ‘Induction of cytotoxicity and production of inflammatory mediators in raw264.7 macrophages by spores grown on six different plasterboards’, Inhal. Toxicol. 13:233-247.

[20] Wang, Y., Hyde, K. D., McKenzie, E. H. C., Jiang Y.-L., Li D.-W. and Zhao D.-G. (2015) ‘Overview of Stachybotrys (Memnoniella) and Current Species Status’, Fungal Divers. 71:17–83.

[21] Semeiks J., Borek D., Otwinowski Z. and Grishin N. V. (2014) ‘Comparative Genome Sequencing Reveals Chemotype-Specific Gene Clusters in the Toxigenic Black Mold Stachybotrys’, BMC Genom. 15:590.

[22] Jagels, A., Lindemann, V., Ulrich, S., Gottschalk, C., Cramer, B., Hübner, F., Gareis, M. and Humpf H.-U. (2019) ‘Exploring Secondary Metabolite Profiles of Stachybotrys spp. by LC-MS/MS’, Toxins.11:133

[23] Yike, I. and Dearborn, D. (2011) ‘Guest Editorial—Novel Insights into the Pathology of Stachybotrys chartarum’, Mycopathologia. 172:1–3. 

[24] Miller, J. D., Rand, T. G. and Jarvis, B. B. (2003) ‘Stachybotrys chartarum: Cause of Human Disease or Media Darling?’ Med. Mycol. 41:271–291

[25] Kuhn, D. M. and Ghannoum, M. A. (2003) ‘Indoor Mold, Toxigenic Fungi, and Stachybotrys chartarum: Infectious Disease Perspective’, Clin. Microbiol. Rev. 16:144–172.

[26] Jagels, A., Stephan, F., Ernst, S., Lindemann, V., Cramer, B., Hübner, F., Humpf, H.-U. (2020) ‘Artificial vs Natural Stachybotrys Infestation—Comparison of Mycotoxin Production on Various Building Materials’, Indoor Air. 30:1268–1282.

[27] Shi, C., Smith, M. L. and Miller, J. D. (2011) ‘Characterization of Human Antigenic Proteins SchS21 and SchS34 from Stachybotrys Chartarum’, Int. Arch. Allergy Immunol. 155:74–85.

[28] Wilkins, K., Nielsen, K. F. and Din, S. U. (2003) ‘Patterns of Volatile Metabolites and Nonvolatile Trichothecenes Produced by Isolates of StachybotrysFusariumTrichodermaTrichothecium and Memnoniella’, Environ. Sci. Pollut. Res. 10:162.

[29] Rudert, A. and Portnoy, J. (2017) ‘Mold Allergy: Is It Real and What Do We Do about It?’ Expert Rev. Clin. Immunol. 13:823–835.

[30] Pestka, J. J., Yike, I., Dearborn, D. G., Ward, M. D. W. and Harkema, J. R. (2008) ‘Stachybotrys chartarum, Trichothecene Mycotoxins, and Damp Building–Related Illness: New Insights into a Public Health Enigma’, Toxicol. Sci. 104:4–26. 

[31] Kordula T., Banbula A., Macomson J. and Travis J. (2002) ‘Isolation and Properties of Stachyrase A, a Chymotrypsin-like Serine Proteinase from Stachybotrys chartarum’, Infect. Immun.70:419–421. 

[32] Tuuminen, T. and Sakari Kyosti, R. (2017) ‘Severe Sequelae to Mold-Related Illness as Demonstrated in Two Finnish Cohorts’, Frontiers in Immunology, 8.

[33] Kuhn, D. M. and Ghannoum, M. A. (2003) ‘Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective’, Clin Microbiol Rev. Jan;16(1):144-72.

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