Stachybotrys, Fusarium and Trichothecene Mycotoxins

[Guest guest]

by Coulter Mulvihill

Stachybotrys, Fusarium and Trichothecene Mycotoxins

Stachybotrys, Fusarium and Trichothecene Mycotoxins

Trichothecenes are mycotoxins produced by certain molds, including some

molds frequently detected indoors. This article discusses (very generally) what

trichothecenes are; some available studies on dosage rates; and briefly, why

" toxic mold " indoors may – or may not – be producing toxins.

What Trichothecenes Are

Trichothecenes are toxic fungal metabolites of certain molds in the genus

Fusarium, Myrotecium (also called Myrothecium in some publications)

Trichoderma, Acremonium (formerly Cephalosporium), Verticimonosporium,

Cylindrocarpon,

Microdochium, and Stachybotrys. Other genus produce mycotoxins, but those are

not grouped as trichothecenes1.

In general, the indoor mold tests that I see test for Fusarium and

Stachybotrys. Sometimes, those tests include Trichoderma, but Trichoderma spp.

are

usually isolated in plants and soil2. So, this article only discusses Fusarium

spp. and Stachybotrys spp.

The species of Fusarium known to produce trichothecenes are Fusarium solani,

Fusarium chlamydosporum, Fusarium lateritium, Fusarium oxysporum and

Fusarium poae. Stachybotrys chartarum (obsolete atra, alternans) can produce

trichothecenes, including satratoxins F, G, and H, roridin E, and verrucarin

J3. I

do not know if the recently identified species Stachybotrys yunnanesis,

Stachybotrys chlorohalonata, Stachybotrys elegans, Stachybotrys microspora,

Stachybotrys nephrospora produce either trichothecenes or other mycotoxins4.

Trichothecenes are the only (declassified) mycotoxin adapted for use in

biological warfare5. Known as T-2, trichothecenes are suspected – but not

proven –

as the " yellow rain " in Laos to a cause of Gulf War Syndrome6.

The Merck Veterinary Manual states, " The trichothecene mycotoxins are highly

toxic at the subcellular, cellular, and organic system level . . . Given in

sublethal toxic doses via any route, the trichothecenes are highly

immunosuppressive in mammals . . .7 "

Trichothecene Dosages

The common wisdom that the dosage of trichothecene mycotoxins needed to

cause injury is unknown is outdated by research gathered and correlated after

the

first Gulf War.

There have been several studies on the ‘efficiency’ of various methods of

using trichothecenes as a biowarfare agent. One 1997 study shows ingestion as

the most lethal route; a 2005 study shows inhalation as the more effective

route8. In the 2005 study, In laboratory rats, the dose to cause 50% lethality

in laboratory rats is 4 mg/kg when ingested. For dermal exposure to rats, the

50% lethality range is 2-12 mg/kg. In mice, the inhalation lethality is 1.2

mg/kg9.

2 mg dermal contact can cause skin damage to humans; 1 microgram contact to

the eye can cause corneal damage to humans; and in inhalation studies, 1/20th

of a milligram per kilogram causes death in half of all rats; heartier

guinea pigs can last up to 2 mg per kilogram10. If I have done my math and

conversions correctly, that is the equivalent of 180 lb person absorbing by

inhalation 16o mg (about 1/100th of an ounce).

The Army estimates that an inhalation dosage with a 50/50 chance to kill a

human is 200 mg to 1800 mg and must take place in a minute11. There are no

controlled respiratory studies done on humans, of course, although there are

several unfortunate post-mortem studies of people and other mammals who died of

stachybotrytoxicosis, particularly in times of food shortages12.

Indoor Mold and the Production of Trichothecenes

It is important to realize that even if a mold capable of producing

mycotoxins is found in an indoor environment, that does not mean that it is

necessarily doing so13. " Isolation of a toxigenic fungus from a building does

not

imply the presence of mycotoxin, since the physical conditions necessary for

mycotoxin production are very specific, and are often different from those

required for growth of the parent mold14. " However, a 2005 study found

aerosolized

trichothecenes produced by Stachybotrys spp. in indoor environments,

confirming it can happen15.

Even in controlled laboratory conditions, the amount of trichothecenes and

the strength of the trichothecenes vary by species and strain of mold16.

Endnotes

1. Wannemacher, W. et. al., Medical and Chemical Aspects of Biological

Warfare, Ch. 34, Trichothecene Mycotoxins, 1997.

2. s, G.J., Chaverri, P., Farr, D.F., & McCray, E.B. (n.d.)

Trichoderma Online, Systematic Botany & Mycology Laboratory, ARS, USDA.

3. Jarvis, B.B. et. al. Trichothecenes produced by Stachybotrys atra from

Eastern Europe. Appl Environ Microbiol. 1986 May; 51(5): 915–918.

4. Li, D.W. et. al. Taxonomic history and current history of Stachybotrys

chartarum and related species. Indoor Air 2005; 15 (Suppl 9): 5-10.

5. Locasto, D.A., et. al., Chemical, Biological, Nuclear, Radiological, and

Explosive (CBNRE) - T-2 Mycotoxins, 2005.

6. Augerson, W. A Review of the Scientific Literature as it Pertains to Gulf

War Illness, Vol 5: Chemical and Biological Warfare Agents, 2000.

Hu, H. et. al. The Use of Chemical Weapons: Conducting an Investigation

Using Survey Epidemiology, Journal of the American Medical Association, August

4,

1989 - Vol. 262, No. 5.

Locasto, D.A., et. al., Chemical, Biological, Nuclear, Radiological, and

Explosive (CBNRE) - T-2 Mycotoxins, 2005.

Vesser, D.A. et. Al. Gulf War Close Out Report, Biological Warfare

Investigation, 2001.

Wannemacher, W. et. al., Medical and Chemical Aspects of Biological Warfare,

Ch. 34, Trichothecene Mycotoxins, 1997.

7. Merck Veterinary Manual (2006) Trichothecene Toxicosis.

8. Locasto, D.A., et. al., Chemical, Biological, Nuclear, Radiological, and

Explosive (CBNRE) - T-2 Mycotoxins, 2005.

Wannemacher, W. et. al., Medical and Chemical Aspects of Biological Warfare,

Ch. 34, Trichothecene Mycotoxins, 1997.

9. National Institutes of Health, Centers for Disease Control. Toxic Effects

of Fungi, Damp Indoor Spaces and Health (2004), p. 131.

10. Augerson, W. A Review of the Scientific Literature as it Pertains to

Gulf War Illness, Vol 5: Chemical and Biological Warfare Agents, 2000.

11. Augerson, W. A Review of the Scientific Literature as it Pertains to

Gulf War Illness, Vol 5: Chemical and Biological Warfare Agents, 2000.

12. Hintikka EL. Human stachybotrytoxicosis. In: Wylie TD, Morehouse LG,

eds. Mycotoxigenic Fungi, Mycotoxins, Mycotoxicoses. New York: Marcel Dekker;

1987:87-89.

Environmental Health Investigation Branch. California Morbidity, Health

Effects of Toxin-Producing Indoor Molds in California, California Department of

Health Services, April 1998.

13. Chapman, J.A. Stachybotrys chartarum (chartarum = atra = alternans) and

other problems caused by allergenic fungi. Allergy Asthma Proc. 2003

Jan-Feb;24(1):1-7.

14. McNeel, S. et. al. Fungi & Indoor Air Quality, Health & Environment

Digest Vol 10, No. 2, pages 9-12, May/June 1996.

Wilkins, K. et. al. Patterns of volatile metabolites and nonvolatile

trichothecenes produced by isolates of Stachybotrys, Fusarium, Trichoderma,

Trichothecium and Memnoniella. Environ Sci Pollut Res Int. 2003;10(3):162-6.

15. Brasel, T.L. et. al. Detection of Airborne Stachybotrys chartarum

Macrocyclic Trichothecene Mycotoxins in the Indoor Environment, Applied and

Environmental Microbiology, November 2005, p. 7376-7388, Vol. 71, No.

110099-2240.