Protect Your Cat From Toxic Black Mold

Filed Under: Cats, Poisoning

Hurricane and flood damage have recently brought exposure to black mold (Stachybotrys chartarum) to the forefront. Today most insurance companies try to exclude mold damage from coverage. Mitigation of mold is commonly the most costly consequence of water damage. Water staining to wood and sheetrock may appear unsightly, but it is the often hidden damage incurred from mold lurking underneath that is of greater concern.

A Veterinary Hospital in Marathon, Florida reported the death of two overtly healthy Himalayan cats from a single household secondary to exposure to anesthesia from a routine dental cleaning. One cat died on day two following the procedure while the other died on day 15. Death was attributed to acute pulmonary hemorrhage (bleeding in the lungs). Both of these cats had been exposed to black mold secondary to flooding from roof damage in an earlier hurricane. The flooding was extensive enough to require mitigation necessitating the removal of sheetrock walls. Until this reported episode in Marathon, Florida, acute pulmonary hemorrhage had not been reported for the cat. The pet owners had two other pets, another cat and a dog. The remaining pets appear fine but have not undergone any anesthetic procedures in which they could have experienced an increase in pulmonary tension.

Physicians have previously linked exposure to black mold and subsequent procedures requiring anesthesia to resulting pulmonary hemorrhage in man.

Black mold spores contain several classes of mycotoxins that are detrimental to the health of people as well as animals. The most important of these mycotoxins are trichothecene satratoxins G and H, which are potent protein synthesis inhibitors. In animals, these mycotoxins appear to cause a fragility of capillaries in the lungs which may lead to pulmonary hemorrhage. The trichothecene toxins are also immunosuppressive (acts to decrease the response of the immune system) with the help of phenylspirodrimanes and cyclosporine. Black mold also produces hemolysin and proteinases (enzymes that break down protein). The trichothecenes and hemolysin can cause cell injury and death. Together with the collagen-degrading proteinases, the trichothecenes cause acute structural damage to the alveolar capillary wall (capillaries in the lungs), making them weak. When pulmonary capillary pressure is high, such as intense physical training or anesthesia, the pulmonary capillaries would be at risk of failure or rupture secondary to the stress of the increase in pressure resulting in hemorrhage within the lung tissues.

This current study suggests that caution should be taken in pets undergoing anesthetic procedures that have a history of exposure to water damage or mold exposure. Pet owners and veterinarians should both be diligent in relaying this information to one another due to the possible dire consequences of exposure. Should complications arise as indicated by a bloody respiratory discharge, the anesthesia should be immediately discontinued. Treatment with corticosteroids should be initiated to hopefully stabilize the capillary epithelium. Antibiotics may be used to prevent secondary pneumonia since blood is a good media for secondary bacterial growth.


Mader, Douglas, DVM, Iwona Yike, PhD, et al. “Acute Pulmonary Hemorrhage during Isoflurane Anesthesia in two Cats Exposed to Toxic Black Mold (Stachybotrys chartarum). JAVMA. Vol. 231, No. 5. September 1, 2007. Pp. 731-735.

Heflin, Marissa. “Findings Show Toxic Mold Can Affect Pets”. Pet Product News. November 2007. p.36.

Topics: mold, prevention

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