A Rare and Fatal Disease

Q. What can you tell me about Tyzzer's disease? I've heard of only two cases in the last 20 years.


A. Tyzzer's disease is a fatal liver disease affecting foals from nine days to six weeks old, commonly seen in the first two to three weeks of age. The cause is a Clostridium bacterium, recently renamed from a Bacillus. Some foals die suddenly, while others develop jaundice and depression, then they die within 12-24 hours of showing clinical signs. The disease seems to be localized to certain regions and farms. The causative bacteria probably get into the soil and bedding from the feces of carrier mares. Once the disease is present in an area, it can occur sporadically year after year. Therefore, some farms and mares have cases in their foals each season; so if a mare has a foal with the disease one year, watch her and the foal closely the next year.

Suspicious cases must be treated immediately with massive amounts of IV penicillin/ampicillin and realistically should be sent to a referral hospital. The survival rate is incredibly low. In fact, I believe Doug Byars, DVM, Dipl. ACVIM, and I have the only published case of survival in literature. That case was intensely managed and very expensive. Most often, the disease is diagnosed postmortem and should be considered as a cause of any sudden death of a foal. Tyzzer's disease is sporadic and not highly contagious.

About the Author

Simon Peek, BVSc, MRCVS

Simon Peek, BVSc, MRCVS, is a clinical associate professor in the school of veterinary medicine at the University of Wisconsin.

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