This is always a potential ranch hazard due to contamination of fish or meat. The cause is high levels of type A, C, or E toxin produced by Clostridium botulinum. The toxin is made by bacterial growth in unfrozen or slowly frozen food. Poorly handled whale or seal meat is most likely to contain the toxin.
The symptoms are flaccid paralysis, abdominal breathing coma and death. Blue foxes appear more sensitive to the toxins.
Diagnosis is by laboratory tests on feed as well as typical symptoms before death.
Prevention is by vaccination. A mink vaccine which combines the toxoid with distemper is good. It should be given between eight and ten weeks of age or two weeks after weaning.