BOTULISM

a. b. c. d. For the answer, turn to page 25.

Mention of botulism strikes fear in people’s hearts, and rightly so. The illness requires intensive supportive care and the outcome is uncertain.

Botulism causes progressive paralysis, starting at the head and spreading throughout the body. Once a horse goes down, his condition deteriorates rapidly, and if his body can’t clear the causal toxin quickly enough, the muscles that control respiration stop functioning. The good news is that botulism is rare and almost entirely preventable through vaccination. The bacterium that causes botulism,

is ubiquitous in the environment but usually in a harmless, dormant state. It’s only under certain conditions---moisture and a lack of oxygen being the most important---that the bacterial spores become active and multiply quickly. When the active bacteria die, they release a toxin known as botulin.

There are seven types of botulin, but only three are likely to cause illness in horses. Type B is the most common, found east of the Mississippi River and most often in the mid-Atlantic states and Kentucky. It accounts for about 85 percent of all cases. Type A is found on the West Coast and is less common.