Botulism

Clostridium botulinum, a bacteria that can be very harmful, even deadly to horses. The disease, Botulism, is caused by the ingest of C. botulinum spores that formed toxins. The way they form toxins is when they are in a damp, anaerobic environment. They also favor low acidity (pH greater than 4.5) and lots of protein conditions. Places like decaying vegetable matter such as soggy hay, or decaying animal tissues are where they are commonly found. Once the toxins enter the horse’s body, they travel through the horse’s bloodstream, and ultimately reach the myoneural junction. There, they pass signals from motor neurons to muscle fibers; they break through the neuron cells and bind to synaptic vesicles (sacs that contain acetylcholine which cause muscles to contract) and prevent the chemicals release. Basically, the toxin disturbs the nerve to muscle communication and will firstly affect muscles used for chewing, swallowing, standing, blinking, and control of tail. The most common signs of Botulism are loss of muscle control and muscle tremors, drooling, a weak walk, can’t eat, doesn’t have any tone in lips, tongue, eyelids and tail, and lots of lying down. Things such as botulism antitoxin, polyvalent antitoxin, or monovalent antitoxin can be given to treat Botulism. They work by using antibodies to bind to free-floating toxins in the blood, which can prevent them from ever attaching to neurons. But they cannot repair the harm previously done so it is best to treat the horse as soon as possible. Ways to prevent Botulism altogether is an equine botulism vaccine, keeping hay properly stored so it won’t get wet, and look for dead animals in feed and water areas.

Botulism seems like a terrible disease, but because it is rare, this information is useful for something to keep in the back of your mind. It is good information for horse owners to be aware of, and to make sure they can prevent it, because it does affect the natural world. But other than that, most people shouldn’t worry about this. Though, states east of the Mississippi should be more cautious because it has been known to occur more it that region; as well as Appalachian states.

Information from Equus Magazine, The Basics of Botulism by Joanne Meszoly.