Information on Botulism in Horses
Friday, September 11, 2009
There is no quick test to determine if a horse has botulism. The diagnosis is based on history and physical exam findings. The abrupt onset of diffuse symmetrical weakness that gradually progresses to recumbency in 1 to 4 days with normal mentation in the presence of an inability to swallow and decreased tongue tone should put the red flag up that botulism may be the cause. The laboratory tests that are available require a specialized laboratory to look for spores or toxin in samples of blood, feed and gastrointestinal contents.
The fundamental principle of treating botulism is to neutralize the circulating toxin with administration of an antitoxin. It is important that the antitoxin be administered early in the course of the disease otherwise the horse may die. Other important aspects of treatment include proper nursing care, fluids and prevention of secondary problems. In general the overall cost to treat a horse with botulism is very expensive. Even with the antitoxin and appropriate treatment it can take 30-90 days for the horse to completely recover, if it survives.
A highly effective vaccine against type B botulism is available (BotVax B made by Neogen Corporation). This vaccine is recommended for horses that reside in or are traveling to areas in which Botulism Type B is endemic (such as Kentucky). Any horse traveling to Kentucky, including those competing in the Alltech FEI World Equestrian Games should be vaccinated for Botulism Type B. Adults should be immunized with an initial series of three doses given one month apart then boostered yearly. Additional preventative measures include good husbandry.
Bonnie S. Barr, VMD, a graduate of the University of Pennsylvania School of Veterinary Medicine, is a board certified Internal Medicine specialist at Rood & Riddle Equine Hospital in Lexington, Kentucky. Dr. Barr has special interests in neonatology and infectious disease. She raises Thoroughbreds and Quarter Horses with her husband.