E805
Tetanus

Clinical Signs: At first, the horse shows signs of stiffness in the head and neck region and inability to move in the hind end. The muscles of the mouth, head, and neck become extremely stiff and often spasm. As the disease progresses, the animal has difficulty turning, backing, and eating. Because the muscles of the head are usually involved, lockjaw, prolapse of the third eyelid (see video clip below), and erect ears are some common signs. The horse is commonly very sensitive to noise and stands in a "sawhorse" stance with the tail extended. Signs usually develop 2 weeks to 1 month after the initial injury. Death occurs in approximately 80% of the non-protected animals.

Disease Transmission: This organism proliferates in areas and tissue that are oxygen deprived. A puncture wound or injury is the most common route of entry. After the bacteria enter the body, they produce a toxin that interferes directly with the body’s nervous system.

Diagnosis: This is usually based on the signs the animal exhibits and the history of a previous wound or injury.

Treatment: Successful treatment involves four different aspects:

1. Prevent additional spread of the toxin in the animal.

1. Administer 10,000 - 50,000 International Units (IU) of tetanus antitoxin intramuscularly (IM), per every 1,200 lbs.  Problems can occur in some horses given the antitoxin, so consult with a local veterinarian.
2. Giving 3,000 - 9,000 IU of the same tetanus antitoxin in the injured area may also be beneficial.
3. It is also necessary to administer 40 mL of procaine penicillin G per 1,200 lbs., IM, twice a day, along with giving some of the antibiotic around and in the injured area.

2. Provide muscle relaxation.

1. Every 4-6 hours, give Acepromazine for muscle relaxation.

3. Provide supportive care.

1. Because the animal has little to no muscle control, provide areas with good footing.
2. Provide plenty of water and food that is easily accessible.
3. Allow plenty of straw and soft bedding to prevent sores, since the horse may spend much of its time down.

4. Establish protection in the future.

1. Give a tetanus toxoid shot, and booster it again in one month.

Prevention: The best prevention for tetanus is vaccination. See the vaccination suggestions on page A905.

The following video clips are of a horse that has tetanus. The second clip shows how the third eyelid will "prolapse" or abnormally cover part of the eye.