Description

Because of its seemingly sudden appearance and the nature of its symptoms, tetanus is a frightening disease that affects animals and humans. Horses are especially vulnerable to tetanus because they possess less natural immunity and are subject to wounds and injuries that come in contact with soil that has been contaminated by horse and cow manure.

Tetanus infections often occur in puncture wounds where the oxygen content is low. Any cut or injury can serve as an entry for the bacteria. In the horse's body, the bacteria produce a potent neurotoxin that is transmitted along the nerves and into the spinal cord. The toxins may also be absorbed locally and carried by the bloodstream into the brain.

Tetanus is not always fatal. In some cases, a horse may experience a mild illness and recover with treatment, but, because of the potentially lethal nature of the disease, a veterinarian should always be called and involved in the diagnosis and treatment whenever the possibility of tetanus exists.

Symptoms

• Great sensitivity to being handled
• Stiff gait
• Colic
• Spasms in the jaw, neck, hind limbs, and muscles around the wound
• Protrusion of the third eyelid, with appearance of a film over the inner third of the eyes
• Labored breathing
• Sawhorse stance
• Unable to eat, drink, and swallow without dribbling
• Horse goes down and can't get up

Causes

Tetanus is caused by a bacteria of the clostridial species that produces powerful exotoxins. These toxins are responsible for the lethal effects of the Clostridium tetani spores that affect all animals, including man.

Clostridium tetani bacteria, thrive in soil contaminated by horse and cow manure and are ever present in the typical horse environment.

Prevention

Prevention includes immunization of all foals with tetanus toxoid and tetanus antitoxin within the first 24 hours of life, if the mare has not been vaccinated. If the mare has been vaccinated on schedule, only tetanus toxoid is given, with vaccinations again at 4 weeks and 4 months. All horses should be vaccinated annually. A horse with a tetanus-prone wound should receive a tetanus toxoid vaccination.

The second layer of prevention includes prompt attention to all wounds by cleansing the area with a sterile surgical scrub solution to remove all dirt and bacteria. Wound lavage, to thoroughly cleanse the tissues, is effective. Any devitalized tissue should be removed. Puncture wounds should be enlarged and left open after thorough cleansing to provide drainage.

Treatment

Treatment of tetanus involves surgical treatment of the wound to remove all devitalized tissue, thorough cleansing, and injecting penicillin into the wound, which is left open for effective drainage. High doses of intravenous penicillin, administration of tranquilizers, muscle relaxants, and tetanus toxoid and antitoxin are necessary. The horse should be kept hydrated with intravenous fluids.

Horses are usually placed in darkened stalls because of their heightened sensitivity to light and sound. Supportive and skilled care in a veterinary hospital is sometimes recommended.