By: Katie Jones, CVT
Tetanus is a disease caused by the organism Clostridium tetani. It affects almost all animals; including humans. Horses are more susceptible to tetanus than any other domestic animal. This is due to their lower natural immunity and they live in environments with a high risk of tetanus.
- Not contagious.
- Anaerobic bacteria. Anaerobic organisms thrive in dark environments lacking in oxygen; however, their spores can survive in the environment for years.
- Disinfectants, heat, or drying can damage the integrity of the organism.
- High mortality rate.
Ideal environment: Deep puncture wound that includes tissue damage.
Process of Infection:
- The organism spores live in the soil and enter the body through wounds or incisions. The toxins produced begin to damage the tissue and decrease the blood supply to the infected area.
- The neurotoxins produced by the organism can enter the bloodstream from the infected site of the body.
- These neurotoxins tightly bind to specific areas of the spinal cord and brain, preventing the body’s ability to process brain signals. It causes the affected muscles to intensely and persistently contract. Once the neurotoxins attach to the spinal cord there is no medical treatment available to dislodge them and the effects must be allowed to slowly wear off.
Clinical Signs: Once the organism has entered the tissue and is producing toxins, the course of clinical signs can be very rapid.
- Beginning signs: Colic, vague stiffness, lameness (if the infected area is the limbs), retraction of the lips, flaring of the nostrils, development of a film over the third eye lid, and difficulty opening the jaw.
- After 24 hours of infection there is generalized spastic activity of the muscle groups that assist in standing.
- As the disease process continues the horse can develop labored breathing, stiffness in the front limbs, and the jaw can become locked preventing eating and drinking. These symptoms are characteristic of fatal tetanus; however, not all horses that are infected with tetanus progress to this state.
- Early diagnosis is needed to prevent the progression of the disease with the use of a manufactured antitoxin.
- If the diagnosis isn’t made early, the wound will need to be surgically opened, effected tissue must be removed, and penicillin will be injected into the wound. The wound will ultimately be left open for continued drainage.
- The horse will remain on a course of penicillin.
- Supportive care is given to maintain nutrition and hydration.
- It can take weeks to see an improvement and clinical signs can last months.
Prevention: Tetanus is a nasty disease with an expensive treatment plan.
- Although the vaccine is not a 100% guaranteed, it has proven to be a successful way of preventing Tetanus. Check with a veterinarian regarding their specific vaccine protocols.
- Cleaning and bandaging wounds immediately will also help with preventing the development of tetanus.