Equine Tetanus

Question 1

What is the organism that causes tetanus in the horse?

Answer 1

Clostridium tetani

Question 2

Where is C. tetani commonly found?

Answer 2

In soil and the intestinal tract of animals

Question 3

Other than horses what species is highly susceptible to tetanus?

Answer 3

Humans

Question 4

Describe the parthenogenesis of C. tetani.

Answer 4

• Enters the tissue via deep puncture wound
• grows in necrotic tissue
• bacterial cells undergo autolysis and release potent neurotoxin
• absorbed by motor nerves - passes up spinal nerve (spinal cord)
• Ascending paralysis/spasmodic contractions of voluntary muscles by nerve cell irritation

Question 5

What is the incubation period for tetanus?

Answer 5

10 to 14 days

Question 6

What are the eight clinical signs of equine tetanus?

Answer 6

1. Muscle stiffness and spasms
2. Hyperesthesia
3. Fever, Anorexia, and Depression
4. Excessive sweating
5. Increased HR and RR
6. Dyspnea
7. Dysphagia
8. Urinary and Fecal Incontinence

Question 7

Define hyperesthesia.

Answer 7

An increased sensitivity to sensory stimuli (light, sound, and touch)

Question 8

List common signs of muscle stiffness in the horse.

Answer 8

• Sawhorse stance
• Outstretched head and neck
• Prolapsed third eyelid
• Stiff erect ears and tail
• Anxious facial expression

Question 9

What causes this “sawhorse” stance?

Answer 9

Generalized stiffness

Question 10

What causes the dyspnea associated with equine tetanus?

Answer 10

• Partly due to laryngospasm

- Flared nostrils

Question 11

How is equine tetanus diagnosed?

Answer 11

• Clinical signs
• History of inadequate vaccination
• Presence of a deep puncture wound

Question 12

What is done for treatment?

Answer 12

Wound care

Question 13

What does wound care include?

Answer 13

• The neutralization of free circulating toxin/TAT
• Penicillin
• Acepromazine
• Supportive treatment
• Phenylbutazone

Question 14

How do you care for a horse with equine tetanus?

Answer 14

• Keep them in a dark heavily padded stall
• Keep cotton in their ears
• Provide fluids with electrolytes
• Feed via a stomach tube
• Tracheostomy tube
• Perform enemas or manual evacuation of the rectum
• Bladder catheterization

Question 15

What are some methods of preventing equine tetanus?

Answer 15

1. Treat any sustained wounds:
   - Give Penicillin G
   - 1500 units antitoxin if vaccination is not current
2. Vaccination

Question 16

What are vaccination guidelines for horses that have not been previously vaccinated?

Answer 16

Adm. 1 mL of tetanus toxoid immediately, repeat again in 3 to 4 weeks; adm. boosters annually.

Question 17

What are the guidelines for giving toxoid to foals?

Answer 17

Adm. 1st dose at 5 to 8 week of age followed by boosters every 3 weeks.

Question 18

What is done for foals in high risk areas?

Answer 18

They can be given antitoxin immediately after birth and every 2 to 3 weeks until they are 3 months old.

Question 19

What is the protocol for administering antitoxin and toxoid at the same time?

Answer 19

Administer one in the neck of the horse and administer the other in the rear end.

Question 20

Why do you administer the antitoxin and toxoid in different locations?

Answer 20

To prevent the two from mixing and allowing the antitoxin to neutralize the vaccine (toxoid).

Question 21

When should pregnant mares be vaccinated?

Answer 21

During the last 6 weeks of pregnancy.

Question 22

If a previously vaccinated horse develops a dangerous wound, what should be done?

Answer 22

Administer another injection of toxoid to increase the circulating antibody.

Question 23

If the horse has not been previously vaccinated and develops a dangerous wound, what should be done?

Answer 23

It should be treated with 1500 to 3000 units of antitoxin and toxoid should be given simultaneously then repeated in 30 days.