Tetanus - Horse

Also known as:

Lockjaw

Description

Tetanus is a highly-fatal infectious disease caused by the neurotoxin of the gram-positive bacterium Clostridium tetani, resulting in spastic paralysis of affected animals. Clostridium tetani causes infection via wound contamination and deposition of bacterial spores in tissue under anaerobic conditions. Cuts, deep puncture wounds, surgical sites may all provide sites of entry for infective spores. C. tetaniproduces tetanospasmin, a neurotoxin that is transferred to distant sites via the vascular system. This causes inhibition of the release of GABA and glycine from interneurons in the spinal cord and brain, resulting in tetanic spasms.

Signalment

All domestic species of all ages may be affected but foals may be particularly susceptible due to the possibility of infection through the umbilicus.

Diagnosis

Diagnosis is often based on history of a penetrating wound and clinical signs. Affected animals may have no history of vaccination against tetanus.

Clinical Signs

• Stiff gait

Treatment

• Wound debridement
  • Surgical removal of dead and infected tissue from the wound.
• Antibiotic treatment.
  • Metronidazole
    • Treatment with metronidazole decreases the number of bacteria but has no effect on the bacterial toxin.
    • Metronidazole is particularly active against anaerobic bacteria, and so is a good choice for use against C. tetani
  • Penicillin
    • Penicillin is becoming a less favoured treatment for tetanus, since there is a theoretical risk of increased spasms.
• Muscle relaxants
  • Diazepam
  • Midazolam
• Supportive therapy, for example:
  • Administering fluids
  • Providing appropriate nutrition
  • Maintaining a quiet environment with dimmed light.
• Remission take several weeks to months