Tetanus infections are exceedingly uncommon in dogs, which is why routine anti-tetanus vaccinations are not administered in veterinary practice, according to David Grant, a veterinarian with over 50 years of experience. Grant has treated only two canine tetanus cases during his extensive career, one in private practice and another at the RSPCA Harmsworth animal hospital.

Both dogs exhibited characteristic symptoms of tetanus, including muscle stiffness that led to permanently erect, inward-turned ears and a wrinkled forehead. They also experienced spasms affecting the jaw muscles, resulting in the inability to open their mouths—commonly referred to as “lock jaw.” These spasms could be triggered by noise. Small wounds were identified as probable entry points for the bacterium Clostridium tetani, the cause of the infection.

Treatment for these cases required intensive care and prolonged nursing support over many weeks, eventually resulting in recovery. Unlike humans and horses, which are more vulnerable to tetanus toxin and thus routinely vaccinated and treated with antitoxins, dogs exhibit a natural resistance to the toxin. This resistance has led to an absence of licensed tetanus vaccines or antitoxin products specifically for canine use.

Because of the rarity of canine tetanus, developing and licensing a vaccine or antitoxin for dogs is not considered feasible. In the unusual instances when treatment is necessary, veterinarians may use antitoxins licensed for other species under regulatory provisions known as the “cascade” system, which allows off-label use when no specific product exists for dogs.

These factors explain why anti-tetanus injections are not typically part of standard veterinary care for dogs presenting with wounds, despite tetanus being a serious condition in other animals and humans.