Dog: Tetanus

General information

Other common/scientific names: lockjaw

Tetanus is a disease which affects the nervous system. Different animals have different sensitivity to the tetanus toxin. Horses and humans are very susceptible while dogs and cats are much more resistant. Therefore, tetanus is rare in dogs.


Tetanus is caused by toxins secreted by the bacterium, Clostridium tetani. These bacteria live in the soil and are anaerobic, meaning they grow in conditions where there is no oxygen. The toxins bind to local nerves and migrate into the spinal cord and can progress to the central nervous system or brain.


The tetanus organism enters the dog’s body through a wound, especially deep puncture type wounds. The wound can be small such as one caused by a foxtail or grass awn. Puppies can acquire the organism through their gums when shedding their baby teeth. The wound may or may not be visible to the owner.

Cardinal symptom

“Sardonic smile”


Clinical signs begin as muscle rigidity and stiffness. Facial muscles become rigid and the lips are drawn back into a fixed “smile or grin”. The nictitating eyelid or third eyelid is seen pulled up or flashed across the eye when the dog blinks. Dogs with ears that hang down may develop erect ears. The jaws become clenched and unable to open - hence the nickname, lockjaw. They may have difficulty swallowing. Dogs with tetanus develop a stiff, awkward gait and a sawhorse stance. They become extremely sensitive to light and sound, reacting with muscle spasms. In the more advanced cases, the dog can no longer walk. Seizures and respiratory paralysis can result in death.


The diagnosis of tetanus is made based on distinctive clinical signs and possibly the appearance of a wound.


If a dog is suspected of having tetanus, hospitalization and intensive care are needed. Injectable antibiotics are use to kill the Clostridial bacteria and tetanus antitoxin is used to neutralize the toxin. Sedation may be needed to control spasms and seizures. The dog is kept in a darkened, quiet room on soft bedding. In severe cases, supportive therapy may include a feeding tube if the dog is unable to open its jaws and swallow.


If tetanus is diagnosed early and prompt treatment is started, the prognosis is good for recovery. However, while improvement is usually seen within the first week of therapy, complete recovery may take months. Severely affected animals have a guarded prognosis.


Dogs are not routinely vaccinated for tetanus because their resistance to infection is high. All wounds found on your dog should be cleaned thoroughly. If the wound is deep, you should contact your veterinarian.

Update version: 4/24/2014, © Copyright by
Join the discussion!
11/29/2013: the bunny
Very informative data. Useful for amateur diagnosis of injury

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