Botulism in Dogs

Botulism is very rare in dogs but can be fatal. Botulinum is the most potent toxin found in nature.

Initial symptoms of vomiting may be attributed to dietary indiscretion, but any dog with an upset stomach who rapidly develops signs of hind limb paralysis needs emergency care.

After being ingested, botulinum toxin is absorbed by the intestines and enters the bloodstream. Once in the bloodstream, the botulinum toxins bind to the nerve cells, causing progressive paralysis.

Clostridium botulinum bacteria can be found in:

• The tissues of dead infected animals (most commonly birds)
• Rotting animal carcasses
• Rotting vegetation

In rare cases, deep wound infections can cause botulism.

Once paralysis sets in, several complications and secondary conditions can develop.

With complete paralysis, the ability to urinate and defecate is lost, leading to further complications.

Early onset of symptoms generally indicates high levels of toxicity.

The most common route of exposure in dogs is ingestion of rotting wild carcasses, so free-roaming dogs are at greater risk.

A neurotoxin produced by the Clostridium botulinum bacteria causes botulism.

Symptoms of botulism generally develop within 24 hours from ingestion but can be delayed up to 6 days. The main initial symptom is weakness in the rear limbs that progressively works its way up with the dog eventually becoming paralyzed.

As botulism affects only the muscles; the affected animal remains mentally alert and aware of its surroundings.

Diagnosis is difficult as the symptoms of botulism are nonspecific and common to a number of other conditions. Diagnosis is suggested by an opportunity for or history of exposure. Botulinum toxin can be detected in samples of blood, food, vomit, or feces.

Most animals presenting symptoms of botulism receive the following work-up:

• Physical examination
• Blood tests
• Diagnosis imaging
• Urinalysis

If botulism poisoning is diagnosed very early a number of steps can be implemented to reduce absorption of the neurotoxin: Decontamination via gastric lavage, enemas, and or cathartics can be implemented to reduce absorption of the neurotoxin.

Note: there is no safe way to induce vomiting or administer activated charcoal at home. Always consult a veterinarian if pets are showing signs of poisoning.

Antitoxin: Botulism antitoxin may be available. Administration of the antitoxin is effective only in the very early stage of the condition, as it is ineffective once the neurotoxin has bound to the nerve endings. Once clinical signs develop, treatment is focused on supportive care and includes the following:

Fluid therapy: if the animal is unable to drink on its own IV fluid therapy is required.

Mechanical ventilation: in severe cases of botulism assisted ventilation may be required.

Topical ophthalmic ointment: if paralysis is impacting blinking or tear production, ophthalmic ointment or drops may be needed to protect the eyes and prevent keratitis.

Decubitus ulcer (bedsores) prevention: A number of steps can be implemented to reduce the risk of decubitus ulcer formation, including:

• Padding the dog’s bedding
• Regular turning
• Regular cleaning and drying of the body

Assistance eating and drinking: if paralysis is severe, assistance with eating and drinking may be necessary.

Note: do not force feed paralyzed animals, as force feeding can lead to the development of aspiration pneumonia. A feeding tube or IV nutrition may be necessary.

Antibiotics: if secondary infections develop (e.g . aspiration pneumonia or infected decubital ulcers), antibiotics may be needed during recovery.

Note: contact a veterinarian before administering antibiotics as they can cause an increase in botulism toxin concentration, and some kinds of antibiotics can cause a worsening in neuromuscular function.

After treatment, frequent monitoring is necessary to ensure proper recovery.

The prognosis depends primarily on the amount of toxin ingested.

When promptly and correctly treated, most dogs recover within 1 to 3 weeks. In some cases, clinical signs can persist for months after treatment.

If dosage is high or treatment is delayed, the prognosis is very poor, with most dogs dying due to paralysis of the lungs..

The only way to prevent botulism is by eliminating opportunities to ingest Clostridium botulinum bacteria. Strategies include:

• Making sure that there are no dead animals on or near the home property
• Proper disposal of raw meat and vegetables
• Heating food up to 212°F (100°C) for 10 minutes, which kills Clostridium botulinum bacteria
• Proper treatment of deep wounds

Botulism is not contagious.

Botulism is very rare in dogs.

• Antitoxin
• Decontamination
• IV fluids
• Supplemental oxygen
• Antibiotics for secondary infections
• Intensive nursing care