Botulism in Dogs | PetMD

What is botulism in dogs?

Botulism is a rare but potentially fatal disease caused by a toxin produced by bacteria. Clostridium botulinum.

Dogs are affected by eating rotting animal carcasses or spoiled vegetation where the bacteria thrives.

Once ingested and absorbed through the stomach and intestines, the toxin attacks the body's nerves, leading to weakness (paresis) and eventually an inability to move (paralysis). This can quickly progress to difficulty breathing or even death if left untreated.

Botulism is considered a medical emergency and can be fatal without prompt treatment. If you think your pet has any of the signs of botulism, contact your local veterinarian immediately.

Symptoms of Botulism in Dogs

Clinical signs of botulism may appear within a few hours but may be delayed for up to six days. The signs may vary depending on the amount of toxin consumed, but the earlier they appear, the more serious the illness.

Clinical signs of botulism include:

• Vomiting/diarrhea

• Progressive, symmetrical, ascending weakness that begins in the hind limbs. This is a classic characteristic sign of botulism in dogs. This means that a weakness that started in the back legs has spread to the front legs and then to the head and neck. When this happens, you may see these additional symptoms:

  
  

  • Inability to walk

  • Inability to raise the neck and head

  • Facial paralysis including decreased jaw tone, decreased ability to chew or swallow, and drooling or hypersalivation

  • Urinary retention (unable to pee) and constipation (unable to poop)

  • Difficulty breathing

  • Paralysis of all four limbs (tetraplegia)

Although paralyzed, affected dogs are mentally normal and can still sense their surroundings and feel pain.

If left untreated, most animals die from botulism due to respiratory distress because the muscles used for breathing, such as the diaphragm, become paralyzed and the dog is unable to breathe. However, paralysis can affect other organs, such as the heart, which can also be fatal.

If your pet exhibits any of the clinical signs of botulism above, contact a veterinarian immediately.

Causes of Botulism in Dogs

Botulism is caused by botulinum toxin, produced by bacteria. C. botulinum.

There are seven subtypes of C. botulinum (A, B, C, D, E, F and G), and all have the same effect on the nervous system. Subtypes A, B, E, and F are associated with botulism in humans, while most cases in dogs are caused by subtype C.

Once a dog consumes the toxin, it is absorbed in the stomach and intestines and carried through the bloodstream to the nerves. Nerves in the body are used to signal muscles to contract. Botulinum toxin blocks this process, preventing muscles from contracting, creating muscle weakness and paralysis.

The diaphragm muscle is the muscle that separates the abdomen and thorax. Its contraction plays a major role in breathing. Fortunately, it is more resistant than other muscles in the body to botulinum toxin, but once affected, a dog can no longer breathe and, without treatment, will die.

How Vets Diagnose Botulism in Dogs

Veterinarians diagnose botulism in dogs based on medical history, symptoms, and ruling out other causes of paralysis because there is currently no quick, reliable test.

Botulism can be difficult to diagnose because it is very rare and its symptoms are very similar to other conditions, including:

If you suspect your dog has botulism, it is very important to share any history of possible exposure to carcasses, dead animals, rotting vegetation or raw meat with your veterinarian to help make a diagnosis.

Current tests to diagnose botulism involve highly specialized laboratory tests to detect botulinum toxin in blood, stool, vomit, or in ingested material. However, these tests are neither fast enough nor accurate enough to make a diagnosis in time and be useful.

Your veterinarian will begin with a thorough physical exam to assess weakness, spinal reflexes, pain and fever. They will also perform a complete orthopedic and neurological examination.

To further evaluate your dog and help rule out other causes of paralysis, your veterinarian may also recommend:

Treatment of botulism in dogs

Although there is an antitoxin for botulism, it is not readily available in veterinary hospitals and must be administered before the toxin reaches the nerve endings and causes clinical signs. Once an animal develops signs of paralysis, the antitoxin is no longer effective.

Treatment of botulism in dogs primarily involves supportive care. This supportive care can be time-consuming and expensive because it will require hospitalization, likely in an intensive care unit (ICU).

Mildly affected dogs may be able to continue eating and drinking on their own with help, while more severely affected dogs will likely need intravenous fluids (to keep them hydrated) and feeding tubes.

Care should be taken to provide sufficient bedding/padding and rotation of positioning to prevent an immobile patient from developing pressure sores. Urinary care should also be taken care of, either by keeping the patient clean and dry or, if the dog loses the ability to urinate, by providing manual bladder expression or urinary catheter care.

Antibiotics and supportive medications, including medications for eye lubrication, pain, nausea, or diarrhea, may also be given.

If the paralysis continues to progress and affects the diaphragm, dogs may lose the ability to breathe on their own and require manual ventilation with a ventilator.

Recovery and Management of Botulism in Dogs

Botulinum toxin does not damage nerves, but rather blocks contraction signals sent to muscles.

Since there is no nerve damage, supportive care often results in complete recovery. However, clinical signs of botulism often last two to three weeks and animals may need intense supportive care throughout this period.

Prevention of botulism in dogs

Prevention is key to protecting dogs from botulism. Never allow your dog to ingest raw meat, dead animals or spoiled vegetation. It is best to keep a close eye on them outside or in wooded areas.

Unfortunately, there is no vaccine against botulism in dogs.