Botulism in Cats

By Krista Williams, BSc, DVM, CCRP; Catherine Barnette, DVM

What is botulism?

Botulism is a rare condition that causes paralysis in cats. Botulism is caused by ingesting the botulinum toxin, a substance produced by the bacteria Clostridium botulinum.

Most cases of botulism in cats are caused by eating dead animals or contaminated raw meat. Clostridium botulinum that grows in/on meat can release the botulinum toxin into its surroundings, allowing the toxin to be ingested by cats who eat the contaminated meat. When cats eat contaminated meat, the toxin is absorbed by the intestines and enters the bloodstream. The botulinum toxin is then carried throughout the body, where it binds to nerve cells, resulting in paralysis.

What are the clinical signs of botulism?

Signs of botulism typically develop hours to days after ingesting contaminated meat, though the onset can be delayed up to six days. Clinical signs vary depending upon the amount of toxin ingested, although an earlier onset of clinical signs is typically associated with more severe disease.

Botulism often affects the body in a characteristic way. It often starts with weakness in the rear legs and, within 24 hours, this weakness progresses to include the front legs and muscles of the head and face.

"It often starts with weakness in the rear legs and, within 24 hours, this weakness progresses to include the front legs and muscles of the head and face."

Affected cats are mentally normal. They can sense pain and are aware of their environment.

Botulism's effects on muscle movement may lead to an inability to swallow, increased salivation, constipation, and eye inflammation (due to decreased tear production and an inability to blink). In some cases, death may occur due to paralysis of the diaphragm. The diaphragm is the muscle that moves to inflate the lungs; when the diaphragm is paralyzed, a cat cannot breathe without the assistance of a mechanical ventilator. Fortunately, the diaphragm is better able to resist botulism paralysis than other muscles within the body; therefore, not all cats require a ventilator.

How is botulism diagnosed?

Diagnosing botulism can be difficult. Your veterinarian will start by doing a full examination of your cat and taking a thorough history to determine possible opportunities your cat may have had to ingest the botulinum toxin, along with the signs your cat has been showing and their duration.

Routine laboratory tests, such as bloodwork and urinalysis, are typically normal in affected cats, so diagnosis is usually based on a history of exposure and observation of the cat. Blood, stool, and/or vomit samples may be tested for the botulinum toxin. X-rays may show evidence of pneumonia or esophageal motility problems, both of which can be seen with this condition.

How is botulism treated?

If botulism exposure is known or suspected before the onset of clinical signs, the botulinum antitoxin can be administered. The antitoxin prevents the botulinum toxin from binding to nerve endings and causing clinical signs. Once signs of paralysis develop, the antitoxin is not effective.

Once signs have developed, treatment of botulism is focused on supportive care. This supportive care will require hospitalization; depending on the severity of your cat’s signs, she may require hospitalization at a facility with an intensive care unit.

"Once signs have developed, treatment of botulism is focused on supportive care."

The signs of botulism will typically resolve with time, and supportive care decreases the likelihood of complications. Affected cats should be kept hospitalized on soft bedding to prevent pressure sores. Mildly affected cats may need assistance with eating or drinking, while more severely affected cats may require intravenous fluids to prevent dehydration and a stomach tube for feeding.

Many affected cats lose the ability to empty their bladder, so the veterinary staff may need to manually express your cat’s bladder or place a urinary catheter to keep the bladder empty. Your cat may require ointment to keep the eyes moist if she is unable to blink. Antibiotics may be given to treat secondary infections that may occur. If your cat’s diaphragm becomes paralyzed, a mechanical ventilator may be used to allow her to breathe.

What is the prognosis for botulism?

Most affected cats recover within 14-24 days if they receive appropriate supportive care. Without treatment, death due to paralysis of the diaphragm or secondary infection may occur.

How can botulism be prevented?

Botulism can be prevented by preventing your cat from eating raw meat or dead animals. There is no vaccine against botulism.

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