Botulism is a rare disease that causes generalized weakness involving many of the nerves that activate the muscles of the body. Information travels down nerves to stimulate muscles to move or contract. This activation of muscles is mediated through a chemical called ACh. Botulism blocks the release of ACh from the nerve endings, which results in neurological dysfunction and weakness.

Animals acquire botulism by ingesting the botulinum toxin, which is produced by a bacterial organism called clostridium botulinum. This organism may be present in spoiled or rotting foods, garbage, and dead animals. After the animal eats spoiled and contaminated material, vomiting and diarrhea may occur prior to the onset of neurological signs, which typically occurs two to five days after ingestion of the botulinum toxin. Affected animals usually develop hindlimb weakness that is rapidly followed by front leg weakness. The animal has difficulty standing and walking. Severely affected animals may not be able to stand, lift their heads up, or even move their legs. They may not be able to eat or drink because of weakness of the jaw and tongue muscles. Affected animals may not be able to bark or vocalize as a result of weakness of the muscles of the larynx. As a consequence, food and water may be regurgitated and can be inhaled into the lungs, leading to pneumonia. If the muscles of the diaphragm are affected, this can lead to respiratory failure and death.

Blood tests to detect the botulinum toxin are often inconclusive at the time the clinical signs occur. This can be frustrating to the veterinarian and to the owner, but especially to the affected animal. There is no specific treatment for botulism. Affected animals require hospitalization and intensive supportive care, such as intravenous fluids and medications for shock and infection. Assistance is needed with urination and defecation to keep the animal clean. Animals unable to eat and drink may require a feeding tube and supplemental nutrition.

Recovery may be rapid in mild cases, but it can take weeks. Continued nursing care at home is commonly needed. Clinical signs usually improve gradually over three to four weeks. Prognosis is very poor for animals with paralysis of the muscles of respiration. Keep your animal from ingesting spoiled or rotting foods, garbage, or dead carcasses.

Dr. Karsten Fostvedt is a veterinarian at St. Francis Pet Clinic in Ketchum.

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