Infectious Diseases

Former wild Mustang survives botulism scare

By Rob Warren

In 2016, the Bureau of Land Management (BLM) rounded up 279 wild horses to prevent the animals from starving following the Idaho Soda Fire. The fire destroyed more than 279,000 acres of critical habitat. Between 2016 and 2019, some of the horses were returned to the wild after their grazing area had grown back, but many were adopted.

Magic, a Mustang mare, was among the adopted horses. Last September, Magic was 13 years old and living a good life in Northern California with adopter Tiffany Tarbet. But following 2 bouts of colic and a suspected case of stomach ulcers within a month, Magic was found frothing at the mouth in an abnormal state. Ms. Tarbet called the UC Davis Equine Field Service, which had treated Magic previously.

Magic’s care team brought her to the UC Davis Large Animal Hospital for further testing. On presentation, the mare showed an inability to move her tongue or swallow appropriately. Physical examination showed reduced eyelid and tail tone, overall body weakness, low neck carriage and muscle tremors.

Botulism was suspected, and Magic was placed in the Equine Intensive Care Unit and administered antitoxins.

Botulism in horses is a severe, often fatal neuromuscular disease caused by toxins produced by the bacterium Clostridium botulinum. Infection can lead to progressive flaccid paralysis, muscle weakness and an inability to swallow. Transmission occurs through ingestion of the toxins, through an infected wound, or when the bacteria release the toxins directly into a foal’s gut. Immediate veterinary care and antitoxins are critical for survival.

“If we had waited one more day for treatment, Magic would’ve died,” Ms. Tarbet said.

Almost immediately upon hospitalization, Magic struggled to stand and was raised to her feet with assistance from the Large Animal Lift pulley system. The lift helped Magic to stand whenever necessary.

“Magic was very critical for the first 2 weeks,” said Emily Berryhill, DVM, DACVIM, the chief of the Equine Internal Medicine Service at UC Davis. “She required daily lifting and rotating since she was too weak to stand on her own; she was fed via a nasogastric tube, [had] a urinary catheter, and [received] around-the-clock supervision.”

Magic consistently improved throughout her 6-week hospitalization and was able to stand on her own at week 4. While she continued to show muscle weakness and had lost weight and muscle mass, she was stable on her walks through her fifth week. After 39 days, her care team was confident enough to discharge her to continue her recovery at home.

Magic required dozens of faculty, staff and students to meet her medical needs, all dedicated to returning her to health. From the initial visits by the Equine Field Service, through intake, intensive care, and continued hospitalization, Magic’s care team included house officer veterinarians Drs. Hillary Bunay (large animal medicine resident), Maria Calero (field service intern), Mathilde Fournier (large animal medicine resident), Mitja Miklavcic (equine emergency and critical care fellow), and Mimi von Zitzewitz (field service intern); faculty internists Drs. Berryhill, Rana Bozorgmanesh, Gary Magdesian and Camilo J. Morales; and many technicians and students.

“Magic was a huge labor of love for our equine medicine team, and we want to give grateful recognition to the technicians who were also critical to her around-the-clock needs,” Dr. Berryhill said. “We are so thrilled she is now back to running around the pasture.”

It took almost 4 months for Magic to regain all her weight and strength. She has now made a full recovery and is a happy horse once again. “She was so happy to get back out in the pasture when she recovered,” Ms. Tarbet said. “She was running around excited and neighing. She feels great now.” MeV

This story originally was posted on the UC Davis website. It has been edited for space and style. Check out our Q&A on botulism with Dr. Kali Slavik.