Katet, one of the first Chincoteague ponies to be successfully treated for Swamp Cancer, and her 2023 foal. Credit Lois Syzmanski.
As test subjects for a new Pythiosis vaccine and immunotherapeutic, the wild Chincoteague Ponies of Assateague Island in Virginia have helped researchers save equine lives.
Pythiosis – commonly known as swamp cancer – once affected animals living in tropical temperatures. It has worked its way up the coast, now affecting horses in colder temperatures, too. Caused by a fungus-like germ called Pythium insidiosum, it infects plants, mammals and birds.
In horses, the disease triggers skin lesions when water contaminated with swimming Pythium spores enters through a cut, even as small as a mosquito bite. Most often, legs or hooves are affected, but it can be anywhere.
From October 2017 through December 2018 seven Chincoteague Ponies were infected, treated and eventually humanely euthanized. There had been others, but seven in one year was just too much. Seeing swollen legs looking like raw meat was not easy. Treatment then included regional limb perfusion, which entails attaching a tourniquet near the target area and injecting an antifungal medication, and/or immunotherapy to trigger the immune system to fight the disease, with low rates of success.
In October, 2018, Dr. George Marble, an attending veterinarian for the wild pony herds, reached out to Dr. Richard Hansen, President & CEO at SolidTech Animal Health, Inc. in Newcastle, OK.
“Dr. Marble became aware of my company’s efforts to develop both an advanced immunotherapeutic and a vaccine to aid in prevention, primarily in at-risk horses,” Dr. Hansen said. “SolidTech has conducted research since 2008.”
At the time, both the immunotherapeutic and the vaccine were awaiting licensure by the USDA. Because they were experimental, they would need emergency use permission from the USDA, permissions from the Chincoteague Volunteer fire Company (CVFC) who owns the ponies, the Virginia’s State Veterinarian Office, and permits from other agencies.
Somehow, this dedicated group prevailed in time to administer vaccines at the 2019 spring roundup.
“We recommended an initial series of 3 administrations, given at about 4-week intervals,” Dr. Hansen said. “This became quite a collaboration among SolidTech, the CVFC, the attending veterinarians, the Chincoteague National Wildlife Refuge, and in no small measure, the saltwater cowboys.”
There are three Chincoteague Pony roundups annually, in April, July and October, and two more were added in 2019 so a second and third vaccination could be given. Yearly boosters have been given during spring roundups each year since.
In September, 2020, a buy-back filly named Katet, who had not yet been vaccinated due to her young age, showed symptoms. Buybacks are foals chosen annually to stay on the island as future herd sires and dams.
“She was seen 9/1/2020 with [right foreleg] lameness,” Dr. Marble said, and she was evaluated and treated that day. “Katet was a little wild and difficult to manage initially, requiring sedation for any hands-on treatments” other than immunotherapy injections.
Katet was treated with antibacterial/antifungal cream under bandages initially, but when she began to chew her bandages off, they moved to a topical spray treatment. The weather became wretched, and the lesion was not improving, so Dr. Marble reached out to Dr. Hansen, who recommended White Oaks Veterinary Clinic in Edmond, OK They were willing to take on the filly for further treatment.
Pennsylvania resident, Tipson Myers of Stoney Creek Chincoteagues transported Katet to Oklahoma.
At the White Oaks clinic on December 16, 2020, Dr. Mark Bianchi met Katet, who arrived road weary and sporting a very large, padded bandage.
“I was warned by Dr. Marble that she was not handled much, but she was for the most part a willing patient,” Dr. Bianchi said. “The first three weeks, she required some sedation to change bandages, perform diagnostic procedures and treat the wound. She became trusting but was very frisky. Since I had no turnout facilities, at times she would chase my help out of the stall during cleaning and bedding changes!”
It took about three months of medical treatment and farrier therapy to get her sound.
“This needed to be done to evaluate if the hoof conformation would hold up as she continued to grow into an adult horse,” Dr. Bianchi explained. “If not, she would require farrier management the rest of her life to stay sound.”
While Katet was in treatment, the mare Catwalk Chaos birthed a palomino pinto colt on March 17, 2021. That July, at Pony Penning roundup, the colt was found to have swamp cancer with a lesion in the right hind pastern and coronary band. Treatment included clipping and cleaning the lesion and applying a topical antibiotic/antifungal cream to the lesion before bandaging. The foal was given an initial dose of immunotherapy, the same batch Katet was receiving.
By late October the colt was doing well.
Meanwhile, Katet continued to heal. In late September, 2021, Tipson transported her home to the island. After spending time at the fire company carnival grounds, she was successfully released into the wild herds.
In time, a fifth isolate was added to the vaccine, coming from kunkers (clumps of pea-sized dead cells) extracted from the eight-year-old mare, Sundance. She’d been euthanized due to Pythiosis in September, 2021.
“Experience with successfully treating Katet definitely contributed to how future cases should be managed,” Dr. Hansen said. “The blood collected from Katet and other Pythiosis patients is helping us to: diagnose Pythiosis; determine nutritional deficiencies: and suggest underlying factors that might make animals more susceptible to infection.”
Katet delivered her first foal on May 25, 2023. After hauling Katet back and forth for treatment, including care on her farm, Tipson had grown to love this mare. Now, she was enamored by Katet’s new foal, so her friends secretly banded together and purchased the foal for Tipson. Named Teeter, Katet’s first foal now resides at Tipson’s Stony Creek Chincoteagues farm in Hughesville, PA.
And the Catwalk Chaos colt? Named Ricky Bobby by Tipson, he made a full recovery and was purchased by Christyn Koerner of Atlantic, VA. He is thriving in his home just 20 minutes from Chincoteague.
This small group of doctors has undoubtedly reduced the mortality rate in the wild Chincoteague Pony herds and other horses across the country.
Dr. Hansen recently shared more news. Through SolidTech’s research, the immunotherapeutic has been administered to five human Pythiosis patients, in the U.S. (as approved by the FDA) with excellent results.
“Being involved with the Chincoteague Ponies and their Pythiosis challenge and getting to know others involved in the care of these animals has been an experience I’ll not forget,” Dr. Hansen said.
Dr. Marble agreed.
“Yes, they are wild ponies,” he said, “however their temperament is unmatched. They’re easy to work with and for the most part, quiet animals. Their size and stature and their willingness to work make them very diverse in what they can do.”
Helping the iconic Chincoteague Ponies thrive has aided the rest of the equine world and humans as well. You can’t beat that.