Bend-based veterinarian develops vaccine for Pigeon Fever

In the late summer and early fall of 2011, Dr. Patrick Young found himself treating horses on a daily basis for pigeon fever, a painful and debilitating disease.
“I just felt sorry for the horses and their owners,” says Young, an equine lameness and sports medicine veterinarian at The Athletic Horse in Bend.

So he did what anyone who studied both animal and biomedical sciences would do, of course: He developed a vaccine.

What is pigeon fever?

Pigeon fever (also called pigeon breast, dryland distemper, and Colorado strangles) is a bacterial infection characterized by deep intramuscular abscesses, says Dr. Paul Edmonds of Cinder Rock Veterinary Clinic in Redmond.

It’s highly contagious and very painful but rarely fatal.

The abscess formations most commonly appear externally in the pectoral area by the breast muscles, along the midline or underside of the belly, or in the armpit or groin.

The abscesses cause a puffed-out appearance resembling a pigeon’s breast, which is how the disease gets its name.

Abscesses may appear internally in the horse’s lungs, liver, kidneys or other organs, and the lymph nodes and legs can also be affected.

Other symptoms include lethargy, stiffness and lameness from the pain and swelling, lack of appetite or fever, Edmonds says.

Pigeon fever occurs most commonly during dry months, when the bacteria thrive and flies are more prevalent.

The bacteria most likely enter a horse’s body through an open wound or fly bite or through mucous membranes.

The state doesn’t track infectious diseases in horses or other animals, but Edmonds says cases of pigeon fever do occur in Oregon annually.

“Incidence of disease fluctuates from year to year, possibly due to herd immunity and environmental factors such as temperature and rainfall,” he says.

Treatment typically involves lancing and draining the abscesses and occasionally a course of antibiotics.

The making of a vaccine

Because treatment can be such a long process – horses can take months to recover – and no vaccine had yet been developed, Young was motivated.

“I felt like I needed a vaccine for pigeon fever disease so that I could help protect my clients and patients,” he says.

A former Oklahoma resident, Young was in Central Oregon competing in the Pacific Crest triathlon when heard about the Bend Venture Conference.

After attending the event in October, he was inspired to pursue a vaccine and launch his biotechnology startup, Bird Dog Bioventures.

Young and his family moved to Central Oregon in June, and he relocated his veterinary practice to Bend.

To develop the vaccine, Young isolated the bacteria that causes pigeon fever from an equine patient in Oklahoma, cultured it and outsourced the vaccine development to Colorado Serum Company.

They purified, sterilized and inactivated the bacteria and added it to adjuvants, which stimulate the immune system.

After testing the vaccine’s safety, he conducted small clinical trials on horses in Oklahoma.

Three titers (tests that indicate an animal’s protection against a disease by measuring the levels of antibodies present in its blood) revealed the horses had developed a strong immune response.

“This technology’s not new,” Young says. “It’s just that nobody really jumped on board and said, ‘Why don’t we make a vaccine for this?”

Large biotechnology companies have little interest in pursuing vaccines that have only regional incidence, he says, preferring to invest in vaccines that can generate millions of dollars annually.

“They saw this as a risk and didn’t invest their resources,” he says, “so I did.”

Young is working towards a conditional license with the U.S. Department of Agriculture in conjunction with Colorado Serum and expects the vaccine will be available in about 18 to 24 months.

The USDA regulations prohibit him from using his existing vaccine across state lines.

If finds a horse with the disease here in Oregon, however, he could develop a local vaccine that would be available sooner.

In the meantime, Young is already working on several other projects, including a vaccine that would protect dogs against salmon poisoning, a potentially fatal condition that can affect dogs that eat raw fish in Northwest.

“My goal is not to get filthy rich doing this,” he says. “I just want to help do my part to help protect animals and their owners and give back the best I can.”


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