Vaccine-Based Treatment for Equine Sarcoids

Horses with sarcoids could soon benefit from a new vaccine-based treatment that is currently being developed by a group of German researchers.

Equine sarcoids, semi-malignant skin tumors caused by bovine papillomaviruses (BPV)-1 and -2, are common in horses.

According to Martin Muller, PhD, group leader at the German Cancer Research Center in Heidelberg, Germany and a co-author on this study, a variety of treatment options are available for sarcoids, including surgical removal and chemotherapy.

"None of the available treatments are effective and spontaneous improvement in the number or size of sarcoids is extremely rare," explained Muller.

In this study, 12 horses with sarcoids were vaccinated with "chimeric virus-like particles" which are microscopic spheres developed by the researchers that contained a small section of a protein found in BPV-1 and -2 and in sarcoids.

"The theory is that by vaccinating a horse with these particles, the horse's immune systems will recognize the viral protein in both the particles and the tumor as 'foreign,'" said Muller, explaining that the horse's immune system will attack the sarcoid causing the tumor to regress.

The researchers found that in 10 of the 12 (83.3%) horses, the number and/or size of the sarcoids either improved or remained stable, and no side effects were noted after a total of 32 vaccines.

"We anticipate that this technology will be especially effective in horses with only a limited number of tumors or with small sarcoids and may also be a useful treatment in combination with surgical removal," concluded Muller.

The study, "Immunotherapy of equine sarcoid: dose-escalation trial for the use of chimeric papillomavirus-like particles" was published in the Journal of General Virology in January, 2008.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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