DNA Lyme Test for Horses

Thomas J. Divers, et al., published an article in the Journal of Veterinary Diagnostic Investigation describing a study by which a DNA test was created and then used to successfully detect neurologic Lyme disease in an infirmed 11-year-old Swedish Warmblood mare.

The special test was developed by Steven Schutzer, a professor of medicine at Rutgers New Jersey Medical School, and was used by a Cornell University School of Veterinary Medicine team to make the diagnosis. Lyme disease was initially suspected; however, a standard PCR test failed to detect Borrelia burgdorferi.

The “genomic hybrid capture assay” developed by Schutzer and his team is a highly sensitive test and effectively identified the Lyme disease pathogen in a spinal fluid sample from the sick horse. This allowed for the mare to be accurately diagnosed and then successfully treated. “Early diagnosis leads to immediate treatment,” said Schutzer, “And, naturally, that gives the best chance for a cure.”

The newly created test works by isolating DNA from Borrelia burgdorferi. Schutzer says, “The method is like having a special, specific ‘fishhook’ that only grabs Borrelia DNA and not the DNA of other microbes, nor the DNA of the host (animal or human). Detecting DNA of the disease is a direct test, meaning we know you have active disease if it’s circulating in the blood or spinal fluid.”

Like humans, horses are dead-end hosts for B. burgdorferi, meaning the level of bacteria in their blood is not significant enough to pass the infection to other ticks that may bite them. Not every horse that is infected with Borrelia burgdorferi develops symptoms of Lyme disease. If clinical signs of infection occur, they can consist of prolonged weight loss, low-grade fever, and lameness. If not detected and treated early, Lyme disease in horses can cause enduring issues such as impairment to the nervous system, joints, skin, and even their vision.

Thomas Divers, the veterinarian who headed the equine team on writing the paper and who is a professor of medicine and co-chief of the Section of Large Animal Medicine at Cornell University’s College of Veterinary Medicine in New York said, “The diagnosis of Lyme neuroborreliosis (neurologic Lyme disease) in horses is rarely confirmed antemortem and has frustrated veterinarians for years. This is a very promising technique. Focused treatment against B. burgdorferi administered in this case resulted in the horse’s complete athletic recovery.”

Read coverage of the study on Phys.org.

Access the paper in the Journal of Veterinary Diagnostic Investigation.

Read more about Lyme disease and horses.