CVM Researchers Develop Diagnostic Test for 11 Tick-Borne Diseases

The warmer weather can mean many things for pet owners in Texas. Chief among those should be ticks.

The domestic Brown Dog, Lone Star, Gulf Coast, and other ticks are the cause of the thousands of tick-borne disease cases reported annually in the United States.

Thanks to a diagnostic test created by researchers in the Texas A&M College of Veterinary Medicine & Biomedical Sciences (CVM), veterinarians now have a tool that can detect 11 types of tick-borne diseases, including the seven most common, in dogs.

EsteveGasent

Better, still, they can do so both earlier and less expensively than ever before.

Dr. Maria Esteve-Gasent, an assistant professor in the CVM’s Department of Veterinary Pathobiology (VTPB), and doctoral student Joseph Modarelli, in collaboration with the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL), developed the tool, the TickPath LayerPlex, using a molecular technique that allows the researchers to determine if causative agents from tick-borne diseases are present in a dog.

“Instead of looking at whether the animal has been exposed to a pathogen-when we would say that the dog may or may not have a disease-we are saying, with this methodology, that the animal has the pathogen-it has the bacteria-that is causing the disease,” Esteve-Gasent said. “It’s very specific; you’re looking for the pathogen itself, not for signs of exposure but of being infected.”

With the TickPath LayerPlex, a dog that exhibits symptoms of a tick-borne disease can be taken to a veterinarian, who can submit to the TVMDL a single blood sample taken during routine testing to check for Lyme disease, relapsing fever, Ehrlichiosis, Rocky Mountain spotted fever, and canine Babesia, and others.

“It’s very novel because there’s no other technique like this in the veterinary field; it’s something completely new that was not possible until now,” said Esteve-Gasent. “We’ve been validating it with thousands of samples to make sure that it’s working, and it has a 98 percent sensitivity specificity.”

Because the test can detect 11 different pathogens, it also is more cost-effective for clients.

“We’ve asked five companies across the country how much they charge and the cheapest for one pathogen, for one disease, was $80. To test for one,” Esteve-Gasent said. “You would have to pay hundreds of dollars to test for 11 diseases. Now, (with our test) you might be paying $90, max.

“So, our test is very competitive,” she said. “And it’s fast and reliable.”

Unlike with other diagnostic tools, the TickPath LayerPlex also more accurately determines the specific type of disease.

“A lot of veterinarians will submit blood for a cytology or serology test,” she said. “For example, in the case of Lyme disease and relapsing fever, the tests are not that easy to differentiate them. Sometimes you can only say, ‘It was either one or the other.’ It’s not clear cut.”

With the Texas A&M test, if a sample falls into the “gray zone,” where the test can’t determine a positive or negative result, “you either collect a sample a few weeks later, or, if the veterinarian feels that the clinical signs correlate with the disease you think it is, then treat it.”

“Either way, this test allows the veterinarian to provide a more educated treatment when they see their patients,” Esteve-Gasent said.

Determining as quickly as possible if an animal has a tick-borne disease, and what kind it may have, can be crucial for a pet.

“Most of these diseases, if you treat your dog early, the animals recuperate, and they are nice and healthy and they live a healthy life for many years,” Esteve-Gasent said. “But if you don’t diagnose them properly or early enough, then they’re going to have problems; they may have heart or joint problems, and you don’t want that.

“Or, if the diagnostics are no good, by the time you get your dog to the vet and they get the samples, they diagnose the disease, and they confirm what it is, your dog may be dead. The problem that we have right now is if a pet is infected with Rocky Mountain spotted fever, the dog will die,” she said. “So, the sooner that you test, the better, because all tick-borne diseases are treatable.”

In addition, knowing the specific disease would allow the veterinarian to track the animal’s progress.

“If you know exactly what the dog has, you can observe the clinical signs much better,” Esteve-Gasent said. “If you start antibiotic treatment and the veterinarian sees progress, they could take a second sample later and see whether we still detect the pathogens. Because it’s very, very, very sensitive, if the test says it’s clean, that animal is cleared.”

The project, funded by Texas A&M AgriLife and the USDA Agricultural Research Services, has been submitted for a provisional patent, and once more sampling has been conducted to further validate the test, a final patent will be submitted. Veterinarians and dog owners can help with that process by submitting ticks found on dogs to the TVMDL for testing.

For more information on submitting ticks to the TVMDL, visit https://tvmdl.tamu.edu.


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