Scientists Create a DNA Test That Identifies Lyme Disease in Horses

A test under development by a Rutgers professor could have applications for humans and dogs, too

A Rutgers scientist aiming to help heal a sick horse created an ultra-sensitive DNA test that could have applications for difficult-to-detect illnesses in humans such as Lyme disease.

As described in a study published in the Journal of Veterinary Diagnostic Investigation, a special DNA test devised by Steven Schutzer, a professor of medicine at Rutgers New Jersey Medical School, helped a Cornell University School of Veterinary Medicine team identify Neurologic Lyme disease in a sick 11-year-old Swedish Warmblood mare.

Although Lyme disease was suspected, a standard PCR test didn’t detect the disease agent, the corkscrew-shaped bacterium Borrelia burgdorferi.

As with the treatment of most diseases, early detection is essential with Lyme.

“Early diagnosis leads to immediate treatment,” Schutzer said. “And, naturally, that gives the best chance for a cure.”

The Schutzer team’s “genomic hybrid capture assay,” a highly sensitive test the team has been developing, identified the pathogen in a sample of the horse’s spinal fluid, allowing it to be diagnosed and successfully treated. The test works by first selectively isolating DNA from the microorganism causing the disease.

“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),” Schutzer said. “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.”

Lyme disease is the most common vector-borne illness in the U.S., according to the Centers for Disease Control and Prevention (CDC). In humans, a characteristic skin rash may or may not occur, along with fever, headache and fatigue. Unchecked, the infection can move to the nervous system, the joints and the heart.

Similar to humans, horses are incidental, dead-end hosts for B. burgdorferi, meaning the hosts carry the infection but do not infect others. Not all infected horses develop clinical signs of Lyme disease. If symptoms occur, they can include chronic weight loss, lameness and low-grade fever. Antibody tests usually are administered when a Lyme disease infection is suspected.

In the case described in the study, an antibody test and a PCR test of the mare didn’t indicate an infection. Only Schutzer’s advanced test detected the disease.

Lyme disease in horses can cause long-term complications that include damage to the nervous system, joints, skin and even vision.

“The diagnosis of Lyme neuroborreliosis (Neurologic Lyme disease) in horses is rarely confirmed antemortem and has frustrated veterinarians for years,” said Thomas Divers, the veterinarian who led the equine team on 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. “This is a very promising technique. Focused treatment against B. burgdorferi administered in this case resulted in the horse’s complete athletic recovery.”

While many illnesses, such as COVID-19 and strep throat, attack humans with many numbers of pathogens, in other diseases, such as Lyme disease, the bacteria slowly reproduce within a host, producing far fewer numbers and making detection more difficult.

Schutzer, an expert in Lyme and other tick-borne diseases, has been working to devise ways to better detect diseases that possess what he terms “low copy numbers” of a pathogen.

According to the CDC, about 476,000 cases of Lyme disease are reported in humans each year. The black-legged tick, also known as the deer tick, is responsible for most cases of Lyme disease in the U.S. and seems to be increasing in abundance and geographic spread.

Other scientists on the study included Claire Fraser and Emmanuel Mongodin of the Institute of Genome Sciences at the University of Maryland School of Medicine; Christopher Miller of Miller and Associates Equine Practice in Brewster, N.Y.; Rodney Belgrave of Mid-Atlantic Equine Hospital in Ringoes, N.J.; and Rachel Gardner of B.W. Furlong and Associates in Oldwick, N.J.

Source: Rutgers University 

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University Research Advances Food Safety with Faster Listeria Test and Norovirus Vaccine

A new way of detecting deadly Listeria contamination in food and a vaccine for troublesome Norovirus are being reported by major research universities.

University of Georgia College of Engineering researchers report they have a new method for Listeria detection, and the Virginia-Maryland College of Veterinary Medicine at Virginia Tech announced it will evaluate a potential live oral vaccine for norovirus, which is the No. 1 cause of foodborne illness.

Listeriosis, an infection caused by eating food contaminated by the bacterium Listeria monocytogenes, is known for causing severe illness in children, pregnant women, newborns, the elderly, and people with compromised immune systems.

It is the third leading cause of death from foodborne illness, or food poisoning, in the United States. An estimated 1,600 people get sick each year and about 260 die, according to the Centers for Disease Control and Prevention (CDC).

At present, Listeria contamination in food products is identified only through molecular tests conducted in diagnostic laboratories on samples taken at specific control points during the manufacturing and distribution process.

Although very accurate, this method requires significant processing time, transportation of samples, and expensive skilled labor and equipment.

In a new study published in the Journal of The Electrochemical Society, UGA researchers introduce a rapid diagnostic method based on electrochemical biosensing principles.

Electrochemical biosensors are promising alternatives to molecular detection methods because of their ease of use, high specificity, sensitivity, and low cost, according to the researchers.

The UGA researchers use bacteriophages, viruses that infect and replicate within bacteria, as receptors to identify Listeria monocytogenes using an electrochemical sensor.

Meanwhile, Lijuan Yuan, professor of virology and immunology at the Virginia-Maryland College of Veterinary Medicine at Virginia Tech, announced the progress being made around a norovirus vaccine. It was developed by Indiana University’s John Patton and colleagues using the Rotarix rotavirus vaccine as a platform.

Using reverse genetics, they will insert a norovirus protein into Gene 7 of the rotavirus. The virus will then express the norovirus protein in the gut, inducing an immune response against norovirus.

Yuan’s Virginia Tech lab will evaluate the replication capacity, immunogenicity, and protective efficacy of the vaccine using gnotobiotic pig models of human rotavirus and norovirus infection and diarrhea. A gnotobiotic animal is one that has been specially raised to contain zero germs or bacteria so researchers can better study the effects of bacteria and viruses such as rotavirus and norovirus.

The CDC says norovirus as the leading cause of vomiting and diarrhea from acute gastroenteritis in the United States, resulting in 19 million to 21 million illnesses every year.

Norovirus tends to affect young children and the elderly the most. It’s responsible for about 24,000 hospitalizations and 925,000 outpatient visits for American children each year, according to the National Center for Biotechnology Information. Rotavirus also causes acute gastroenteritis and hits young children the hardest.

“Together, rotavirus and norovirus cause over 415,000 deaths every year, and norovirus also has a very significant burden even in the countries that don’t have a lot of deaths. The economic cost is huge, with $4.2 billion in direct costs and $60 billion in indirect societal costs. You hear about norovirus outbreaks on the news all the time in hospitals, nursing homes, and cruise ships and how it’s closing down restaurants, so it’s got a lot of economic implications,” said Yuan.

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