New test for Lyme disease in horses

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A new DNA test developed at Rutgers New Jersey Medical School helped confirm a diagnosis of Lyme disease in a horse. A report is published in the Journal of Veterinary Diagnostic Investigation.

 

Lyme disease (LD) is caused by the corkscrew-shaped bacterium (spirochete) Borrelia burgdorferi. The organism infects white blood cells and cells lining synovial cells, resulting in an inflammatory response. 

 

It is transmitted by ixodes ticks – (typically I ricinus in UK, I scapularis (deer tick) in the north eastern US and Atlantic coast, and I pacificus on the US west coast.) 

 

Many horses in areas where the infection is present carry antibodies without showing signs of disease. Conversely, infected animals may take a long time to produce a detectable antibody response.

  

Signs are generally non-specific. Swollen joints and uveitis (inflammation within the eye) have been reported. Other possible signs include stiffness, lameness, lethargy and behaviour change.

Rare cases may develop neuroborreliosis, in which the bacteria reach the central nervous system, resulting in neurological signs, fever, muscle wasting and difficulty eating.  

 

Clinicians at the Cornell University School of Veterinary Medicine were struggling to diagnose a neurologic case of LD in a sick Swedish Warmblood mare. Although they suspected Lyme disease, standard PCR and antibody tests did not detect the organism. 

 

The new “genomic hybrid capture assay,” a highly sensitive test developed by Steven Schutzer and the team at Rutgers New Jersey Medical School, 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.”

 

“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.”

 

For more details, see: 

 

Genomic hybrid capture assay to detect Borrelia burgdorferi: an application to diagnose neuroborreliosis in horses

Thomas J. Divers, Emmanuel F. Mongodin, Christopher B. Miller, 

Rodney L. Belgrave, Rachel B. Gardner, Claire M. Fraser, Steven E. Schutzer

Journal of Veterinary Diagnostic Investigation (2022). 

https://doi.org/10.1177/10406387221112617

North American horse owners sought for biosecurity study

Even with vaccination and modern medicines, biosecurity plays a crucial role in preventing the spread of infectious disease.

 The Equine Disease Communication Center, with the support of the United States Department of Agriculture, is conducting a study into the awareness and knowledge of biosecurity in the horse industry. Based at the American Association of Equine Practitioners (AAEP) headquarters in Lexington, Kentucky, the EDCC provides real-time and accurate information about diseases, vaccination and biosecurity.

 

They have devised an online survey, which they say will take about ten minutes to complete. The findings will be shared with all parts of the horse industry and used to create educational information and resources to help owners protect their horses. 

 

“Dealing with Covid-19 has highlighted the need for biosecurity procedures to reduce risk of infection; however, most horse owners are still not fully aware of the threat to their horses from both endemic and foreign animal diseases either at home or when traveling,” said Dr. Nathaniel White, EDCC director. “We need to understand the gaps in biosecurity knowledge. Armed with that information, we will create specific plans for facilities and events, enabling the industry to react to domestic and foreign disease threats.”

 

Owners or carers of horses in the USA and Canada are asked to participate in the survey

 

To take part in the survey, go to:

 

https://www.research.net/r/EDCCowner

 

For more about the EDCC, see:

 

https://www.equinediseasecc.org

How well do horses hear electric cars?

38426137(c) Virgonira Dreamstime.com

Electric cars are becoming more common. They make less noise than vehicles with petrol or diesel engines, raising a concern that people may not hear them coming. What about horses? Can they hear electric cars in time? 

A new study instigated by the British Horse Society (BHS) in conjunction with the Electric Vehicle Association (EVA) Scotland. and Robert Gordon University in Aberdeen, Scotland, investigated the reaction of horses to the noise of an electric car.

 

They research team monitored the response of three different horses to approaching cars (three electric and one petrol).

 

A horse, with rider, stood facing along the road with the car approaching from behind. The noise produced by the car was recorded using a high sensitivity microphone. The horse’s reaction to the car was recorded using a smartphone video camera. 

 

They conclude that: “the low-level noises produced by electrical vehicles are being detected by the horses quite early on and they are aware of the presence of the vehicle much before the humans are.”

 

Presenting the report at a launch in Eglington Country Park (Scotland), Alan Hiscox, Director of Safety at The British Horse Society said:

 

“With more and more electric cars on Britain’s roads, this report’s new data and analysis provides significant insight. Not only will it help to alleviate concerns from riders about how their horse reacts to electric vehicles due to limited sound levels, but it will also be a vital tool when it comes to encouraging drivers, regardless of whether they are driving an electronic or conventional vehicle, to be careful when passing horses on the road.” 

 

Professor James Njuguna, Research Strategic Lead at Robert Gordon University, added: “The number of horse and electrical vehicle accidents and incidents are on the rise with society's shift to electric vehicles, bicycles, and scooters. A better understanding of horse behaviour in the presence of an electric vehicle is a step forward for the shared road safety of all road users: drivers, riders, and horses alike. It is a pleasure to support this effort alongside the BHS and EVA Scotland in this campaign. The findings clearly indicate the horse is cautiously recognising EVs long before the rider does and forms a baseline for detailed studies in future.”

 

For more details, see:  

https://www.bhs.org.uk/media/j4vntucq/bhs-horseev-feild-study-report_final-1.pdf

Use of tools by horses

(c) Krueger et al

It used to be thought that using tools was one of the things that set us apart from the animal kingdom. 

However, it is now known that some species use tools. Reports include chimps using sticks to reach food, sea otters using stones to break open shellfish and even elephants deactivating an electric fence by dropping rocks on it.

What about horses? Konstanze Krueger and co-workers conducted an investigation into “unusual” behaviour in horses.

The topic did not lend itself to conventional methods. Instead, they collected reports and video records of unusual behaviour using a dedicated website*. They also searched online for videos showing equids using tools. 

Analysing 635 reports, including 1014 behaviours, they found 20 cases of tool use, 13 of which they termed “unambiguous,” in that it was clear that the behaviour was not trained, caused by reduced welfare, incidental or accidental.

Their findings are published in the journal Animals. 

They report that “the most frequent tool use, with seven examples, was for foraging, for example, equids using sticks to scrape hay into reach. There were four cases of tool use for social purposes, such as horses using brushes to groom others, just one case of tool use for escape, in which a horse threw a halter when it wished to be turned out, and one case of tool use for comfort, in which a horse scratched his abdomen with a stick.”

 

They then assessed the effect of management conditions on tool use and whether the animals used tools alone, or socially, involving other equids or humans. 

They report that management restrictions were associated with tool use in 12 of the 13 cases – such as the use of sticks to scrape hay within reach when feed was restricted. 

“Furthermore, 8 of the 13 cases involved other equids or humans, such as horses using brushes to groom others. The most frequent tool use was for foraging, with seven examples, tool use for social purposes was seen in four cases, and there was just one case of tool use for escape. There was just one case of tool use for comfort, and in this instance, there were no management restrictions.”  

They conclude: “Equids therefore can develop tool use, especially when management conditions are restricted, but it is a rare occurrence.”

For more details, see

Tool Use in Horses. 

K Krueger; L Trager; K Farmer; R Byrne. 

Animals 2022, 12, 1876. 

Possible blood marker for lymphoma?

 Thymidine kinase 1 (TK1) could prove to be a useful biomarker to identify horses with lymphoma, according to recent research.

 Lymphoma is the most common hematopoietic neoplasm (tumour affecting the blood-producing cells) in horses. Lymphomas are less common than sarcoids, squamous cell carcinoma and melanoma, and account for about 2% of all equine neoplasia.

 

Lymphomas can appear in different forms depending on which tissues are involved. Those involving the skin are easier to identify and treat. Tumours involving lymphoid tissue in the chest or abdominal organs are more of a challenge. They tend to produce non-specific signs such as fever, weight loss, colic, ventral oedema, and diarrhoea.

 

Confirmation of a diagnosis relies on identification of malignant lymphoid cells in blood or bone marrow, or in pleural or peritoneal fluid. An accurate serum biomarker would make the task much easier.

 

Thymidine kinase 1 (TK1) plays an important role in DNA replication and cell division. It is only present in cells when they are dividing and is quickly broken down afterwards. Cells dividing normally do not release significant amounts of TK1 into the extracellular body fluids, but cancer cells do.

 

Serum TK1 activity has been used as a biomarker for health screening for malignant diseases and to monitor response to treatment in humans and in dogs.

 

Liya Wang and colleagues at the Swedish University of Agricultural Sciences, Uppsala, Sweden and the University of Bern, and Agroscope, Bern, Switzerland, conducted a study to evaluate the serum level of TK1 as a biomarker for equine lymphoma. 

 

They collected serum samples from healthy and diseased horses, and measured the levels of TK1.

 

They took blood from seven horses with confirmed lymphoma, five horses with suspected lymphoma, 107 control horses with concurrent diseases and 42 healthy horses.

 

They found that “serum TK1 activity was significantly higher in the lymphoma (p <  0.0005), suspected lymphoma (p <  0.02) and tumour-free with concurrent diseases (p <  0.03) groups than in the controls without concurrent diseases, and there was a significant difference between the lymphoma group and the tumour-free group with concurrent diseases (p <  0.0006).” 

 

They conclude: “These results demonstrated that serum TK1 could serve as a useful biomarker to distinguish individuals with lymphoma from control horses with and without concurrent diseases.”

 

For more details, see: 

 

Molecular characterization of equine thymidine kinase 1 and preliminary evaluation of its suitability as a serum biomarker for equine lymphoma. 

Wang, L., Unger, L., Sharif, H. et al.

BMC Mol and Cell Biol (2021). 22, 59. 

https://doi.org/10.1186/s12860-021-00399-x