What To Know About Vesicular Stomatitis

Vesicular stomatitis, or VSV, is a virus endemic to the warmer regions of North, Central, and South America. Texans with livestock and horses are likely familiar with the disease, as outbreaks of VSV typically occur in the state every few years.

A light brown horse with a long mane eating grass in a fieldThe current national outbreak of VSV began on April 13, when the National Veterinary Services Laboratory reported VSV-positive premises in New Mexico. On April 23, the first in-state VSV finding of this outbreak was reported at an equine facility in Starr County, Texas.

Dr. Leslie Easterwood, a clinical assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, informs horse and livestock owners on what they should know about this virus and how they can keep their animals safe and healthy.

“Vesicular stomatitis is a viral disease that affects horses, donkeys, mules, cattle, and swine,” Easterwood said. “This virus is spread by insect vectors, including blackflies, sand flies, and members of the Culicoides species (usually ‘no-see-um gnats’).”

The current serotype, or “version” of VSV, causing this outbreak is known as the New Jersey serotype, which Easterwood characterizes as being very virulent and contagious.

The virus causes crusting, ulcerative, and vesicular (fluid-filled) lesions of the lips, tongue, coronary bands (where the hairline meets hoof), mammary glands, muzzle, and nostrils.

“These lesions are very inflamed, causing swelling, pain, and excess salivation,” she said. “Many affected animals are lame due to the inflammation of the coronary bands, and have a hard time chewing and swallowing their feed due to the lesions on their lips and tongue.”

Easterwood says that VSV is self-limiting, meaning the disease tends to go away on its own, but that anti-inflammatory medications may help to decrease pain and swelling caused by the lesions.

To protect animals from contracting VSV, Easterwood recommends practicing good fly control and limiting exposure to infected animals, as the virus can be spread directly from animal to animal or between shared spaces and equipment, such as water buckets.

In addition to causing harm to individual animals, VSV can also be more broadly dangerous to agricultural industries.

“This virus can be especially detrimental to our milk producing cows,” Easterwood said. “They can become lame and the lesions decrease their milk production.

“With horses, infected individuals are not allowed to travel to events where they could be comingled and transmit the virus. VSV could have economic impacts on our show horses, racehorses, commercial dairy cattle, and commercial swine operations.”

If an owner suspects that one of their animals is suffering from VSV or has been exposed to an infected animal, they should consult their veterinarian promptly due to the highly contagious nature of the condition.

“This viral disease is a reportable disease, which means that the Texas Animal Health Commission (TAHC) will be informed when an animal tests positive,” Easterwood said. “TAHC will then control how the animal’s movements are restricted until the symptoms resolve and the outbreak is over.”

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at vetmed.tamu.edu/news/pet-talk. Suggestions for future topics may be directed to editor@cvm.tamu.edu.

Reining In The Facts On Equine Strangles

Since the first vaccine was invented in 1796, the practice of immunization has transformed how we view infectious diseases, taking many pathogenic invaders from being deadly threats to easily preventable maladies. For humans and animals alike, vaccines are important healthcare tools.

Two horsesDr. Leslie Easterwood, a clinical assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, says the equine strangles vaccine is one that is of particular importance for horse owners in protecting their animal.

“Strangles is the common term for the bacterial respiratory disease caused by Streptococcus equi, subspecies equi,” Easterwood said. “Strangles infections most commonly present as an upper respiratory infection that primarily involves the lymph nodes in a horse’s jaw. Symptoms include high fevers, thick nasal discharge, depression, and a lack of appetite.”

The bacteria that causes strangles in horses may sound familiar to their human owners; a cousin of this bacteria, called Streptococcus pyogenes, causes strep throat in people. Though these bacteria are genetically similar and cause upper respiratory symptoms in both species, horses with strangles cannot infect humans, and humans with strep throat cannot infect horses.

“Strangles is spread via respiratory secretions from infected horses,” Easterwood said. “It is highly contagious from horse to horse and is pretty common.”

Since strangles is easily transmitted between horses, vaccination is an important tool for minimizing the spread of this disease.

“Although the disease rarely results in a fatality, it will make horses sick and can lead to loss of production, decreased performance, and quarantine, in some circumstances,” Easterwood said. “Vaccination does not provide complete protection, as with all vaccinations, but it can help to decrease the chance of contracting the disease in susceptible populations.”

Since horses are often kept in groups—grazing together at pasture, sharing pens, or neighbored in stalls—contagious diseases can quickly work their way through a herd. As such, vaccination remains an essential tool for both individual and herd health.

Ultimately, the decision of whether to vaccinate an animal comes down to the owner, Easterwood says, although there might be situations during which a third party takes interest in a horse’s vaccination records.

“There are no governmentally mandated vaccinations in horses,” Easterwood said. “Some boarding and breeding facilities will require vaccination to board at their location, but that is not a legal requirement.”

Even if no legal requirement enforces the vaccination of horses, owners should still consider consulting with their veterinarian to determine what care is best for maintaining the health of their animal.

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at vetmed.tamu.edu/news/pet-talk. Suggestions for future topics may be directed to editor@cvm.tamu.edu.

CVM Researcher Fights Antibiotic Resistance, Improves Foal Health

Story by Margaret Preigh

Dr. Noah Cohen with a foal
Dr. Noah Cohen

Dr. Noah Cohen, the Patsy Link Chair in Equine Research at the Texas A&M College of Veterinary Medicine & Biomedical Sciences (CVM), has identified an alternative treatment for foal pneumonia that avoids the use of often over-prescribed antibiotics.

In research funded by the Morris Animal Foundation, Cohen and collaborators found that gallium maltolate (GaM), a metal-based compound with antimicrobial and anti-inflammatory properties, resolved subclinical pneumonia (i.e., pneumonia identified in foals that did not have clinical signs, such as fever, coughing, a depressed attitude, etc.) without increasing the number or diversity of antibiotic-resistant bacteria in the foals’ fecal samples.

Antibiotic resistance is a pressing issue in today’s world. Overuse and incorrect use of antibiotics have increased the prevalence and diversity of bacteria that are resistant to antibiotic medications. This creates “superbugs” that doctors have no way of combatting, opening vulnerabilities in human health, the health of our animals, and the health of our food system.

Foal pneumonia is one of the leading causes of death and disease in foals and has no licensed vaccine. It is often caused by the bacteria Rhodococcus equi (R. equi), which occur naturally in soil.

Pneumonia caused by R. equi is insidious, meaning it progresses gradually and is well established by the time symptoms appear, so many farms screen foals using chest ultrasound examinations to find foals that are developing pneumonia before they show clinical signs of disease.

Veterinarians then treat the foals that have chest lesions indicating pneumonia. However, because many of these foals that have chest lesions seen on ultrasound won’t go on to develop pneumonia, a large proportion of foals get treated with antibiotics needlessly.

“While that treatment strategy saves lives in the short term, it’s really driving this resistance problem because, for every one foal that needs treatment, several foals that don’t need treatment wind up getting antibiotics,” Cohen said.

In this study, published in the journal Scientific Reports, researchers from Texas A&M and the University of Georgia investigated the use of GaM as an alternative to a macrolide antibiotic plus rifampin (MaR), an antibiotic combination that is the standard used for treating R. equi foal pneumonia.

Foals with signs of subclinical pneumonia were given either GaM or MaR for two weeks.

Dr. Noah Cohen and graduate student Susie Kahn with a foal
Dr. Noah Cohen and graduate student Susie Kahn

After two weeks, foals treated with MaR displayed an increase in their number and diversity of antibiotic-resistant bacteria in their fecal samples. Alarmingly, many of these bacteria were resistant to multiple drugs and antibiotics.

In foals treated with GaM, however, bacteria collected from fecal samples showed no change in the number or diversity of antibiotic-resistant bacteria. This finding suggests that while treatment with MaR promotes the abundance of antibiotic resistant bacteria, treatment with GaM did not affect the amount of these harmful germs.

This is important because horses are often kept in groups; therefore, the fecal bacteria of one animal may infect or colonize another healthy foal living on the same soil.

Another concern of using MaR in the treatment of foal pneumonia is that the excrement of horses taking this medication may contain traces of unabsorbed antibiotic. This study showed that antibiotic entering soil will increase selection for bacteria that are resistant in the soil.

Researchers hope to next test the effectiveness of GaM on foals that are clinically infected with R. equi.

This study comes at a vital time, as bacteria evolve faster than scientists develop new drugs. Antibiotic alternatives, such as the substance investigated by Cohen and his colleagues, are integral to ensuring the future of our food systems, our animal friends, and our own health.

“The World Health Organization has identified antimicrobial resistance as a top threat to human health,” Cohen said. “There is an urgent need in human and veterinary medicine to identify alternative antimicrobials because bacteria can evolve resistance so rapidly, and often to multiple classes of drugs.”


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Contact Information: Jennifer Gauntt, Director of CVM Communications, Texas A&M College of Veterinary Medicine & Biomedical Science; jgauntt@cvm.tamu.edu; 979-862-4216

The Rundown on Equine Shoulder Sweeney

Horses are remarkably active animals that make good use of their limbs and joints as they canter, gallop, and trot. As such, it is important that owners are cognizant of their horse’s health and of potential conditions that might arise.

Three horses in a fieldDr. Jeffrey Watkins, a professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, weighs in on shoulder Sweeney, also known as suprascapular neuropathy, a condition affecting the nerves and muscles of a horse’s shoulder region.

“Shoulder Sweeney refers to an injury of the suprascapular nerve, which runs over the front part of the scapula and provides the nerve supply to two major muscles that support the shoulder joint,” Watkins said. “When the nerve is injured, these muscles are unable to function normally and will undergo atrophy, which can occur very rapidly.”

This condition presents in two forms, chronic and acute, according to Watkins.

The chronic form of shoulder Sweeney was once common in horses that often pulled heavy loads, such as wagons and farm equipment, and was attributed to repetitive nerve injury often associated with ill-fitting harness collars.

In these chronic cases, clinicians typically find significant atrophy of the two major muscles that are supplied by the nerve overlying the scapula, and when these muscles atrophy, the bony spine of the scapula becomes very prominent.

Chronic shoulder Sweeney has become less frequent, as workhorses are less common.

“What we see today, most of the time, is a much more acute injury,” he said. “Usually, it’s because the horse is running fast and hits something immovable, another horse or a fence post, very forcefully with the point of their shoulder.”

This impact causes an acute nerve injury that results in dysfunction of the two major muscles noted above.  These muscles are responsible for maintaining the lateral stability of the shoulder joint and when they lose their nerve supply acutely, the shoulder region becomes unstable.

Watkins said it is important to consider other potential conditions that can occur secondary to a high-impact injury to the shoulder region. An examination by a veterinarian, including high-quality radiographs of the shoulder region, is necessary to rule out other injuries, such as a fracture.

Shoulder Sweeney is usually diagnosed by observing the gait of the horse and tends to be straightforward.

“They have a very characteristic gait where whenever they try to put weight on their leg, their shoulder joint partially dislocates to the outside,” Watkins said. “These horses don’t walk well; they have a very obvious gait abnormality that basically makes them unusable in the short-term.”

Though this condition can significantly impact a horse’s function in the short term, the good news is that most horses suffering from an acute shoulder Sweeney will recover stability in that joint over time and will be able to function normally again. But the process requires rest and patience.

“It’s important to recognize it can take quite a long time for that nerve to heal and to basically regrow,” Watkins said. “We usually say it will take six to eight months for that nerve to begin to regain function and for that shoulder to stabilize and no longer have issues.”

Although most horses recover their ability to move normally, atrophy of the muscles overlying the shoulder blade will usually be permanent and the horse will have the characteristic boney protrusion of the shoulder area associated with shoulder Sweeney for the remainder of its life.

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at vetmed.tamu.edu/news/pet-talk. Suggestions for future topics may be directed to editor@cvm.tamu.edu.

CVM Veterinary Students Host 2020 SCAAEP Wet Lab

Veterinary students from three different colleges
Veterinary students from across the country came to learn at Texas A&M’s SCAAEP Wet Lab

More than 200 veterinary students from 23 different veterinary schools across the country visited the Texas A&M College of Veterinary Medicine & Biomedical Sciences (CVM) on Jan. 18 to participate in the Texas A&M Student Chapter of the American Association of Equine Practitioners’ (SCAAEP) annual wet lab.

The lab provides veterinary students with the opportunity to practice a variety of skills in the field of equine medicine.

“The SCAAEP wet lab provides an environment to learn new skills and network with students, instructors, veterinarians, and veterinary clinics from across the nation,” said 2020 wet lab coordinator Sarah Caty Cochrum. “This collaborative event, unique to the Texas A&M College of Veterinary Medicine, is the only equine, student-run wet lab in the country in which students from all veterinary colleges are invited to participate.”

The day began with a case panel breakfast session and dentistry aging session in the Veterinary & Biomedical Education Complex (VBEC), followed by 21 different lab options in four, one-hour time slots.

Students learning in a lab, feeling a horse's legAfter lunch with guest speaker Dr. Chris Ray, “Rock Star Vet,” the students attended a job fair with equine and mixed-animal veterinary clinics from several states.

Labs were offered on a variety of topics, including alternative medicine, field anesthesia, lower limb surgical procedures, laceration repair, and stallion reproduction.

The event was made possible by the support and hard work of the wet lab officer team, 62 clinicians and lab instructors, 35 student volunteers, and 14 sponsors.

“Every year we have a team of 20 students working together to make the wet lab an incredible opportunity for our students,” Cochrum said. “It’s an intensive and collective effort that is made possible through the dedication and passion of the SCAAEP wet lab team. Dr. (Canaan) Whitfield and many other faculty members, in addition to their rigorous schedules, provide extraordinary support for an event of this magnitude.”

The SCAAEP officer team
The SCAAEP officer team

The SCAAEP wet lab, which has been an annual event for the past 25 years, typically involves 10 months of planning, budgeting, and gathering supplies by students and faculty members.

“There are hundreds of people who deserve recognition including the many student volunteers, SCAAEP officer team, and especially the faculty and staff of Texas A&M who devoted their Saturday to teach these labs and showcase what an amazing institution we have here,” said Whitfield, the wet lab faculty adviser and an assistant professor of large animal surgery at the CVM.

“The TAMU SCAAEP wet lab 2020 was a great success,” Cochrum said. “It has been an honor to work with my colleagues in coordinating such an exciting event! The student chapter of the AAEP looks forward to hosting another incredible wet lab in 2021.”

What to Know About Equine Osteoarthritis

Osteoarthritis is a progressive disease that compromises the joint health and mobility of many animals. While osteoarthritis is the most common joint disorder for people in the United States, the condition is also prevalent in horses.

Dr. Jeffrey Watkins, a professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, provides insight into equine osteoarthritis and how owners might manage this condition in their horses.

“Osteoarthritis refers to deterioration of a joint or joints that is characterized by progressive loss of cartilage,” Watkins said. “The inflammation associated with osteoarthritis causes pain and swelling of the affected joints.”

Cases of osteoarthritis can be divided into two groups: primary and secondary.

Primary osteoarthritis arises from the wear and tear of everyday activities, resulting in a slow breakdown of joint cartilage. Performance horses are at particular risk for this form of osteoarthritis.

“Often, the first indication of a problem is a change in the horse’s behavior, willingness to perform, and/or ability to perform at their expected level,” Watkins said. “These are often subtle indications of a developing joint problem and are due to the low-grade pain associated with the insidious onset of osteoarthritis.”

Secondary osteoarthritis comes when an injury to a joint is severe enough to begin the process of cartilage breakdown. Horses with a history of joint infections, fractures involving the joint, ligament and tendon injuries, and preexisting joint defects are at risk for secondary osteoarthritis.

“Osteoarthritis secondary to an injury or infection will be characterized initially by the signs associated with the inciting injury. Once the initial injury has been resolved, osteoarthritis is manifested as continued loss of function due to pain and stiffness of the affected joint,” Watkins said.

If an owner suspects that their horse might be suffering from osteoarthritis, they should contact their veterinarian, who might conduct a physical evaluation and lameness examination, as well as recommend diagnostic imaging such as radiography, ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI).

Prevention of equine osteoarthritis varies depending on the type. For secondary osteoarthritis, prompt and proper treatment of the initial joint injury is vital. Primary osteoarthritis is more complicated, involving many factors including proper hoof care, responsible training regimens, and the monitoring of any predisposing factors.

“Management of osteoarthritis is a multifaceted approach and includes modification of the affected horse’s activity level, attention to body weight and body condition, appropriate hoof care, medical therapy, and surgical therapy,” Watkins said.

As with all conditions, owners concerned for their horse’s health should consult with their veterinarians to establish an individualized management strategy. Luckily, research into osteoarthritis management is ongoing, so we might one day see options for complete rehabilitation.

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at vetmed.tamu.edu/news/pet-talk. Suggestions for future topics may be directed to editor@cvm.tamu.edu.

Preparing your horse for severe weather

three horsesAdverse weather can be troublesome for humans and animals, alike. While small, indoor pets are easier to board and travel with, horses require additional preparedness and precautions.

Dr. Jessica Millwood, a resident in equine practice at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, said that planning ahead and paying attention to weather alerts are the keys to keeping horses safe during severe weather.

“Pastures should be clear of hazardous items, debris, and known entrapments for horses, and safe fencing and holding areas should be available around the property,” Millwood said. “Owners should install lightning suppression systems, sprinkler systems, and smoke detectors on all high-risk buildings, in particular those where animals are kept.”

Millwood suggests considering several factors before determining the most ideal form of shelter.

“Owners should consider their horse’s anxiety level during storms, the horse’s past experience during severe weather, the severity of the thunderstorms forecasted, and the storm-worthiness of the barn,” she said.

If a horse spends more time outdoors and is not accustomed to any other housing, it could be more stressful to try and place them in an enclosed environment, according to Millwood. A small, semi-covered secure paddock might be a better alternative for horses that react poorly to being stalled.

“On the other hand, if the horse tends to show nervousness or anxiety outside during storms, a stall in a strongly-built barn may be a better alternative than being left outdoors,” she said. “Visual contact with herd mates may also help diffuse anxious behavior.”

Contact information for you or your local veterinarian should be posted in the barn or stable. Horses should also have a microchip, brand, or any other form of identification to ensure they are returned home safely if they escape from the enclosure.

In the case of flooding, Millwood says that owners should ensure their horses have safe drinking water, without which horses may become dehydrated or be forced to drink contaminated flood water.

“Flooding may also destroy food resources available to horses and eating moldy hay or feed can lead to clinical signs such as colic or respiratory disorders,” she added. “Owners should ensure adequate food is available for at least 72 hours after a predicted flooding event is suspected to subside, and they should store feed securely to prevent contamination or spoilage.”

Another concern that comes with flooding is standing in polluted water through which the horse’s skin is exposed to irritants and contaminants. Owners should bathe their horses as soon as possible after a flood and keep their horses up-to-date on core vaccines to prevent any potentially fatal diseases.

Most severe weather conditions are tracked in advance, with the most likely scenarios forecasted. If necessary, Millwood suggests that owners evacuate their horses while it is still possible to do so.

Owners have a heightened responsibility to care for and keep their animals safe during severe weather. By taking the necessary precautions and having a disaster plan ready, you can ensure that you and your horse are prepared when a situation arises.


Pet Talk is a service of the Texas A&M College of Veterinary Medicine & Biomedical Sciences. Stories can be viewed on the web. Suggestions for future topics may be directed to editor@cvm.tamu.edu.