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The Modern

Equine Vet

Vol 7 Issue 11 2017

NEAEP Annual Meeting:

Create a Living Biosecurity Plan Scintigraphy's Role in Sport Horses Vaccination or Acute Disease? Horse Vets Keep Humans From Going Hoarse



Create a Living Biosecurity

4 Plan for the Horses Cover photo: courtesy of Dr. Claire Card


Scintigraphy’s Role in the Sports Horse ............................................................................... 8 TECHNICIAN UPDATE

Came as Strangers; Left as Friends........................................................................................12 NEWS

Influenza Vaccine Now Includes New Circulating Strain ........... 3 Vaccination or Acute Disease? ..............................................................10 Champion Roping Horse Returns after Botulism Poisoning .......................................................................11 Research in Horses Could Help Prevent Humans from Getting Hoarse...............................................................15

ADVERTISERS Equinosis........................................................................ 3 Merck Animal Health.................................................. 5


The Modern

Equine Vet SALES: Matthew Todd • Lillie Collett • EDITOR: Marie Rosenthal • ART DIRECTOR: Jennifer Barlow • CONTRIBUTING WRITERS: Paul Basillo • Carol Jean Ellis COPY EDITOR: Patty Wall Published by PO Box 935 • Morrisville, PA 19067 Marie Rosenthal and Jennifer Barlow, Publishers PERCYBO media  publishing


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LEGAL DISCLAIMER: The content in this digital issue is for general informational purposes only. PercyBo Publishing Media LLC makes no representations or warranties of any kind about the completeness, accuracy, timeliness, reliability or suitability of any of the information, including content or advertisements, contained in any of its digital content and expressly disclaims liability of any errors or omissions that may be presented within its content. PercyBo Publishing Media LLC reserves the right to alter or correct any content without any obligations. Furthermore, PercyBo disclaims any and all liability for any direct, indirect, or other damages arising from the use or misuse of the information presented in its digital content. The views expressed in its digital content are those of sources and authors and do not necessarily reflect the opinion or policy of PercyBo. The content is for veterinary professionals. ALL RIGHTS RESERVED. Reproduction in whole or in part without permission is prohibited.


Influenza Vaccine Now Includes New Circulating Strain Merck Animal Health recently updated its influenzacontaining killed virus vaccines (Prestige) to include the Florida ’13 strain, which was responsible for a large influenza outbreak in well-vaccinated horses. In February 2013, the annual Ocala Horse Shows in the Sun (HITS) international event experienced a large outbreak of equine herpesvirus type 1 and equine influenza virus (EIV) that affected hundreds of horses. The highly pathogenic EIV strain was later identified as Florida ’13 through the Merck-University of California, Davis School of Veterinary Medicine ongoing, voluntary equine biosurveillance program. The program studies the prevalence and epidemiology of relevant viral and bacterial respiratory pathogens. The process of minor evolutionary equine influenza virus (EIV) mutations and alterations, known as antigenic drift, eventually leads to new strains that a horse’s immune system doesn’t recognize. Clade is used to describe recently isolated strains of EIV that belong to the same family, but have antigenic differences. All recently isolated influenza strains in North

America and Europe belong to the Florida clades 1 and 2 sublineages. Clade 1 primarily circulates in the United States, while clade 2 predominantly circulates in Europe. Florida ’13 is a clade 1 strain. The World Organization for Animal Health (OIE) recommends that vaccines contain both clades. Prestige now includes Florida ’13, Richmond ’07 and Kentucky ’02 strains. EIV is a common and highly contagious infectious upper respiratory disease; the infection rate among unvaccinated horses is nearly 100%. EIV spreads rapidly and can be transmitted more than 200 yards by a coughing horse. Clinical signs appear within 24 to 48 hours following exposure. MeV

For more information: Pusterla N, Kass P, Mapes S, et al. Surveillance program for equine influenza virus in the United States (2010-2013). J Equine Vet Sci. 2016;39(S) April Published online DOI:


Create a

The term “biosecurity” often brings to mind images of sterile environments, personal protection protocols, infection control checklists and other clinical safeguards to ensure the health of the patients and the staff. In addition to knowing when to break out the plastic boot cov-



Issue 11/2017 |


ers, a proper biosecurity protocol also includes management tools for communicating with client farms, according to Claire Card, DVM, PhD, DACT, who spoke recently at the Northeast Association of Equine Practitioners annual meeting in Norfolk, Va. “Think of biosecurity as an








evidence-based living process that is continuously updated,” said Dr. Card of the Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Canada. “It has to be individualized for each premise, because each one has a different level of risk.





Photo courtesy of Dr. Claire Card

Living Biosecurity Plan

The Science of Convenient Protazil® (1.56% diclazuril) is the only FDA-approved alfalfa-based top dress antiprotozoal pellet for the treatment of EPM. • Equine Protozoal Myeloencephalitis (EPM) is a serious neurological disease that can strike anytime, anywhere. Make treatment easy with Protazil® • Safe and accurate dosing with a calibrated scoop • Easier to use than paste, less stress for you and your horse • Rapid absorption — no loading dose required1 Now that’s convenient.

Ask your veterinarian for Protazil®. Visit us at to learn more about Merck Animal Health and the equine products and programs that help keep horses healthy. Use of Protazil® (1.56% dicazuril) is contraindicated in horses with known hypersensitivity to diclazuril. Safe use in horses used for breeding purposes, during pregnancy, or in lactating mares has not been evaluated. The safety of Protazil® (1.56% dicazuril) with concomitant therapies in horses has not been evaluated. See related page in this issue for details. For use in horses only. Do not use in horses intended for human consumption. Not for human use. Keep out of reach of children.

The Science of Healthier Animals 2 Giralda Farms • Madison, NJ 07940 • • 800-521-5767 Copyright © 2017 Intervet Inc., d/b/a/ Merck Animal Health, a subsidiary of Merck & Co., Inc. All rights reserved. 3654 EQ-FP AD Protazil®


Hunyadi L, Papich MG, Pusterla N. Pharmacokinetics of a low-dose and DA-labeled dose of diclazuril administered orally as a pelleted top dressing in adult horses. J of Vet Pharmacology and Therapeutics (accepted) 2014, doi: 10.111/jvp.12176. The correlation between pharmacokinetic data and clinical effectiveness is unknown


(1.56% diclazuril)

FOR ORAL USE IN HORSES ONLY For the treatment of equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona in horses. CAUTION Federal (U.S.A.) law restricts this drug to use by or on the order of a licensed veterinarian. NADA #141-268 Approved by FDA DESCRIPTION Diclazuril, (±)-2,6-dichloro-α-(4-chlorophenyl)-4-(4,5 dihydro-3,5-dioxo-1,2,4-triazin-2(3H)-yl) benzeneacetonitrile, has a molecular formula of C17 H 9 CI 3 N4O2, a molecular weight of 407.64, and a molecular structure as follows:

Diclazuril is an anticoccidial (antiprotozoal) compound with activity against several genera of the phylum Apicomplexa. PROTAZIL® (diclazuril) is supplied as oral pellets containing 1.56% diclazuril to be mixed as a top-dress in feed. Inert ingredients include dehydrated alfalfa meal, wheat middlings, cane molasses and propionic acid (preservative). INDICATIONS PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets are indicated for the treatment of equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona in horses. DOSAGE AND ADMINISTRATION Dosage: PROTAZIL® (1.56% diclazuril) is administered as a top dress in the horse’s daily grain ration at a rate of 1 mg diclazuril per kg (0.45 mg diclazuril/lb) of body weight for 28 days. The quantity of PROTAZIL® necessary to deliver this dose is 64 mg pellets per kg (29 mg pellets/ lb) of body weight. Administration: To achieve this dose, weigh the horse (or use a weigh tape)). Scoop up PROTAZIL® to the level (cup mark) corresponding to the dose for the horse’s body weight using the following chart: mLs of Pellets 20 30 40 50

Weight Range of Horse (lb) 1275 - 1524 1525 - 1774 1775 - 2074 -

mLs of Pellets 60 70 80 -

One 2-lb bucket of PROTAZIL® will treat one 1100-lb horse for 28 days. One 10-lb bucket of PROTAZIL® will treat five 1100-lb horses for 28 days. CONTRAINDICATIONS Use of PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets is contraindicated in horses with known hypersensitivity to diclazuril. WARNINGS For use in horses only. Do not use in horses intended for human consumption. Not for human use. Keep out of reach of children. PRECAUTIONS The safe use of PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets in horses used for breeding purposes, during pregnancy, or in lactating mares has not been evaluated. The safety of PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets with concomitant therapies in horses has not been evaluated. ADVERSE REACTIONS There were no adverse effects noted in the field study which could be ascribed to diclazuril. To report suspected adverse reactions, to obtain a MSDS, or for technical assistance call 1-800-224-5318. CLINICAL PHARMACOLOGY The effectiveness of diclazuril in inhibiting merozoite production of Sarcocystis neurona and S. 1 falcatula in bovine turbinate cell cultures was studied by Lindsay and Dubey (2000). Diclazuril inhibited merozoite production by more than 80% in cultures of S. neurona or S. falcatula treated with 0.1 ng/mL diclazuril and greater than 95% inhibition of merozoite production (IC 95 ) was observed when infected cultures were treated with 1.0 ng/mL diclazuril. The clinical relevance of the in vitro cell culture data has not been determined. PHARMACOKINETICS IN THE HORSE The oral bioavailability of diclazuril from the PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets at a 5 mg/kg dose rate is approximately 5%. Related diclazuril concentrations in the cerebrospinal fluid (CSF) range between 1% and 5% of the concentrations observed in the plasma. Nevertheless, based upon equine pilot study data, CSF concentrations are expected to 2 substantially exceed the in vitro IC 95 estimates for merozoite production (Dirikolu et al., 1999) . Due to its long terminal elimination half-life in horses (approximately 43-65 hours), diclazuril accumulation occurs with once-daily dosing. Corresponding steady state blood levels are achieved by approximately Day 10 of administration. EFFECTIVENESS Two hundred and fourteen mares, stallions, and geldings of various breeds, ranging in age from 9.6 months to 30 years, were enrolled in a multi-center field study. All horses were confirmed EPM-positive based on the results of clinical examinations and laboratory testing, including CSF Western Blot analyses. Horses were administered PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets at doses of 1, 5, or 10 mg diclazuril/kg body weight as a top-dress on their daily grain ration for 28 days. The horses were then evaluated for clinical changes via a modified Mayhew neurological scale on Day 48 as follows: 0. Normal, neurological deficits not detected. 1. Neurological deficits may be detectable at normal gaits; signs exacerbated with manipulative procedures (e.g., backing, turning in tight circles, walking with head elevation, truncal swaying, etc.). 2. Neurological deficit obvious at normal gaits or posture; signs exacerbated with manipulative procedures. 3. Neurological deficit very prominent at normal gaits: horses give the impression they may fall (but do not) and buckle or fall with manipulative procedures. 4. Neurological deficit is profound at normal gait: horse frequently stumbles or trips and may fall at normal gaits or when manipulative procedures were utilized. 5. Horse is recumbent, unable to rise. Each horse’s response to treatment was compared to its pre-treatment values. Successful response to treatment was defined as clinical improvement of at least one grade by Day 48 ± conversion of CSF to Western Blot-negative status for S. neurona or achievement of Western Blot-negative CSF status without improvement of 1 ataxia grade. Forty-two horses were initially evaluated for effectiveness and 214 horses were evaluated for safety. Clinical condition was evaluated by the clinical investigator’s subjective scoring and then corroborated by evaluation of the neurological examination videotapes by a masked panel of three equine veterinarians. Although 42 horses were evaluated for clinical effectiveness, corroboration of clinical effectiveness via videotape evaluation was not possible for one horse due to missing neurologic examination videotapes. Therefore, this horse was not included in the success rate calculation. Based on the numbers of horses that seroconverted to negative Western Blot status, and the numbers of horses classified as successes by the clinical investigators, 28 of 42 horses (67%) at 1 mg/kg were considered successes. With regard to independent expert masked videotape assessments, 10 of 24 horses (42%) at 1 mg/kg were considered successes. There was no clinical difference in effectiveness among the 1, 5, and 10 mg/kg treatment group results. Adverse events were reported for two of the 214 horses evaluated for safety. In the first case, a horse was enrolled showing severe neurologic signs. Within 24 hours of dosing, the horse was recumbent, biting, and exhibiting signs of dementia. The horse died, and no cause of death was determined. In the second case, the horse began walking stiffly approximately 13 days after the start of dosing. The referring veterinarian reported that the horse had been fed grass clippings and possibly had laminitis. ANIMAL SAFETY PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets were administered to 30 horses (15 males and 15 females, ranging from 5 to 9 months of age) in a target animal safety study. Five groups of 6 horses each (3 males and 3 females) received 0, 5 (5X), 15 (15X), 25 (25X) or 50 (50X) mg diclazuril/kg (2.27mg/lb) body weight/day for 42 consecutive days as a top-dress on the grain ration of the horse. The variables measured during the study included: clinical and physical observations, body weights, food and water consumption, hematology, serum chemistry, urinalysis, fecal analysis, necropsy, organ weights, gross and histopathologic examinations. The safety of diclazuril top-dress administered to horses at 1 mg/kg once daily cannot be determined based solely on this study because of the lack of an adequate control group (control horses tested positive for the test drug in plasma and CSF). However, possible findings associated with the drug were limited to elevations in BUN, creatinine, and SDH and less than anticipated weight gain. Definitive test article-related effects were decreased grain/top-dress consumption in horses in the 50 mg/kg group. In a second target animal safety study, PROTAZIL® (1.56% diclazuril) Antiprotozoal Pellets were administered to 24 horses (12 males and 12 females, ranging from 2 to 8 years of age). Three groups of 4 horses/sex/group received 0, 1, or 5 mg diclazuril/kg body weight/day for 42 days as a top-dress on the grain ration of the horse. The variables measured during the study included physical examinations, body weights, food and water consumption, hematology, and serum chemistry. There were no test article-related findings seen during the study. STORAGE INFORMATION Store between 15°C to 30°C (59°F to 86°F). HOW SUPPLIED PROTAZIL® (1.56 % diclazuril) Antiprotozoal Pellets are supplied in 2-lb (0.9 kg) and 10-lb (4.5 kg) buckets. REFERENCES 1. Lindsay, D. S., and Dubey, J. P. 2000. Determination of the activity of diclazuril against Sarcocystis neurona and Sarcocystis falcatula in cell cultures. J. Parasitology, 86(1):164–166. 2. Dirikolu, L., Lehner, F., Nattrass, C., Bentz, B. G., Woods, W. E., Carter, W. E., Karpiesiuk, W. G., Jacobs, J., Boyles, J., Harkins, J. D., Granstrom, D. E. and Tobin, T. 1999. Diclazuril in the horse: Its identification and detection and preliminary pharmacokinetics. J. Vet. Pharmacol. Therap. 22:374–379. May 2010 Intervet Inc. 56 Livingston Ave, Roseland, New Jersey 07068 © 2010 Intervet Inc. All rights reserved. 08-10 211.x.3.1.0

Photo courtesy of Dr. Claire Card

Weight Range of Horse (lb) 275 - 524 525 - 774 775 - 1024 1025 - 1274

Biosecurity protocols must be individualized for each stable or event.

Some premises are pure breeding farms, some also have show horses, and others are places with high traffic where horses come and go all the time. There is often a need for a veterinarian to step back and look at the risks that are going to be present and relevant for a particular premises.” Dr. Card is no stranger to outbreaks. The clinical practice at her institution and its client farms have seen multiple outbreaks of herpesvirus, strangles and other diseases that can run through a barn in the blink of an eye. Just as outbreaks can affect the horses, they can also affect a practice’s reputation. “It’s important for practitioners to focus on biosecurity because it can be a cause of economic loss and it can harm a reputation,” she said. “Veterinarians often become collateral damage during an outbreak of disease.” In general, she said, farms that do a good job with general health management are often the ones that escape some of the worst effects of these outbreaks.

Action plan

Before the storm hits, it’s important to have an action plan in place. “It’s important to think through what would happen if a group of horses came back from a show after exposure to a her6

Issue 11/2017 |

pesvirus,” Dr. Card said. “There has to be a plan that involves knowledgeable people who are speaking for the farm and for the clinic. The more those two are coordinated, the better everybody looks.” Social media offers an efficient method of having a reputation anonymously dragged through the mud, she added. A point person can take over the role of chief communicator for the farm and for the practice. The spokesperson will be the go-to for information and answers. This can demystify the process and keep people informed of the next steps. If not, speculation takes over, and the problems begin.

Risk assessment

The current industry standard for biosecurity risk assessment involves understanding horse traffic, the nature of the farm, the density and demographics of the horses, and the geographic location. In a breeding environment, it will also include regulations that control movement to and from the premises, considerations for the gametes, and the risks of handling them. “One of the key things is to have staff trained to recognize infectious disease,” Dr. Card explained. “The people who clean stalls can spend a lot more time with the horses than others on the farm. Treat

Photo courtesy of Dr. Claire Card

Often, a veterinarian must step back and look at the risks that will be present for a particular premises.

them as professionals, and make sure they’re knowledgeable enough to recognize some signs of infectious or venereal disease, for example.”

Standardize, standardize

When Dr. Card visits a farm, she considers it a good sign to see peo-

ple wearing clothes associated with their employment rather than street clothes. She likes to see staff who take care of their footwear, who are trained in proper hand washing techniques, and who know that shared equipment should be disinfected using specific disinfection

techniques whenever possible. “Visitor access on farms should also be controlled,” she said. “Of course it’s a business and people will come and go, but an important part of biosecurity protocol includes where people are allowed to go, when they are allowed to go there, and who goes with them. Good facilities have secure areas for loading and unloading animals, for handling manure and for handling dead horses.” Ideally, Dr. Card would like a premises to have a pre-entry health inspection so that only healthy horses are allowed on the farm. “If you have the ability to do so, that would be best,” she said. “Horses that have fevers or evidence of infectious disease would be denied access in that situation. People should know in advance that if a horse has a healing strangles abscess, it is not going to be allowed entry. I would recommend AAEP core vaccines for all of the horse residents of the farm, and all of those coming to the farm.” MeV

The Social Neigh-twork


One of the first security measures to take with pregnant mares is to keep them separate from the rest of the horses. As a theriogenologist who has dealt with many problems with pregnant mares, Claire Card, DVM, PhD, DACT, said they should also live in stable social groups of no larger than 20 mares—particularly after the fifth month of pregnancy. “Horses can only remember about 20 close friends,” she explained. “When the group gets larger than that, every moment becomes a little more stressful because they’re not sure if they’re dominant or submissive to the other horses. In groups of 20, they can figure out where they are on the ladder of social dominance.” Social stress can be a constant monkey on the mare’s back at a particularly vulnerable life stage. This constant stress may lead to the shedding of herpesvirus that may cause abortions or neurologic disease. Most horses are latent carriers of the virus and infected when they are foals. Keeping stress to a minimum is the key to keeping the mare’s pregnancy safe. | Issue 11/2017




Sports Horse

B y


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M a r i e

R o s e n t h a l ,


gy, nuclear scintigraphy plays a role in localizing performance problems in the sport horse, which are frequently multifactorial involving the limb and the skeletal structure, Sarah M. Puchalski, DVM, DACVR, said at the Northeast Association of Equine Practitioners Annual Meeting in Norfolk, Va. “It can be a valuable way to look at the area that is already localized. Or the classic thing [to look for] is the non-localized lameness, or multiple limb lameness, especially in sport horses,” explained Dr. Puchalski, who practices at Circle Oak Equine Sports Medicine in Petaluma, Calif. Performance horses in particular are at risk for stress remodeling and stress-induced pathology. Jumpers and race horses see a lot of repetitive stress remodeling, she said and “scintigraphy is one of the best diagnostic techniques to try to find it. Bone scan helps us understand stress remodeling.” Nuclear scintigraphy uses very small, trace amounts of an isotope (Technetium-99m), which begins to decay once it is injected

Nuclear scintigraphy can help localize performance problems in the sport horse, which often are multifactorial. into the horse. A gamma camera picks up the radioactive decay to create images. The technique is used frequently to diagnose conditions that are more difficult to see with other imaging modalities, such as radiographs. Images typically are made within two to three hours of injection. The diagnosis of skeletal issues and large part imaging are by far the best uses of nuclear scintigraphy scans, but they can also be used to pick up soft tissue injuries and vessel disorders. The horse’s size presents a host of limitations for other imaging, but the emission imaging technique can more easily evaluate the upper portions of the appendicular and the axial skeleton, especially the pelvis or lumbar spine. Nuclear scintigraphy is excellent for obtaining information about certain clinical sce-

narios, such as stress-induced or training-related skeletal remodeling in young horses, pinpointing multiple limb lameness, evaluating poor performance, a horse with decreased enthusiasm for work or when the lameness cannot be localized using other modalities, Dr. Puchalski explained. Bone phase scintigraphy is also useful for localized lameness when radiographs or ultrasonography cannot pinpoint the problem. She has seen cases of lameness localized to the fetlock region showing up as marked subchondral bone remodeling on scintigraphy but are normal on radiographs. Nuclear scintigraphy can be useful for more complex problems, too, she said, especially when multiple sites are involved because it can yield information about the whole horse that would otherwise be difficult or impossible to garner. “In some instances, scintigraphy can be arguably used as tool to tweak management of upper level performance horses,” she said. Nuclear scintigraphy provides an incredible amount of information but that information must be interpreted with the clinical picture in mind. She suggests dividing the findings into major and minor findings—what is acute and what is chronic. Degenerative lesions may warrant different consideration than a tissue that is torn due to supraphysiologic forces, she explained. Since all of the imaging modalities have limitations, combining modalities might form the most complete picture, she said. MeV

©Shutterstock/Marcel Jancovic

Although an older technolo- | Issue 11/2017



Vaccination or Acute Disease? By Paul Basilio There are few things more frustrating than when a horse or foal shows signs of disease shortly after vaccination. Owners frequently think the vaccine caused the disease, and seldom consider that perhaps, the animal was already infected. It’s a potential source of conflict with clients that may threaten a veterinarian’s reputation. “We worry about these things,” said Frank M. Andrews, DVM, DACVIM-LAIM, LVMA, equine committee professor of Equine Medicine and Director of the Equine Health Studies Program at Louisiana State University. “The client might say that we ‘gave’ their horse West Nile virus (WNV) or Eastern Equine encephalitis (EEE). In addition, an increase in an IgM [immune globulin M] titer one week after vaccination may cause a false-positive result.” The incubation periods for WNV and EEE are seven to 14 days and four to 10 days, respectively, so it is important to know if the vaccines stimulate an antibody response to these diseases. Dr. Andrews and his team measured plasma IgM and IgG levels in adult horses and naïve pony foals to see if the antibody titers would have a result of more than 1:400, which is used to diagnose acute disease. “If that happens, then you could have a false-positive result after vaccination,” Dr. Andrews said. The horses and foals in the study were housed on a farm in Montana in the spring. The six adult horses were Percheron geldings that ranged from 8 to 25 years of age. The six pony foals were 4 months of age at the time of the study. Their mares were used as sentinels for acute disease. While the herd was vaccinated yearly for WNV and EEE, the dose was delayed that year for the purposes of the study. “If we saw an increase in the IgM titer in one of the foals, we wanted to be able to tell if it was a West Nile outbreak, so the mares were tested also at the same time, because a high IgM titer in the mares would indicate disease, as they were not vaccinated,” Dr. Andrews said. The vaccine used in the study was the multivalent vaccine containing components of WNV and EEE (Vetera Gold; Boehringer Ingelheim Vetmedica). Boeh-

ringer supplied the vaccine for the study. For the adult horses, a blood sample was taken prior to vaccination, and then additional samples were taken on days 7, 14, 21, 30 and 60. No booster was administered, as these horses had been receiving yearly WNV/ EEE vaccinations with Vetera Gold. For the ponies, the schedule was a little more involved. A blood sample from the ponies and dams was drawn prior to the initial vaccination with the multivalent vaccine. On days 7, 14 and 21, blood was obtained again from the ponies and the dams. On day 21, a booster dose of the same vaccine was administered to the ponies. On days 28, 35, 42 and 51, blood was obtained once more. All samples were analyzed using a capture ELISA test for IgM and a plaque reduction neutralization test (PRNT) for IgG titers.

The Results

“If you vaccinate a horse that becomes ataxic or has fever, and then you run a capture ELISA for EEE or West Nile virus that is more than 1:400, then you can say that the horse was likely incubating disease when you vaccinated it,” Dr. Andrews explained. During the study period, the sentinel pony dams showed no results that would indicate an outbreak of acute disease. IgM titers were less than 1:400 in all adult horses 7 days after vaccination for WNV. “When we looked at IgM capture ELISA results on days 0 through 60, there was no increase in these horses,” he said. Similar results were seen in the ponies. IgM titers were <1:400 in all foals after vaccination and the booster dose. However, one pony foal failed to develop an antibody titer to the vaccine. “This shows us that a few foals may not respond due to passive immunity from the mare,” Dr. Andrews said. “If you’re going to start vaccinating at 4 months of age, then you’ll probably need a booster at 5 months and again at 6 months to ensure protection.” Overall, the study appeared to confirm that while an IgM and IgG antibody response may be seen following vaccination, the IgM titer is not high enough to interfere with the current diagnostic testing procedures for acute disease in cases of West Nile and EEE. MeV

For more information: The study was funded in part by Boehringer Ingelheim Vetmedica. A student worker from the Merial-NIH Veterinary Summer Scholars program also participated in the study. Additional funding came from the LSU Equine Health Studies program, for which Dr. Andrews serves as the director. Funding was also provided by the LSU Foundation. 10

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Champion Roping Horse Returns after Botulism Poisoning John, an 11-year-old American Quarter Horse gelding, and his owner/rider Doug Parker worked for years to qualify for the World Series of Team Roping in Las Vegas. Just before that became a reality in 2016, however, John was stricken with botulism, which had already killed one of his stablemates. Mr. Parker raced to the University of California Davis veterinary hospital to save John’s life. “After what happened to our other horses just two weeks earlier, we got him to Davis as fast as we could,” said Mr. Parker, recalling two other horses of his herd of 25 that were treated for botulism. One didn’t survive. Parker recalled John looked just as bad as that one, and he wasn’t optimistic. With three horses testing positive for botulism in such a short time, Mr. Parker immediately instituted strict biosecurity measures at his farm and an investigation determined a bad batch of grain was the culprit.

that he described as “an exceptional athlete…a high powered machine.” Parker worked with John for two years to get him to competition level. He was determined to save his gelding, and worked with the UC Davis equine specialists to do everything he could for a positive outcome. Mr. Parker took John home and placed him in their arena. The first day home, John couldn’t stand on his own, so Parker used a lift affixed to his tractor to get him up. John stayed up all day, but Parker found him down the next morning. When John heard Mr. Parker start the tractor, he got up on his own. “I think he thought, ‘Well if you’re going to hoist me up with the tractor again, I’ll just stand up on my own,’” Mr. Parker joked.

John remained hospitalized for 26 days. During that time, he was treated with botulism antitoxin plasma. He received other supportive care including IV fluid therapy, antiinflammatories and vitamin E. John was unable to stand without help, so faculty, staff and students John (right), ridden by owner Doug Parker, overcame botulism poisoning to qualify for the World Series of Team Roping. in the Large Animal Clinic It took John about three months (February 2017) instituted the Large Animal Lift to assist him to stand to gain his weight and strength back. Mr. Parker took whenever necessary. Once standing, he was disconhim to a roping competition in Arizona, but John just nected from the lift so he could move about freely didn’t have it in him yet. Realizing he needed a lot and lie down when he wanted. more rest, and unsure if he’d ever compete at a high Over the following weeks, John was assisted to level again, Mr. Parker took off John’s shoes and let stand as needed and became gradually stronger. On him out to pasture for four months. day 22 of his hospitalization, John stood unassisted In June 2017, Mr. Parker thought he would try for the first time. He continued to need minor assisJohn again. He took him to a competition, and he was tance via the lift until day 26, when he again stood back to his old self, winning the event. They qualified unassisted. At that time, his care team believed it was again for the 2017 World Series of Team Roping. reasonable to send John home to continue recuperat“I never realized what that horse meant to me uning in a larger space than the stalls in the hospital’s til I didn’t have him to ride and compete with anyIntensive Care Unit. more,” Mr. Parker said. “I’ve searched for many highMr. Parker said he searched for a long time to find end horses, but have never seen one as good as John. a horse with the potential to compete at the highest He’s a one-in-a-thousand horse.” MeV levels of roping. He finally found a horse in Arizona

Photo courtesy of Doug Parker

Long Ride | Issue 11/2017



Came as Strangers; Left as Friends By Deborah B. Reeder, RVT, VTS-EVN

Photos courtesy of Deborah B. Reeder, RVT, VTS-EVN

Twenty-five members of the American Association of Equine Veterinary Technicians and Assistants gathered at Peninsula Equine for the AAEVT Anesthesia Society Weekend Oct. 20â&#x20AC;&#x201C;22. They came from more than 15 states and Canada, along with Peninsula Equine staff members to this beautiful facility tucked away in the rolling oak-studded hills of Woodside, Calif., inside the Portola Valley Training Center. The AAEVT recently formed the Anesthesia Society to promote excellence in the discipline of equine veterinary anesthesia among its members Instructor Lori Bidwell, DVM, DACVS, CVA, and her assistants Nicole Bone, LVT and Maggie Pratt, LVT, VTS-Anes , offered presentations, insight, shared stories ( both good and what went wrong), discussions, wet labs and demonstrations for a full two days and everyone left empowered, more confident, and eager to learn more! We had a fun welcome reception Friday night, sponsored by Zoetis, so we could all get to know each other, learn where we were from, and just chat. Dr. and Mrs. Russ Peterson and Dr. Lauren Work joined us, welcomed us all and made everyone feel at home and ready for the weekend. Saturday morning kicked off bright, crisp and early with a Panera breakfast and then Dr. Bidwell gave pre-


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sentations on the basics of equine anesthesia and a review of the anatomy relevant to anesthesia. Her presentation was made all the more real when she shared some of her personal experiences. She entertained questions and there was a good deal of discussion. Lunch from LuLuâ&#x20AC;&#x2122;s Mexican was sponsored by Dechra, and Shelly Derks and Jessica Morris were in attendance along with Dr. David Stone who gave a presentation on fluids and fluid therapy. He kept the group engaged with some great questions and answers. We then headed out into the sunshine, took a quick break, watched the Sport horses training in the ring and began our wet labs. Half the group participated in the gas anesthesia wet lab while the other group rotated between dissection of the head and hind limb, catheter placement on models, and practicing suturing and knots. This group was led by Nicole and Maggie and they really got into finding the veins and arteries, performing a tracheotomy, and learning the structures underneath the skin that they would deal with for sedation and catheters. Everyone studied the sponges and practiced their knot techniques and helped each other. It was awesome to witness the support and sharing. We then went back and discussed the Anesthesia Society and our certification process as well as how to do case studies. The anesthesia group placed catheters, sedated the horse and then reviewed the anesthesia machine and set up. Once in the knockdown room, the group got to see how different drugs can work for sedation, they placed the endotracheal tube in sternal recumbency, and got the

AAEV T M E M b E r s h i p Membership in the AAEVT is open to all veterinary technicians, assistants, support staff and those employed in the veterinary health care industry worldwide. Student membership is open to those currently enrolled in an AVMA/CVMA accredited veterinary technology program.

AAEVT Membership • • • • • • • • • • •

Bi-Annual Newsletter Weekly “HoofBeats” Email Newsblast Full access to, including the Career Center and the Library Up-to-date information on the AAEVT Discounted registration for AAEVT Regional Meetings and the annual AAEP/AAEVT Convention NTRA, Working Advantage and Platinum Performance Benefits The opportunity to participate in the AAEVT Online Certification Program or to become a member of the AEVNT Academy-Specialty in Equine Veterinary Nursing Scholarship opportunities. AAEVT’s Equine Manual for Veterinary Technicians (Blackwell Publishing 20% discount on purchase price) Opportunity to attend Purina’s Annual Equine Veterinary Technician Conference - All Expenses paid!

AAEVT Objectives • • • •

Provide opportunities for CE, training, communication, and networking Educate the equine veterinary community and the public about our profession Inform Members of issues affecting our profession Assist in providing the best medical care to improve the health and welfare of the horse

AAEVT Online Equine Certification Program

• A three course, 10 module, equine-only online program offered through ACT • Geared toward Credentialed Veterinary Technicians, Assistants, Support staff, & Students • Areas of study include: equine medical terminology, anatomy and physiology, parasitology, laboratory, diagnostics, equine basics (breeds, wellness, husbandry,) diagnostic procedures, emergency medicine, restraint, pharmacology, surgical assistance and anesthesia, equine office procedures • A certificate of completion is awarded to those who: Successfully complete required courses Complete the list of required skills (per a supervising DVM who is an AAEP member) Attend an AAEVT regional CE symposium and participate in the we labs • Those individuals who successfully complete the programs will be recognized as AAEVT Certified Equine Veterinary Technicians / AAEVT Certified Equine Veterinary Assistants depending on their current designation. The certificate is recognized by the AAEVT and the AAEP but does not grant the credentialed status by the AVMA • For more information go to or call 800-357-3182

AAEVT Mission Statement: To promote the health and welfare of the horse through the education and professional enrichment of the equine veterinary technician and assistant.

Fo r m o re i n f o r m a t ion v ist w w w.a ae vt.or g

*American Association of Equine Veterinary Technicians and Assistants

Photos courtesy of Deborah B. Reeder, RVT, VTS-EVN


horse on the hoist and onto the surgery table. Dr. Bidwell encouraged everyone to take over different roles, and to try to place arterial catheters, and they practiced different models of monitoring. We used the new MAI ECG handheld monitor—which was a big hit—while working with fluids and with the anesthesia machine. There were lots of discussions and questions and sharing of different scenarios. It was inspiring to see everyone trying to hit arteries they never had and celebrating each other’s successes! After about an hour and a half, the horse was moved to recovery and everyone got to participate there and watch the horse recover successfully. It was a full day, but the group was ready to start again Sunday morning. We were blessed again with amazing weather. We started off with breakfast courtesy of Mayfield Bakery, and then began with lectures on monitoring and pain management, more advanced anesthesia techniques and discussed emergency procedures and drugs, and then delved into some worse-case scenarios. Everyone commented that they truly appreciated Dr. Bidwell’s relevant and down-to-earth approach to not only her lectures and anesthesia in the surgery room, but her honest sharing of her mistakes and learning curves: “Keep calm and carry on," "Do the best you can,” and “There is no 14

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perfect equine anesthesia.” We then enjoyed an awesome lunch from Avanti’s Pizza and Pasta courtesy of Luitpold Animal Health and split into groups again. The anesthesia group had a pony this time and Dr. Bidwell demonstrated another method of sedation. Once again the groups were able to try different procedures and supported each other’s learning by sharing and helping. We ended the day around 5 pm—everyone thoroughly inspired to go back and put what they learned into action and share their experiences. Twenty-five strangers left as colleagues and friends, forming a network and a bond that was an inspiration to witness and be a part of. We succeeded in our goal with creating this Anesthesia Society—to prepare, train, encourage and inspire a group of dedicated equine veterinary technicians and assistants to own their place among the best equine anesthetists we have to offer our profession. Humbled and proud…. MeV

About the author

Deborah B. Reeder, RVT, VTS-EVN is the AAEVT Executive Director and Anesthesia Society Director.


U.K. animal health researchers and U.S. researchers in human health showed once again that it is all One Health. They have identified new genes linked to how, Streptococcus pyogenes—an important cause of human disease—survives in people. The number of cases of infections caused by S. pyogenes around the world has increased dramatically over the past 20 years, and this organism is responsible for 600 million cases of pharyngitis in people each year. The bacteria is also responsible for another 100 million cases of invasive disease including scarlet fever, acute rheumatic fever and the flesh-eating disease necrotizing fasciitis—the onset of which often follows initial cases of pharyngitis. However, despite the cost to human health, relatively little is known about which of the approximately 1,800 genes in S. pyogenes are required for it to infect people, and persist in their throats. Unraveling the diseasecausing processes of bacteria has traditionally needed to be carried out one-gene-ata-time. However, scientists at the Animal Health Trust working on a close relative of S. pyogenes—Streptococcus equi, which causes the devastating disease strangles in horses—had developed a new technique that enables the importance of every gene in the organism to be tested at once. This technique was transferred to the Houston Methodist Research Institute, where it also proved to be effective for the study of S. pyogenes. Here, the Houston scientists were quickly able to identify 92 genes that were needed by this organism to grow in human saliva in the lab—replicating the critical first stage required on the path it uses to cause disease in people. “The ability to establish the importance of every gene in Streptococcus pyogenes within one experiment has the potential to accelerate research into this important human pathogen” explained James Musser, PhD, professor of pathology and genome medicine at the Houston Methodist Research Institute. “In

Photos courtesy of Rebecca Calver

Research in Horses Helping to Keep Humans from Getting Hoarse

S.pyogenes in the lab and in the horse.

follow-up tests, we were immediately able to confirm that six of these new genes really did affect growth in human saliva, suggesting that this new information has exciting potential for developing novel therapeutics and vaccines to improve human health.” “We are delighted that a technique developed at the AHT to learn more about Streptococcus equi and Strangles in horses has provided new results that could benefit people, too” said Andrew Waller, BSc, PhD, head of bacteriology at the AHT. “We have learned a huge amount about our bug through following the work being done on human diseases, and it is great to be able to give something back in return. This study highlights the similarities of animal and human pathogens. We hope that our technique will also prove useful for the study and prevention of other diseases, regardless of the animal they affect.” MeV

For more information: Zhu L, Charbonneau ARL, Waller AS, et al. Novel genes required for the fitness of Steptococcus pyogenes in human saliva. mSphere. 2017 Nov. 1 DOI: 10.1128/mSphereDirect.00460-17 | Issue 11/2017


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