Published by the Florida Association of Equine Practitioners, an Equine-Exclusive Division of the Florida Veterinary Medical Association Issue 2 • 2015
GETTING STARTED on the RIGHT FOOT TRACY A. TURNER | DVM, MS, DACVS, DACVSMR
Biosecurity
in the EQUINE PRACTICE DR. NICOLA PUSTERLA | PHD, DACVIM
EQUINE LYME DISEASE THOMAS J. DIVERS | DVM, DACVIM, DACVECC
Update on UFCVM’s Animal
TECHNICAL RESCUE IN FLORIDA JOHN HAVEN | UF CVM DIRECTOR
Join us at the
11TH ANNUAL Promoting Excellence OCTOBER 15 – 18, 2015 Naples Grande Beach Resort • Naples, FL
SYMPOSIUM
INSIGHTS INTO OPTIMIZING EQUINE ATHLETIC PERFORMANCE
OSPHOSÂŽ
(clodronate injection) Bisphosphonate For use in horses only. Brief Summary (For Full Prescribing Information, see package insert) CAUTION: Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. DESCRIPTION: Clodronate disodium is a non-amino, chlorocontaining bisphosphonate. Chemically, clodronate disodium is (dichloromethylene) diphosphonic acid disodium salt and is manufactured from the tetrahydrate form.
A stride forward
INDICATION: For the control of clinical signs associated with navicular syndrome in horses. CONTRAINDICATIONS: Horses with hypersensitivity to clodronate disodium should not receive OSPHOS.
for Navicular Syndrome
WARNINGS: Do not use in horses intended for human consumption. HUMAN WARNINGS: Not for human use. Keep this and all drugs out of the reach of children. Consult a physician in case of accidental human exposure.
Introducing OSPHOS, the new
PRECAUTIONS: As a class, bisphosphonates may be associated with gastrointestinal and renal toxicity. Sensitivity to drug associated adverse reactions varies with the individual patient. Renal and gastrointestinal adverse reactions may be associated with plasma concentrations of the drug. Bisphosphonates are excreted by the kidney; therefore, conditions causing renal impairment may increase plasma bisphosphonate concentrations resulting in an increased risk for adverse reactions. Concurrent administration of other potentially nephrotoxic drugs should be approached with caution and renal function should be monitored. Use of bisphosphonates in patients with conditions or diseases affecting renal function is not recommended. Administration of bisphosphonates has been associated with abdominal pain (colic), discomfort, and agitation in horses. Clinical signs usually occur shortly after drug administration and may be associated with alterations in intestinal motility. In horses treated with OSPHOS these clinical signs usually began within 2 hours of treatment. Horses should be monitored for at least 2 hours following administration of OSPHOS.
FDA approved intramuscular bisphosphonate injection from Dechra Veterinary Products
Easily administered via intramuscular injection
Well tolerated* in clinical trials
Proven efficacy* at 6 months post treatment
No Reconstitution required
OSPHOS contains clodronate disodium, a bisphosphonate indicated for the control of clinical signs associated with navicular syndrome in horses. OSPHOS is the only FDA-approved bisphosphonate for use in horses that is labeled for intramuscular injection. In a clinical trial evaluating OSPHOS in 86 horses, lameness improved in 74.7% of horses by at least one grade 56 days after treatment. Only 9% of horses displayed clinical signs of being uncomfortable, nervous, colicky and or pawing after receiving OSPHOS. Less than 1% of horses experienced colic requiring treatment.
WITH OSPHOS THE BENEFITS ARE CLEAR . . .
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Bisphosphonates affect plasma concentrations of some minerals and electrolytes such as calcium, magnesium and potassium, immediately post-treatment, with effects lasting up to several hours. Caution should be used when administering bisphosphonates to horses with conditions affecting mineral or electrolyte homeostasis (e.g. hyperkalemic periodic paralysis, hypocalcemia, etc.). The safe use of OSPHOS has not been evaluated in horses less than 4 years of age. The effect of bisphosphonates on the skeleton of growing horses has not been studied; however, bisphosphonates inhibit osteoclast activity which impacts bone turnover and may affect bone growth. Bisphosphonates should not be used in pregnant or lactating mares, or mares intended for breeding. The safe use of OSPHOS has not been evaluated in breeding horses or pregnant or lactating mares. Bisphosphonates are incorporated into the bone matrix, from where they are gradually released over periods of months to years. The extent of bisphosphonate incorporation into adult bone, and hence, the amount available for release back into the systemic circulation, is directly related to the total dose and duration of bisphosphonate use. Bisphosphonates have been shown to cause fetal developmental abnormalities in laboratory animals. The uptake of bisphosphonates into fetal bone may be greater than into maternal bone creating a possible risk for skeletal or other abnormalities in the fetus. Many drugs, including bisphosphonates, may be excreted in milk and may be absorbed by nursing animals. Increased bone fragility has been observed in animals treated with bisphosphonates at high doses or for long periods of time. Bisphosphonates inhibit bone resorption and decrease bone turnover which may lead to an inability to repair micro damage within the bone. In humans, atypical femur fractures have been reported in patients on long term bisphosphonate therapy; however, a causal relationship has not been established. ADVERSE REACTIONS: The most common adverse reactions reported in the field study were clinical signs of discomfort or nervousness, colic and/or pawing. Other signs reported were lip licking, yawning, head shaking, injection site swelling, and hives/pruritus.
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As with all drugs, side effects may occur. In field studies, the most common side effects reported were signs of discomfort or nervousness, colic, and/or pawing. OSPHOS should not be used in pregnant or lactating mares, or mares intended for breeding. Use of OSPHOS in patients with conditions affecting renal function or mineral or electrolyte homeostasis is not recommended. Refer to the prescribing information for complete details or visit www.dechra-us.com. CAUTION: Federal law restricts this drug to use by or on the order of licensed veterinarian. * Freedom of Information Summary, Original New Animal Drug Application, NADA 141-427, for OSPHOS. April 28, 2014.
Distributed by: Dechra Veterinary Products 7015 College Boulevard, Suite 525 Overland Park, KS 66211 866-933-2472 Š 2015 Dechra Ltd. OSPHOS is a registered trademark of Dechra Ltd. All rights reserved. NADA 141-427, Approved by FDA
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OR YOU COULD JUST USE WEST NILE-INNOVATOR® Mosquitoes may be small, but as transmitters of West Nile virus, they can cause big problems for your horse. Talk with your veterinarian about WEST NILE-INNOVATOR®, the West Nile vaccine that has helped protect more horses than any other.1 1 Data on file, sales report data from 2001 through October 2012, Zoetis Inc. All trademarks are the property of Zoetis, Inc., its affiliates and/or its licensors. ©2013 Zoetis Inc. All rights reserved. EQB13005
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The President's Line Corey Miller, DVM, MS, Diplomate ACT - FAEP President
The first half of 2015 has been very productive for the FAEP. In Tallahassee, our legislative efforts during the Florida Legislative Session paid off for our veterinary community as priority legislation introduced in the legislature on our behalf was passed and signed into law by Governor Scott on June 20, 2015. The law, “Practice of Pharmacy (HB1049),” became effective on July 1, 2015. By its passage, Florida veterinarians are allowed to administer compounded medications and dispense the same to their patients, owners and caretakers. This bill trumps a Board of Pharmacy rule that was enacted June 2014, which had inadvertently restricted veterinarians from dispensing compounded drugs. The passage of HB 1049 was a significant legislative victory for our membership and the veterinary medical profession in Florida. This legislative effort was not without cost and was partially funded with your membership dues. At mid-year, we are making final preparations to host the 11th Annual Promoting Excellence Symposium (PES), which is scheduled for October 15 through 18, 2015 in Naples, FL. I hope you are planning to join us for an exceptional program themed, “Insights into Optimizing Equine Athletic Performance.” I encourage you to register early and take advantage of our early bird registration discount, as well as secure your place in the Biomechanics and Ultrasound Wet Lab, which will be instructed by foremost equine musculoskeletal system anatomist, Professor Jean-Marie Denoix. PES this year provides 48 hours of CE and also includes a rehabilitation track which is open to veterinarians and rehabilitation professionals, as well as sessions in dispensing legend drugs and laws and rules for Florida licensed veterinarians, as required for Florida license renewal next year. You may wish to participate in PES special activities such as the fishing and golf tournaments, and the FAEP Charitable Gala. All these activities have limited availability, and it is important that you register early to participate. Our 2015 calendar also includes an event on August 22nd that we always enjoy. Student Appreciation Day is held semi-annually in Ocala. This is a collaboration of FAEP members and three private veterinary practices to provide hands-on experience for UF veterinary students who have an equine interest. We take pride in being able to offer this kind of support to our students. We are also well underway with planning next year’s CE offerings. You will soon begin to hear from us about the Ocala Equine Conference in January 2016, our Equine Foot Symposium scheduled for June 2016, and PES 2016. Next year is also a license renewal year, and Florida licensed veterinarians need to secure their required CE by May 31, 2016. As always, please feel free to contact anyone on the FVMA staff or FAEP Council with your questions or suggestions. We are proud to serve in a leadership capacity in YOUR association. Have a GREAT summer!
Corey
• EXECUTIVE COUNCIL •
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Suzan C. Oakley, DVM, MS, Diplomate ABVP(Equine), Cert. ISELP FAEP COUNCIL PAST PRESIDENT oakleyequine@gmail.com
Anne L. Moretta, VMD, MS marochel@aol.com
Mr. Philip J. Hinkle EXECUTIVE DIRECTOR phinkle@fvma.org
Armon Blair, DVM abeqdoc@aol.com
•
•
Adam Cayot, DVM adamcayot@hotmail.com
Amanda M. House, DVM, Diplomate ACVIM REPRESENTATIVE TO FVMA EXECUTIVE BOARD housea@ufl.edu
Liane D. Puccia, DVM pucciavet@aol.com
Ruth-Anne Richter, BSc (Hon), DVM, MS rrichter@surgi-carecenter.com
Jacqueline S. Shellow, DVM, MS docshellow@bellsouth.net
STOP LOVING their horse to DEATH
HELP YOUR CLIENTS
“Food is not love, especially when a horse is prone to EMS. Metabarol is quite useful in managing these horses.” —Dr. Peter Morresey, Rood & Riddle Equine Hospital, Lexington, KY
To aid these horses: Metabarol is proven to reduce insulin levels in EMS horses. Simple, daily dosing may reduce the risk of grass foundering when combined with proper diet and exercise. Metabarol contains Resveratrol, the healthy ingredient in red wine. The product is scientifically formulated to improve the health of obese and insulin resistant horses, which are prone to foundering.
Order online and get copies of “Signs of EMS” for your clients at Equitthrive.com or call 866.721.1412 Lagouge et al.2006. Cell 27: 1109-1122 Adams, A. A. (2013). Abstract Title. Journal of Equine Veterinary Science. Abstracts. 33 (321-399). pg. 343. EQT 5588-13
GETTING STARTED on the RIGHT FOOT TRACY A. TURNER | DVM, MS, DACVS, DACVSMR * Images Courtesy of Dr. Steve O'Grady
Introduction “No foot, no horse” is a common phrase indicating the importance of the hoof to the mature equine athlete. But it is decisions and management concerning feet and limbs during the first 2 years of life that produce a strong foundation for the animal’s future athletic career. Unfortunately, not all recognize the importance and influence of hoof care during this period as affecting the horse’s longterm future. This manuscript will focus on routine farriery in young horses and those limb deformities that can be addressed through farriery.
Evaluating the Hoof Good record keeping is important. Records are designed for the individual needs of the farm/owner and should reflect the physical appearance of a foal's feet and limbs at birth and any subtle changes that occur during development, on at least a monthly basis. Digital images (pictures and radiographs) can be taken and added to the foal's record. Pictures are very helpful in determining changes in the foal’s feet/limbs. Foals should always be observed walking each time they are trimmed. The author prefers to observe the foal walking before the feet and limbs are examined. Watching the young foal walk can be challenging as it seldom walks in a straight line. This can be remedied by walking the mare along a fence or wall and letting the foal walk alongside or follow the mare. The foal is observed as it walks toward and away from the examiner. Here the foal is evaluated for any lameness that may be present, the pattern of the foot flight, how the foot breaks over at the toe and how the foot contacts the ground. When examining the feet and limbs from the front, it is useful to use imaginary lines through the bones. This way, it is easy to see if, and/or where an angular limb deformity exists. However, one must be careful to note the presence of a rotational deformity. In these cases, both carpi are rotated outward, leading to a toe out or splay‐footed conformation, yet axial alignment of the limb forms a straight line. The coronary band is observed to see if it is level or parallel with the ground. Examining the feet and limbs from the side should note whether the carpus is flexed or hyperextended. The hoof‐pastern axis is evaluated to determine if it is aligned and not broken forward (flexural deformity) or broken backward (flexor flaccidity). Any swellings along the limb or involving the physis are noted and recorded. Each deformity is noted and should be scored on a scale of 1‐5; grade one being mild, while grade five is severe. Finally, the foot is evaluated off the ground, observing its position relative to the bones of the digit, symmetry of the foot, and the integrity of the horny structures of the foot. The above examination enables the examiner to evaluate the feet, limbs and movement in a systematic manner.
6 The Practitioner
Trimming the Foal:
Birth to One Month. At birth, the foal's hoof is enveloped in a gelatinous perioplic membrane which reduces the risk of trauma to the mare's reproductive tract during birth. Shortly after birth, with the first steps of life, the perioplic membrane on the solar surface of the foot wears and retracts proximally on the hoof wall and dries out. The foal's foot will be tapered, being wider at the coronet and becoming narrower distally at the ground surface. A foal's foot does not only grow in a distal direction, it also expands. As the foal's feet are tapered, expansion occurs proximally, and as the ground surface of the distal hoof is relatively small, the weight‐ bearing area is positioned dorsally. Exercise and trimming will enlarge the area on the ground surface of the foot and move it in a palmar/plantar direction. The pointed or tapered appearance will gradually disappear in the first few months of life. In foals with acceptable limb conformation, there is little need for trimming during the first month of life. One Month. Foals should be presented to the farrier at one month of age for routine trimming. All that will generally be necessary at this time is to square or roll the toe of the hoof to encourage the foal to break over in the center of the foot. At this age, due to the pointed toe, the foal may break over to either the outside or inside of the toe. This first farrier examination will also allow the foal to get used to having its feet handled. The farrier should be patient and the trimming procedure should be performed as gently and efficiently as possible. Two to Six Months. In the first few months of life, attention should be directed toward the structural integrity of the foot (foot mass) rather than to cosmetics. The important issues here are to promote the growth of thick, durable hoof wall, to ensure maximum sole depth in order to protect the vulnerable sole wall junction and developing distal phalanx, and to develop the structures in the palmar/plantar section of the foot. The structural mass of foot, defined as a strong hoof wall, adequate sole depth and a solid heel base, is vital for future soundness. It is the opinion of many authors that a hoof pick, wire brush and a rasp are the only tools necessary to trim foals that are kept on a monthly schedule. The goal is not to have the foal walk entirely on the hoof wall, but to load all the structures on the bottom of the foot. This makes the foot load sharing. Foals that are trimmed frequently and have a lot of horn removed tend to develop weak fragile hoof walls. Dr. Steve O’Grady has described an excellent technique for trimming these foals. Dirt and debris is removed from the foot using a hoof pick. The bottom of the foot is then cleaned vigorously using a wire brush to remove any loose exfoliating horn. Otherwise, the ground surface of the foot and the frog are left untouched. This affords the foal ample protection on the ground surface of the foot. Exfoliating horn from the sole will be continuously shed through an abrasive mechanism with Issue 2 • 2015
the ground as the foal exercises. The sole in the foot of a foal is extremely thin and as much protection as possible is necessary to protect the immature developing structures above. Removing excess sole with a hoof knife is a primary cause of sole bruising in foals and often leads to flexural deformities as a result of the pain response. The health of the foot throughout the animal's life is based on a good, solid heel area. The heel base includes the hoof wall at the heel, the bars and a nice wide frog. The bars are needed to stabilize the hoof capsule and are never removed. The heels are rasped gently from side to side until the rasp just comes in contact with the frog. The hoof wall at the heels will now be on the same plane with the frog. The excess hoof wall at the toe and quarters is then lowered as necessary, using a rasp placed at a 90° angle, just in front of the sole wall junction (white line). When the desired amount of hoof wall is removed, the outer sharp edge of the angle is removed *Figure 1a by running the rasp around the perimeter of the hoof, thus creating a nice rounded edge (Figure 1a). This will help to prevent cracks and chips in the hoof wall. The method of using the rasp on an angle leaves the hoof wall and the adjacent sole on the same plane, allowing both structures to share the bulk of the weight when the animal moves (Figure 1b). This appears to stimulate the horn to grow thicker and stronger. Foals do not grow an *Figure 1b excessive amount of hoof wall in the first few months of life and our ability to influence the foot/limb by excessive trimming on one side of the foot in the horizontal plane is limited. If it becomes necessary to lower one side of the foot past the point of being level due to a developing hoof capsule distortion or to affect landing, it should not be any more than 2‐3 millimeters at one time. Trimming at two‐week intervals may be useful in this situation. The traditional theory of lowering the lateral side of the foot on a foal that stands toed‐out and lowering the medial side of the foot on a toed‐in foal is inaccurate. In fact, it is more likely to be harmful than beneficial. The cause of the foal having a toe‐in or toe‐out stance is rarely in the foot. The problem is generally found in the axial alignment of the limb above the foot; therefore, when one side of the foot is lowered excessively, the www.faep.net
cosmetic appearance may be improved, but over time, will lead to distortion of the hoof capsule. Or worse, this practice will place stresses on the physis and overload the joints on the side that is being lowered. This can be shown radiographically a few days after trimming. This can lead to axial skeleton issues later in life. Rotational limb deformities. Rotational deformities are very common in foals. Most are due to the narrow chest together with the relatively long limbs which cause many foals to adopt a base‐wide stance in front, which is often accompanied by outward rotation of the entire limb. As the foal moves, the outside of the hoof wall of the foot contacts the ground first as a result of the foot flight pattern caused by the rotated position of the limb. These foals should be trimmed level and not have their feet lowered on the outside wall. If attempts are made to "correct" this physiologic stance by lowering the lateral wall, there is a risk of creating an angular limb deformity where none existed previously. Therapeutic trimming does not offer favorable results in the rotationally malpositioned limb, as this deformity is corrected through growth. As the musculature of the chest increases, the elbows are pushed outward, rotating the limbs inward. Angular limb deformities. Angular limb deformities are common limb abnormalities in foals that require early recognition and treatment.1,2,4 The primary lesion is an imbalance of physeal growth; for various reasons, growth proceeds faster on one side of the physis. Angular limb deformities can be further classified based on the direction of the deviation. Valgus deformities occur when the deviation occurs lateral to the axis of the limb, and varus deformities occur when the deviation is medial to the axis of the limb. The most common location of valgus angular limb deformity is the carpus, while varus deformities are most often seen at the fetlock. Mild carpal valgus deviations of 2‐5 degrees are considered acceptable. However, deviations exceeding 5‐8 degrees become a concern and should be monitored (Figure 2a). Radiographs should be part of the physical examination in a foal with an angular limb deformity. Occasionally, osseous abnormalities such as hypoplastic carpal bones will preclude correction of the problem without splints or a cast. Radiographs will also reveal the site and *Figure 2a degree of deviation, and allow comparison at a later date. Conservative therapy for the management of many angular limb deformities may be successful in the newborn foal. A few days of stall confinement on firm bedding or limited exercise in a small paddock (2‐3 times a day) is a rewarding, cost‐effective treatment for the early carpal valgus. This allows the physis to be stimulated, but prevents stress and compression on the affected side of the growth plate. If the The Practitioner 7
knee can be corrected by applying pressure with one hand on the inside of the knee and counter pressure with the other hand applied to the outside of the fetlock, then a splint made from polyvinylchloride (PVC) pipe fitted from the elbow to the fetlock applied for a few hours daily may be useful. A full‐length bandage is applied to the limb first, and then the PVC pipe is placed on the outside of the limb and secured with a bandage. This will distract the carpus laterally. The splint is often the most cost‐effective treatment available, but must be applied with caution. Mild to moderate valgus will generally respond to restricted exercise and the use of a composite extension applied to the medial side of the foot, while the more severe cases require surgical intervention combined with farriery. The extension on the medial side and toward the heels redirects the forces on the physis on the overloaded side of the limb by moving the plane of weight bearing toward the *Figure 2b midline (Figure 2b).3 The extension also promotes centerline breakover. The extension can be made from any number of materials. The material is applied directly to the foot and shaped to the desired width. It is trimmed like normal hoof as the foot grows distally, or additional applications can be applied if necessary. In severe cases of carpal valgus where surgery is necessary, a medial extension is combined with the surgery. Carpal valgus angular limb deformities respond well to surgery. Intervention up to four months of age has an excellent prognosis for full correction. After four months, the prognosis is dependent on the severity of the deformity and the age of the horse when correction is attempted. Varus deformities usually involve the fetlock in either the front or hind limb of foals. This deformity can be congenital or acquired within the first few weeks of life. A varus fetlock deformity requires early detection and treatment, as functional closure of the distal physis of the third metatarsal/metacarpal bone is approximately twelve weeks of age. Foals with fetlock varus should have their exercise restricted and will generally respond to an extension applied to the lateral side of foot. The window of opportunity for treatment is small and the extension should be applied at 2‐3 weeks of age. Caution must be used because the exothermic reaction of the extension materials could damage the sensitive tissues of the young foal. In severe cases, surgical intervention will be necessary, combined with an extension. If the foal is presented for treatment after thirty days of age, treatment becomes difficult and less effective. Flaccid tendons, tendon laxity. Flexor tendon flaccidity is a relatively common limb deformity seen in newborn foals usually involving the hind limbs, but may affect all four limbs (Figure 3a). This condition is thought to be the cause of digital hyperextension, where weight‐bearing is on the palmar/plantar aspect of the phalanges and the toe of the hoof is raised off the ground. The 8 The Practitioner
condition often tends to selfcorrect within days after birth as the foal gains strength and is allowed moderate exercise. However the tendon laxity can persist. It is not uncommon to see a foal that still has digital hyperextension at 4 weeks of age. Treatment is *Figure 3a sequential depending on the severity of the tendon laxity and the response of the foal to treatment. Therapy is based on controlled exercise and therapeutic trimming plus shoeing (if necessary). The foal is allowed access to a small area with firm footing for one hour three times daily. The toe of the foot can be shortened and the *Figure 3b heels can be rasped gently from the middle of the foot palmarly/plantarly to create ground surface, and a palmar/plantar extension can be applied if necessary. This extension which extends approximately 3‐4 centimeters behind the bulbs of the heels immediately relieves the laxity (Figure 3b). There are several different shoes that have appropriate extension that can be used. Although some apply these with adhesives, many believe that in these young foals shoes should only be taped on. It is believed that the heat generated by composites as they cure may damage the sensitive tissues of the hoof in foals less than 3 weeks of age. Regardless of the method of application, the extensions should be changed at 10‐day intervals. Bandaging the limb is contraindicated as this will cause further laxity of the tendons. Flexural deformities. Flexural deformities have been traditionally referred to as "contracted tendons." But this is a misnomer, as the primary defect is a shortening of the musculotendonous unit, not a contraction of the tendon portion, making "flexural deformity" the preferred term.1,4 This shortening produces a unit of functional length less than necessary for normal limb alignment of the digit, resulting in fixed flexion of the various joints of the distal limb, especially the distal interphalangeal joint. Congenital flexure deformities are thought to result from intrauterine positioning, genetics, nutritional management of the mare during gestation and the influenza virus, but no causes have been proven. These deformities involve a combination of joints in the distal limb causing the foal to assume a "ballerina" stance with weight‐bearing on the toes. Congenital flexure Issue 2 • 2015
deformities usually resolve in the first few days of life. The best therapy is repeated intervals of brief exercise in a small paddock, physical therapy and full limb bandages to relax the muscles in the forearm. If limited or no improvement is noted by 3 days post foaling, 3‐5 gms of oxytetracycline is administered intravenously.5 It is repeated a second time after skipping a day if necessary. Toe extensions made from wood or aluminum taped on the feet may be useful. Acquired f lexural deformities occur during the first four months of life and generally involve the distal interphalangeal joint (Figure 4). These deformities are thought to be part of the developmental orthopedic disease (DOD) complex; however, pain initiating the pain withdrawal reflex is an important aspect of this condition. Any discomfort in the foot or lower limb *Figure 4 will initiate the flexor withdrawal reflex which causes flexor muscle contraction and altered position of a joint. Feet trimmed too short with excess sole removed causing toe bruising is a common cause of acquired flexure deformities. The first clinical sign one may see during routine trimming is abnormal wear of the hoof wall at the toe. A closer look may reveal heat in the feet, increased digital pulse, pain on hoof testers, a prominent coronary band and an upright hoof/ pastern angle. Conservative treatment consisting of restricted exercise to decrease continued trauma, the judicious use of anti‐ inflammatory drugs to relieve pain, and the administration of oxytetracycline which will cause muscle relaxation, can help restore the normal footpastern alignment. Therapeutic trimming consisting of lowering the heels gently with a rasp and a composite toe extension can be applied to the dorsal hoof wall and the composite can be extended over the solar surface of the foot to protect that area from further bruising (Figure 5).3 The toe extension should act as an extension of the foot and it should place continuous tension on the musculotendonous unit. If this condition is allowed to persist, it will result in irreversible changes in the foot and joint capsule, requiring surgical intervention. *Figure 5 If the acquired flexural deformity shows a marked broken forward hoof‐pastern axis and the heels of the foot are raised off the ground and unable to bear weight, the hooves should be radiographed. If the radiograph reveals a flexural deformity involving the distal interphalangeal joint with a significant broken forward hoof‐ pastern axis signifying a shortening in the musculotendonous unit, surgical intervention in the form of an inferior check ligament desmotomy should be performed. This is combined www.faep.net
with lowering the heels of the foot from the widest part of the foot palmarly, and applying a composite toe extension. A more complex deformity is the metacarpophalangeal flexural deformity seen as knuckling forward at the fetlock. Once thought to be shortening of the superficial digital musculotendinous unit, it is now known that the deep digital is also affected; occasionally, the suspensory ligament and metacarpophalangeal joint capsule are involved. Traditional and present day farriery treatment is to shoe with a raised heel and toe extension.6 The raised heel reduces tension on the flexor tendons (allowing the fetlock to descend), and the toe extension is to prevent further knuckling. It is the author’s opinion that this therapy should be initiated as soon as possible. In addition, restricted exercise to decrease continued trauma, and the judicious use of anti‐inflammatory drugs to relieve pain, are essential parts of treatment. If this therapy fails, surgery will be necessary. Unfortunately, surgery for this condition is much less successful than surgery for distal interphalangeal flexure deformity.
References: 1.
2.
3.
4. 5.
6. 7.
Greet, T. R. C., Managing Flexural and Angular Limb Deformities: The Newmarket Perspective. In Proceedings. Amer. Assoc of Equine Pract 2000; 46: 130‐136. Foot management in the foal and weanling. Greet, T. R. C., Curtis, S. J. In O'Grady, S.E., ed. The veterinary clinics of North America, vol. 19:2. Philadelphia: W.B. Saunders, 2003; 501‐517. Hoof repair and glue‐on shoe technology. Cheramie, H. S., O'Grady, S. E. In O'Grady, S.E., ed. The veterinary clinics of North America, vol. 19:2. Philadelphia: W.B. Saunders, 2003; 519‐530. Hunt, R. J., Management of Angular Limb Deformities. In Proceedings. Amer. Assoc of Equine Pract 2000; 46: 128‐129. Madison, J.B., Garber, J. L., Rice, B., et al., Effects of oxytetracycline on metacarpophalangeal and distal interphalangeal joint angles in new born foals. J Am Vet Med Assoc 1994; 204: 240249. O’Grady, S.E., Farriery for the Young Horse. In Proceedings. Amer. Assoc of Equine Pract Focus Meeting 2008. Curtis, S., Farriery for the Young Horse: Flexural Deformities. In Proceedings. World Equine Vet Assn 2011, 12:1‐8.
Tracy A. Turner, DVM, MS, DACVS, DACVSMR Dr. Tracy Turner received his DVM degree from Colorado State University in 1978, and interned at the University of Georgia. He completed a surgical residency and Master's degree at Purdue University. He has served on the faculties of the University of Illinois, University of Florida and the University of Minnesota. He joined Anoka Equine Clinic, Elk River, MN in 2004, where he practices in sports medicine, lameness and surgery. Dr. Turner's primary area of research interests has focused on equine lameness with particular interest in equine podiatry and thermography. He has spoken nationally and internationally on lameness topics. He has written over 100 peer reviewed manuscripts, over 250 non peer reviewed papers, and over 30 book chapters on equine lameness, podiatry and thermography. He is board certified by the American College of Veterinary Surgeons and the American College of Veterinary Sports Medicine and Rehabilitation. He is a Fellow of the American Association of Thermology.
The Practitioner 9
biosecurity in the equine practice NICOLA PUSTERLA | PHD, DACVIM
Introduction Application of the concepts of biosecurity and biocontainment is important not only in veterinary hospitals, but also for ambulatory practices, equine breeding facilities, training facilities, and other facilities that house horse populations. A passive attitude towards infection control may have detrimental consequences, including a large financial impact. Outbreaks at equine veterinary hospitals are often associated with public relations issues, such as loss of confidence and business of those who would bring their animals to the premise. Further, some contagious diseases can lead to severe disease with possible death in infected animals. This may potentially lead to litigation issues. Last but not least, outbreaks diminish morale of hospital staff and clinicians.
Basic Principles of Biosecurity Properly implemented biosecurity measures may significantly decrease the risks for disease introduction and spread of infectious pathogens. Infectious disease control relies on several basic principles, which include understanding the biology of infectious pathogens and route of pathogen transmission, housing horses based on exposure risk, daily monitoring for signs associated with infectious diseases, implementing proper hygiene and cleanliness protocols, educating the horse community and having a contingency plan in place in case of an outbreak. Most of these steps will prevent and minimize exposure to infectious pathogens at an individual and population level. Farm-based infectious disease control measures should include the segregation of horses into small groups based on age, use, and gestational time. This measure may not eliminate infectious diseases in horses, but hopefully, may limit the severity of the problem by minimizing the number of affected animals. Housing at boarding facilities or horse event may represent a true challenge due to the high traffic and horse density. However, in order to minimize the risk of disease outbreak, each horse should be considered at risk and handled like a single unit. Ideally, such horses should be kept in individual stalls with no direct contact to other horses. The health status of such horses needs to be assessed and possibly recorded daily. Further, reducing unnecessary movement of animals and humans is an effective way to minimize spread. If equipment (grooming, cleaning and tack equipment) is shared between horses, it should be cleaned and disinfected after every individual use. Specific housing measures apply to hospitalized patients. This means that all patients are to be screened before admission to the hospital for signs of contagious disease (physical examination and accurate history). Patients should be hospitalized in dedicated stalls/barns based on 10  The Practitionerâ€
their infectious status. Isolation wards should be available for patients with confirmed and/or suspected contagious diseases. It is important to maintain hygiene of personnel and facility so that hospitalized horses and their bodily fluids and excrements stay separated from other horses. It is important to monitor patients daily for the occurrence of infectious diseases through observation of clinical signs (fever, diarrhea, nasal discharge, coughing) and through strategic testing of biological samples. For example, feces may be collected for culture or PCR to detect Salmonella spp. in high-risk patients on admission and at regular intervals thereafter, during the entire hospitalization time. Even with well-established infectious control protocols, it may not be possible to virtually eliminate all risks of nosocomial infections. Probably one of the most underutilized principles of biosecurity is the daily monitoring of at-risk horses. The idea behind the assessment of daily health is to recognize early clinical signs and to take proper action to prevent disease spread. Daily monitoring by owners, trainers and caretakers should include the assessment of attitude, appetite and rectal temperature. Additional signs such as nasal discharge, coughing, changes in fecal character, and acute onset of neurological signs should also be recognized and reported to a health care provider. Of all the possible measures that can be taken to reduce nosocomial and zoonotic infections, hand hygiene is perhaps the most important and cost-effective, easiest to use, but also most underused measure. Hands should be washed before and after attending each individual animal. In addition to soap and Issue 2 • 2015
water, alcohol-based hand sanitizers can be a useful adjunct to hand washing in veterinary hospitals and can provide a practical option for improving hand hygiene for ambulatory practitioners. One additional means to prevent exposure to zoonotic pathogens and prevent transmission via contaminated hands and clothing is the use of personal protective equipment (PPE). Standard outerwear should be clean and should be changed if contamination occurs. Also, dedicated clothing and footwear should be worn when working with infectious patients and in high-risk areas such as intensive care unit, isolation, foaling facility, quarantined barns, etc. Minimal PPE, when working with infectious pathogens, should include designated scrubs/ coveralls/lab coats, disposable gloves and shoe covers/dedicated shoes/boots. Contamination of personal items such as stethoscope, thermometer, pencil, phone, pager, etc. occurs routinely when working with horses. In order to minimize transmission with infectious pathogens, one should strongly consider disinfecting all mentioned items if such items have been used while attending the patient. Virtually all pathogens in equine facilities are associated with some organic matter, including feces, urine, saliva and sweat. Experimentally, cleaning alone has been shown to decrease the bacterial load by 90% on a concrete surface. Another 6-7% of bacteria are killed by disinfectants. There is enough convincing evidence of the necessity to clean surfaces thoroughly before disinfection. Even the best disinfectants are less effective in the presence of organic matter. Housing stalls and trailers should be cleaned and disinfected between horses. Also, consider regular hosing and disinfection of aisles and high-traffic areas such as wash stalls and treatment/examination rooms. It is important to have a contingency plan in place on what to do when dealing with a potentially infectious animal. The plan should be known by all caretakers, trainers and owners at a boarding facility and by all staff and veterinarians at a veterinary hospital. Ideally, written protocols should be available and regularly reviewed and updated if needed. A logical action plan for a horse owner should include: general recommendations to what represents a trigger point (i.e. fever, acute onset of nasal
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discharge, coughing, ataxia, diarrhea); isolating a sick animal(s) in previously designated areas; designate a dedicated caretaker and equipment to attend the care of the sick horse; use of PPE when attending the sick horse; close or disinfect areas where the sick horse was housed or held; institute barrier nursing to prevent spread of infectious pathogens (foot bath, gloves, dedicated clothing and foot wear); contact the care provider to evaluate the horse and collect diagnostic samples; reduce overall traffic within the premise and monitor horses with possible contact to the index case.
Infection Control for Gastrointestinal Pathogens Horses are very vulnerable to infectious enteric disorders, especially salmonellosis and clostridial infections. Several factors, including stress, transportation, changes in feed, fasting, surgery, antimicrobial use, concurrent GI disturbances, and elevated ambient temperature, have been linked to an increased susceptibility to Salmonella enterica infection. Salmonellosis and/or clostridial infection should be considered when horses develop gastrointestinal signs (colic, diarrhea), fever and leukopenia. Further, the previous use of antimicrobials in patients developing any of the mentioned clinical signs is highly suggestive of an infectious gastrointestinal disorder. Outbreaks with enteric pathogens can be devastating in any situation (farm and hospital). To determine the magnitude of the outbreak, all horses or a representative sample of resident horses should be screened for enteric pathogens using conventional microbiology and/or PCR detection. Horses testing positive for an enteric pathogen (clinical or subclinical) should always be isolated from the rest of the population to decrease the exposure risk and environmental contamination. Establish barrier nursing in the form of footbath or mats in front of the isolation unit and each stall. This will minimize the spread of pathogens from stalls to clean areas. Phenolics compounds, quaternary ammonium compounds (QAC) and peroxygens compounds have been shown
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to retain activity in the presence of organic matter. Phenolics and peroxygen compounds are the only disinfectant to have an activity against rotavirus. Peroxygens and high concentration of bleach (8 oz/gallon) are effective at neutralizing clostridial spores. Phenols, QAC and bleach at 4 oz/gallon are effective against Salmonella. Caretakers and owners should wear gloves, protective clothing (coveralls, disposable gowns) and dedicated footwear. Good hand hygiene should be instituted (faucet with warm/cold water or hand sanitizer). It is very important to control traffic and minimize contact of affected horses with the general public. Remember that enteric pathogens such as Salmonella, Cryptosporidium and Clostridium difficile are potential zoonotic agents and represent a greater risk for immunocompromised humans, infants, and elderly people. Instruct caretakers/owners to handle diseased horses last and to use separate equipment (cleaning equipment, tractor, hay wagon, wheelbarrow, etc). Hygiene should be maximized by regular cleaning and disinfecting. Waste from positive animals should be either removed from the premise, or composted or spread in sunlight in a place with no direct access to horses.
Infection Control for Respiratory Pathogens During an outbreak of respiratory disease, aerosol and droplet infection can be minimized by separating animals according to their infection status (infected, exposed versus non-exposed). Air movement may play an important role in transmission of aerosolized virus, since viral respiratory pathogens such as equine influenza virus have been shown to be transmittable over a distance of 150 feet. The α-herpesviruses (EHV-1/-4) require closer contact and are generally transmitted via nose-to-nose contact or fomites. Transmission of Streptococcus equi subsps. equi usually
12 The Practitioner
requires direct physical contact between infected and susceptible horses but can also be transmitted via fomites (hands, shared equipment). Fortunately, outbreaks of respiratory pathogens can successfully be controlled via appropriate infectious disease control measures (separation of infected animals, cleanliness and hygiene, restricting movement and traffic, use of PPE and barrier nursing). Common infectious respiratory pathogens are susceptible to the majority of commercially available disinfectants.
Nicola Pusterla, DVM, PhD, DACVIM Dr. Nicola Pusterla graduated from the School of Veterinary Medicine at the University of Zurich, Switzerland in 1991, and worked in the private and academic sector with a focus in large animal internal medicine. He earned his PhD degree from the University of Zurich with an emphasis on vector-borne diseases. Dr. Pusterla joined the University of California, Davis in 1998, where he currently holds an appointment as professor in Equine Internal Medicine. Dr. Pusterla is also Chief of Large Animal Medicine Services at the William R. Pritchard Veterinary Medical Teaching Hospital. He is a Diplomate of the American College of Veterinary Internal Medicine with an equine emphasis, and he has ongoing interest in all aspects of equine internal medicine and dentistry. Dr. Pusterla’s research focuses on selected aspects of equine infectious diseases with an emphasis on epidemiology, clinical disease understanding, diagnostics, prevention, and treatment.
Issue 2 • 2015
EQUINE LYME DISEASE THOMAS J. DIVERS, DVM, DACVIM, DACVECC
Borrelia in Vitreous Fluid of Horse
Borrelia burgdorferi infection in horses is common in some areas of North America, yet the incidence of clinical disease has not been determined, which makes Lyme disease in the horse controversial. Progress is being made, case-by-case, in defining the several clinical presentations of Lyme disease in adult horses. Current serologic tests are sensitive and specific for detecting antibody but may not distinguish between previous or current infections since an antigen test is not used. Treatment protocols are available for Lyme disease in the horse, however, their ability to eliminate the organism, especially chronic infections, remains questionable. Currently, minocycline and doxycycline are the most commonly used antibiotics for presumed Lyme cases in horses. Oxytetracycline is considered to be a preferred treatment; likely due to higher tissue concentrations following intravenous administration. Vaccination, like many aspects of Lyme disease, remains controversial, although the canine-approved vaccines have the potential to prevent infection based upon vaccine studies in ponies and other animals. The mid-Atlantic and northeastern states have a high seroprevalence for Borrelia in the equine population, as do areas of Minnesota and Wisconsin and extending into southern Canada. Infected horses are also reported in some regions of California and are fairly common in central Virginia (certainly as far south as Charlottesville). The geographic areas with confirmed horse and human infections appear to be spreading. In one New England survey, 45% of horses had B. burgdorferi antibodies. A Wisconsin study found that 118 of 190 horses were serologically positive. Borrelia infections in the Southeastern U.S. are less common. Borrelia burgdorferi resides in the infected Ixodes sp. tick gastrointestinal tract and is transferred to the salivary gland and then into horses or other mammals during tick feeding. Generally, 24 +/- hours of attachment are required to transfer the organism successfully www.faep.netâ€
from the tick to the mammalian host. This time may be needed for the organism to down-regulate an outer membrane protein (OspA), a process that may be important to maintaining survival once in the mammalian host. Simultaneously, other outer surface proteins (e.g., OspC, OspE and OspF) that are normally in low concentration in the tick gastrointestinal tract are up-regulated. This is particularly true for OspC (upregulated in the tick salivary gland), which enhances complement resistance and other methods of immune evasion in the mammalian host. These changes in expression of surface proteins may be triggered by the blood meal. Other proteins found in a dominant invariable region of the variable major protein-like gene VisE, permit antigenic variation, ensuring survival in the host. B. burgdorferi may also survive in the host by residing in collagen and connective tissue, likely via low molecular weight decorinbinding proteins, and has no requirement for iron. Although not confirmed, female adult Ixodes ticks are believed to be most responsible for transmitting B. burgdorferi infection to horses. Several strains of B. burgdorferi are known to occur, and prior infection with one species may not provide protection against other strains. After experimental infection of ponies, the organism appears to reside mostly in skin near the tick bite, as well as in connective tissue and muscle and around nerves and blood vessels near synovial membranes. Persistent infection with B. burgdorferi has been very controversial in humans and most studies do not support chronic infection/chronic Lyme disease in properly treated human patients. However, a small number of scientific publications have provided evidence that both cysts (round bodies) and biofilm colonies exist and may cause chronic and difficult to treat infections. In infected horses, eliminating B. burgdorferi may be more difficult than in humans because of delayed recognition of infection in horses, and the
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markedly lower bioavailability of orally-administered doxycycline and minocycline in the horse, compared to humans. A wide variety of clinical signs have been attributed to B. burgdorferi infection in horses, but cause and effect have been difficult to document in most cases! Because of both the high prevalence of antibodies against B. burgdorferi in horses in some regions of the U.S. and the difficulty in proving clinical disease in most cases, Lyme disease has become the most controversial and possibly over-diagnosed equine disease in those areas. The clinical signs most often attributed to equine Lyme disease include stiffness and lameness generally in multiple limbs, muscle tenderness, hyperesthesia, lethargy, behavioral changes and signs suggestive of neurologic disease. Unlike with human Lyme disease, joint effusion has been minimal in most Lymesuspect horses. Muscle wasting and pain upon palpation of the topline have been present in a few horses with high serum titers and some of these horses have also had ataxia and paresis. In one report, two horses diagnosed with Lyme neuroborreliosis had chronic, necrosuppurative-to-nonsuppurative, perivascularto-diffuse meningoradiculoneuritis on necropsy examination. Hyperesthesia, lumbar pain and muscle wasting were the initial clinical findings followed by ataxia of all four limbs, facial nerve paralysis, and finally head tremors with depression in one horse. On necropsy, spirochetes were identified by Steiner silver impregnation in both cases, predominantly in the affected dura mater of brain and spinal cord. Borrelia burgdorferi was identified by polymerase chain reaction, with the highest spirochetal burdens in tissues with inflammation, including the spinal cord, muscle, and joint capsules. In another report, a horse with severe neck stiffness that progressed to ataxia had lymphohistiocytic meningitis and B. burgdorferi DNA in the cerebrospinal fluid (CSF). That horse originally responded to doxycycline treatment but relapsed after discontinuing the treatment. Another case was a Thoroughbred hunter that presented for lameness and ataxia and had lymphocytic pleocytosis and was PCR positive for B. burgdorferi on CSF analysis. The horse initially responded well to doxycycline but had some deterioration when treatment was discontinued. The author has examined three other suspect neuroborreliosis horses with ataxia and severe lymphocytic
or mixed cellular infiltration and thickening of the meninges. Based upon these few cases, it may be that ataxia and lumbar muscle wasting caused by lymphohistiocytic or neutrophilic meningitis and radiculoneuritis, with occasional fasciculations, cranial nerve dysfunction and neck stiffness, are common characteristics of neuroborreliosis in the horse. CSF would likely show a lymphocytic or mixed neutrophilic/lymphocytic or lymphocytic pleocytosis and, although uncommon in humans with neuroborreliosis, some horses have CSF that is PCR positive for B. burgdorferi. Bilateral uveitis has been reported in 2 horses associated with Borrelia burgdorferi infection of the eye. Borrelia burgdorferi was found on cytologic examination and confirmed by PCR in the vitreous in both horses. No organisms were observed in the aqueous although one aqueous sample was PCR positive. Borrelia burgdorferi was also observed with silver stain in the inflamed uveal tissue. In addition to the uveitis, a chronic, multifocal, lymphohistiocytic ganglioradiculitis and neuritis with presumptive neuronal degeneration in the spinal nerves was found in one of the horses with uveitis. Another report describes a horse with Lyme pseudolymphoma (multiple lymphohistiocytic cutaneous nodules). There was a complete resolution of signs following doxycycline treatment, as might be expected for a cutaneous form of borreliosis. The diagnosis of B. burgdorferi infection (but not clinical disease) can usually be determined by serology. Enzyme-linked immunosorbent assay (ELISA) and Western Blot testing are used as a two-step method for detection of antibodies in humans. The C6 SNAP test (IDEXX Laboratories, Westbrook, Maine), which is based on antibody to a peptide that reproduces the sequence of the invariable region 6 (an immunodominant, conserved region), has good correlation of results with whole cell or OspF ELISA results in horses; specificity of the C6 snap test may be better than sensitivity. Borrelia burgdorferi vaccination alone should not cause the C6 SNAP test to be positive. For canine Lyme testing, a quantitative C6 is available which is somewhat helpful in determining response to treatments in dogs but the quantitative test is specific for canine samples. A multiplex quantitative antibody bead test for OspA, OspC and OspF antibody detection is available for the serodiagnosis of equine B. burgdorferi infection. The interpretation concept is that high levels of OspA usually suggest vaccination, elevated OspC indicates recent infection (antibody against this antigen typically increases within a couple of weeks after infection and then becomes negative 3-5 months after the initial infection), and OspF elevations suggest either chronic infection or more long-lasting antibodies from a prior infection. Since the introduction of the multiplex assay, an increased number of unvaccinated horses have been found to be OspA antibody positive; importance of this is unknown, but a few horses with a rather solid diagnosis of Lyme disease have been seropositive for OspA and negative for OspC and OspF. Clinical diagnosis of Lyme disease is very difficult and should be based upon the following parameters: (1) Exposure to and infection with B. burgdorferi (i.e., geographic location and positive serologic testing which is present in most but not all cases), (2) Reasonable probability of the clinical signs being due to B. burgdorferi infection based upon knowledge of the most common anatomical locations for the organism to reside in the horse (synovial membranes, skin, meninges, nerves, and sometimes
Neuroborreliosis in a 10 TB Horse
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vitreous fluid), (3) Similarity to reported and confirmed clinical syndromes, (4) Laboratory testing of tissue or fluid by PCR and/ or histopathology (usually a lymphoplasmacytic, histiocytic or mixed monnuclear/neutrophilic inflammation), and (5) Most importantly ruling out other causes for the clinical signs! Diagnosis of neuroborreliosis should be based upon clinical signs such as ataxia, signs of peripheral neuropathy, cranial neuritis or radiculoneuritis, eg. muscle wasting, hyperesthesia, reluctance to hold the head up, cranial nerve dysfunction and uveitis, in addition to CSF pleocytosis ( 95% of humans with neuroborreliosis have a lymphocytic pleocytosis but in horses neutrophilic pleocytosis may be found); evidence of intrathecal production of antibodies to B. burgdorferi outer surface antigens and occasionally B. burgdorferi PCR positive CSF. The serum/CSF antibody ratio can be used to help determine intrathecal antibody production. This concept is similar to the commonly used EPM test where a serum to CSF antibody concentration (against surface proteins) ratio is both sensitive and specific for the disease. What is different for B. burgdorferi serum/CSF-ratio testing is that: the serum is diluted prior to testing in approximately the “normal ratio” of IgG in serum and CSF. I therefore, do not strongly consider a diagnosis of neuroborreliosis unless the CSF antibody against one or more OSP antigens is at least 2-fold more than serum values. It may be important diagnostically, if one of the Osp antigens has a markedly higher antibody ratio than do the others, as this would be further suggestive of intrathecal production of antibody against that particular antigen. It would be interesting to use the standard C6 snap test on CSF to see if that may be clinically useful. The most frequently used drugs for treatment of Lyme disease in horses are oxytetracycline (6.6 mg/kg q 12 or 8.4 mg/kg Q 24 intravenously) and doxycycline (10 mg/kg q 12 per os) or minocycline (4 mg/kg q12h per os). Minocycline has better oral bioavailability than doxycycline in the horse and it attains higher concentration in CSF and aqueous fluids because it is more lipophilic and less protein bound than doxycycline. Doxycycline and minocycline treatments for Lyme disease in horses may not have the same success as routinely reported in human Lyme treatment because of the relatively low bioavailability of both drugs in horses and the likelihood of more long-standing B. burgdorferi infections in horses than in humans prior to beginning treatment. Proper duration of treatment is unknown in horses but is commonly 1-2 months for doxycycline or minocycline. In experimentally infected ponies, oxytetracycline administered intravenously was superior to doxycycline (per os) in eliminating B. burgdorferi infection. The practical aspects of I.V. administration of Oxytetracycline and potential side effects (thrombophlebitis and renal failure) have prevented this from becoming a standard therapeutic treatment in equine practice. In our pony treatment study, ceftiofur at 2.2 mg/kg/ day I.M. for 28 days was moderately successful in eliminating the B. burgdorferi infection. In human Lyme disease, tetracyclines and beta lactams are the predominant antimicrobials used, and with excellent success. The use of metronidazole as treatment for possible cystic borreliosis currently lacks sufficient clinical information in either humans or domestic animals but could be a treatment option for chronic infections that do not respond to the more tradition treatments. Until more information is www.faep.net
available on actual incidence of clinical disease in the horse, treatment of asymptomatic but seropositive horses would seem highly questionable. Prevention of B. burgdorferi infection in horses has centered around avoiding tall grasses and other areas that ticks commonly reside, the use of preventative tick sprays and canine Lyme vaccines. Canine Lyme vaccines appear to be safe (based upon antidotal reports of hundreds of horses being vaccinated) and those that maintain high OspA antibody would be expected to provide protection against infection. Interestingly, natural infection is not believed to provide a high level of protection against re-infection possibly due to strain variation and the frequent lack of OspA antibody with natural infection. Dose and frequency of vaccination that have been empirically used are similar to what is suggested for dogs. Many horses appear to develop a good initial OspA antibody although the resulting antibody level is frequently of short duration. It is possible that subcutaneous or intradermal administration could better utilize dendritic cells and provide a better immune response and more prolonged protective antibody. Long term adverse but difficult to recognize effects from the vaccine are always possible as was implicated with the previously approved human vaccine. An OspA vaccine for humans was voluntarily withdrawn because of lack of sales; concerns over adverse effects were never proven. It is interesting, to me at least, that after litigations and a congressional hearing over possible adverse effects of the vaccine, one million dollars in legal fees was reportedly paid to the prosecuting lawyers, but no financial compensation was provided to the claimants who had been vaccinated.a Several canine-approved tick repellants are used in horses but dose, application sites and efficacy are unknown. An equine-approved permethrin and piperonyl butoxide product for tick prevention is available but I could not find published clinical studies on its efficacy in horses.
Footnote: a
Nigrovic LE, Thompson KM: The Lyme vaccine: a cautionary tale. Epidemiol Infect 135(1):1-6, 2007.
Additional Reading:
Brorson O, Brorson SH: An in vitro study of the susceptibility of mobile and cystic forms of Borrelia burgdorferi to metronidazole. Acta Pathol Microbiol Immunol Scand 107(6):566-576, 1999. Burgess EC: Borrelia burgdorferi infection in Wisconsin horses and cows. Ann NY Acad Sci 539:235-243, 1988. Chang YF, Novosol V, McDonough SP, Chang CF, Jacobson RH, Divers T, Quimby FW, Shin S, Lein DH.: Experimental infection of ponies with Borrelia burgdorferi by exposure to Ixodid ticks. Vet Pathol 37(1):6876, 2000. Chang Y, Novosol V, McDonough SP, Chang CF, Jacobson RH, Divers T, Quimby FW, Shin S, Lein DH: Vaccination against Lyme disease with recombinant Borrelia burgdorferi outer-surface protein A (rOspA) in horses. Vaccine 18(5-6)540-548, 1999. Chang YF, Ku YW, Chang CF, Chang CD, McDonough SP, Divers T, Pough M, Torres A: Antibiotic treatment of experimentally Borrelia burgdorferi-infected ponies. Vet Microbiol 107(3-4):285-294, 2005. DeVilbiss BA, Mohammed HO, Divers TJ: Perception of equine practitioners regarding the occurrence of selected equine neurologic diseases in the northeast over a 10-year period J Equine Vet Sci 29(4):237-246, 2009. Eugene D, Shapiro, MD: Lyme disease. N Engl J Med 370(18):1724-1731, 2014.
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Lantos PM Auwaerter PG, Wormser GP:. A systematic review of Borrelia burgdorferi morphologic variants does not support a role in chronic Lyme disease. Clin Infect Dis 58(5):663-671, 2014. Imai DM, Barr BC, Daft B, Bertone JJ, Feng S, Hodzic E, Johnston JM, Olsen KJ, Barthold SW: Lyme neuroborreliosis in 2 horses. Vet Pathol 48(6):1151-1157, 2011. Johnson AL, Divers TJ, Chang YF: Validation of an in-clinic enzyme-linked immunosorbent assay kit for diagnosis of Borrelia burgdorferi infection in horses. J Vet Diagn Invest 20(3):321-324, 2008. Magnarelli LA, Ijdo JW, Van Andel AE, Wu C, Padula SJ, Fikrig E: Serologic confirmation of Ehrlichia equi and Borrelia burgdorferi infections in horses from the northeastern United States. J Am Vet Med Assoc 217(7):1045-1050, 2000. Priest HL, Irby NL, Schlafer DH, Divers TJ, Wagner B, Glaser AL, Chang YF, Smith MC: Diagnosis of Borrelia-associated uveitis in two horses. Vet Ophthalmol 15(6):398-405, 2012. Sears KP, Divers TJ, Neff RT, Miller WH Jr, McDonough SP: A case of Borrelia-associated cutaneous pseudolymphoma in a horse. Vet Dermatol 23(2):153-156, 2011. Schnabel LV, Papicih MG, Divers TJ, Altier C, Aprea MS, McCarrel TM, Fortier LA: Pharmacokinetics and distribution of minocycline in mature horses after oral administration of multiple doses and comparison with minimum inhibitory concentrations. Equine Vet J; 44(4):453-8. 2012. Wagner B, Glaser A, Bartol J, Mahar O, Johnson A, Divers T: A new sensitive Lyme multiplex assay to confirm neuroborreliosis in horses: a case report. Proc Am Assoc Equine Practit 57:70-75, 2011.
Loading can trigger a lot more than fear.
Wagner B, Freer H, Rollins A Erb HN, Lu Z, Gröhn Y: Development of a multiplex assay for the detection of antibodies to Borrelia burgdorferi in horses and its validation using Bayesian and conventional statistical methods. Vet Immunol Immunopathol 144(3-4):374-381, 2011.
Thomas J. Divers, DVM, DACVIM, DACVECC Dr. Thomas J. Divers earned his DVM from the University of Georgia. He attended the University of California School of Veterinary Medicine for an internship in equine medicine, and returned to the University of Georgia for his residency in large animal internal medicine. Currently, Dr. Divers is a professor of medicine and chief of large animal medicine at the Cornell University College of Veterinary Medicine. He is a Diplomate of the American College of Veterinary Internal Medicine, and of the American College of Veterinary Emergency and Critical Care. Dr. Divers’ research interests include equine motor neuron disease, equine lyme disease, equine protozoal myelitis, and advances in internal medicine and critical care for horses or cows.
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The Practitioner 25
Update on
UFCVM’S ANIMAL TECHNICAL RESCUE IN FLORIDA
John Haven, UF CVM Director
As many veterinarians may know, after the terrible 2004 hurricane season, the FVMA, American Veterinary Medical Foundation, and others, contributed a lot to help the University of Florida College of Veterinary Medicine develop its “VETS Team” for disaster response. Combined with the Florida Veterinary Corps (which are private practitioners coordinated through the FVMA and who are willing to respond in disasters), the VETS Team gives the state considerable capability to deal with veterinary issues during disasters. What you may not realize though, is that beyond providing basic veterinary medical care with its “M*A*S*H” style team, performing infrastructure assessment, and assisting with logistical support to veterinary practices, the UF VETS team has developed a world-class animal technical rescue team with additional support from United States Equestrian Federation, American Association of Equine Practitioners, US Rider, Florida Quarter Horse Association, and others. A major overnight workshop was coordinated in Lee County in April 2013 where UF VETS, FL Vet Corps, FDACS, SARC, and federal partners totaling over 100 people participated. Haven is currently planning a similar activity for the Florida Panhandle for the spring of 2016. The team members have taken the internationally-renowned Technical Large Animal Emergency Rescue (TLAER) courses, and it partners with TLAER in putting on advanced programs here in Florida; even conducting a week-long training and assessment with USDA at Miami International Airport for the Import/Export Center in 2011. Unlike many teams in the country, the core members have gone on and received advanced training in human technical rescue, having completed technician-level training in confined space, swift-water, and instructor certification in high-angle technical rescue. These advanced skills allow the UF team to respond to a variety of rescues with and without the assistance of local fire rescue. The team provides 24/7/365 animal technical rescue support within 2 hours of Gainesville. The team also is enabled to provide a series of ‘wet labs’ for DVM students in the fall semester on animal technical rescue, with the hope that they will become a resource in their communities after graduation. A local veterinarian providing sedation during a rescue and managing injuries is essential, and most agencies don’t have one on staff they can call. As an added incentive for those students completing all the labs, a day of repelling at Ben Hill Griffin Stadium is included. Because of the combined human and animal technical rescue knowledge, John Haven, the team leader and CVM College Director, was asked to join the National Fire Protection Association committee for search and technical rescue (Committee standard 1670), to co-chair the development of a first chapter on animal technical rescue, for both livestock and 26 The Practitioner
Issue 2 • 2015
household pets. He worked with subject matter experts from around the world for over a year to complete the draft, and the new national standard was published in December 2013. The new national standard is significant because without standards, training was inconsistent. First responder agencies were not allowed to use their training dollars to obtain animal technical rescue training. Without proper training, some agencies would refuse livestock calls, only to then have to respond to rescue the general public who tried the rescue anyway. In some cases, responders have been injured using unsafe rescue methods when finding themselves under pressure to do something. At the same time Haven began working on engaging the fire rescue community and the need for standards, he recognized Florida’s need for a training program, and trained teams around the state to perform animal technical rescue. The state veterinarian’s office supported the needs from local emergency management to establish a network across the state. A plan to use federal grant funds to acquire caches of equipment to station around the state in strategic locations, and to design an approved course of training was developed. While the state veterinarian’s office purchased the equipment Haven specified, which included “A” frame cranes, rescue glides, mud rescue gear, harnesses, etc., he partnered with UF’s Institute of Food and Agricultural Sciences (IFAS)’s education team, to develop the only Department of Homeland Security Operations Level Animal Technical Rescue Course. The significance of the operations-level class is that students perform a complete rescue unassisted, as part of a ‘capstone’ learning experience, demonstrating they are operationally ready to respond. Grant funds have been obtained to provide training around the state. There are now seven state-supported teams in Florida, and Haven is in the process of providing a two-year refresher training to the existing agencies. Host agencies for the caches of equipment are: Walton County Sheriff’s Office, Gadsden County Sheriff’s Office, St John’s County Fire Rescue, Volusia County Fire Rescue, Polk County Sheriff’s Office, Martin County Fire Rescue, and Lee County Sheriff’s Office. While these are the host counties, members of fire, animal control, sheriff, city police, and county extension, and private DVMs from surrounding counties have been involved in the trainings, developing a true regional and multi-agency response capability. The Lee County team is a great example of 5 counties training together on a regular basis, working together on calls, and in the past two years, having completed over a dozen successful rescues of livestock. There are additional large animal technical rescue sources at Wellington Fire Rescue, Southwest Ranches Fire Rescue, and Miami-Dade Fire Rescue (two caches). Essentially
anywhere in the state, there is now a cache of equipment, and team, within two hours response. The UF VETS Team has been involved in several high risk, high reward technical rescues since developing its technical rescue skills in support of local emergency management. Some of the more notable include the dog “Joe” extraction from a 50 ft. hole during a night rescue, the horse “Midnight” from the Paynes Prairie mud flat on a Christmas Eve, and two cows in water at the bottom of a 35 ft. sink hole in Levy County. The team has also provided “Smartphone Rescue Assistance” to teams that have arrived on site, sent a picture of the situation, and called for a quick consult to ensure their plan is solid. Never wanting to be complacent in disaster response planning and training, Haven completed “Animal Technical Rescue 2.0” the first re-write of the animal technical rescue course since its inception in 2011 – completely embedding the new National Fire Protection Association standard material, including both large and small animal technical rescue. Recognizing the comprehensive nature of the course, other veterinary colleges have contacted UF about credentialing a team of instructors at other schools to provide the course. In October 2014, Haven instituted a “train the trainer” program at Texas A & M, which credentialed them to use the UF developed animal technical rescue course. Additionally, UF CVM has developed a ‘turnkey cache’ of equipment that local governments can purchase, and UF will configure the kit for them. For those wanting to know more about the VETS Team, or animal technical rescue, Haven can be contacted at havenj@ufl. edu or his office at 352-294-4254. John Haven MAcc, CPA Mr. John Haven is Director, Disaster Response Programs at the University of Florida College of Veterinary Medicine. Mr. Haven’s disaster response interest stems from his Air Force experience as part of a human air transportable hospital, and from being a volunteer firefighter. After leading the college’s responses to Hurricanes Charlie, Frances, and Jeanne, he organized a formal veterinary emergency response team consisting of faculty, staff, and students, “VETS,” and raised funds for equipment and training. The team has since responded to Hurricane Wilma, the Buggaboo Wildfires, and an equine herpes disease outbreak. In September 2007, he helped to launch Vet Corps, which is the statewide reserve corps of veterinarians and technicians. Both programs are partnerships between the college, the state veterinarian’s office, and the Florida Veterinary Medical Association. Mr. Haven helped to create the National Alliance of State Animal and Agricultural Emergency Programs. His experience in disaster response includes being part of the general and command staffs.
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The Practitioner 27
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