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• Research Fund Awards $410,000 to Three Equine Research Projects at Western College of Veterinary Medicine
• Second Edition of Informational Booklet on NAIS and Horses Released
• Outbreaks of Equine Herpes Virus Occurring Across the Nation
• Equine Infectious Disease Book Available for Veterinarians and Horse Owners
• Reports of Lyme Disease Increasing in Vermont
• Eastern and Forest Tent Caterpillars Currently Feeding; Timing Right for Horse Farms to Implement Control Strategies

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Research Fund Awards $410,000 to Three Equine Research Projects at Western College of Veterinary Medicine 

The Heather Ryan and L. David Dubé Veterinary Health and Research Fund has awarded $410,000 for three cutting-edge research investigations of equine endotoxemia, neonatal Rhodococcus equi pneumonia, and genetic ocular disorders at the University of Saskatchewan's Western College of Veterinary Medicine (WCVM).

“All three research projects will be conducted by multi-disciplinary teams of scientists from WCVM, the University of Saskatchewan, and other research institutions across North America,” says Dr. Norman Rawlings, the veterinary college's associate dean of research. “Each collaborative team brings a great deal of clinical and laboratory expertise to the table, and we're very excited about their potential for making real, concrete progress in overcoming these long-standing issues in horse health.”

These are the first research projects to receive financial support from the new research fund that was created in August 2006 when the Heather Ryan and L. David Dubé Foundation contributed $1.07 million to WCVM's equine and companion animal health programs. Based on the donors' wishes, the college will use $750,000 of the contribution toward large-scale, WCVM-based equine research projects over the next 5 years.

Rawlings says all submitted grants underwent a stringent review process that was conducted by three prominent Canadian veterinary scientists. The grant review committee specifically considered the scientific merit of each grant proposal, the collective expertise of each research team, and the potential impact for each project to improve horse health care in Canada and around the world.

For more detailed information about each research project, please visit www.ehrf.usask.ca (click “News”).

In addition to their initial $1.07 million gift, Ryan and Dubé have pledged to “match” any new money contributed to the fund that they created for major equine research projects at WCVM or any increased amounts in contributions to the college's Equine Health Research Fund. The donors' foundation will annually contribute up to $100,000 in matching funds— providing WCVM with the opportunity to potentially raise $1 million for its equine health research programs by 2011. Visit www.ehrf.usask.ca for further details.

WCVM (www.wcvm.com) is a Canadian center for veterinary education, expertise, and research located on the University of Saskatchewan campus in Saskatoon, Saskatchewan. Nearly 400 undergraduate and graduate students are enrolled at the college that annually attracts more than $5 million in research funding from public and private sources.

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Second Edition of Informational Booklet on NAIS and Horses Released 

The Equine Species Working Group has released the second edition of an informational booklet titled: NAIS and Horses: The Facts Surrounding the National Animal Identification System and the Horse Industry in the U.S.

The NAIS is a voluntary program intended to identify premises and livestock, and to record certain livestock movements for the purpose of disease management and control. The program's ultimate goal is to protect the health of US livestock, as well as our ability to move and market animals, through a state-federal-industry partnership.

The NAIS and Horses booklet contains much useful information on the NAIS, and includes the following sections:

“There is a great deal of misinformation regarding the NAIS that has and continues to be spread throughout the horse industry,” say Dr. Jim Morehead, ESWG co-chair. “This booklet is an important resource that attempts to address this misinformation while providing up-to-date information on the program. It is important that industry members know the facts so they can learn about the NAIS, the efforts of the ESWG, and how a national identification plan might affect them.”

The booklet has been updated to reflect recent changes to the program, including USDA's position that it is a voluntary program. It also includes the latest ESWG recommendations submitted to USDA in August 2006.

One of the key recommendations made by the ESWG is that no equine movements should be reported. The group proposed that horses that move to a location where a Certificate of Veterinary Inspection (CVI), Brand Inspection, VS-127 permit, or International CVI are required should be officially identified and that the records maintained through those currently existing and utilized movement permits capture the high-risk movements that pose the largest threat of spreading disease. Animal health officials would be able to query the state databases in the event of a disease emergency to obtain the necessary records.

If horse owners choose to use microchips for the purpose of official identification, the ESWG recommends use of the ISO/ANSI-compatible RFID chip (11784/85, 134.2 kHz) and that RFID reader and scanner manufacturers and suppliers should make an immediate effort to provide readers and scanners that can read ISO/ANSI 11784/11785 microchips, and read or at least detect all 125-kHz frequency companion animal microchips. USDA has recently announced its endorsement of the ISO standards if an owner decides to use RFID technology for NAIS participation.

The NAIS and Horses booklet is available on the ESWG website www.equinespeciesworkinggroup.com, along with other important and useful information regarding the ESWG and the NAIS, including the latest ESWG recommendations.

The ESWG is the designated United States Department of Agriculture (USDA) working group for horses on the issue of the National Animal Identification System (NAIS). It is the working group's responsibility to review and evaluate the NAIS and the possible participation of the horse industry in the program, as well as developing recommendations for a national equine identification plan that is in the best interests of, and protects the rights of, horse owners and breeders.

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Outbreaks of Equine Herpes Virus Occurring Across the Nation 

Many strains of equine herpes virus 1 (EHV-1) exist, which may cause a flu-like respiratory disease, abortion in pregnant mares and, in some cases, neurologic disease in horses.

EHV-1 is not a new virus and is not normally deadly. The same is true for a similar virus called equine herpes virus 4 (EHV-4), which causes respiratory illness. However, certain strains of EHV-1 that affect a horse's spinal cord seem to have resulted in more prominent and frequent outbreaks and more serious problems in horses during the past few years. These outbreaks are particularly significant because this neurologic form of the disease, which can lead to paralysis and death, cannot be prevented through vaccination.

This past winter, racetracks in Florida and California implemented quarantines for several weeks on thousands of horses sent to compete there after multiple cases of EHV-1 that caused neurologic disease occurred and resulted in the deaths of several horses. Last year, tracks in New Jersey, Kentucky, and Maryland also experienced outbreaks of this disease.

Equine herpes virus is highly contagious. This makes it a concern for horse shows, events, farms, and clinics with a high volume of horse traffic. The most recent outbreaks caused horses to experience signs that varied from mild respiratory infections to occasional cases of severe neurologic disease.

“It is a complicated disease,” said Dr. Debra Sellon, a Washington State University board-certified equine internal medicine specialist and professor. “Once infected, most horses carry the virus in a dormant state for the rest of their lives. As many as 80% of horses in the United States have some latent strain of equine herpes virus, but there is no easy way to identify them.

“The virus can be latent in a horse for its entire life. But when the horse is under stress, such as from competition or travel, the virus begins to replicate, is shed in nasal secretions, and other horses can be exposed and infected without the original horse becoming sick itself,” she explained. “Outbreaks probably represent new infections with a virulent strain of EHV-1 that occur in a large number of horses over a short period of time.”

EHV-1 spreads easily through the air from nasal and respiratory secretions that can travel up to 35 feet away and survive a wide temperature range. The virus may survive for 3 to 4 weeks in the environment without a host. It spreads in much the same way that seasonal flu is spread among humans, although humans cannot contract equine herpes virus. Unfortunately, people can help spread EHV-1 to other horses through the use of contaminated equipment such as buckets and brushes, and from exposed shoes, clothing, and hands.

The virus incubates in a horse for approximately 4 to 12 days before it becomes sick. Once the horse becomes sick, it can shed the virus and serve as a source of infection for other horses for up to 10 days.

Horses that experience the respiratory form of EHV-1 may have a fever of approximately 102.5°F or greater, nasal discharge, and a cough. The signs may be minimal and last only a short time, and in some cases, an increased rectal temperature is the only symptom displayed. Pregnant mares that contract the disease may spontaneously abort their fetus within a week to several months after being exposed.

Horses that contract a strain of EHV-1 that causes neurologic disease may experience sudden lack of muscle coordination, inability to empty their bladder, and tail weakness. Most horses survive and return to normal function after several months, but in some cases, the horse becomes recumbent and paralyzed. The prognosis is often poor in those cases.

If a horse is suspected of having EHV-1, it should be removed to an isolated place to prevent the spread of disease to other horses. Horses already exposed to the sick horse should be quarantined. People who handle sick horses should practice sanitary measures to minimize the risk of infecting other horses.

A veterinarian also should be contacted to examine and treat sick horses. Veterinarians can make a definitive diagnosis of EHV-1 by collecting appropriate samples and submitting them for laboratory testing. The veterinarian also can supervise and advise owners and trainers on appropriate quarantine procedures.

“There is no cure for EHV-1, and treatment is largely supportive,” Dr. Sellon said. “There are one or two anti-viral drugs that are showing some promise in horses, but they are expensive.”

“There are vaccines that will prevent the flu-like symptoms and abortions caused by EHV-1, but they will not prevent neurologic disease,” she said. “But the vaccine will decrease the amount of virus a horse sheds in its nasal secretions. If that horse does develop neurologic disease, it will shed fewer virus particles and be less likely to spread the disease to other horses. For this reason, I strongly recommend routine vaccination of horses of all ages for equine herpes virus. There are a variety of vaccines available. Owners should contact their veterinarian for advice and recommendations about a vaccination schedule most appropriate for their horse.”

For more information about EHV-1, contact Dr. Debra Sellon at 509-335-0733 or the WSU Veterinary Teaching Hospital at 509-335-0711.

Reprinted from: Equine News, Spring 2007, Vol. 4, Number 2, Washington State University College of Veterinary Medicine

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Equine Infectious Disease Book Available for Veterinarians and Horse Owners 

Recently, a Washington State University (WSU) equine professor and former WSU veterinary assistant authored a book about equine infectious diseases designed for veterinarians and veterinary students, but it can also be useful for horse owners.

“There really wasn't a text on the market covering equine infectious diseases before this,” said Dr. Debra Sellon, a WSU professor and equine internal medicine specialist who co-authored the book with Dr. Maureen Long, also board certified in large animal internal medicine. Dr. Long earned her doctorate in 1998 at WSU and is currently on the faculty at the University of Florida.

“Because these issues are becoming more and more important, and we had been active in research for years, we decided to write the book,” Dr. Sellon said.

After 3 years of work, the book contains 72 chapters that cover the diagnosis, treatment, and prevention of infectious diseases in horses. Also included are chapters on individual diseases caused by viral, bacterial, rickettsial, and parasitic infectious organisms. It addresses ways to prevent and control infectious disease outbreaks with coverage of epidemiology, biosecurity, antimicrobial therapy, and how to recognize foreign equine diseases. There is also information about the public health importance (potential for spread of disease to humans) for each disease.

“It was written for veterinarians and students, and is a bit technical, but it has detailed information on how to prevent diseases on farms, contains a lot of color photographs of various diseases, and has vaccination protocols that many horse owners may find useful,” Dr. Sellon said.

The book is published by Elsevier and is currently available for purchase at Amazon.com.

Reprinted from: Equine News, Spring 2007, Vol. 4, Number 2, Washington State University College of Veterinary Medicine

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Reports of Lyme Disease Increasing in Vermont 

The incidence of Lyme disease in Vermont has seen a “sudden and dramatic increase” since the end of 2003, a Shelburne veterinarian says.

Before 2003, the cases of Lyme disease Gary Solow saw in dogs were usually in animals that had visited Connecticut, Rhode Island, or southern Maine.

Solow used to treat less than one case of Lyme disease per year; now he sees 25 or more per year. The number of people with Lyme disease increased from 54 in 2005 to 105 last year, and the number of cases contracted within the state increased from 29 to 62, the Vermont Health Department said. More than half the cases were in Bennington County.

Lyme disease is transmitted by the black-legged tick, also known as the deer tick, said Health Department epidemiologist Patsy Tassler.

State entomologist John Turmel said climate changes and close proximity between deer and humans could explain why the disease is spreading.

Symptoms of Lyme disease include lethargy, joint pain, fever, limping, and loss of appetite.

Animals and humans can be treated with antibiotics.

Experts say that if ticks are removed from their hosts—both human and animal—within a short period of time there is little chance of becoming infected. Tassler said an infected tick must stay attached to a person for at least 36 hours to spread the disease. For dogs the duration is less.

Veterinarian Karen Bradley, of the Vermont Veterinary Medical Association, said the increase in Lyme disease cases could be due to increased testing for the disease.

“The basic sense I'm getting, is yes, we are seeing more positives, but we are not seeing a sharp rise in cases for illness.”

For more on Lyme disease in horses, see www.TheHorse.com/ViewArticle.aspx?ID=5691.

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Eastern and Forest Tent Caterpillars Currently Feeding; Timing Right for Horse Farms to Implement Control Strategies 

by: Lee Townsend, Holly Wiemers University of Kentucky, Gluck Equine Research Center

Experts report that eastern tent caterpillars and forest tent caterpillars are developing normally this spring with egg hatching complete and populations feeding, making this an optimal time for area horse farms to assess caterpillar activity and implement control strategies while the larvae are still small and most susceptible.

“There is no indication of widespread high populations of the eastern tent caterpillar this year,” said Lee Townsend, University of Kentucky College of Agriculture entomologist. There are, however, abundant populations of the caterpillar in some localized areas.

Townsend added that this week's freezing nighttime temperatures will not adversely affect populations of the eastern tent caterpillar.

“The eastern tent caterpillar is an early spring insect so it typically faces erratic weather patterns like abnormal warm or cold spells,” he explained. “It is well-protected by its ‘hairy’ body insulation and aggregating (gathering) with other caterpillars in the tents.”

Controlling eastern tent caterpillars is vital to area horse farms, as UK research has strongly linked the caterpillars with outbreaks of Mare Reproductive Loss Syndrome (MRLS), which can cause late-term foal losses, early-term fetal losses, and weak foals.

During 2001, when MRLS hit Central Kentucky particularly hard, an estimated 30 percent of the 2002 Thoroughbred foal crop was lost and the state suffered an economic cost of approximately $336 million due to losses suffered in all breeds of horses.

Epidemiological and field studies conducted by UK researchers demonstrated that MRLS was associated with unprecedented populations of eastern tent caterpillars, wild black cherry trees, and waterfowl on horse farms in Kentucky. A series of studies over the next 5 years has subsequently revealed that horses will inadvertently eat the caterpillars and that the caterpillar hairs embed into the lining of the alimentary tract. Once that protective barrier is breached, normal alimentary tract bacteria may gain access to and reproduce in sites with reduced immunity, such as the fetus and placenta. Fetal death from these alimentary tract bacteria is the hallmark of MRLS.

Now is an optimal time for controlling populations because the caterpillars are still gathered together in the trees, Townsend said. Currently, small caterpillars are moving to feed on the leaves that have been appearing in trees and have built tents at branch and limb forks.

“Initial growth of the caterpillars will be slow, but over the next 2 to 3 weeks caterpillars in limb nests will begin to move to the main truck branches and join together in a smaller number of large tents on individual trees. This aggregation behavior can be used advantageously to manage the caterpillars by destroying or treating accessible populations,” he said.

After a few weeks, the caterpillars will leave the trees where they've eaten the available foliage and search for food to complete their development. Once the caterpillars have reached these dispersing stages, controlling them becomes much more difficult, Townsend said.

Townsend offered the following recommendations for controlling populations. “Foliar sprays for caterpillar control can be made during this time period. Spray residues of products based on Bacillus thuringiensis (Bt) must be eaten by small caterpillars to be effective; there is no contact effect. Consequently, applications should be made to as much of the canopy as is feasible, especially the foliage around active nests. Direct application to nests will not provide any control. Bt residues on foliage can be broken down by sunlight in 3 to 4 days, so it is important to assess control and re-treat if necessary. Effectiveness of Bt decreases as caterpillar size increases,” he explained.

“Foliar sprays with products such as bifenthrin (Talstar) or carbaryl (Sevin) have both stomach and contact activity so they can be effective when sprayed on foliage or tents. The residual life of carbaryl is about a week; that of bifenthrin is at least 2 to 3 weeks. Another option is to inject trees with either bidrin (Inject-A-Cide “B” or 2% Abacide). Regardless of the treatment used, it is important to revisit the sites in about 5 days to assess caterpillar activity,” he said.

Additionally, experts recommend that horse farms scout for the telltale white tents in cherry and crabapple trees and err on the side of caution by keeping mares away from any caterpillar locations.

Townsend also explained that forest tent caterpillars have been at outbreak levels along the Ohio River for the past 2 years and appear abundant in the Boone County area. The forest tent caterpillar is similar to the eastern tent caterpillar and Townsend did not rule out the possibility that it could cause similar problems in horses as the eastern tent caterpillar does. He added that the forest tent caterpillar does not seem to be active in Central Kentucky.

Reprinted from: Mare Reproductive Loss Syndrome website, News Update April 5, 2007, University of Kentucky, College of Agriculture, Gluck Equine Research Center, http://www.ca.uky.edu/gluck/MRLSindex.asp