Page 11 - 22 February 2013

STRESS IS A FACTOR
Although a multitude of factors can cause stress in the horse, one of the most signifi- cant stressors is transportation. In the initial study, recent transportation history was available for 667 horses and revealed that 192 horses (28.8 percent) had been trans- ported within 7 to 10 days prior to the onset of clinical signs.
It is important to remember the immuno- suppressive effect travel can have on horses. Trailers should be well ventilated and long- distance transportation should be broken into segments to help reduce the horse’s chance of contracting an IURD as a result of travel.
UNKNOWN PATHOGENS
Of the 761 horses, mules and donkeys enrolled in the biosurveillance study, 201 (26.4 percent) tested PCR-positive for one or more of the four major IURD pathogens. However, for the remaining 560 horses, the type of infec- tion causing clinical signs of IURD was not determined.
“The first 24 months of data from the biosurveillance program have provided great insight to the frequency and prevalence of the four major IURD pathogens,” Dr. Pusterla said. “We are looking forward to continuing this research partnership with Merck Animal Health in an effort to gather data that helps
us better understand some of the unknown pathogens that have been revealed in order
to improve the accuracy of the diagnosis and treatment we provide our equine companions.”
ONGOING RESEARCH
The Merck Animal Health ongoing biosurveillance study is now in its fifth year. Since the initial data was published in June 2011, Merck Animal Health and the University of California-Davis have received data for more than 1,300 additional horses, mules and donkeys.
Of the additional samples collected, more than 150 have tested PCR-positive for one of the four major IURDs. The highest detection rate is still for EHV-4, followed by a tie for the second highest detection rate with S. equi and EIV. The lowest detection rate remains with EHV-1. However, a significant increase during the EHV-1 neurologic outbreak that occurred in May and continued into June 2011 was evident.
“The updated data has been relatively consistent with the data that was initially published,” Dr. Pusterla said. “However, the key take-away is that we are still seeing cases of all four primary respiratory pathogens. We must remain vigilant on our horses’ vac- cinations, as well as biosecurity measures.”
Photos courtesy Merck Animal Health
In the Merck Animal Health respiratory biosurveillance study, veterinarians were asked to collect blood and nasal secretions from horses presenting signs of acute infectious upper respiratory disease and/or onset of neurologic disease. The samples were sent to the University of California-Davis for real-time PCR testing for each of the four major respiratory diseases.
TO LEARN MORE
Veterinarians who are interested in enroll- ing in the voluntary biosurveillance program and/or receiving the complete updated data should contact their Merck Animal Health sales representative, or call 1-800-521-5767. Horse owners interested in the biosurveillance program should contact their veterinarian.
The research abstract including the initial results of Merck Animal Health’s biosurveillance
study was published in volume 56 of the 2010 AAEP Proceedings, and the full white paper was published in the Veterinary Record in June 2011.
1 Townsend HGG: Onset of protection against live-virus equine influenza challenge following vaccination of naïve horses with a modified-live vaccine.
This article was provided by Merck Animal Health.
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