By Dave Sauter, DVM
The 2011 National Cutting Horse Association Western National Championship was not a good year in terms of a specific contagious disease, the neurologic form of Equine Herpes Virus type 1 (EHV-1). The event held in Ogden, Utah from April 29 to May 11 had over 700 entries that traveled from 19 different states and two Canadian Provinces. After the event, some horses went home and many traveled on to other shows. The first EHV-1 positive horse that was at event in Ogden was diagnosed on May 11th in Colorado and died shortly after with EHM (Equine Herpes Myeloencephalopathy). The second was diagnosed on May 13th in Bakersville, California and was later euthanized with EHM. Word got out through social media before all the affected state veterinary offices were notified that there was big trouble. By the time state officials were able to track all the movements and establish quarantines, it was determined there with 421 primary exposed horses. Primary cases were those horses that had been at the NCHA Western National Championship in Ogden. Secondary horses were those that were not in Ogden but were exposed to horses that were. Tertiary horses were horses that were horses that were exposed to the secondary horses. There were 1685 secondary & tertiary exposures. In total, there were 242 premises with exposed horses. Sixty-two of these premises had positive EHV-1 cases. In the end, there were 90 cases of EHV-1, 33 of which developed EHM. A total of 13 horses died or were euthanized. It wasn’t until June 23rd, 43 days after the final day at Ogden, that the USDA considered the outbreak “contained.” Over 400 horse shows in California alone were canceled. The loss of life was tragic. The time, effort and resources to treat sick horses was tremendous. The same could be said for the establishment and maintenance of quarantines. The loss of training, showing and competing was staggering.
This example was a rare event but does serve as a dramatic example of why Biosecurity is an important topic. A concise definition for Biosecurity can be found in the Merck Veterinary Manual as “all procedures implemented to reduce the risk and consequences of infection with a disease-causing agent.” For disease to occur, there needs to be a perfect storm of three main factors that intersect: a susceptible host that is exposed to the infectious agent in an environment suitable for the agent. Biosecurity is all about exerting control over these factors.
Biosecurity begins at home, well before you hit the road. Good animal husbandry (how we care for our animals) is a fundamental aspect of increasing your horse’s resistance and reducing susceptibility to disease. Good animal husbandry provides a healthy environment with proper preventative medicine – good fencing, safe and secure barns, good ventilation, balanced nutrition, established routines, proper manure management, and regular hoof care. Regular veterinary care is included here, such as parasite control, dental work and appropriate vaccination. The emphasis is on appropriate as the selection and timing of vaccination is important to establish effective protection against common pathogens. At larger farms, it is helpful to segregate differing groups of horses. For example, keeping show horses separate from the horses that stay on the farm. Another example is separating show horses from breeding stock. New arrivals should be separated from the rest for three weeks. If possible, make sure new arrivals are current on vaccinations and deworming at least two weeks prior to their arrival. New arrivals could be incubating disease without obvious symptoms. Not only should new arrivals be segregated but so should their discharges. The new arrivals should be the last horses to be handled and to have their pens cleaned. If they are shedding a pathogen, it can literally be carried on clothing, footwear, in wheelbarrows, on hoses or on implements. Ideally use items designated for the new arrivals and dispose of their waste in a separate area. Take their temperatures twice a day and keep a written record during the three weeks of separation. Fever can be an earlier indicator of illness, before showing other symptoms of illness. Pay attention to personal hygiene, including frequent hand washing, cleaning footwear, etc.
When planning a trip or heading to a show, don’t be a Typhoid Mary. Make sure your horses are healthy before they leave. Monitor temperatures at least once a day for three days prior to leaving to help detect subclinical illness that would not otherwise be noticed. You know your horse. If something is off, such as appetite, stool appearance or amount, energy levels, etc., this is a red flag. Beware that traveling could endanger your horse, not to mention causing the disease to spread to other horses. Pay attention to what is happening with other horses on your barn. If a cough, nasal discharge, fever or some other illness is spreading in the barn, your horse could be incubating the disease even if it has no symptoms when you hit the road. The threat is real; it might be better to stay home, for all concerned.
BYOB – Bring your own bedding and buckets. Bring your own feed tubs, implements, etc. Upon arrival, check out the stalls. Strip, clean and disinfect before bringing your horse in. While at the show, refrain from sharing any tack, grooming supplies, etc. Avoid allowing nose to nose contact with other horses. Don’t dip hoses into your water buckets; there could be pathogens on the outside of the hose. Better yet, bring your own hose. Like the scenario with new arrivals, keep other horses and their discharges separate from yours. Finally, if you see something concerning, such as a coughing horse with a nasal discharge, report it to the show officials.
Biocontainment is an extension of Biosecurity. It refers to containment of a disease once it has occurred. We’ll cover this subject in a separate article. Until then, enjoy your travels but don’t forget Biosecurity!