The equine neurologic herpesvirus outbreak that occurred in Ogden, Utah, in 2011 is one of many equine epidemics that have spurred industry professionals to take a critical look at the logistics of horse events.
Proactive steps are being taken to ensure greater health and safety standards throughout the United States through a National Equine Health Plan implemented by the AAEP and the American Horse Council (horsecouncil.org/issues/nationalequine-health-plan). As part of this program, an Equine Disease Communication Center improves communications and implementation of alerts and biosecurity strategies during an infectious disease outbreak. Communications are synchronized between states, federal agencies, universities and within the industry in an effort to mitigate the effects of a disease outbreak and to disseminate accurate information.
Yet, having experienced the virulence of spread from isolated cases of infectious disease, the industry is taking steps to stop infection from occurring in the first place. This is the basis for the recent equine vaccination rule change mandated by the United States Equestrian Federation (USEF).
Kent Allen, DVM, chair of the USEF Veterinary Committee and the USEF Drug and Medications Committee, explained that this rule has developed for a couple of reasons: “A primary objective in formulating the new USEF vaccine rule has at its heart the protection of the welfare of the horse and improvements in biosecurity where horses congregate at competitions. Another objective focuses on standardizing requirements for horses entering shows. In the past, there have been complaints from membership about the wide variability of requirements between different shows.”
Merck Animal Health collaborated with Nicola Pusterla, DVM, PhD, DACVIM, and colleagues at the University of California, Davis, in a study on respiratory and neurologic disease cases since 2008.
Of nearly 5,000 upper respiratory cases evaluated across all disciplines and ages of horses, the most prevalent diseases identified were influenza (EIV) and rhinopneumonitis (equine herpesvirus type 4 or EHV-4). Various horses involved in the study had participated in USEF events, further stimulating the Veterinary Committee at USEF to take a more careful look at improving horse protection against communicable diseases.
The New Vaccine Rule
The rule (see sidebar below), which went into effect on December 1, 2015, is fairly straightforward: Immunize against respiratory diseases using EIV and EHV-1 and -4 vaccines within the six months prior to attending a USEF event. Many questions about the rule have come up as vets help clients prepare for the show season.
The rule stipulates the following: Every horse entering the grounds of a USEF-licensed horse show must be accompanied by documentation of immunization against equine influenza and equine herpesvirus (types 1 and 4) within the six months prior to entering the grounds. If documentation is not forthcoming, then the horse is likely to be asked to leave the competition grounds. Preferably, these immunizations should be “administered by or under the direction of a veterinarian,” but the current USEF rule allows for owner administration, provided there are signed documents showing the receipt for vaccine purchase, the serial number and expiration date of each vaccine, and the date administered.
For horses that are not able to receive immunization with a particular product due to a history of adverse reactions or for other medical reasons, the horse’s veterinarian must provide a written statement on letterhead along with a log of twice-daily temperature readings within the seven days preceding the horse’s entry onto the show grounds. Twice-daily temperature readings should continue to be taken while the horse resides on the competition grounds.
Allen pointed out the simplicity of the rule: “The horses should be vaccinated against equine influenza and equine herpesvirus according to the manufacturer’s vaccine recommendations, and then boosted within six months of coming onto USEF competition grounds.”
He said that while most show horses are extremely well vaccinated, this ruling gets around any exceptions and puts every horse on the same footing. Most importantly, the ruling is for the benefit of the horses. A horse that contracts a viral respiratory infection caused by EIV or EHV is often put out of action for many weeks to allow for recovery. The impact on the immune system due to stress from travel and competition adds another layer to the need for better protection against contagious disease at events. Implementation of this rule will improve herd immunity so the bulk of the horses at USEF competitions are well protected against these diseases.
“If a horse comes onto the show grounds without required documentation of receipt of the vaccinations within six months, then the horse can be immunized upon entry to the show grounds,” noted Allen.
However, this is where veterinarians have a large role to play in educating clients about the preferred strategy of immunizing at least two weeks in advance, to stimulate a sufficient antibody response from intramuscular vaccine products.
Allen also advised that veterinarians may improve client motivation to prepare in advance of their show seasons if they are counseled that an adverse reaction, such as sore muscles from an intramuscular vaccine given too close to competition day, could interfere with their horses’ performances.
“If there is concern about a respiratory viral outbreak, the intranasal vaccine is useful to generate the fastest immunity within seven days of a single administration,” recommended Allen. The intranasal form also eliminates the concern that a horse might incur muscle soreness.
Veterinarian Involvement with the USEF Rule
Allen has found that most clients prefer to have their veterinarians administer the vaccines and provide documentation rather than working through the associated paperwork and verification involved with giving the immunizations themselves. “Veterinarians may receive a fair number of requests for documentation of vaccination from clients attending USEF shows,” said Allen. “It is good to be prepared by reading through the rule, as well as having the link to the USEF Vaccine Form to print out the necessary paperwork to provide to clients (usef.org/documents/membership/EquineVaccinationRecord.pdf).”
Although a name and signature are all that are required on the form, obtaining an ink stamp with the veterinarian’s name and address on it facilitates filling out multiple forms for clinics with a large number of show clients.
The Importance of Biosecurity
Vaccination is only one aspect of an effective program to minimize the presence or impact of infectious disease. A very important component of protecting the horse centers on improved biosecurity at equine events to minimize transmission of infectious disease.
Educational efforts are critical for dissemination of this information, and veterinarians have an invaluable role in providing guidance on this topic. (See “Teaching Biosecurity at Shows and at Home” article.)
Clients can be directed to several links on the USEF website. One brochure discusses basic biosecurity strategies: usef.org/documents/drugsMeds/Biosecurity.pdf.
A tool kit from the California Food and Drug Administration explains scenarios in disease control and how to implement appropriate biosecurity at an equine event. You can download that document at cdfa.ca.gov/ahfss/animal_health/pdfs/Biosecurity_Toolkit_Full_Version.pdf.
The Bottom Line
“The new vaccine rule is predicated upon a scientific level through respiratory surveillance
studies and upon an organizational and regulatory level that makes the rules the same for every competitor. With this in mind, it only made sense to go forward to formalizing this as a rule,” stated Allen. With the welfare of the horse at the forefront of the discussion to implement this rule, there could be little argument against it. These vaccines are known to be effective against respiratory disease, and there are very few downsides to biannual boosters with these products.
Since 2005, the Fédération Equestre Internationale (FEI) has mandated influenza immunizations within six months of competition for all of its equine competitors, and this policy has proved effective in curtailing outbreaks. In addition, there has been very little pushback from competitors about having to comply with this rule. Such proactive policies are good for the horses and good for the industry as a whole.
While there might be a few challenges for USEF organizers in the initial logistical implementation of the new vaccine ruling, it will likely get sorted out fairly quickly with a simple tactic, such as asking competitors to bring their documentation letter to the show secretary upon entry to the grounds. This achieves another of the objectives that stimulated the new policy standardizing the rules for everyone.
USEF GR845 Equine Vaccination Rule
Effective December 1, 2015
At Federation-licensed competitions, horses entering the grounds must be accompanied by documentation of Equine Influenza Virus and Equine Herpesvirus (Rhinopneumonitis) vaccinations within six months prior to entering the stables. Horses not in compliance with this rule may be required to leave the competition grounds upon request by Competition Management. Documentation should consist of one of the following methods mentioned below. The frequency of vaccine administration should be per the vaccine manufacturers’ or veterinarian’s recommendations. It is recommended that vaccines are administered by or under the direction of a veterinarian.
In the case of vaccines administered by a veterinarian, the exhibitor, upon request by Competition Management, must provide documentation from the veterinarian on documenting that the horse in question received the vaccinations; name of the vaccines and date of vaccine administration.
In the case of vaccines administered by a person other than a veterinarian, the exhibitor, upon request by Competition Management, must provide a receipt of the vaccine purchase which is signed by the owner, or agent with care, custody, and control of the horse; name, serial number and expiration date of the vaccine; and date of vaccine administration.
In the case of a horse that is unable to receive either of the vaccinations due to a history of adverse reactions, the exhibitor, upon request by Competition Management, must provide a letter from the veterinarian on official letterhead stating that the horse in question cannot be vaccinated due to medical concerns and a log of temperatures taken twice daily for the seven days prior to entering the competition grounds. These horses must also have their temperatures taken and logged twice daily while on the competition grounds. The log of temperatures should be provided to the Competition Management, steward, or technical delegate when requested.
Competition Management may not amend or enhance vaccination requirements without prior approval of the Veterinary Committee.