An Ounce of Prevention by Kristen Weiss

An Ounce of Prevention

by Kristen Weiss, DVM

Show season is upon us! The old adage, an ounce of prevention is worth a pound of protection becomes the motto during this period of pre-show preparation. Many state equine health requirements have been established to protect your horse and prevent the spread of disease. In addition to state regulations and routine veterinary attention, there are a great variety of vaccines available to combat the emerging infections and better defend your horse against the standard viruses. By following the regulations enforced in each state through which you will travel and ensuring your horse has been adequately protected through a tailored vaccination protocol, you should be able to enjoy a disease-free show season.

Health Certificate
Any time your horse travels across state lines or the United States’ border, you may be required to provide a certificate of veterinary health inspection. Accredited veterinarians must perform a physical examination of your horse before a certificate can be issued, so be sure to schedule the veterinary visit well in advance of your departure. It is vital that you understand the individual regulations regarding the transport of livestock for each state through which you will be traveling. Some states aggressively inspect health certificates prior to allowing your horse to enter their state, while others never check. Since the larger equine competitions often draw horses from across the nation, or even overseas, many will require presentation of health papers prior to allowing access to the show grounds. You never know when you will be requested to present papers, so you should always carry a valid copy when you travel with your horse.

Coggins Test
Equine Infectious Anemia (EIA) is a reportable viral disease transmitted by blood-sucking insects. Once injected, the virus causes the body to mount an immune response against its own red blood cells, resulting in life-threatening anemia. Although EIA is most commonly seen in the warm, moist regions of the South and Southeast, it can occur nearly anywhere in the U.S. There is no effective treatment for EIA and no vaccines are currently available, therefore state veterinary agencies and the United States Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) strongly recommend euthanasia of all infected animals.

One method of preventing the spread of EIA is through routine serological blood screens called Coggins tests. Each state defines its own testing parameters for EIA. These may be further limited by the requirements of the competitive event you plan to attend. For example, the state of Wisconsin requires a negative Coggins test to be performed within the current calendar year. A horse show scheduled later that year may require a negative Coggins test within the last six months. It may seem inconvenient to test your horse twice a year, but these rules are strictly enforced with the health of your horse in mind.

Blood samples for Coggins testing must be submitted to approved laboratories by state or federal animal health officials or accredited veterinarians. Several days are required to interpret the test results and return the necessary paperwork to your veterinarian before it will be made available to you. If you are planning to attend a competition or travel across state lines, arrange to have your horse tested in time to receive your paperwork before your date of departure. To learn more about the individual health certificate and Coggins test requirements for each state, you can contact your local veterinarian or visit the USDA’s Animal Import Regulations website at www.aphis.usda.gov.

Vaccinations
The core vaccines that any horse should receive, regardless of geographic location or plans to travel, are Tetanus, Influenza, Rhinopneumonitis (Equine Herpesvirus Types 1 and 4), and Western Equine Encephalomyelitis (WEE). Horses living in or traveling to the East and Southeastern states should also be vaccinated for Eastern Equine Encephalomyelitis (EEE).

In addition to the core vaccines, there are a number of optional vaccinations to consider. Which vaccines you should utilize depends upon the geographic location you plan to visit and the various diseases that are known to exist there. If you are confused about which injections your horse should receive, ask your veterinarian to customize a vaccination protocol to suit your needs. Allow several weeks prior to your event to administer vaccines that require a series of injections and provide your horse adequate time to mount an effective immune response.

Equine Protozoal Myeloencephalitis (EPM)
EPM is caused by the protozoal parasite, Sarcocystis neurona, which is transmitted to horses by opossums. The parasite attacks the nervous system, resulting in dramatic neurologic disease including incoordination and collapse. EPM can be seen sporadically across the United States, with outbreaks noted in Midwestern states and Florida. A conditional license has been provided for the manufacture of an Equine Protozoal Myeloencephalitis vaccine. In order to gain this conditional licensure, the vaccine has been proven to be safe and reasonably efficacious. It is available only to veterinarians and each state must evaluate the risks of exposure before approving its use.

Potomac Horse Fever
Potomac horse fever (equine monocytic ehrlichiosis) is a disease that can cause explosive diarrhea, dehydration, colic, and/or laminitis. Although horses exhibiting mild signs usually recover within a week, many others experience serious complications that lead to death or euthanasia of the affected animal.

Potomac Horse Fever is seen predominantly in the Eastern states, but has been identified in many regions of the U.S. Vaccination will not provide complete protection, but it will reduce the severity of the signs that your horse will exhibit. Potomac Horse Fever is a seasonal disease, most commonly seen in late spring or early fall. Schedule your vaccines so that one of the boosters occurs during May or June.

Rabies
Rabies is not a common disease in horses, however a horse infected with the virus will ultimately die. Prior to death, an infected horse has the potential to transmit the disease to humans and other animals to which it has contact. Rabies has occurred heavily in the Eastern states, Texas and California, but can occur anywhere in North America.

Strangles
Strangles is a highly contagious respiratory disease caused by the bacteria Streptococcus equi. The bacteria are easily transmitted directly from horse to horse or through contact with contaminated items such as buckets, grooming supplies, stalls, etc.

If you are visiting a facility where Strangles has been a problem or if your veterinarian feels your horse may be at risk, you may wish to consider adding the Strangles vaccine to your equine health protocol. The two different forms of vaccinations for Strangles are the intramuscular vaccine and the new intranasal vaccine. Neither vaccine is 100% effective; however the intranasal vaccine seems to be winning the favor of veterinarians and horsemen across the nation.

The intramuscular vaccine has been used for years. It causes antibodies to form in the blood, but not within the mucous membranes of the throat where the bacterial organism lives. In addition, it has been associated with causing abscesses at the site of the intramuscular injection. The intranasal vaccine, on the other hand, is administered into the nostrils of the horse via inhalation. This method allows antibodies to be produced within the mucous membranes of the respiratory tissue where they will be readily available to fight off potential infections. Another advantage to this vaccine is that it will not cause vaccination site abscesses when it is properly administered.

Venezuelan Equine Encephalomyelitis (VEE)
VEE is a viral infection transmitted to horses by mosquitoes that have been feeding on infected birds or rodents. The virus attacks the nervous system and results in death of the majority of horses that are infected.

The most recent outbreak of VEE was in Mexico in 1996; however the disease has not affected horses in the U.S. since the early 1970’s. If the competition you plan to attend borders Mexico, consider vaccinating your horse for VEE.

West Nile Virus
The West Nile Virus is a relatively new infection to the United States. It is transmitted by mosquitoes and has been detected in states east of the Mississippi River. This virus affects the central nervous system, causing incoordination, paralysis, convulsions, coma and death. A vaccine for this disease is available for horses visiting or residing in endemic areas. Like the vaccine for Equine Protozoal Myeloencephalitis, it is a conditional vaccine and is available only through your veterinarian.

You can see that it is extremely important to familiarize yourself with the individual health requirements enforced by the state agencies and equine events you plan to visit. Each rule has been established to protect the well-being of your horse and to prevent the spread of debilitating disease. If you carry your responsibility a step beyond the minimum requirements and take the initiative to vaccinate for the pathogens to which your horse may be exposed, you can rest assured that you have done all that you can to prevent your horse from contracting infectious illnesses and keep him on the road to show ring success.