An ounce of prevention
Eastern Equine Encephalitis (EEE) was recently diagnosed in one of two Marathon Township horses, after both were put down within a day of each other. Because the first horse was euthanized without testing, his cause of death will never be known, but speculation is that he also was positive for EEE.
Area veterinarians had hoped that the media wouldn’t panic equine owners and the public, but did want everyone to be aware so they could be proactive. Several local papers used the word outbreak, which also makes the veterinarians cringe because that is a bad choice of words. There will definitely not be an outbreak. Will a few more cases appear in Lapeer County? Probably, simply because the mosquito population is expected to be on the rise with the recent rains.
Although rare among horse diseases, the mosquito-borne disease is generally always fatal as it causes swelling in the brain and other neurological damage. Although there is no cure for EEE, it is quite preventable. Horses cannot pass EEE on to one another or to humans. Mosquitoes pick up the viral disease by biting infected birds. They then transmit the disease to horses by biting them and the life cycle of the disease ends with each bitten horse.
Ralph Huff, DVM, the vet from Animal Healthcare of North Branch who tended to both animals, stressed the need to not alarm the equine owners, the majority of whom vaccinate their horses against EEE and two other mosquito-borne diseases — West Nile Virus and Western Equine Encephalitis. This is part and parcel of a typical spring vaccination schedule that comes in the form of a three-in-one or five-in-one combo vaccine.
The first question that will pop into some people’s minds is “If this is so preventable, why in the world weren’t the two horses vaccinated?”
The reasons are as varied as the horses and their owners. Because the horses that died were quite young — two and three years old — a vaccination schedule may not have been established. Some horses that never leave their property often are not as susceptible to some horse diseases as show horses or trail horses that travel from barn to barn or to large arenas and gatherings. Also, money dictates what kinds of vaccines are given to horses. Perhaps these owners felt they were at low risk and had vaccinated against some of the more common diseases such as flu, pneumonia or Potomac Horse Fever. Lesson learned, albeit the hard way.
All horses are at risk for a variety of equine diseases, including rabies, also fatal. If bitten by a bat, skunk, raccoon or other rabies carrier, the horse dies. Bitten by a skunk? Now how common is that, some will ponder. I watched one of my horses get bit on the nose several years back by a skunk in broad daylight. That’s a red flag situation because at the time, he had not yet had his annual rabies vaccine. The only way to verify a positive rabies diagnosis in any animal is to quarantine for symptoms and if positive, after the death, have the head sent to a state certified lab, such as Michigan State University.
Dogs and cats receive yearly vaccinations, and horses should as well. But those vaccinations can impact the old wallet pretty hard, depending on the size of the herd. Some owners choose to forgo the preventative measures, while others are not even aware they need them. First-time horse owners should always seek counsel from their veterinarian about how best to protect their horses, and longtime owners follow said advice based on their horses’ surroundings, exposure to other horses and potential to become ill.
The main thing to remember is that this is not a public health threat. More cases will be reported across the nation this year, especially with all the flooding that has inundated a large portion of the country. Dealing with flooded homes will likely come first on the to-do list, but hopefully good preventative measures have already taken place in the spring and the majority of horses will be protected.
For more information on the case in Marathon Twp., see the story on page A-3. And, if you haven’t already done so this year ... call your equine veterinarian to protect your horses.

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