Lyme disease is a bacterial illness caused by a spirochete called Borrellia burgdorferi. The bacteria are spread by a tick, commonly called the deer tick, and can infect pets, horses, cattle, as well as humans. Lyme disease in horses is quite common for animals living in high risk areas.Equine Lyme disease is not easy to identify, as less than 10% of the horses will show any symptoms at all. The most common symptoms are lameness and changes in the animal’s behavior. Usually, you will see the animal shifting frequently from limb to limb, and showing signs of a general stiffness. The horse can also show signs of irritability and refuse to work.
Lyme disease in horses is a tricky diagnosis even for experienced veterinarians, since these animals are prone to muscle and joint injuries, so it’s difficult to relate such problems immediately to a bacterial infection. Also, the blood test can only show that the animal has been exposed to the bacteria and that its immune system reacted, but this doesn’t mean that the disease has been triggered.
The only treatment available is based on antibiotics, and it takes several weeks. The good news is that, if equine Lyme disease is diagnosed correctly, the animal responds quickly to the treatment, and the first signs of improvement can be seen in 2 to 5 days. If there is no quick response, it’s most likely that the diagnosis was not correct in the first place, and the horse has some other problem. One can also use anti-inflammatory drugs against the pain and stiffness and stomach medicine to help the horse cope with the antibiotic treatment – these are useful, but have no influence on the infection itself.
At present, there is no licensed vaccine for equine Lyme disease, but, since vaccines have been developed for dogs and one also exists for humans, there are hopes that one for hoses will follow shortly. Until then, the only prevention method is the tick control. The animal needs frequent grooming and all the ticks have to be removed quickly. On horses, the ticks are most likely to be found on the head, throat, stomach or under the tail. Use tweezers to remove the ticks, pulling straight upwards in order to make sure you remove the insect completely; otherwise, mouth parts of the tick may remain imbedded in the animal and infection is still possible. The ticks need to be on the animal for 12 to 24 hours before they can transmit the infection. Also, you can check with the veterinarian about the use of tick repellants; those based on chemical permetherin are particularly effective.
Equine Lyme disease is not contagious, and one sick animal cannot infect the rest. However, an infected animal is a sign that there are ticks in the area, and that the others are at risk as well.