Equine lyme disease is a bacterial infection that is not considered fatal in most cases, although very young horses are more seriously affected. While it can cause other serious problems and if not caught in time may cause death. Once caught, lyme disease in horses is treatable however, it can be difficult to diagnose and owners need to be aware of what to look for. Constant monitoring of your horses is necessary and like most diseases prevention is better than attempts to cure. Lyme disease is more prevalent in hot climates but there is no location immune to the possibility during warm weather.
Lyme disease is a bacterial infection but it is somewhat unique in that there is only one way to transmit the bacteria---through the bite of an infected deer tick. The fact that transmission is so specific to a single type of insect would seem to make it difficult to contract, however deer ticks are the most commonly found tick and the disease is very common. Lyme disease is serious because it is also zoonotic, meaning it can be transmitted to many different species including humans.
Symptoms and Diagnosis
The biggest difficulty with lyme disease in horses is the difficulty of recognising the symptoms. In fact, many horses will appear perfectly fine with no symptoms whatsoever. Careful observation will show stiffness and sore joints and muscles. However, those are easily signs of many problems, including simple sprains. The only accurate method of diagnosis is a blood test. If you suspect your horse has been in contact with ticks and notice any lameness, it is important to call your veterinarian for further testing.
Once diagnosed by a blood test equine lyme disease is treated with antibiotics. Response is generally fast and improvements are visible in less than a week. Full recovery may take weeks but if there is no improvement as treatment begins test should be run to determine if diagnosis was inaccurate. Prompt treatment is very important because the longer the disease continues undiagnosed the more likely it is that it can trigger other issues that may be permanently damaging or even fatal. Some of the possible illnesses that can be triggered by lyme disease are Laminitis, a serious swelling of the delicate laminae tissues in the hoof caused by the heat and swelling in the muscles and joints created by lyme disease, brain swelling, heart and other organ damage.
In most cases once treatment is begun recovery is steady and the likelihood of full recovery is high. Young foals are more severely affected by the disease and fatality is higher. Older animals usually suffer no long term problems from lyme disease unless it goes untreated where secondary illnesses that can be long-term or permanent may appear.
Equine lyme disease is not contagious from animal to animal. However, congested herds are more at risk than small groups or large numbers spread out across larger areas because infections are spread to uninfected ticks and passed from animal to animal in that method. The only true prevention for equine lyme disease is tick control. Keep grassy areas short. Avoid wooded areas if possible. Use a good tick control spray when horses are pastured in areas that are likely to contain deer ticks, or when riding in wooded areas. Thorough daily grooming with close attention to removing ticks on the body is very important during warm months when deer ticks are active and present. Prompt removal is very effective because even if an infected deer tick is found it takes 12 to 24 hours before infections are passed from tick to host, regardless of the type of animal the host is, including humans.