Lyme disease is a bacterial infection. It affects humans, dogs, horses and a few other domestic species. Most cases of Lyme disease in the USA are caused by the species Borrelia burgdorferi. Other Lyme disease-causing species of the Borrelia genus, such as Borrelia afzelii and Borrelia garinii are found primarily in Europe. There's an interesting story behind the name 'Lyme disease'. In 1975, before the causes of this disease were discovered, many cases of this then-unknown disease were reported in the town of Lyme, Connecticut, giving rise to the name of the disease. It was identified as a tick-borne disease in 1978 by Allen Steere, but he couldn't lay his hands on the specific disease-causing pathogen. It remained a mystery until 1981, when Willy Burgdorfer identified the bacterial species responsible for the disease. The species was named Borrelia burgdorferi in his honor. The disease is transmitted in a unique way, i.e., the bite of the deer tick. Although the disease has only one vector (disease-carrying organism), deer tick is the most commonly found type of tick, which makes the propagation of Lyme disease quite easy. It is usually not fatal, though foals are more at risk. But if left unchecked, Lyme disease in horses can lead to liver damage, hepatitis and severe encephalitis, causing drastic behavioral changes. The symptoms of Lyme disease can be very hard to identify, making it difficult to treat the disease in the early stages. Also, while some horses can withstand quite severe infection without showing any distinct physical signs, some take ill at the smallest incursion of the bacteria. The varying ability of individual horses to withstand early Lyme disease symptoms makes it difficult to pinpoint one common set of conditions. If the symptoms are discovered early, though, it can be completely cured with the help of antibiotics. This disease is tough to diagnose as there are no overt symptoms. Only a close scrutiny of the horses can lead to the knowledge that they have contracted it. The first and foremost symptom is stiffness/soreness of joints and muscles, sprains or lameness. However, since these are very generic occurrences, it is difficult to trace them back to Lyme disease. The behavior of the horses may alter during this disease, though the behavioral changes are yet to be classified or categorized. But some horse owners have reported unwillingness to work and increased irritability, along with other behavioral changes. Blood tests like ELISA or Western Blot check for the antibodies to Borrelia burgdorferi, but these tests can turn out to be void due to the low number of antibodies during the early stages of the disease. Since diagnosis of this disease is very difficult, emphasis should be laid on prevention. The most elementary way to prevent it from spreading in domestic animals is to keep the grass short and implement an effective pesticide to keep the number of ticks down. A daily grooming and cleaning routine, especially in the summer, helps in keeping the horses safe. So, do not let the ticks tick away in your stable, and protect your horses from this disease.