Definition of Lyme Disease (Borreliosis)
Lyme disease, also called Borreliosis, is one of the most common tick-borne diseases in the United States. It is caused by bacteria called Borrelia burgdorferi. The main reservoir for these bacteria is the white-footed mouse, although they can live in other small mammals, lizards and birds. The bacteria are transmitted to larger animals by tiny, hard-shelled, slow-feeding deer ticks, which carry the bacteria after feeding on the blood of infected reservoir animals. Dogs develop Lyme disease when an infected female tick feeds on them for a prolonged time, although there is some disagreement about just how long that meal must be, ranging somewhere from 5 to 50 hours or more. The actual transfer occurs when the tick regurgitates into bite wound after it finishes feeding, causing local irritation and infection. Over weeks to months, the bacteria migrate throughout the dog’s bloodstream. They tend to lodge in joints, muscles, tendons, skin, heart, lymph nodes and other areas high in collagen. They reproduce vigorously, triggering an immune response and causing lameness and other signs in affected dogs. Many dogs never show signs of Lyme disease.