Lyme disease is a clinical disorder caused by a microscopic organism, the spirochete, Borrelia burgdorferi
, and is spread by ticks. The bacteria normally feed on small mammals, especially mice. Ticks then feed on the mammals and carry the bacteria to their victims. The deer tick is the most common tick involved in spreading the disease, although other ticks can pass it along, too. Ticks capable of spreading Lyme disease are most commonly found in the eastern United States, the upper Midwest and the Pacific Northwest. Lyme disease can affect different organs and body systems. The disease is named because of the initial discovery in human beings that occurred in 1975 in Lyme, Connecticut.
Lyme disease is most common in dogs but has been reported in other species. There appears to be no breed or sex predisposition. Outside, hunting and working dogs are more likely to be exposed to ticks than dogs kept indoors. Puppies
appear to have a higher risk, and it is thought that less than five percent of dogs exposed to Lyme disease in an endemic (prone) area may develop clinical signs.
Human data from the Centers of Disease Control suggests that 85 percent of cases are from Eastern coastal states, 10 percent from the Midwest, 4 percent from the western states and 4 percent from the remaining states. The same figures may be true for dogs.
For more information about the relative risk of Lyme disease in the United States, see the risk map at: www.cdc.gov/ncidod/dvbid/lyme/riskmap.htm.