Lyme Disease in Horses: Facts and Fallacies

Lyme disease is caused by a spiral-shaped bacterium called Borrelia burgdorferi that is spread to some mammals via the bite of specific hard-bodied ticks. Also known as borreliosis, it is widely considered the most important insect-borne bacterial infection in North America. But it is unknown whether ticks transmit the bacterium to horses and cause disease or because the two coexist.