Lyme disease is a bacterial infection transmitted to people and animals through the bite of an infected black-legged tick. Lyme is caused by a bacterium called Borrelia burgdorferi.
Here's what you need to know about Rocky Mountain spotted fever, which is widespread in the U.S.
Information about laboratory tests that help support a diagnosis of Lyme disease
Information about ticks...did you know there are more than 800 different species and some transmit disease?