Borrelia burgdorferi is a spirochete bacteria that causes Lyme disease. It is similar in shape to the spirochetes that cause other diseases, such as relapsing fever and syphilis. (Image courtesy of the Centers for Disease Control and Prevention.)

Diseases are often carried by ticks, including Rocky Mountain Spotted Fever, Colorado Tick Fever, Lyme disease, and tularemia. Less common or less frequent diseases include typhus, Q-fever, relapsing fever, viral encephalitis, hemorrhagic fever, and babesiosis.

There are many species of ticks. Of these, a large proportion are capable of carrying disease. Diseases carried by ticks include Lyme disease, Erlichiosis, Rocky Mountain Spotted Fever, Colorado Tick Fever, tularemia, typhus, hemorrhagic fever, and viral encephalitis. (Image courtesy of the Centers for Disease Control and Prevention.)

Lyme disease is caused by a bacterium called Borreliaburgdorferi. It is known as a spirochete because of its long, corkscrew shape. This photograph shows the typical corkscrew appearance of a spirochete. (Image courtesy of the Centers for Disease Control and Prevention.)

Tertiary Lyme disease is a late, persistent inflammatory disease characterized by skin changes, neurological and musculoskeletal symptoms caused by the bacterium Borrelia burgdorferi transmitted by the bite of a deer tick. Tertiary Lyme disease is indicated by chronic arthritis.

This is a close-up photograph of a tick embedded in the skin. Ticks are important because they can carry diseases such as Rocky Mountain spotted fever, tularemia, Colorado tick fever, Lyme disease, and others.