Rocky Mountain spotted fever is a tick-borne disease first recognized in 1896 in the Snake River Valley of Idaho. It was originally called “black measles” because of the look of its rash in the late stages of the illness, when the skin turns black. It was a dreaded, often fatal disease, affecting hundreds of people in Idaho. By the early 1900s, the disease could be found in Washington, Montana, California, Arizona, and New Mexico.
Tick-borne diseases are becoming a serious problem in the United States as people increasingly build homes in formerly uninhabited wilderness areas where ticks and their animal hosts live. Tick-borne diseases can be caused by viruses, bacteria, or parasites. Most people become infected through tick bites during the spring and summer months.