In the U.S., the number of confirmed cases of the tick-borne illness in 2015 was nearly 29,000, compared to 23,000 ten years earlier. Lyme disease can be treated with antibiotics if it is caught early. The CDC reports that those patients who get antibiotics during the early stages of the illness normally recover quickly and completely, and those who take antibiotics in later stages also tend to respond well.

The distinctive erythema migrans rash that occurs in around 70 to 80 percent of those infected starts at the site of the tick bite anywhere from three to 30 days afterward and expands to cover an area of 12 inches across, or more. It is not usually painful or itchy, but it can feel warm. It can clear up as it enlarges, which gives it the appearance of a target or bulls-eye.