While it is undisputed that people can have severe symptoms of an illness, the cause and appropriate treatment promoted by "chronic Lyme" advocates are controversial. The symptoms are similar to those of fibromyalgia or chronic fatigue syndrome.[4][2] Fibromyalgia can be triggered by an infection, and then persist when the infection is completely removed from the body.[6] A few doctors attribute these symptoms to persistent infection with Borrelia, or co-infections with other tick-borne pathogens, such as Ehrlichia and Babesia.[20][21][22] Some conclude that the initial infection may cause an autoimmune reaction that continues to cause serious symptoms even after the bacteria have been eliminated by antibiotics.[23]