Lyme disease, called "the great imitator" because its symptoms are so similar to other illnesses, is often misdiagnosed. One of the reasons it is misdiagnosed so frequently is that for some reason many doctors deny that it exists, or that it can exist, in their locale. So these doctors are not even looking for it.
Lyme disease has been mistaken for autism, multiple sclerosis, Parkinsons' disease and schizophrenia, to name just a few. In actuality Lyme disease is an illness transmitted by ticks carrying the bacterium Borrelia burgdorferi.
"Early symptoms may include fever, headache, fatigue, muscle and joint pains as well as a characteristic 'bulls eye' rash. Generally, if the illness is treated early the infection and its symptoms can be eliminated by antibiotics. If left untreated, however, the bacteria can move through the bloodstream and more serious symptoms can develop, which can be disabling and increasingly difficult to treat."
Even after a proper diagnosis, Lyme is difficult to treat. The bacteria Borrelia burgdorferi has an ability to transform itself, so that treatment that was previously successful will now miss the mark.