In vitro experiments by the same group on rat primary neurons, astrocytes, and microglia have shown that 2–8-week exposure to Borrelia burgdorferi induces AD-like changes, such as overexpression of the amyloid precursor protein (APP), tau hyperphosphorylation, and the accumulation of Aβ inclusions reminiscent of amyloid plaques. Here, APP is linked to Alzheimer disease.