Pearls A Disconnect between the Neurospirochetoses in Humans and Rodent Models of Disease

The human spirochetal diseases share many clinical similarities despite their diverse epidemiology. Syphilis is a sexually transmit-ted infection, whereas the leptospiroses and the borrelioses are zoonoses. The clinical similarities among the spirochetoses include a relapsing-remitting course of infection. The recurrent pattern of illness has three invariant features that are shared by all human spirochetoses. Entry of spirochetes is achieved through breaks in the skin or through mucous membranes. Cutaneous lesions such as the syphilitic chancre or the erythema migrans of Lyme disease constitute the earliest manifestations of these two diseases. In all three spirochetoses, there is dissemination to distant organs through tissues, blood, and other fluids. Late disease, often with intervening relapses and latent periods, can involve one or more organ systems. The spirochetal diseases also share tropisms for skin, nervous system, and heart and arteries