Syphilis
In neurosyphilis, the syphilis infects the central nervous system (the brain and spinal cord). In some people, neurosyphilis happens soon after they get syphilis. (This is called early neurosyphilis.) Some of these people have no symptoms of neurosyphilis. Others get syphilitic meningitis, a dangerous infection of the meninges (the protective layers which line the brain and spinal cord).