| outbreak of syphilis among men who have sex with men--southern california, 2000. | syphilis is a sexually transmitted disease (std) caused by infection with the spirochete treponema pallidum, and like other genital ulcer diseases, syphilis enhances the transmission of human immunodeficiency virus (hiv). during the 1990s, syphilis occurred predominantly among heterosexual blacks in the south and in large cities. however, recent outbreaks of syphilis have occurred among men who have sex with men (msm). a large syphilis outbreak occurred among msm during january-july 2000 in sout ... | 2001 | 11393490 |