Syphilis is a sexually transmitted infection (STI), once responsible for devastating epidemics. It is caused by a bacterium called Treponema pallidum. The rate of primary and secondary syphilis in the United States declined by 89.2 percent from 1990 to 2000. The number of cases rose, however, from 5,979 in 2000 to 6,103 in 2001.
The U.S. Centers for Disease Control and Prevention reported in November 2002 that this was the first increase since 1990.
Of increasing concern is the fact that syphilis increases by 3- to 5-fold the
risk of transmitting and acquiring HIV (human immunodeficiency virus), the virus