<http://health.usnews.com/usnews/health/healthday/080312/us-syphilis-rate-grows-f
or-7th-year-in-row.htm>:

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For the seventh year in a row, rates of syphilis infection have
increased in the United States, driven largely by cases among gay and
bisexual men, according to a new federal report.

"CDC's preliminary 2007 data indicate that the rate of primary and
secondary syphilis -- the earliest and most infectious stages of the
disease -- increased by 12 percent between 2006 and 2007," Dr. Hillard
Weinstock, of the U.S. Centers for Disease Control and Prevention's
Division of STD Prevention, said during a Wednesday teleconference.
Weinstock spoke at the CDC-sponsored 2008 National STD Prevention
Conference in Chicago.

The number of reported cases of syphilis increased from 9,756 in 2006
to 11,181 in 2007, Weinstock said. "This is the seventh consecutive
annual increase in national syphilis rates," he said.

Continuing with recent trends, 2007 statistics showed that men who
have sex with men accounted for the majority of syphilis cases in the
United States and contributed significantly to the overall increase in
the disease among men, Weinstock said.

[...]

The increase in the syphilis rates among gay and bisexual men is a
significant health concern, Weinstock said. "Syphilis, like other STDs
[sexually transmitted diseases], can increase the likelihood of HIV
transmission two- to five-fold. For individuals already infected with
HIV, syphilis can increase viral load, which can accelerate HIV
disease progression and the potential for HIV transmission," he said.

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