Syphilis, HIV link in doubt.

Many health care professionals have argued that a recent spike in syphilis is the result of increasing unsafe sex, particularly among gay and bisexual men, and that a rise in HIV infections would soon follow. But a study published in January in the journal Nature argues that spikes in syphilis are more likely due to a natural eight- to 11-year cycle for the disease rather than an increase in unsafe sex.

The results were encouraging to health care professionals who have worried that increasing syphilis infections are a sign that people at risk for HIV have become complacent about practicing safe sex. But John Douglas, MD, of the Centers for Disease Control and Prevention worried that the study itself could cause complacency. "It is important for people to realize that sexual risk behavior is the critical factor in determining risk of syphilis and other STDs," he said.