March 8, 2004 (Philadelphia) -- After increasing rates for three consecutive decades, there was a sharp decline in the late 1990s in the number of teenagers and adults who contracted the virus that usually causes genital herpes.
But with a new decade comes an upswing in other sexually transmitted diseases -- including syphilis, human papillomavirus, genital warts, and chlamydia, according to research presented Monday at 2004 National STD Prevention Conference.
Two studies presented at the nation's leading STD conference indicate that overall, the prevalence of herpes simplex virus type 2 -- the primary cause of genital herpes -- declined 17% during the 1990s among Americans between ages 14 and 49. Among men, there was a 35% decrease.
Health officials say reasons for the downward trend are unclear but note that younger people, in particular, are contracting herpes less often. Studies indicate a 74% decrease among teenagers over previous rates, and a 48% drop among those in their 20s.
Yet from 2000 to 2003, the number of reported cases of syphilis jumped 18% -- from nearly 6,000 cases to nearly 7,100. Cases skyrocketed 65% among men but decreased 50% among women.
Although the CDC doesn't track syphilis data by sexual orientation, John Douglas, MD, director of the agency's STD Prevention Programs, estimates that nearly 60% of cases that occurred in 2003 were in gay and bisexual men. That compares with only 5% of cases in 1999.
This resurgence in that high-risk group is of particular concern because syphilis helps facilitate the spread of HIV.
"These are troubling rates," says Douglas. "It appears that many [men] may be tuning out the message of safe sex."
Meanwhile, University of Colorado researchers report that in a study of nearly 1,600 people, nearly one in three women and 19% of men were found to be infected with a particularly "risky" strain of human papillomavirus (HPV) that drastically increases risk of cervical and anal cancers. And in contrast with earlier research, they note that their sexual behavior was riskier over the previous three months prior to diagnosis and was a stronger predictor of infection than their number of lifetime sex partners.
News of the conflicting results -- a decline in herpes but rise in other STDs -- comes as no surprise to one expert.
"If you look over a long period, you always see rises and falls (in certain sexually transmitted diseases)," says James Allen, MD, MPH, president of the American Social Health Association. "In general, you see falls when there is increased funding for prevention programs."
Budget cutbacks in recent years have affected many STD prevention programs -- especially among many state and local agencies. Just weeks ago, CDC researchers estimated that one of every two new STDs diagnosed each year occurred in Americans between ages 15 and 24, even though they represent only a quarter of the U.S. population.
In 2000, the CDC estimated some 19 million new cases of a sexually transmitted disease in Americans, says Douglas, and the U.S. has the highest rates of STDs of any industrialized country. Nearly half were in young people.
"The best time to educate young men and women about how to avoid STDs is long before there is a diagnostic," says Douglas. "We really need an open dialog with youth about these issues."