STDs: major problem that falls through cracks.
About half of all Americans will acquire at least one STD by age 35 years, the Centers for Disease Control and Prevention has estimated. Many of those will be adolescents, as it is estimated that 2.5 million to 4 million teenagers contract an STD each year, with 1 in 4 acquiring an STD before their high school graduation.
Physicians should reassert to patients the fact that many people have STDs, said Dr. Rosen, professor of dermatology at Baylor College of Medicine, Houston. Tell them that safe, protected sex; monogamous sex; and abstinence are the best ways of preventing the spread of STDs.
Dr. Rosen outlined some of the latest findings in STD research and treatment strategies:
* Syphilis. The rates of primary and secondary syphilis have declined to all-time lows in the United States, from 135,000 cases in 1990 to 32,000 in 2001. However, syphilis has become more focally geographic. It is absent from 75% of all U.S. counties, but 1% of all counties, most of which are in the South, account for 50% of cases, he said.
Penicillin, tetracycline, and erythromycin all work in treating syphilis, Dr. Rosen noted. But if a patient has syphilis that is penicillin resistant and you don't think the patient will be able to take tetracycline or erythromycin for 2 weeks on their own, a single 2-g oral dose of azithromycin has been reported to be just as effective as a single intramuscular injection of 2.4 million units of Bicillin for primary or secondary syphilis in HIV-negative patients, he said.
Intravenous immunoglobulin, commonly used in the treatment of numerous dermatologic diseases, has the potential to impart a false-positive serologic test for syphilis that may persist for years, Dr. Rosen noted.
* Genital herpes. In 1997, 45 million Americans were infected with genital herpes, with 1 million new infections occurring every year. In fact, more than 20% of people over age 12 years are seropositive for herpes simplex virus-2 (HSV-2), Dr. Rosen said.
Most people will say that the chance that a sexual partner has herpes is only 1 in 1,000, but the answer is actually 1 in 5, according to a survey conducted by the American Social Hygiene Association. College- and high school-aged respondents thought the chance was even lower, at 1 in 10,000, he said.
"There's a huge disconnect between the perception of risk and reality, and that accounts, I think in part, for why people assume risky behavior patterns," he said.
Cigarette smoking recently was shown to be an independent risk factor for the acquisition of genital herpes. A derivative of nicotine that is selectively secreted in genital fluids suppresses T-cell activity.
"Anything you read about herpes serology [tests] several years ago is not relevant" any longer, he warned.
The company that made the original serologic test for HSV-1 and HSV-2 is out of business. The relatively new HerpeSelect tests from Focus Technologies Inc. are as sensitive and specific as Western blots.
In the HerpeSelect tests, individuals who were seronegative before may take up to 3 weeks to seroconvert. In the old tests, IgG and IgM titers could be used to distinguish an old infection from a new one, he said. However, the new test cannot distinguish between an old and a new infection, because 30% of IgM titers reflect longstanding infection.
HSV-2 seropositivity means that a person is infected with genital herpes. In one study, 53 asymptomatic patients who thought that they did not have herpes turned out to be HSV-2 seropositive. The patients received counseling on what herpes could look like, from the most minimal to the most severe cases. During the following year, 46 of the patients were able to recognize clinical herpes attacks. Polymerase chain reaction (PCR) tests identified 44 patients as positive when swabs of their normal genital skin revealed viral shedding at times when they had no lesions.
About 70%-80% of HSV-2 transmission occurs with asymptomatic viral shedding. Asymptomatic shedding occurs on 1%-2% of days in men and on 5%-8% of days in women, although shedding may be as high as 30% of days when measured by PCR. The number of days "doesn't matter," Dr. Rosen advised, it's just conceptually important.
Episode-by-episode treatment of genital herpes does not address the problem of asymptomatic shedding, so physicians should consider chronic antiviral suppression as routine prescription, he advised. Chronic suppression reduces clinically evident herpes attacks by at least 75% if a patient has six or more attacks per year, but the treatment only reduces asymptomatic shedding and does not eliminate it.
An international, 8-month study of nearly 1,500 couples (in which one partner had genital herpes and the other was seronegative and had no history of genital herpes) showed that only 0.5% of seronegative partners acquired symptomatic genital herpes when their partner used 500 mg valacyclovir / day, compared with 2.3% of seronegative partners whose partner took a placebo.
HIV-negative patients have less than a 1% incidence of viral resistance to HSV-2 treatment, even during a 20-year period, he said. About 5% of HIV-positive patients will have viral resistance to HSV-2 treatment.
* Anogenital warts. Between 10% and 20% of people in the United States aged 15-49 years have evidence of human papilloma virus (HPV). About 1% have clinically evident warts, while 4% have a subclinical variety.
Imiquimod alone completely clears HPV warts in more than 70% of females and in 33% of males. However, an effective way to combat HPV is to use imiquimod in combination with ablation, performed either before or after treatment with imiquimod, Dr. Rosen said.
Two separate studies have indicated that 75%-80% of subjects achieve complete clearing after an initial 16-week course of imiquimod; 59%-75% of recurrences will clear with another 16-week course of treatment with imiquimod.
BY JEFF EVANS
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|Title Annotation:||Across Specialties; sexually transmitted diseases|
|Publication:||Clinical Psychiatry News|
|Date:||Apr 1, 2004|
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