Scientists Using New Tactics To Curb STD Rates In U.S.

'PERSONAL GOAL': NIAID's Penelope Hitchcock would like home STD tests to be as convenient as home pregnancy tests. While great attention has been focused on development of better therapies for HIV, incidence rates of other sexually transmitted diseases (STDs) in the United States remain alarmingly high. Yet, as pointed out in an Institute of Medicine (IOM) report entitled The Hidden Epidemic: Confronting Sexually Transmitted Diseases (Washington, D.C., National Academy Press, 1997), the American public's inability to face human sexuality and its consequences hampers STD prevention efforts. The report advocates the creation of a national system for preventing STDs; meanwhile, scientists and public health officials are working to make help more accessible to high-risk individuals. Their efforts are resulting in better detection methods, more therapies and cures, and improved public health measures to control the spread of STDs. "Sexually transmitted disease rates in the United States are the highest in the industrialized world," says Judith Wasserheit, director of the Division of STD Prevention at the Centers for Disease Control and Prevention (CDC) in Atlanta. Rates of syphilis, chlamydia, gonorrhea, and chancroid reported to CDC for 1996 were 4.3, 198, 124, and 0.1 per 100,000 civilian population, respectively. Wasserheit adds that these rates are as much as 50 to 100 times higher than those of other industrialized countries. Among some U.S. populations, rates may be even higher than in developing countries. Community outreach programs could decrease the spread of STDs, especially among the most vulnerable populations, including women, adolescents, and disenfranchised groups, such as substance users, the homeless, prisoners, and migrant workers, who need nontraditional methods of outreach. But, Wasserheit observes, "as a nation, we don't do a great job of providing STD services." She says there is widespread ignorance about STDs. "Twelve percent of Americans can't name a single STD. . . . We're not giving the American public the knowledge and skills to protect themselves." Simple screening may decrease STD prevalence and sequelae. For example, Wasserheit points out that chlamydia screening of asymptomatic health- maintenance organization enrollees has been shown to decrease cases of pelvic inflammatory disease. CONCERNED: Baltimore medical researcher Wayne Cohen notes the occurrence of frequently obscure STDs in HIV-positive patients. The high rate of STDs in the U.S. concerns clinicians, researchers, and patients, states Wayne Cohen, chairman of obstetrics and gynecology at Sinai Hospital of Baltimore. The problems are magnified in people with HIV. "In HIV-positive patients, we're sometimes seeing STDs that previously were seen only in textbooks." Among these are lymphogranuloma venereum and granuloma inguinale, the latter caused by the bacterium Calymmatobacterium granulomatis. New, more effective means of diagnosis and treatment are coming into use; several others are on the horizon. "We have single-dose therapy for gonorrhea, and single-dose injectable therapy for syphilis," explains Penelope Hitchcock, chief of the Sexually Transmitted Diseases Branch, National Institute of Allergy and Infectious Diseases (NIAID). And better means of diagnosis, including rapid, accurate, inexpensive test kits-even some that can be used at home-may mean that more people will be willing and able to be screened for STDs. "My personal goal is to ultimately have these tests done in the bathroom just like pregnancy tests are done," says Hitchcock. "I want to see self-administered vaginal swabs or [tests] through urine." The ultimate goal is for vaccination against these diseases, but that may be more elusive-or will take more time to develop-than diagnostics and treatments. Most Common Diseases According to the IOM report, women are disproportionately affected by STDs; more than 150,000 women died between 1973 and 1992 because of complications from STDs. And of the more than 12 million new cases of STDs reported annually, 3 million are among adolescents, who are physiologically more vulnerable to infection and more likely than adults to have unprotected sex. CDC ranks chlamydia as one of the most common of all STDs in women, with nearly 384,000 cases reported in female patients in 1995-twice the number of cases of gonorrhea in women that year. However, not all states require cases of chlamydia to be reported and the infection often is asymptomatic, so the actual figure is likely much higher. The old scourge, gonorrhea, has been decreasing in prevalence since the mid-1970s. The disease is much more prevalent in African Americans than in any other group. CDC statistics for 1995 show that infection rates for African Americans were 1087 per 100,000 population, as opposed to 29 per 100,000 population for whites. And some strains have become resistant to standard antibiotic treatments of penicillin or tetracycline. This means that treatment may require more exotic, and expensive, antibiotics to eradicate the disease in the population. Nationwide, syphilis is being contained: Only 31 percent of U.S. counties reported cases of primary and secondary syphilis in 1995. (Primary syphilis is the earliest stage of the disease in which lesions develop on the genitalia and lymph nodes swell; secondary syphilis occurs several weeks later when the patient develops skin and mucous membrane lesions and rashes.) CDC statistics indicate that the southeastern U.S. has a greater prevalence of the disease-and more people living in poverty, according to Department of Commerce figures-than other areas of the country. "You're 60 times more likely to have syphilis if you're black than if you're white," points out NIAID's Hitchcock. She adds that the relationship is not racial, but rather socioeconomic, with members of lower socioeconomic groups bearing the brunt of the infections. Many researchers agree with IOM's call for improved public health measures to control spread of STDs. CDC's Wasserheit sees preventive efforts and treatment of STDs as a means "to improve women's health, adolescent health, [and] infants' health, and reduce spread of HIV." CDC's effort, she says, is four-pronged: increase public awareness and education; improve health-care provider training; improve monitoring, especially of at-risk populations; and garner broad-based community involvement. As part of its strategy, IOM recommended that policymakers at all levels "design and implement essential STD-related services in innovative ways for adolescents and underserved populations." Such new approaches are now being funded by CDC. William C. Levine, chief medical epidemiologist in CDC's Surveillance and Special Studies Section of the Epidemiology and Surveillance Branch, notes that funding is going toward helping to "design innovative interventions for syphilis control" to decrease the high rates of syphilis in five Southern states: Arkansas, Louisiana, Mississippi, South Carolina, and Texas. In one such CDC-funded program, the Louisiana Department of Health and Hospitals is using a unique method to track-and prevent-spread of syphilis. In order to reach high-risk individuals in Baton Rouge, the department uses a mobile medical facility that goes into neighborhoods and offers tests for STDs and other health problems, says Thomas Farley, medical director for HIV and STD prevention at the Office of Public Health in New Orleans. The mobile staff offers individuals at high risk for syphilis prophylactic antibiotics: an intramuscular injection of penicillin or two doses of oral azithromycin. The injection, according to Farley, may prevent syphilis for about a month. The two doses of azithromycin are given two weeks apart, so the patient must return for the second dose. With this method, individuals may be protected for as long as two weeks after the last dose. The department is collecting one- and four-month follow-up data to determine if such treatment is effective. Such preventive health measures, however, must be coupled with better, more accessible detection methods, some of which may be done in the privacy of the home to avoid the social opprobrium of a visit to an STD clinic. Although home-testing kits for all STDs are quite a way off, there are improvements in testing that make it easier to diagnose STDs more accurately. Of the two home tests approved for HIV, one, Confide, produced by Direct Access Diagnostics of Bridgewater, N.J., a subsidiary of Johnson and Johnson, was recently withdrawn from the market because of a lack of consumer interest (see Notebook, page 31). UNDER STUDY: Attila Lorincz of Digene reports that his company has chlamydia and gonorrhea tests in clinical trials. Digene Corp. of Beltsville, Md., is marketing to physicians and clinical laboratories a first- generation DNA probe based-assay for human papillomavirus (HPV) called Hybrid Capture. According to the company, the test detects 14 different types of HPV, not all of which lead to development of cervical cancer. Cervical cancer develops with high-risk HPV infection only. "These women require closer monitoring," says virologist Attila Lorincz, Digene's vice president of research and scientific director. When used with a Papanicolaou smear, the test is more accurate in detecting and monitoring cervical lesions. Digene is working on a more sensitive HPV test. The company has introduced a second- generation test outside the U.S. that covers chlamydia and gonorrhea. These tests are undergoing clinical trials in the U.S. QUICK TEST: Litmus Concepts' FemExam TestCard is a convenient way of testing for vaginosis during an office examination. Bacterial vaginosis, often caused by Gardnerella vaginalis, may result in early labor and delivery. Litmus Concepts Inc. of Santa Clara, Calif., now has a test approved by the Food and Drug Administration (FDA) for detecting the infection. The presence of amines, a pH equal to or greater than 4.7, homogeneous white vaginal discharge, and vaginal epithelial cells coated with bacteria are the standard criteria for determining the presence of bacterial vaginosis. The FemExam TestCard allows health-care providers to conduct initial testing quickly during office examinations, according to the company. The disposable device is the size of a credit card. To use the product, the physician rubs a cotton swab containing undiluted vaginal fluid over two circular test areas. One test indicates whether the pH is high or normal, and the other test detects volatile odor-causing amines. "If it's positive, they get blue plus signs on a yellow background," explains biochemist Paul Lawrence, CEO of Litmus. The company is working on tests for vaginal yeast and Trichomonas infections. New therapies also are adding to clinicians arsenals' for fighting STDs. Azithromycin, a new erythromycin-derived antibiotic, is being used against syphilis and chlamydia, and even for chancroid. Single-dose antibiotic therapy is available for chancroid, chlamydia, gonorrhea, syphilis, and trichomoniasis. Antivirals decrease the severity of one of the viral infections, herpes simplex virus (HSV), and are being used successfully to decrease viral load in HIV. Research Triangle Park, N.C.-based Glaxo Wellcome's Valtrex (valacyclovir HCl) antiviral medication was approved in October 1996 by FDA for use in initial HSV infections. The drug decreases the duration of and discomfort from initial HSV infection by preventing reproduction of the herpesvirus. The drug also is prescribed for recurrent HSV infections. GROUP EFFORT: CDC's Judith Wasserheit says "it takes a community to prevent STDs." Research on the biology of HSV by Bernard Roizman of the University of Chicago's department of biochemistry and molecular biology is a basis for R&D by Aviron, a Mountain View, Calif.- based biopharmaceutical company, on a live attenuated vaccine against HSV-2. The vaccine, currently in animal studies, is "targeted at those genes [in the HSV virus] responsible for neurovirulence," states pediatric infectious disease specialist Martin L. Bryant, vice president of research at Aviron. He explains that HSV attacks the nervous system, entering into a nerve root and later emerging, leading to symptoms. Clinical trials with the vaccine could begin as early as 1998. Aviron has another STD-related vaccine candidate, against cytomegalovirus (CMV). The virus creates significant health problems, such as blindness, for AIDS patients, transplant recipients, or immunosuppressed cancer patients. Bryant anticipates that this vaccine will be clinically tested in the first half of 1998. Although an HIV vaccine has been pursued for years, researchers point out that the numerous strains of the virus-along with its rapid mutation rate-mean a standard vaccine would be ineffective. However, new cocktails of drugs that suppress HIV replication are allowing people with the infection to live longer, healthier lives. Recent studies by researchers at University of North Carolina, Chapel Hill, School of Medicine show that STD treatment for men infected with HIV and STDs decreases HIV present in semen. No matter what therapies, vaccines, or screening tests exist, the bottom line in preventing STD transmission is modifying behavior. Public health measures that openly promote prevention and awareness are an essential part of the equation. As CDC's Wasserheit points out: "If it takes a village to raise a child, it takes a community to prevent STDsl." Myrna E. Watanabe is a science writer based in Yonkers, N.Y.

Scientists Using New Tactics To Curb STD Rates In U.S.

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