CHAPEL HILL -- Men infected with HIV -- the virus that causes AIDS -- shed eight to 10 times as much virus in their semen if they also have other sexually transmitted diseases at the same time, according to a new study conducted in Africa.
The study, done by University of North Carolina at Chapel Hill School of Medicine researchers and colleagues, proves that aggressively treating those other illnesses cuts virus levels dramatically, the scientists say. Widespread STD screening and therapy could help curtail the HIV/AIDS epidemic in Africa and other parts of the world, the study suggests.
"The more virus in semen, the greater the chance for transmission to someone else," said principal investigator Dr. Myron S. Cohen, professor of medicine and chief of infectious diseases at UNC-CH. "We believe transmission of HIV is more efficient in Africa and some other areas because STDs are more prevalent there, and more HIV is transmitted during sex."
A report on the findings appears in the June 28 issue of the Lancet, a British medical journal. Besides Cohen, UNC-CH authors of the report are Irving F. Hoffman, research instructor in infectious diseases, and Drs. Rachel A. Royce, assistant professor of epidemiology at the School of Public Health; Susan A. Fiscus, associate professor of microbiology; and Joseph J. Eron, assistant professor of medicine.
The study involved analyzing semen from 135 HIV-infected men living in Malawi, an AIDS-ravaged nation in southern Africa where most HIV transmission is between men and women during sex. Of those patients, 86 were treated for other sexually transmitted diseases such as gonorrhea, chlamydia and trichomonas. Another 49 HIV-positive subjects, who did not have other STDs, were treated for skin problems.
"We found that after a week of treatment, the amount of virus in the semen of the men with STDs dropped significantly," Cohen said. "After two weeks treatment, the levels were similar to those in men treated only for skin problems and without other diseases."
"These findings are very significant," said Dr. Peter Lamptey, director of the AIDS Control and Prevention (AIDSCAP) Project of the United States Agency for International Development and Family Health International. "This study provides us with biological proof that the traditional STDs play a very important role in the HIV epidemic."
"The study also demonstrates that some of the control measures that already are being implemented around the world to contain HIV, especially rapid detection and treatment for STDs, are right on," added Hoffman, who did much of the field work in Malawi. "Treating people with traditional -- and treatable --STDs, especially those individuals also infected with HIV, could have a profound effect on HIV transmission throughout the world."
Dr. Paul DeLay, chief of the United States Agency for International Development's HIV-AIDS division, said STD control efforts should be expanded, citing epidemiologic studies showing such efforts could cut HIV transmission by 40 percent.
"With the results from this study and others, cost-effective STD prevention and control programs can be proposed which will have a major impact on the spread of HIV," said Dr. Penny J. Hitchcock, chief of the sexually transmitted diseases branch of the National Institute of Allergy and Infectious Diseases.
The UNC-CH researchers collaborated with Drs. Peter Kazembe and Martin Maida of the Lilongwe Central Hospital staff in Lilongwe, Malawi in testing and treating the patients. Besides USAID, the World Health Organization, the National Institutes of Health's Office of AIDS Research, the National Institute of Diabetes and Digestive and Kidney Diseases and the National Institute of Allergy and Infectious Diseases supported the study.
Researchers were able to identify study subjects in only two months because, unlike in the United States, a high percentage of people in some African nations carry the virus, Hoffman said.
As many as 15 percent of sexually active adults in Malawi are thought to be infected with HIV, Cohen said. As many as 30 percent of women living in towns and cities are infected. Africans who contract HIV are almost certain to die of AIDS within a few years because few can afford the most promising treatments being developed and offered in the United States and Europe.
Other authors of the Lancet paper include John R. Dyer of UNC-CH, Celine Costello Daly of the Malawi STAFH Project, Dick Zimba of Lilongwe Central Hospital, Pietro L. Vernazza of the Kantonsspital in St. Gallen, Switzerland, and the AIDSCAP Malawi Research Group.
Note: Cohen and Hoffman can be reached at (919) 966-2536. Contact: David Williamson Family Health International contact: Mary O'Grady, (703) 516-9779, ext. 196