The herpes virus has been further implicated in the spread of AIDS. Saidi Kapiga, assistant professor of reproductive health in the Department of Population and International Health, and his colleagues have conducted a study in Moshi, Northern Tanzania and have found that women with herpes simplex virus type 2 (HSV-2), or genital herpes, had more than three times the risk of becoming HIV-infected than women without HSV-2. The association between herpes and AIDS is not new, but Kapiga’s findings strengthen an increasingly complicated body of evidence about what makes someone susceptible to HIV. The research also has implications for addressing the AIDS epidemic in Africa, where the majority of new HIV cases continues to emerge.

Genital herpes is a sexually transmitted disease currently without a cure, but antiviral medications help manage the symptoms. The virus causes lifelong infection and tends to spread through sores on the skin, although sometimes HSV-2 passes through unbroken skin.

Genital herpes does not cause AIDS, but some researchers have theorized that the recurrent sores that herpes causes may allow easier transmission of HIV. And more transmission factors may be evident at a molecular level.

"HSV-2 may interact with HIV in the body in ways that we do not yet understand," said Kapiga. "These interactions may reinforce the transmission of both viruses."

Kapiga published a paper, "HIV-1 Epidemic among Female Bar and Hotel Workers in Northern Tanzania: Risk Factors and Opportunities for Prevention," in the March 4 issue of the Journal of Acquired Immune Deficiency Syndromes. Starting in 2000, he and his colleagues at Harvard and Kilimanjaro Christian Medical Center in Tanzania conducted a study involving more than 300 women working in the bars and hotels in Moshi, a town at the foot of Mt. Kilimanjaro.

More than 50 percent of the women had HSV-2.

"Genital herpes may be the most common sexually transmitted disease in Africa," said Kapiga. "Studies have indicated that herpes may be a major factor driving the AIDS epidemic in Africa."

The researchers also found that more than one-quarter of the women had HIV–and none claimed to know it. The prevalence of HIV in the study population was about three times higher than in the general population.

In addition to genital herpes, Kapiga and his colleagues confirmed several risk factors for HIV infection among the study’s participants. Women with multiple sex partners had the greatest risk for HIV (Most of the women in the study had multiple sex partners, and about one-third had exchanged sex for money or gifts). Similarly, women who slept with men who had multiple sex partners were also at increased risk of HIV.

Alcohol use was implicated, increasing a woman’s risk for HIV, probably because alcohol impairs judgment, said Kapiga.

Women with moderate to severe bacterial vaginosis (BV) were at higher risk for HIV. Bacteria called lactobacilli grow normally in the vagina as part of the body’s defense system. BV occurs when levels of lactobacilli decrease, allowing opportunistic bacteria called anaerobes to proliferate. Why BV would increase the risk for HIV infection is not understood.

Condom use was sporadic among the study participants, despite the fact that most of the women were aware that condoms could protect them against HIV and knew that condoms could be easily obtained in the area. Condoms do not fully protect against genital herpes.

Kapiga is planning to conduct a study to assess the safety and effectiveness of topical microbicides, products that can be applied in the vagina before intercourse to prevent HIV. The research, to be funded by the National Institutes of Health (NIH), will be part of the HIV Prevention Trials Network, a worldwide collaborative network of clinical trials established by the NIH.

Kapiga is also seeking funding for a pilot program that will assess the feasibility of implementing long-term behavioral interventions to reduce further spread of HIV in the high-risk population he identified in his study. He sees educational programs that empower women as key to the interventions’ success, as well as programs aimed at men who may be engaging in risky sexual behavior and then infecting their female partners.