Although the early stages of the AIDS epidemic saw more men infected with HIV than women, a new study from UC San Francisco suggests that certain factors unique to women could be contributing to the current spread. More specifically, the study found that the bacteria in those dirty vaginas of theirs (We kid! Love you, ladies!) can make women more likely to transmit the virus to their male partners.

Published in the journal PLoS Medicine last month, the study looked at 2,236 couples in sub-Saharan Africa where women, especially those aged 15-24 are already eight times more likely to be HIV-positive than men. The study found that women with bacterial vaginosis — or as it's more poetically known: "a disruption of the normal vaginal flora" — were three times more likely to pass the virus on to their male partners than women with (ahem) healthy flora.

While it's still unclear what it is about BV that makes one more likely to transmit HIV, lead author Dr. Craig Cohen of UCSF's OB/GYN & Reproductive Sciences Department, explained that the condition is incredibly common, almost to the point of normality. It affects up to 55% of women in parts of Africa and other resource-poor countries and it is hard to spot because it generally doesn't have much in the way of visible symptoms. As Dr. Cohen put it to the Chronicle: "People don't consider bacterial vaginosis a healthy, natural state. But if you have half the population of women with BV, it begs the question of what's normal."

Meanwhile, Dr. Michael Horberg, director of HIV/AIDS over at Kaiser Permanente, helpfully offered some advice on what this means for the ladies in the audience: "The take-home message is clearly that bacterial vaginosis, when seen, needs to be treated."

[PLoS Medicine]