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Common Bacterial Infection Increases Woman's Risk Of HIV Infection

Researchers in South Africa say a common bacterial infection makes women more susceptible to HIV/AIDS and other diseases. And they say that very often the condition goes untreated. Voice of America’s Joe De Capua reports.

It’s called bacterial vaginosis. Researchers at the University of Cape Town’s School of Public Health – including Dr. Landon Myer – found it widespread among the 5,000 women taking part in a two-year study. Dr. Myer says bacterial vaginosis creates conditions that allow harmful bacteria or viruses to flourish.

“Under normal conditions, the vagina is colonized primarily by lacto-bacilli, which produce hydrogen peroxide – or most of which produce hydrogen peroxide – that maintains an acidic PH in the vagina. And under conditions of bacterial vaginosis, these lacto-bacilli die off and they’re replaced with anaerobic organisms – organisms that don’t require oxygen to survive – and they lead to a raised PH in the vagina, a less acidic vagina, a more basic vagina, and this condition is association with symptoms of vaginal discharge that are pathogenic,” he says.

Just how widespread was the problem among the 5,000 women studied?

Dr. Myer says, “More than half of women had micro-biologic evidence of bacterial vaginosis. And certainly this finding is corroborated by data we have from Uganda, data from Kenya and other parts of South Africa where bacterial vaginosis appears more common in the (United) States or in Europe, where generally somewhere between 10 and 30 percent of women have bacterial vaginosis, depending on the particular study population. Here in our study we found well over 50 percent.”

Doctors are not sure what causes the condition, but certain things can increase the risk by interfering with normal bacteria. These include having a new sex partner or multiple sex partners, douching and using an IUD, or intrauterine device, for contraception. However, Dr. Myer says there’s at least one other contributing factor.

“In addition, a second mechanism that’s commonly cited is an inflammatory mechanism. HIV thrives under conditions of inflammation. And bacterial vaginosis is associated with increased inflammation of the vagina in the expression of cytokines that facilitate viral expression, viral adhesion and infection,” he says.

A Cytokine, as mentioned by Dr. Myer, is a substance produced by the body’s immune system.

Besides making a woman more susceptible to HIV and other infections, bacterial vaginosis can also increase the risks during pregnancy.

“Bacterial vaginosis is very strongly associated with an infection of the placental membranes - and as a result is strongly associated with the premature rupture of membranes in premature birth, leading in turn to low birth weight. And the context in which bacterial vaginosis has received the most attention before the HIV epidemic was as a cause of low birth weight and premature births,” Dr. Myer says.

The University of Cape Town researcher says studies show treatment of the condition “may be a strategy for reducing low birth rate in high risk women.” A common antibiotic has been used as treatment, but Dr. Myer says it’s not always 100 percent effective.

“The treatment success rate of metronidizol not brilliant. Depending on the study, anywhere between 20 percent and 70 percent of women have a recurrent infection, recurrent bacterial vaginosis after receiving apparent successful treatment. So, this ties back to the notion that we don’t understand the causes of bacterial vaginosis very well. And we don’t understand exactly how to go about treating it optimally as a result,” he says.

Dr. Myer says studies in South Africa indicate many women with the condition did not realize the serious health risks involved and failed to go for treatment.