The female body has often been overlooked in science, and the vagina remains the most taboo part of it.

This reproductive organ houses billions of bacteria, archaea, fungi and viruses in a complex community crucial for overall health. But there’s a dearth of data on vaginal microbiota — the microbes and their functions, says microbiologist Sarah Lebeer of the University of Antwerp in Belgium. Citizen science can help build data on what constitutes healthy vaginal microbiota, giving researchers the tools needed to identify when things go awry, she and her colleagues propose February 6 in Trends in Microbiology.

“If we better understand when a vaginal microbiome is disrupted and how it can cause disease, then we can have better diagnostic tools … and can think of new therapies,” Lebeer says.

A 2011 paper in the Proceedings of the National Academy of Sciences identified five categories of vaginal bacterial communities in North American women who showed no signs of illness. That list eventually expanded to more than 20 categories, Lebeer says.

But her own recent study, which included more than 3,000 women in Belgium, found that more than 10 percent of participants had a microbial composition that sat in between previously defined categories, and could not easily be sorted.

To understand the full spectrum of healthy vaginal microbiota, Lebeer and colleagues are calling upon citizen science. The Belgian study relied on citizen scientists mailing in their own samples and filling out surveys through the Isala project, named after the first woman doctor in Belgium. Scientists in around 10 more countries are now starting their own regional projects as part of the Isala Sisterhood consortium.

Internationally, vaginal microbiota are “even more diverse,” Lebeer says. Thanks to this diversity and advanced computing power, she says researchers should consider the whole composition of the vaginal microbiota and go beyond categorizing microbial community types.

Easier identification of healthy microbiota could be useful for physicians on the lookout for microbial communities that are out of balance. For instance, a lack of Lactobacillus bacterial species and an overgrowth of others — a condition called bacterial vaginosis — has been associated with myriad issues, including preterm birth, urinary tract infections, reduced HIV drug efficacy and an inflamed uterine lining, known as endometritis.

Many factors can influence the vagina’s microbial makeup. Diet, hormone levels, experiences with childbirth, hygiene practices and more can alter microbe diversity, Lebeer notes. These factors should take precedence over associations with race or ethnicity, which many studies have attributed differences to, she says. “If you look at the vaginal microbiome, which is inside the human body, race or skin color doesn’t seem to have a direct impact.”

Genomicist Jacques Ravel, who led the 2011 PNAS study and wasn’t involved in the new report, agrees. Race is a stand-in for a group’s collective experiences, says Ravel, of the University of Maryland School of Medicine in Baltimore. Those experiences include stress, disparities, discrimination and passed-down cultural norms, such as vaginal douching, known by scientists not to be great for health, he says. Previous research suggests the practice increases the risk for pelvic inflammatory disease by nearly 75 percent.

While Ravel applauds Lebeer and colleagues’ overarching argument for more research, he’s not convinced that additional surveys are currently needed. Instead, he wants to know how various microbes can help or harm health. This kind of research will mostly require participants to come into a lab or clinic for health workers to collect samples that will be analyzed right away, Ravel adds.

That mechanistic work could help find better prevention and treatment methods for health issues like HIV, pelvic inflammatory disease and bacterial vaginosis. The latter has been primarily treated with two antibiotics for decades, Ravel says. “We have had zero innovation in this field, in treating a [condition] that is responsible for a huge amount of disparities around the world.” Among reproductive-age women, the global prevalence of bacterial vaginosis is about 26 percent, but it’s more common in areas with fewer resources and limited access to health care, according to the World Health Organization.

A better understanding of well-balanced vaginal microbiota could help combat these conditions, too, Lebeer says. For instance, scientists have recently started studying vaginal transplants of Lactobacillus bacteria as a potential treatment, she says.

Citizen science can also drive research in new directions. One of Lebeer’s current projects on how menstrual hygiene products affect vaginal microbes was proposed by people working on and around the Isala project. “If you do citizen science,” Lebeer says, “you have more experts around the table.”