(HealthDay)—Women appear to have a natural defense against the world's most common sexually transmitted infection, a new study says.
This natural protective barrier consists mainly of lactic acid bacteria—called lactobacilli.
The finding appears online May 29 in the journal Sexually Transmitted Infections.
The discovery could lead to new treatments for "trich," which affects an estimated 174 million women and men around the world each year, according to a journal news release.
Trich is caused by the parasite Trichomonas vaginalis or T. vaginalis. Symptoms of the infection include pain, irritation and discharge. About 50 percent of all people who have this condition, however, don't develop symptoms and are unaware that they are infected.
Researchers Augusto Simoes-Barbosa, of the University of Auckland in New Zealand, and colleagues examined how easily three different strains of T. vaginalis bound to vaginal cells. They repeated the process when nine different types of lactobacilli were also present.
In the vast majority of instances, lactobacilli prevented the parasite from binding to the cells. Some types of lactobacilli were better at preventing the parasite from binding to the cells than others, the study authors pointed out.
"This study reinforces the important role that our microbiomes play in health, infection and disease," they wrote. "Understanding the role that Lactobacillus plays in T. vaginalis infection/disease might reveal new therapeutic approaches, which include taking advantage of the natural probiotic activity of lactobacilli."
Explore further: New research discoveries shed light on common STI
The U.S. Centers for Disease Control and Prevention has more about trich infections.