A new study has found that the diversity and number of bacteria in semen are connected with the level of HIV virus and thus the risk of transmission.

While bacteria are common in semen, the study found that HIV-infected men who have sex with men have lower bacterial diversity than uninfected controls. They also found that higher bacterial load is associated with higher virus load and molecules that indicate inflammation.

The authors suggest that controlling the mix of bacteria in semen could be one way of reducing the likelihood of transmission.

Original research paper published in the journal PLOS Pathogens on July 24, 2014.

Names and affiliations of selected authors

Rupert Kaul, University of Toronto, Ontario

Lance Price, Translational Genomics Research Institute, USA