The Centers for Disease Control and Prevention (CDC) has reported a rare case of apparent sexual transmission of HIV between two women, MedPage Today reports. Publishing the case in the March 14 issue of Morbidity and Mortality Weekly Report, the CDC describes a 46-year-old woman in Texas who appears to have contracted the virus from her HIV-positive partner, a 43-year-old woman with whom she'd been in a monogamous relationship for six months.

In April 2012, when the 46-year-old woman attempted to sell her plasma, an enzyme immunoassay (EIA) test found that she was HIV positive. She had made a similar attempt to sell plasma one month before and had tested HIV negative. Ten days after that earlier donation attempt, she visited an emergency room with a sore throat, fever, vomiting, decreased appetite, painful swallowing, dry cough, diarrhea and muscle cramps—symptoms consistent with seroconversion illness. While she tested HIV negative at that point, researchers think that, because that EIA screen was likely conducted during the test's “window period,” she received a false negative result.  It is also possible that the previous test was a false negative.

Her partner was diagnosed with HIV in 2008 and had begun taking antiretrovirals, but she stopped taking them in 2010. Had she continued taking the ARVs, her likelihood of transmitting the virus would have been reduced by 96 percent, according to current research.

The couple reported oral and vaginal sexual contact without barrier protection (such as a dental dam). In addition, they shared insertive sex toys among themselves and had sex during their respective periods. Their sexual contact was on occasion “rough to the point of inducing bleeding,” the CDC reports.

The woman who contracted HIV in 2012 said she had not had sex with a man during the previous 10 years, nor had she used injection drugs or received acupuncture, transfusions, transplants, or engaged in any other risky sexual behavior.

Genetic analysis of HIV in each woman showed that the virus was nearly identical between them, all but confirming the transmission between them.

To read the MedPage Today story, click here.

To read the CDC report, click here.