( CNN ) -- A Texas woman apparently contracted HIV through sexual contact with another woman , the Centers for Disease Control reported Thursday , a rare female-to-female transmission of the virus . Testing confirmed the 46-year-old woman with newly diagnosed HIV `` had a virus virtually identical to that of her female partner , who was diagnosed previously with HIV and who had stopped receiving antiretroviral treatment in 2010 , '' according to the CDC 's Weekly Morbidity and Mortality Weekly Report . HIV transmission through female-to-female sexual contact `` has been reported rarely and is difficult to ascertain , '' officials said . Past confirmation of such transmission `` has been difficult because other risk factors almost always are present or can not be ruled out , '' the report said . `` In this case , other risk factors for HIV transmission were not reported by the newly infected woman , and the viruses infecting the two women were virtually identical . '' The CDC said it was contacted by the Houston Department of Health about the case in August 2012 . The woman newly diagnosed with HIV did not report any other risk factors , such as injection drug use , tattooing , transfusions or transplants , officials said . She supplemented her income by selling plasma , and tested negative for HIV in March 2012 . Ten days after donating plasma , however , in April 2012 , she went to an emergency room complaining of a sore throat , fever , vomiting and decreased appetite , among other symptoms . She again tested negative for HIV . However , she tested positive for HIV when attempting to sell plasma 18 days later , and further testing confirmed the diagnosis . The woman is believed to have been infected by her 43-year-old sexual partner , the CDC said . She told officials the woman was her only sexual partner during the six months before she tested positive . The couple said they routinely had unprotected sexual contact and shared sex toys between them . At times , the contact was `` rough to the point of inducing bleeding in either woman , '' according to the CDC . The women said some of the unprotected sexual contact occurred during menstruation . Commonly , HIV infections in women who have sex with women are traced to risk behaviors such as intravenous drug use or heterosexual sex , the CDC said .
A Texas woman apparently infected her female partner with HIV . Such transmission is rarely reported and `` difficult to ascertain , '' the CDC says . TL;DR