Female-to-female transmission probably caused an HIV infection in a Texas woman, according to a report from the Centers for Disease Control and Prevention.
The 46-year-old woman was in a monogamous relationship with an HIV-positive 43-year-old woman. The patient reported no sexual contact with a man for 10 years prior to infection. She regularly sold plasma to supplement her income, and learned of her HIV status in April 2012*, when routine lab work required before every donation came back positive. The labs from her last donation 6 months earlier were clean, Shirley K. Chan and her colleagues wrote in the March 14 issue of the Morbidity and Mortality Weekly Report (2014; 63:209-12).
The patient* did not have any of the classic HIV risk factors, including intravenous drug use, tattoos, acupuncture, transfusions, or transplants. The strains in both women were nearly 98% genetically identical. Therefore, wrote Ms. Chan of the Houston Department of Health and Human Services and her coauthors, fluid exchange with the partner was the most likely source of transmission. The women reported sharing sex toys, engaging in sex during menstruation, and having sex rough enough to cause bleeding in either.
The HIV-positive partner had been diagnosed in 2008. At that time, her HIV-1 viral load was 82,000 copies/mL, and her CD4+ T-lymphocyte count was 372 cells/mm3 (25%). She began antiretroviral treatment in early 2009, but stopped in November 2010. When she was lost to follow-up in January 2011, her HIV-1 viral load had dropped to 178 copies/mL, and her CD4+ T-lymphocyte count had increased to 554 cells/mm3 (44%).
At the time of diagnosis, the patient’s HIV-1 viral load was 23,600 copies/mL. When the partner was tested at that point, her HIV-1 viral load was much lower than the last measurement (69,000 copies/mL).
Woman-to-woman HIV transmission is considered very rare, but the true rate is difficult to determine because confounding risk factors – most often intravenous drug use and sex with men – are usually present, the authors wrote in an editorial note. This finding underscores the need for preemptive counseling for all HIV patients, regardless of their sexual orientation and relationship status, the investigators noted.
"All persons at risk for HIV, including all discordant couples, should receive information regarding the prevention of HIV and sexually transmitted infections to prevent the HIV-negative partner from acquiring the infection. Furthermore, all persons identified as infected with HIV should be linked to and retained in medical care. Control of HIV infection with suppression of viral load can result in better health outcomes and a reduced chance of transmitting HIV to partners," Dr. Chan and her associates said.
As public health care workers, none of the authors had any financial disclosures.
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*Correction, 3/13/2014: An earlier version of this article misstated the time of the patient's diagnosis. In addition, only that the patient did not have any of the classic HIV risk factors.