A rare case of female- to -female sexual transmission of HIV (human immunodeficiency virus) has been reported in the United States. (Purple Sherbet Photography/Flickr)Purple Sherbet Photography

A rare case of female-to-female sexual transmission of HIV (human immunodeficiency virus) has been reported in the United States.

According to a report released by the Centers for Disease Control and Prevention (CDC) on March 14, a 46-year-old woman from Texas contracted the deadly virus from her HIV positive female sexual partner. The woman, who stopped heterosexual intercourse 10 years before the diagnosis and sexual relationships with her three female partners five years later, had been on a monogamous relationship with the 43-year-old female sex partner, from the past six months until her HIV diagnosis.

The woman was reported engaging in unprotected oral and vaginal sex with her partner. They also shared the same insertive sex toys, engaged in rough sex and also unprotected sex during menstrual periods.

The incident came to light only in April 2012, when the woman tried to sell her plasma. Her plasma was rejected as she tested positive for HIV. Medical tests showed that the virus involved in both cases were the same. Further investigation showed that the female partner, who tested positive for HIV in 2008, had stopped taking the antiretroviral treatment in 2010.

The rare transmission of HIV soon captured attention of health authorities and the Houston Department of Health notified CDC about it in August 2012.

In their report titled "Likely Female-to-Female Sexual Transmission of HIV - Texas, 2012," the health officials said that unprotected exposure to body or vaginal fluids, menstrual blood, bleeding caused by rough sex can increase the risk of female-to-female transmission of HIV. Apart from these, their list included some other factors including injection drug use (IDU), heterosexual sex, tattooing, acupuncture, piercing and sharing of sex toys, organ transplantation or blood transfusion.

However, in the Texas case, the woman was reported as not engaging in any of these activities except sharing sex toys with partner and engaging in rough sex and exposure to menstrual blood.