An extremely rare
case of female-to-female sexual transmission of HIV has been reported in the
United States. The report concerns a 46-year-old woman who appears to have acquired HIV during a six-month monogamous HIV serodiscordant sexual relationship
with a 43-year-old woman. The newly
diagnosed woman had no other risk factors for HIV and phylogenetic analysis revealed
that the viruses the two women have are closely related. The case is
reported in the March 14 edition of Morbidity
and Mortality Weekly Report.
describes a case of HIV transmission likely by sexual contact between female
partners,” comment the authors. “Other risk factors for HIV transmission were
not reported by the newly infected woman, and the viruses infecting the two
women were virtually identical.”
Confirmed cases of
female-to-female transmission of HIV via sexual contact are extremely rare.
However, possible modes of female-to-female transmission during sex include
exposure to vaginal or other body fluids, blood from menstruation, or blood
from damage sustained during rougher sex. A
rare instance female-to-female sexual transmission was reported over ten year
years ago and was attributed to the sharing of sex toys.
The latest case
was reported to US Centers for Disease Control and Prevention (CDC) in August 2012.
The woman who acquired HIV regularly sold plasma to supplement her income and had a
negative HIV antibody screen when donating plasma in March 2012. Shortly after,
she presented to the emergency department with sore throat, fever, vomiting,
lack of appetite, dry cough, diarrhoea and muscle cramps. These can be symptoms
of an HIV seroconversion illness and the woman had an HIV antibody test but this
However, 18 days
later, an attempt by the patient to donate plasma was refused because HIV
antibodies were detected. Repeat testing confirmed the woman had
It is highly
likely that the source of the patient’s infection was her female partner, who
was diagnosed with HIV in 2008. The partner started antiretroviral therapy in
February 2009 but stopped in November 2010, dropping out of HIV care in January
diagnosed woman had no other recent risk factors for HIV. Nor were any
identified in her past. She had a history of heterosexual intercourse, but not
in the ten years before acquiring HIV. Three female sexual partners
during the previous three years were also reported but the woman had no history
of injecting drug use or other more unusual modes of HIV transmission such as
tattooing, acupuncture, transfusion or transplant.
That her current
female sexual partner was the likely source of her HIV infection was confirmed by
a technique called phylogenetic analysis, which showed that the genetic
sequences of the viruses infecting the two women were highly related.
The couple reported routinely having unprotected (using no barrier precautions) oral and vaginal contact and using insertive sex toys that were shared between them but were not shared with any other persons. They described their sexual contact as at times rough to the point of inducing bleeding in either woman. They also reported having unprotected sexual contact during the menses of either partner.
describes likely female-to-female transmission of HIV-1 supported by phylogenetic
analysis in a WSW [women who have sex with women] couple who had unprotected
sex during a 6-month monogamous relationship,” conclude the authors. “Although
rare, HIV transmission between WSW can occur. All persons at risk of HIV,
including all discordant couples, should receive information regarding the
prevention of HIV.”
The newly infected
woman’s partner had a viral load of 69,000 copies/ml, a level that is known to
be infectious. The authors therefore believe the case underscores the
importance of retaining patients with diagnosed infection in long-term care, as
“control of HIV infection with suppression of viral load can result in better
health outcomes and a reduced chance of transmitting HIV to partners.”