HIV attacks normal, healthy genital tissue, suggests a newly released study by U.S. researchers, which offers new insights into how the virus spreads.
Previously, researchers thought the human immunodeficiency virus, or HIV, could only get through already damaged skin in the vagina to infiltrate the immune system cells deeper within the tissue.
“Normal skin is vulnerable. We previously thought there had to somehow be a break in it,” said Thomas Hope of Northwestern University's Feinberg School of Medicine.
The findings were presented December 16 at the American Society for Cell Biology 48th Annual Meeting (ASCB) in San Francisco.
Until now, scientists had very little understanding of how the virus is transmitted in women.
For the study, Hope and Northwestern colleagues and collaborators at Tulane University studied vaginal tissue removed during hysterectomy procedures and introduced the virus which carried fluorescent tags.
By using a microscope they were able to observe the virus as it penetrated the outer lining of the female genital tract, called the squamous epithelium.
It took just four hours for the viral particles to move between skin cells and reach a depth of 50 microns - similar to the width of a human hair - where they were able to target immune cells, which the virus targets.
The findings may also shed some light on why some prevention efforts have continuously failed. A clinical trial in Africa, in which women used a diaphragm to protect the cervix, was ineffective at reducing virus transmission, said Hope. And various studies of drugs designed to prevent lesions in genital herpes have also been unsuccessful thus far.
The study emphasizes the need for treatments such a vaccine to prevent the virus, said Hope.
“Sadly, if more people practiced safe sex and used a condom, we wouldn’t have this problem,” said Hope. “Condoms are highly effective in preventing HIV.”
A recent study released by researchers of the Centers for Disease Control and Prevention estimates 250,000 Americans in non-high-risk groups are HIV positive, but don’t know it.
A person who is HIV-positive, but unaware they are infected, is three times more likely to transmit the infection than a person who is aware they have it.
Acquired immunodeficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV) and may be contracted through exposure to bodily fluids, including but not limited to blood and semen.
Women and female adolescents account for 26 percent of all new HIV cases in the U.S. The CDC estimates that about 56,300 people were infected with HIV in 2006 (the most recent year data is available). Visit the HIV incidence page for more details. #