Friday, April 26, 2013

How Circumcision Reduces HIV Risk

The Tara KLamp*, credit:

Past studies have shown that circumcision reduces female-to-male HIV transmission.

Circumcision also lowers the risk of infection with other sexually transmitted viruses such as human papillomavirus and herpes simplex virus type 2.

A new study suggests a possible mechanism for HIV protection - the dramatic reduction  bacteria living on the penis

The research showed that removing the foreskin affects the type of bacteria that live on the penis. This international collaboration, focused on 156 men in Rakai, Uganda, further found that the decrease was primarily found in 12 types of bacteria, most of which were intolerant to oxygen.

"From an ecological perspective, it's like rolling back a rock and seeing the ecosystem change. You remove the foreskin and you're increasing the amount of oxygen, decreasing the moisture -- we're changing the ecosystem," study corresponding author Lance Price, of the Translational Genomics Research Institute in Arizona and George Washington University, explained

In heterosexual transmission of HIV, the virus on the foreskin needs to reach its target cells, the CD4+ T-cells, which reside primarily in blood or the lymph nodes.

The exact way that the bacterial community on the penis may affect the risk of HIV infection is not known.

The researchers hypothesize that penis bacteria may activate cells in the foreskin called Langerhans cells, preventing them from carrying out their normal role of fighting off viruses. Instead, the activated Langerhans cells may actually help HIV infect by delivering the virus to susceptible T-cells.

They hope their findings could lead to nonsurgical alternatives to circumcision that would alter the bacterial community on the penis and reduce the risk of HIV infection in men.


The above story is based on the April 16, 2013 news release by The Translational Genomics Research Institute.

The findings were published April 16 in the online journal mBio of the Amercian Society for Microbiology:

Liu CM, Hungate BA, Tobian AAR, Serwadda D, Ravel J, Lester R, Kigozi G, Aziz M, Galiwango RM, Nalugoda F, Contente-Cuomo TL, Wawer MJ, Keim P, Gray RH, Price LB. 2013. Male circumcision significantly reduces prevalence and load of genital anaerobic bacteria. mBio 4(2):e00076-13. doi:10.1128/mBio.00076-13.

You can read the Full Text HERE.

More information

The U.S. Centers for Disease Control and Prevention has more about HIV transmission.

* The Tara KLamp circumcision device is the worlds first device based on Non-Invasive Surgery and has been described as the last frontier in circumcision surgery. It was developed by Malaysia’s Dr. Gurchran Singh Tara Singh (strange, because Sikhs don’t believe in circumcision).

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