When AIDS viruses are transmitted despite treatment
Berne, 24 June 2013
While antiretroviral drugs offer an efficient means of preventing the replication of HIV in the blood, shedding of HIV may
occur in semen, so that other persons can become infected during unprotected sexual intercourse. This occurs in particular if the male
genital tract also has other viral infections. That is the conclusion reached by a scientist who is supported by the Swiss National
Science Foundation (SNSF).
In principle, modern combination therapies are very effective at keeping AIDS causative agents in check. The treatment
usually leads to a situation in which there is no longer any evidence of Human-Immunodeficiency Viruses (HIV) in the body. In this
way, the drugs can also reduce the disease transmission rate to just one tenth. So why do new infections occur despite treatment?
Sperm containing a cocktail of viruses
The answer, according to findings recently published(*) by the Swiss researcher Sara Gianella Weibel and her American colleagues, is that
other viruses also play a role. Working at the University of California in San Diego, the SNSF-funded scientist studied the semen of
114 HIV-infected men undergoing treatment who have sex with men. She found that the seminal fluid of 11 of the men contained a
considerable quantity of HI viruses, even though the viral load of the blood of all of the men was very low. In eight of
these 11 cases, Gianella Weibel also found evidence of various forms of herpes.
Locally activated immune system
Some of these herpes viruses, such as cytomegalovirus, often remain unnoticed. However, if the viruses infect the male genital tract, they
locally activate the immune system. As a result, there is a build-up of immune cells, including those in which HIV replicate, in the
genital area. "Our data suggests that we must also direct our focus towards other viruses, if we really want to interrupt the
transmission of AIDS," explains Gianella Weibel.
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(*) Sara Gianella, Davey M. Smith, Milenka V. Vargas, Susan J. Little, Douglas D. Richman, Eric S. Daar, Michael P. Dube, Fan Zhang,
Christina G. Ginocchio, Richard H. Haubrich, Sheldon R. Morris and the CCTG 592 Team (2013). Shedding of HIV and human herpesviruses
in the semen of effectively treated HIV-1 infected men who have sex with men. Clinical Infectious Diseases online. doi: 10.1093/cid/cit252
(Manuscript available from the SNSF; e-mail: com@snf.ch)
Contact:
Dr. Sara Gianella Weibel
Center For Aids Research (CFAR)
University of California San Diego
La Jolla CA, 92093-0679, USA
E-mail: gianella@ucsd.edu
Source: Swiss National Science Foundation (SNSF)
About Swiss National Science Foundation (SNSF)
Every year the Swiss National Science Foundation (SNSF) supports approximately 8,500 scientists. It is Switzerland's foremost institution in the promotion of scientific research. One of its core tasks is the evaluation of research proposals and, every year, the SNSF awards over 700 million Swiss francs to the best applications. By distributing public research money based on a competitive system, the SNSF contributes to the high quality of Swiss research.
To ensure its independence in research, the SNSF was established as a private foundation in 1952. Mandated by the federal authorities, the SNSF supports basic science in all academic disciplines, from history to medicine and engineering sciences.
In close collaboration with higher education institutions and other partners, the SNSF works towards creating the best possible conditions for the development and international integration of Swiss research. The SNSF is paying particular attention to the support of young scientists. www.snf.ch
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