Scientists have discovered how HIV is transmitted

A team of scientist have discovered the origin of strains of the AIDS virus that affect gay and bisexual men and the findings were published in the Feb 10 issue of Science Translational Medicine.

"If we want to stop the HIV epidemic then we must know the mechanisms by which HIV uses human sex to spread," said Dr. Davey Smith an Associate Professor of Medicine at the University of California San Diego. Smith and a group of researchers used a genetic analysis to study men who had sexually transmitted HIV to other men.

By comparing genetic characteristics, called phylogenetic analysis and studying a group of men who had transmitted the HIV virus, the researchers were able to determine the source of the HIV viruses. "Until now, it had not been established whether HIV RNA or DNA is transmitted during sex. By analyzing the genetic differences between these two forms and the virus that was ultimately transmitted to newly infected individuals, we found that it was the HIV RNA form present in seminal plasma that was transmitted," said Dr. Smith.

By knowing the origin scientists will now be able to develop new drugs and vaccines to prevent the spread of HIV.  The transmission of HIV to women has not been confirmed, but is thought to be HIV RNA in the seminal plasma.