NIH Logo Genital herpes is a commonly encountered STD and is not easily diagnosed. A recent study by a team at National Institutes of Health including the Catholic University and the University of Rome has revealed that a common anti-HIV drug could reduce the expansion of the genital herpes virus.

The medicine achieves this by apparently deactivating a vital DNA enzyme of the herpes virus. Known as tenofovir, the scientists found that if it is used in the form of a vaginal gel, herpes simplex virus (HSV) infection as well as HIV infection risks may decrease. Though this medication worked as an anti-HIV agent, its role in herpes had not been known.

“HIV infection is closely associated with herpes viral infection. When people with genital herpes are exposed to HIV, they are more likely to become infected than are people who do not carry the herpes virus. Human tissues convert tenofovir to a form that suppresses HIV. We found that this form of tenofovir also suppresses HSV. This discovery may help to identify drugs to treat the two viruses even more effectively,” commented Leonid Margolis, Ph.D., head of the Section on Intercellular Interactions at NICHD and one of the authors of the study.

As part of the research, the team analyzed individual cells and sets of cells afflicted with HSV and found that large concentrations of tenofovir apparently cut the reproduction of the virus. They also affirmed that the drug on its own does not harm the cells. The latter are seen in the vaginal lining, which are the usual targets of HSV and HIV.

Tenofovir is possibly transformed to some other kind of chemical by cellular enzymes. It is this form that seemingly shows shielding effects not only in HIV but HSV too. Basically, this active form of gel appears to switch off an enzyme that is critical for the virus to spread.

The investigators also administered HSV in the tonsil and cervix tissue followed by the application of tenofovir. After a span of 12 days, it was observed that just 1 to 13 folds of virus levels in untouched tissues, were prevalent in the tissues that were treated. When mice were tested, the drug seemed to prohibit the symptoms of the condition and also extended their lifespan.

However, when the aforesaid medicine was taken orally, it didn’t seem to reach sufficient levels for it to work suitably. The vaginal gel essentially looked beneficial since it comprised higher concentrations of tenofovir. The researchers are all set to look for other forms of such drugs that may have the potential to work against both the viruses simultaneously.

The research is published in the journal Cell Host and Microbes.