The discovery sheds light on an important tool for fighting drug-resistant strains of herpes simplex virus, or HSV, and points to new pathways for treating herpesviruses and other kinds of DNA viruses (those that have DNA as their genetic material and can replicate inside host cells).

The study is published in Cell.

As an infectious disease doctor at Brigham and Women’s Hospital, study co-senior author Jonathan Abraham has seen many patients with compromised immune systems develop dangerous drug-resistant HSV infections. Such resistance can evolve when the virus is repeatedly treated with the same type of antiviral.