“We can take these targeted endonucleases, we can introduce them into a mouse that has a latent herpes infection, we can get them to where the virus lies dormant and we can successfully attack that virus in its dormant state,” Jerome said. “The process can work.”

Researchers in Jerome’s lab deployed DNA-cutting enzymes called targeted endonucleases to damage the herpesvirus genome, inducing mutations that destroy the virus’ ability to replicate. The study is the first in a living organism — rather than a lab dish — to show that gene-editing tools can be delivered to the herpes simplex virus in its latent state or to a latent viral infection of any kind. Doing so is key to curing herpes because a latent infection can reactivate and seed new outbreaks.

The study, published today in the journal JCI Insight, “lays out the pathway toward a potential cure for human herpesvirus infections,” said Dr. Keith Jerome , a Fred Hutch and University of Washington virologist and the paper’s senior author.

Herpes researchers at Fred Hutchinson Cancer Research Center have used a gene-editing technique to attack the DNA of the herpes simplex virus in infected mice. This new research is a key step toward a cure for herpes, an often stigmatized virus that infects one in six people in the United States alone.

Drs. Martine Aubert and Keith Jerome showed for the first time in a living organism that DNA-cutting enzymes called targeted endonucleases can be used to disrupt latent herpes simplex virus.

The plan going forward is to “optimize every step of the process,” including using a newer generation of gene-editing tools such as CRISPR (more on that below), to attack the virus more effectively and boost mutation rates enough for a true cure. Jerome said it would take “several years of work” before researchers could think about testing the approach in human trials.

“But we’re certainly thinking about that,” he said. “That is the goal.”

The physical — and psychological — toll of herpes

There are two types of herpes simplex virus. The most widespread is herpes simplex virus 1, or HSV-1, which is usually transmitted through mouth-to-mouth contact. During an active infection, HSV-1 can cause so-called cold sores around the lips. Globally, it infects more than 3.7 billion people under the age of 50, or 67 percent of the world’s population, according to the World Health Organization.

More troublesome is genital herpes, which is usually caused by herpes simplex 2, or HSV-2, and affects about 417 million people, or about 11 percent, worldwide. It is transmitted through skin-to-skin contact during vaginal or anal sex and can cause painful genital and anal lesions. Another 140 million people have genital lesions caused by HSV-1 transmitted through oral sex, bringing the total number of those with genital herpes to more than half a billion.

With genital infections, the virus can be passed to newborns, a “devastating complication” that can cause serious illness or death if not treated early, Jerome said. In people with suppressed immune systems, such as those undergoing chemotherapy or other cancer treatments, sores can be severe. Genital lesions also can increase the risk of transmitting or getting HIV.

Then there’s the psychological toll. The U.S. Centers for Disease Control and Prevention states that 776,000 Americans are newly infected with genital herpes each year. Even when symptoms are nonexistent, mild or suppressed by medication, infected people can still spread the disease to their sexual partners, making a genital herpes diagnosis a source of embarrassment, shame or stress that can interfere with relationships.

“I felt like someone had just shot me in the chest every single day for those first six months,” wrote Ella Dawson, a self-described feminist millennial sex writer who was diagnosed with genital HSV-1 at age 21 and has since written openly about it in an effort to eradicate the stigma.

Numerous online support groups provide a safe place for the newly diagnosed, who often prefer to be identified only by their screen names, to talk about such things as when to have “The Talk” with a potential romantic partner.

“While many people associate herpes with outbreaks, they don't realize the emotional pain it causes,” said "Dex," who created and runs an online dating site for people with herpes. “The stigma of herpes is often worse than the physical effects. It's not like you can easily tell your friends and family of your new herpes diagnosis. In our world, it is known as ‘The Talk.’ Often, the fear of rejection and the anxiety can keep some from attempting to date at all.”

A cure, Dex said in an email, “would mean so much to so many.”

Reaching the latent virus

HSV infections occur at mucosal surfaces — the mouth, the genitals. The virus is then picked up by sensory nerve endings on those surfaces and travels along axons to neuronal cell bodies, where it persists in a dormant state. But unlike some other lifelong infections that have latent stages — HIV, for example — dormant herpes simplex viruses rest in just two places in the body: a nerve cluster called the trigeminal ganglion in the skull for HSV-1 and, for genital herpes, the dorsal root ganglia adjacent to the spinal cord.

Having these virus dormitories confined to such specific sites is a huge advantage for researchers seeking to cure herpes, as is the relatively small number of neurons infected. By comparison, said Jerome, latent HIV is found in T cells, which are everywhere in the body, and researchers still don’t know the full extent of the latent HIV reservoir.