Herpes simplex virus 1 (HSV-1), which causes cold sores, uses a short, double-stranded RNA to outwit a cell's defensive measures. That's why it can hang out in the body indefinitely, new research suggests. By disrupting this mechanism, scientists may eventually find a way to permanently eradicate herpes infections in people.
Both HSV-1 and its close relative HSV-2, which typically causes genital herpes, infect the nerve cells located outside the brain and spinal cord. Once a person becomes infected, HSV-1 and HSV-2 stick around in a dormant state and can intermittently cause breakouts in some people. The virus succeeds in its long-term residency because it prevents immune system prompts that usually lead virus-infected cells to sacrifice themselves, says microbiologist Nigel Fraser of the University of Pennsylvania School of Medicine in Philadelphia.