Discovery explains how the chickenpox and shingles virus remains dormant

A research team led by UCL and Erasmus University has found a missing piece to the puzzle of why the virus that causes chickenpox and shingles can remain dormant for decades in human cells. Described in a recent paper , researchers discovered there is an RNA transcript in the varicella zoster virus (VZV), that continues to remain active after a person has recovered from chickenpox. Most adults worldwide are infected with VZV, which stays dormant after chickenpox has cleared, but can reactivate later in life - in about 30% of people - as shingles, which causes both a painful rash and the potential for more serious complications including debilitating pain, blindness or a stroke. "It's been more than 30 years since VZV latency in human nerve cells was first described, and ever since then, researchers have been trying to identify the factor that causes the virus to remain latent. Our discovery provides an important step forward towards control of this virus," said the study's lead author, Professor Judith Breuer (UCL Infection & Immunity). Previous studies were unable to identify how VZV latency works, partly because, unlike the herpes simplex viruses, which are also alphaherpesviruses that remains dormant after initial infection, there are no animal models of VZV latency. To overcome this challenge, the researchers developed a new technique using human neurons that were obtained very quickly after the patients had died (6 hours on average), when previous studies had shown that fewer post mortem changes had occurred in the tissues.