Researchers in Canberra have discovered the herpes virus remains active in the body even when there are no symptoms, potentially opening the door to new treatments and clues as to why cold sore flare up sporadically and why some infected people never get them.
Scientists from the Australian National University Research School of Biology have found the herpes virus is more active than initially thought, offering new insights into what the body intrinsically does to fight the virus.
Associate Professor David Tscharke said it had been discovered that the virus could be "fully awake" even if a person did not have symptoms, such as a cold sore.
"It turns out that that the virus is waking up more often than we thought, but our cells are constantly pushing it down," he said.
He said the herpes virus tended to "hide" in certain neurons in the body's nervous system when the virus was in a dormant state.
"We expected to find very little viral activity going on and that the virus wasn't trying to turn itself on, but we found that in something like two thirds of the neurons, the virus was actually turning itself on," he said.
"The more the virus was turning its genes on, the more the neuron was turning on genes to try and fight the virus. It's like a low-grade battle going on in the neuron very often with the virus trying to come out and the host cells and the neurons themselves trying to keep the virus under control."
He said this offered a possible explanation as to why some infected people did not constantly have cold sores.
"This is very different to an idea which says the virus has just gone into those neurons, has completely gone to sleep and it goes to sleep until there's some trigger, for example, stress or a UV burn (on the lips) and then the virus completely wakes from doing nothing," he said.
"In fact, what's happening is the virus looks like it is trying to wake up a little bit all the time and so what these triggers are doing are probably inhibiting our neurons' ability to stop the virus."
The research was conducted in mice, and Associate Professor Tscharke believes it could open the door to new treatments and offer clues into why cold sores flared up only sporadically and some infected people never suffered cold sores.
"The important thing with this research is that it allows us to know more about what the body is doing intrinsically to fight the virus and so that gives us insight into pathways and things that we might want to try," he said.
"What our study suggests is that there's a whole new range of human genes that may be useful targets for new therapies."
Herpes Simplex Type 1 is a virus which causes cold sores and it is believed 80 per cent of Australians carry it. There is no cure.
He said the research could also be applied to genital herpes as the viruses were "almost exactly the same".