Australasian Science: Australia's authority on science since 1938

Herpes Remains Active Even without Symptoms

Scientists investigating the herpes virus have been surprised to find an ongoing conflict in the cells of sufferers, even when the virus seems to be dormant.

Herpes simplex type 1 is a virus that causes cold sores. Around 80% of Australians carry the virus, although it is usually in a dormant state. It remains in the body’s nervous system indefinitely after infection.

“We thought when the disease was dormant it was a truce,” said A/Prof David Tscharke of The Australian National University. “It turns out that the virus is waking up more often than we thought, but our cells are constantly pushing it down.”

The findings, published in PLOS Pathogens, could lead to new treatments and help researchers understand why cold sores only flare up sporadically and why some infected people never suffer cold sores at all.

Tscharke’s team used both cells and viruses that were genetically modified so that infected cells changed colour to a bright yellow – even if the virus was dormant. These individual cells were then identified using a microscope equipped with a laser to cut them out, allowing their level of virus activity to be measured.

“We expected that we would see no activity in the dormant cells,” Tscharke said. “The surprise came when we found the virus was doing something in many cells.

“Not all of these cells have the same level of virus activity either. For some it’s very low and in others more of the virus genes are turned on. The host cells were responding most strongly when there was lots of virus activity.”