A 53,000-year-old strain of hepatitis B unique to the Northern Territory is giving new hope for preventative treatment against liver cancer.
New research has suggested the strain – C4 hepatitis B – entered Australia tens of thousands of years ago.
That subtype has not been found anywhere else in the world outside of the Northern Territory, where there are high rates of liver cancer among Indigenous Australians.
Dr Josh Davis, from Menzies School of Health Research, said the strain seemed to be “more aggressive than the strains found elsewhere”.
“This particular C4 virus is quite ancient and probably entered Australia around 53,000 years ago. That also happens to be when we also think that people entered Australia based on the fossil records,” he said.
“So this virus has probably co-evolved with anatomically modern humans since leaving Africa and this particular strain has branched off just before Indigenous people came to Australia.
“Like all organisms, HBV can be divided into subtypes, and in all other regions of the world there are several subtypes of HBV within the population.
“However in the NT, there is only one subtype of HBV, and this has only ever been found in northern Australian Indigenous people.”
Dr Davis said researchers uncovered the rare strain while undertaking “genetic fingerprinting” research among Territorians infected with hepatitis B.
“There was a previously rare or rarely described subtype of hepatitis B that we found in every single person we have tested,” he said.
Researchers also discovered the subtype appeared to make sufferers more susceptible to liver cancer.
That means researchers can now focus on diagnosing the disease early so it can be effectively treated to prevent cancers developing, Dr Davis said.
‘Nothing to do with the behaviour of the individual’
While liver disease and hepatitis B are often assumed to be caused by environmental, social and lifestyle factors, including alcohol use, this research shows that is not always the case, Dr Davis said.
“People sometimes don’t realise … it’s a very common infection in northern Australia and in Indigenous people. Between 5 and 10 per cent of adults have this virus.”
“It’s generally acquired at birth or during early childhood. In other words, [it has] nothing to do with the behaviour of the individual.
“It shouldn’t be seen as a stigma. It’s been around at least 50,000 years.”
One to 1.5 per cent of the broader Australian population have chronic hepatitis B.
The findings, from the Characterising Hepatitis B in Northern Australia Through Molecular Epidemiology project (CHARM), were released as part of World Hepatitis Day.