Researchers found 12 ancient hepaтιтis B genomes, including one variation of the virus that’s now-extinct.

Hepaтιтis B virus (HBV) is a major cause of human hepaтιтis, which afflicts over 250 million people. Now, we know that is has been infecting people for at least 4,500 years.

Research published in the journal Nature on May 9, 2018, revealed that Hepaтιтis B was found on skeletons from the bronze age, making it the oldest human virus ever discovered.

MSN NewsPrior to the study, the oldest human virus detected was from 450 years ago.

A team of geneticists sampled DNA from around 300 skeletons when the discovery was made. The skeletons, between 200 and 7,000 years old, were from Europe and Asia.

They found 12 HBV genomes in 12 ancient humans, which showed that the same types of HBV prevalent in Asia and Africa today were present thousands of years ago. They also found an extinct variation of the virus, though it wasn’t previously known that viruses could become extinct, the study said.

The 4,500-year-old ancient human was from the “Beaker Bell” culture in Osterhofen, Germany, named for the bell-shaped pottery cups they left behind.

Nicole NicklischSkeletal remains of HBV positive individual from the Stone Age site of Karsdorf, Germany.

Before this, the oldest virus detected in humans dated back just 450 years. “We’re all quite excited that we can actually go [this] far back with HBV,” said Johannes Krause, an evolutionary geneticist at the Max Planck Insтιтute for the science of Human History in Germany.

According to Lilly Yuen, a senior medical scientist at the Victorian Infectious Diseases Reference Laboratory, they’ve found the HBV in ancient bird genomes that suggest it could actually be millions of years old.

Hepaтιтis B is an infection of the liver that can lead to liver failure or cancer. Though there is a vaccine for Hepaтιтis B, chronic infections still have no cure. People who have chronic Hepaтιтis B are often infected during childhood and don’t know it because symptoms are dormant for many years. Meanwhile, the disease progresses and patients only become aware later in life when the liver begins to scar.

Hepaтιтis B has many mutations that no longer exist. The new information found in this study can provide insight into the continuing evolution of the virus, which can help us prepare for dangerous new strains.

“It’s a hugely important moment in our understanding of one of the most important pathogens of humans,” said Edward C. Holmes, a virologist at the University of Sydney.