The DNA analysis of the remains of a 16th century mummy has confirmed that the complex Hepatitis B virus (HBV) has existed in humans for centuries, researchers say.

HBV is a deadly viral infection that attacks the liver, can cause both acute and chronic disease and kills nearly one million people every year.The findings are based on DNA extracted from the mummified remains of a small child buried in the Basilica of Saint Domenico Maggiore in Naples, Italy.Previous analysis of the 450-year old mummified remains -- which did not include DNA testing -- suggested that the child was infected with Variola virus or smallpox. 

Using advanced sequencing techniques, researchers now suggest that the child was actually infected by HBV, throwing light on the evolution of the disease."These data emphasise the importance of molecular approaches to help identify the presence of key pathogens in the past, enabling us to better constrain the time they may have infected humans," said lead investigator Hendrik Poinar, an evolutionary geneticist at McMaster University in Hamilton, Canada.While viruses often evolve very rapidly, this ancient strain of HBV has changed little over the last 450 years and that the evolution of this virus is complex, the researchers noted, in the paper published in the journal PLOS Pathogens.

Over 350 million people living today have chronic HBV infections while approximately one-third of the global population has been infected at some point in their lives, emphasising the importance of studying ancient viruses."The more we understand about the behaviour of past pandemics and outbreaks, the greater our understanding of how modern pathogens might work and spread, and this information will ultimately help in their control," Poinar stated.