For the first time ever, researchers from the University of Helsinki and the University of Edinburgh have discovered the genetics of a virus from skeletal human remains. The findings were published in Scientific Reports, where the study analyzed the bones of 106 casualties from the Karelia battlefields of the Second World War.

"Human tissue is like a life-long archive that stores the fingerprint of the viruses that an individual has encountered during his or her lifetime," Klaus Hedman, who oversaw the research, said in a press release.

Once viruses infect their host, many of them remain in tissue for decades, allowing scientists to analyze their DNA years later. Although scientists have long found virus genetics in organs, this is the first time that researchers have discovered them in bones.

Since most bones are preserved long after death, this new finding opens the door to many avenues of research and gives scientists the ability to study viruses that were the root of past infections.

"By mapping and analyzing the viral genes in old human samples, we can deepen our understanding of the way viruses develop and spread," the scientists explained. "The results can be compared to those with contemporary viruses and their virulence, improving our ability to prevent and eradicate infectious diseases."

Using the bones of two casualties, the scientists discovered the DNA of a parvovirus that has never before found its way into Nordic countries. They then combined the results with the DNA profiles of the bones and were able to infer that they were soldiers of the Red Army.

"Such a combination of human and viral DNA can help us both identify the recently dead - making it a new tool for forensic identification or ancestry investigation- and determine how ancient humans migrated around the globe," said Antti Sajantila, co-author of the study.