Viral infections leave trace information in our tissues. Researchers can read it like a history book extending from mediaeval smallpox epidemics to ancient Egypt.
Virologist Mari Toppinen began her journey through history at a lecture on identifying war dead, focusing on corpses left on the Russian side of the border after the war between Finland and the Soviet Union. The dead have been transported to Finland for identification, beginning in 1992.
“I was listening to professor of forensic medicine, Antti Sajantila, and I started wondering if the bones on the former battlefield could have signs of parvovirus, which was one of the research topics of our group,” Toppinen says. “During the infection, the parvovirus multiplies specifically in the bone marrow.”
The parvovirus causes a common, typically harmless disease known as fifth disease, which is characterised by an intense red rash. Scientists at the Department of Virology in the Academic Medical Center Helsinki place a special significance on it: It was while studying the very parvovirus that they found what a fascinating compendium of information viruses can leave in the tissues of their hosts during their visit.
Toppinen and her colleagues joined forces with forensic scientists, and found parvovirus DNA in the bones. “We analysed 106 of the war dead. Approximately every other individual had traces of the virus, despite the bones being exposed to UV radiation and the acidic earth.”