After infection, some viruses leave their genetic material, or genome, permanently in the tissues of the host. This phenomenon is known as persistence, and it is often life-long. For many viruses, the mechanisms of persistence are so far unknown.
In her doctoral thesis, Mari Toppinen, MSc, studied the persistence of parvovirus genomes in human soft tissues and bones, as well as the occurrence of other viral genomes in human bones. The study demonstrated that both fresh and age-old human bones are excellently suited to investigating the prevalence and evolution of viruses.
Initially, parvovirus genomes were discovered in the bones of people who had died during the Second World War.
“In studies carried out after the find, we uncovered an exceptionally large quantity of human virus genomes in contemporary bones, including herpes, papilloma and polyomaviruses, the hepatitis B virus and the torque teno virus,” Toppinen says.
Archaeovirology – A key to the causes underlying past pandemics
The find launched an entirely new research field known as archaeovirology where the origin of viruses and infectious diseases can be determined by studying ancient human remains. The new approach can provide valuable information on the types of viruses that have caused past epidemics and pandemics.
“Several new viral discoveries have been published recently after our initial study, including historical smallpox virus types and hepatitis B virus types from the teeth and bones of people who lived as long ago as several thousands of years,” Toppinen notes.
Moreover, archaeovirological research may in the future be conducted with the help of viral genomes preserved in bones to, for example, identify individuals or investigate historical migrations. In fact, the persistence of viral genomes in human tissue can benefit not only virologists and epidemiologists, but also anthropologists, archaeologists and specialists in forensic medicine, among others.
Mari Toppinen, MSc, defended her doctoral thesis entitled ‘Parvoviral genomes in human soft tissues and bones over decades’ on 19 February 2021 at 13.00 at the Faculty of Medicine, University of Helsinki. Professor Anna Maria Eis-Hübinger from the University of Bonn will serve as the opponent and Professor Klaus Hedman as the custos.
The thesis is also available in electronic form through the Helda repository.
The public examination can be viewed online. Further information on the event and a link to the live stream are available in the University of Helsinki events calendar.
Read more about the research in an article of the Yliopisto magazine entitled ‘Time travel with viruses’.