In a groundbreaking discovery, scientists have identified the oldest confirmed human RNA virus, dating back to about 250 years ago. The virus was found in a woman in London, and genetic analysis has allowed researchers to trace its origins. While DNA sequencing has enabled the recovery of traces of ancient viruses from human skeletons up to 50,000 years old, RNA viruses like the rhinoviruses that cause common colds are much more challenging to detect due to the instability of RNA.
Recent advancements in technology have allowed scientists to push the boundaries of ancient RNA recovery, with one team even extracting RNA from a woolly mammoth that died 40,000 years ago. However, most ancient RNA studies have been limited to well-preserved materials like permafrost samples or desiccated seeds. Erin Barnett from the Fred Hutchinson Cancer Center in Seattle, Washington, explains that these limitations have hindered our understanding of past human diseases.
To overcome these challenges, Barnett and her team scoured pathology collections across Europe for well-preserved human specimens older than those typically studied. At the Hunterian Anatomy Museum at the University of Glasgow, they discovered lung tissue samples from two individuals – a woman from London who died in the 1770s and another person who died in 1877. Both individuals had documented cases of severe respiratory disease.
Despite the degraded nature of the RNA recovered from the lung tissue samples, the researchers were able to reconstruct the entire RNA genome of a rhinovirus from the 18th-century woman. They also found evidence of bacterial infections in her lungs, including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.
By comparing the ancient RNA virus genome to a database containing millions of viral genomes, the researchers determined that the historical virus belonged to the human rhinovirus A group and shared a common ancestor with the modern genotype A19 in the 1600s. This discovery sheds light on the evolution of RNA viruses and highlights the potential for studying virus evolution over long timescales.
Overall, this study represents a significant milestone in the field of ancient RNA research and opens up new possibilities for understanding the evolution of RNA viruses. Love Dalén from Stockholm University in Sweden emphasizes the importance of this discovery and anticipates a surge in studies on RNA viruses in the future. The stories of these two individuals from history have been brought to light through this research, showcasing the power of genetic analysis in unraveling the mysteries of the past.
