Reconstruction of the 1918 Influenza Virus Genome from Swiss Historical Specimen

Researchers from the University of Basel and the University of Zurich have successfully reconstructed the genome of the influenza virus responsible for the devastating 1918–1920 pandemic in Switzerland. Utilizing a century-old specimen from UZH’s Medical Collection, the team decoded the viral genetic material, revealing that the virus had already developed critical adaptations to infect humans at the pandemic's outset.

This groundbreaking study provides new insights into the virus’s early evolution and adaptation processes during the pandemic. The virus was obtained from an 18-year-old Zurich patient who died during the first wave in July 1918, and the genome was sequenced despite the challenges posed by the RNA's rapid degradation over time.

By comparing the Swiss genome with previously published influenza genomes from North America and Germany, the researchers identified three key mutations that the virus carried at the start of the pandemic. Two mutations increased the virus’s resistance to human immune components, hindering the immune system’s ability to prevent infection. The third mutation involved a viral membrane protein that enhanced its capacity to bind to human cell receptors, making it more infectious.

To accomplish this, the scientists developed a new method for recovering and verifying ancient RNA fragments, which is crucial because influenza viruses carry their genetic information in RNA, a molecule that degrades quickly under long-term preservation conditions. This innovative technique not only facilitated the genome reconstruction but also allowed researchers to authenticate the RNA, ensuring the accuracy of their findings.

This study underscores the importance of medical collections as valuable archives for studying ancient RNA viruses. Collaborating with UZH's Medical Collection and the Berlin Museum of Medical History, the team highlights the underutilized potential of such specimens in researching the history of pandemics.

Understanding how viruses evolve and adapt over time is vital for predicting and mitigating future outbreaks. The insights gained from studying long-preserved viral genomes can inform the development of models for future pandemic preparedness. An interdisciplinary approach that combines historical, epidemiological, and genetic data forms the foundation for this predictive capability, enabling better understanding and response strategies.

This pioneering research was published in BMC Biology and was led by paleogeneticist Verena Schünemann, with contributions from Christian Urban and Kaspar Staub, showcasing the crucial role of interdisciplinary work in advancing pandemic research.

For more detailed information, see the publication: Christian Urban et al, "An ancient influenza genome from Switzerland allows deeper insights into host adaptation during the 1918 flu pandemic in Europe," BMC Biology (2025). Source: https://medicalxpress.com/news/2025-07-swiss-genome-influenza-virus-reconstructed.html