🦠 Scientists Decoded Genome of Early "Spanish Flu"
An international team from the Universities of Basel and Zurich assembled the full genome of the 1918 influenza virus (H1N1) from lung tissue that had been stored in formalin for more than a century.
The lung sample belonged to an 18-year-old Zurich local who died during the first wave of the pandemic in July 1918.
The work provides new data on one of the deadliest pandemics of the 20th century, which claimed an estimated 17 million to 100 million lives.
For the first time, researchers obtained the genome of the virus that circulated in Switzerland. Comparing the Swiss genome with samples from Germany and North America revealed three mutations already present early in the pandemic.
Two mutations increased the virus's resistance to the human immune response. A third enhanced its ability to bind to cells in the human respiratory tract. This last change helped the virus infect people far more efficiently than its original avian hosts, enabling it to spread widely.
Until now, such old formalin-fixed samples were considered almost unsuitable for research, but a new RNA-extraction method overcomes this barrier, the authors note. The approach expands the study of historical pathogens and will help track their evolution more precisely and model the risks of future pandemics.
