Scientists have used controversial gain-of-function research to resurrect the deadly Spanish Flu that killed millions of people around the world in the early 20th century.
The team of gain-of-function researchers in Canada and the US reports that they successfully re-created the 1918 influenza virus and used it to infect macaques.
Shortly after World War I, Spanish Flu infected over one-third of the global population and killed an estimated 17 to 100 million people worldwide.
Epidemiologists regard it as the worst plague since the Black Death in the 14th century.
Five hundred million people caught it.
The 1918 flu first became apparent in Kansas City in military camps in April 1918, but the information was kept secret.
When it appeared in Spain in May 1918, the officials talked openly about it, and it became known as the Spanish Flu.
For the past two decades, scientists have been trying to resurrect the deadly virus.
About 20 years ago, a small team of researchers led by Jeffery Taubenberger and Ann Reid figured out how to sequence the genome of the 1918 flu, Forbes reported.
In a series of papers spread over six years, they described how they recovered pieces of the flu virus from human samples frozen for nearly 100 years, including corpses buried in the permafrost of Siberia and Alaska.