Scientists resurrect 1918 flu virus

Scientists have resurrected the influenza virus that killed an estimated 50 million people in 1918, the worst pandemic in history.

They used a process known as "reverse genetics" to reconstruct a living flu virus from dead fragments retrieved from stored hospital tissue samples and a corpse that had been buried in the frozen tundra of Alaska for 80 years. Tests on animals and human lung cells showed that the reconstructed virus retained the highly lethal properties that made the 1918 strain of influenza such a killer.

Scientists working for the US Centres for Disease Control and Prevention (CDC) in Atlanta, Georgia, said the virus was being kept in one of its high-security laboratories.

The reconstructed virus quickly killed laboratory mice and chick embryos when they were infected with the agent. It also grew rapidly in cultured human lung cells.

In contrast, most flu viruses that infect humans today show none of these lethal characteristics, said Terrence Tumpey, whose study is published today in the journal Science.

The influenza outbreak of 1918 was the largest of the three flu pandemics of the 20th century. A separate study in the journal Nature reveals that the 1918 virus was in effect an avian flu virus that had jumped the species barrier into humans.