WASHINGTON, Oct 5: Scientists who resurrected the 1918 ‘Spanish flu’ virus that killed as many as 50 million people said on Wednesday they are beginning to understand why it caused such a deadly pandemic and say it could happen again.

They have begun comparing the genetic mutations in the 1918 flu to those being seen in the H5N1 avian flu virus killing tens of millions of poultry and some people in Asia, in the hope of being able to predict and perhaps even prevent a similar pandemic.

“We felt we had to recreate the virus and run these experiments to understand the biological properties that made the 1918 virus so exceptionally deadly,” said Terrence Tumpey of the US Centers for Disease Control and Prevention in Atlanta, who helped write the reports published jointly this week in the journals Nature and Science.

The experiment, in which the virus was recreated employing a process called reverse genetics using preserved samples of the 1918 virus, allowed the researchers to test it in the laboratory and in several animals.

It will help answer important questions, said Dr. Jeffery Taubenberger of the Armed Forces Institute of Pathology in Rockville, Maryland.

“How did the virus get into humans and how did the pandemic start? Second is to understand how this particular virus was so virulent,” Taubenberger told reporters in a telephone briefing.

“What can we learn from the lessons of 1918 to prepare for and mitigate against a future influenza pandemic?” he asked.

Drugs and vaccines could be designed to target the mutations found in the research, Taubenberger said.

Taubenberger’s team used pieces of virus taken from preserved samples from 1918 victims, as well as from the corpse of a victim dug up from a frozen grave in Alaska in 1998.

They used these pieces to make a replica of the 1918 virus, and brought it back to ‘life’ — viruses are not truly alive like other microbes — by combining it with modern influenza virus pieces and growing it in bacteria.

“We now think that the best interpretation of the data available to us is that the 1918 virus was an entirely avian-like virus that adapted to humans,” Taubenberger said.

This, he said, was different from the two other 20th century flu pandemics, in 1958 and 1967, in which different flu viruses actually swapped genes to become especially virulent.—Reuters