Scientists have reconstructed the genetic code of the deadly 1918 "Spanish flu," which swept the globe and killed an estimated 20 to 40 million people. Among their findings: The 1918 virus strain developed in birds and was similar to the "bird flu" that today has spurred fears of another worldwide epidemic.
By studying the once deadly 1918 virus's genetic information, scientists may become better able to predict future pandemics, or widespread epidemics. It may also aid the development of new vaccines, antiviral medicines, and other treatments to cope with flus.
"The purpose was to get at questions relating to the 1918 pandemic," said Jeffery Taubenberger, of the Armed Forces Institute of Pathology (AFIP) in Rockville, Maryland. Taubenberger co-authored one of several related papers in this week's issues of the journals Nature and Science.
"How did this particular virus form and get into humans? How did a pandemic start?" Taubenberger said. "Why was this particular virus so virulent? And in a broader sense what can we learn from the lessons of 1918 that can help us in the future?"
Influenza viruses were unknown in 1918, so there was no way for doctors or scientists to directly study the flu during or after the outbreak.
But some institutions, like the AFIP, preserved tissue samples from 1918 flu victims. Those 87-year-old samples—and others from a victim who was buried in, and preserved by, Alaskan permafrost—yielded tiny fragments of genetic material that were used to piece together the virus's genetic coding signature.
The final genes of the virus's genome sequence are being published this week. Scientists used the completed, full viral sequence to create a live virus with the eight viral genes of the Spanish flu, named for an early, devastating outbreak in Spain.
Even if somehow released, that virus would be unlikely to cause a pandemic like that of 1918, because humans have likely acquired some immunity in the intervening decades. Nonetheless, it is currently contained at Atlanta, Georgia's Centers for Disease Control and Prevention (CDC) under extremely strict security.
A Weapon Against the Next Pandemic?
Many experts warn that the world is overdue, and unprepared, for a global influenza pandemic. The next outbreak could well be as deadly as the Spanish flu, also known as H1N1, and potentially leave tens of millions dead.
Currently experts can't determine exactly which viruses might spark pandemics, though the Spanish flu data may help to identify which strains bear close observation.
H5N1, a strain of avian influenza called the bird flu, is the most likely candidate. The largely Southeast Asian disease is commonly found in birds but also occurs in mammals like pigs, cats, and humans. It has killed several dozen people, but as of yet it cannot be easily transferred from person to person and so has not developed into a pandemic outbreak.
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