June 12, 2014
Lawrence LeBlond for redOrbit.com – Your Universe Online
Avian bird flu strains that exist today share very similar characteristics with the deadly 1918 Spanish Flu strain that killed nearly five percent of the world’s population. That flu virus pandemic was the worst outbreak ever recorded and new research has found that only a few amino acids separate viral proteins currently found in bird populations from those that existed during the 1918 virus. The new evidence suggests a similar deadly virus may emerge in the near future.
Publishing a paper in the journal Cell Host & Microbe, an international team of researchers searched public databases to identify eight genes from influenza viruses isolated from wild ducks that possess remarkable genetic similarities to the genes that made up the 1918 pandemic flu virus. The Spanish Flu infected some 500 million people around the world, killing an estimated 40 million of them.
Led by Yoshihiro Kawaoka, an international expert on influenza from the University of Wisconsin-Madison, the new work shows “there are gene pools in nature that have the potential to cause a severe pandemic in the future.”
“Because avian influenza viruses in nature require only a few changes to adapt to humans and cause a pandemic, it is important to understand the mechanisms involved in adaptation and identify the key mutations so we can be better prepared,” Kawaoka said in a statement. “Research findings like this help us assess the risk of outbreaks and could contribute to routine surveillance of influenza viruses.”
To assess the risk posed by a virus that could acquire all eight of the 1918 flu genes, Kawaoka and colleagues used reverse genetics methods to generate a virus that differed from the Spanish Flu virus by only three percent of the amino acids that make the virus proteins. They discovered the resulting virus was more pathogenic in mice and ferrets than a typical avian flu virus, but was not as pathogenic as the 1918 virus and did not transmit via respiratory droplets, the typical mode of flu transmission.