Flu viruses currently circulating in birds closely resemble the one that caused the 1918 pandemic that killed about 50 million people worldwide, researchers say.
Only a few differences separate proteins in current flu viruses found in birds and proteins in the virus that caused the 1918 Spanish Flu pandemic, the investigators found.
This suggests that a similar deadly virus could emerge in the near future, according to the authors of the study published in the journal Cell Host & Microbe.
Assessing risk of outbreaks
"Because avian [bird] 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," senior author Yoshihiro Kawaoka, of the University of Wisconsin-Madison, said in a journal news release.
"Research findings like this help us assess the risk of outbreaks and could contribute to routine surveillance of influenza viruses," he added.
It would take just a few mutations for one of the current bird flu viruses to become as deadly and infectious as the 1918 virus, according to the researchers.
"Our findings demonstrate the value of continued surveillance of avian influenza viruses and reinforce the need for improved influenza vaccines and antivirals to prepare for such a scenario," Kawaoka said.
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