An emerging bird flu virus could cause a pandemic if action is not taken to prevent it.

A recent study showed that circulating bird flu strains are similar to those that caused the devastating 1918 pandemic, a Cell Press news release reported.

"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," senior study author Yoshihiro Kawaoka of the University of Wisconsin-Madison said in the news release. "Research findings like this help us assess the risk of outbreaks and could contribute to routine surveillance of influenza viruses."

In 1918 a flu pandemic, dubbed the "Spanish flu," killed about 50 million people across the globe. Today's bird flu virus genes could encode proteins that are similar to those seen in 1918.

Researchers generated a flu virus that was made up eight "currently circulating gene segments encoding proteins that resemble the 1918 viral proteins," the news release reported. The result was a strain very similar to the Spanish Flu.

The virus proved to cause flu-like symptoms in ferrets. The virus acquired seven amino acid mutations and a few "key proteins" and spread between animals; the findings suggest the virus has the potential to cause a pandemic.

The Spanish flu differed from currently-circulating viral proteins by only a few amino acids; a few mutations could potentially cause a pandemic.  

"The worst-case scenario is the emergence of a novel avian influenza virus that exhibits high pathogenicity in humans, like H5N1 viruses, and efficient transmissibility in humans, like seasonal influenza viruses," Kawaoka said. "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."