The strain of influenza that has swept across China is the second wave of bird flu to hit the country and has mutated frequently.  Scientists now believe that this strain of bird flu "should be considered as a major candidate to emerge as a pandemic strain in humans."

While it is simply much too early to predict what might happen with this virus, some scientists believe there is cause for alarm because the H7N9 virus jumps to humans much more quickly and easily compared to past strains previously found in mammals.

"This virus is more dangerous," said Yi Guan of the University of Hong Kong, one of the authors of a research letter published online Wednesday in the journal Nature.

Scientists are currently unsure why this latest outbreak, which began in 2013, has re-emerged after fading.  However by September 2014, this strain of influenza had infected 318 people and killed more than 100 of them, twice as many as the first wave. 

According to the World Health Organization, many people that become infected with this type of flu also suffer severe pneumonia.   This strain of flu, originally began in China but has already spread across the globe and has also been found in Taiwan, Hong Kong, Malaysia and even Canada.

"What we don't know from this paper is the significance of all these mutations that are accumulating as the virus persists and spreads," Wendy Barclay, an expert in flu virology at Britain's Imperial College London, told Reuters. "This is especially relevant for human health - does any of this change the pandemic potential of the virus?"

This isn't the only variant of bird flu that causes physicians and researchers concern.  Another strain, H5N1, has infected nearly 650 humans in fifteen countries since 2003 and continues to spread.

On Wednesday, the U.S. government announced that it had discovered yet another new case of a different bird flu in Arkansas.  This strain, the H5N2, appears to be spreading from commercial turkey flocks in Missouri and Minnesota.  This strain of avian flu has not yet been found in humans, however, and many experts believe the risk to people is very low compared to other, more dangerous strains of influenza.

However, this strain of flu does pose a danger to flocks as it can kill a bird in as little as 24 hours and quickly spread to other birds among the flock.  It also poses a risk to U.S. exports leading more poultry to be available in the local markets.  There will be "more product on the domestic market and that will depress prices," said Jessica Sampson, agricultural economist at Livestock Marketing Information Center.