New Bird Flu Strain Is 'One of the Most Lethal' Viruses of Its Kind

By Tara Culp-Ressler, ThinkProgress

25 April 13

he World Health Organization (WHO) is warning that the new bird flu currently spreading in China, H7N9, appears to be "one of the most lethal" of its kind. So far, it's been spreading among humans more rapidly than its H5N1 predecessor, another strain of bird flu that emerged in the country in 2003.

"When we look at influenza viruses, this is an unusually dangerous virus for humans," Keiji Fukuda, the WHO's assistant director-general for health security, said at a press briefing this week.

Since the H7N9 strain was first detected last month, it has infected about 108 people in China - and on Wednesday, the first report of an infection outside China emerged. A Taiwanese man contracted bird flu while on a business trip in China and was hospitalized in Taiwan once he returned.

Chinese health officials report that samples from chickens, ducks and pigeons at poultry markets have tested positive for H7N9. But it's not yet clear where the virus is originating - and new data shows that half of the infected people may not have come into any contact with poultry at all. Until scientists are able to identify the source, they expect the bird flu to keep spreading. Fortunately, there's been no evidence so far that the H7N9 strain can be transmitted from human-to-human contact.

Still, the emergence of H7N9 has troubled health experts, since it's a strain of the flu that has never been seen in humans before. And after dead pigs and dead ducks suddenly flooded China's rivers last month - Chinese officials have not yet been able to explain the cause of the animal's deaths - there has been some speculation that this mystery may be related to the current outbreak, signaling the beginning of a pandemic.

There haven't been any reported cases of the new bird flu in the United States yet, but the CDC has warned U.S. hospitals to be on the lookout for patients exhibiting those symptoms.