Emergent virus

China has confirmed the first known human case of the H3N8 strain of avian flu, but health authorities say there is a low risk of widespread transmission among people.

H3N8 is known to have been circulating since 2002 after first emerging in North American waterfowl. It is known to infect horses, dogs and seals, but has not previously been detected in humans.

Discussion in the international scientific community about the possibility of new or emerging viruses with the ability to unleash a pandemic date back to the 1990s, gaining momentum with the advent of SARS in 2003 and the H1N1 flu in 2009.