H7N9 Pandemic threat

Human infections with a new avian influenza A (H7N9) virus continue to be reported in China. The virus has been detected in poultry in China as well. While mild illness in human cases has been seen, most patients have had severe respiratory illness and some people have died. The only case identified outside of China was recently reported in Malaysia.
An investigation by Chinese authorities is ongoing. Many of the people infected with H7N9 are reported to have had contact with poultry. However some cases reportedly have not had such contact. Close contacts of confirmed H7N9 patients are being followed to determine whether any human-to-human spread of H7N9 is occurring. No sustained person-to-person spread of the H7N9 virus has been found at this time.
Human infections with avian influenza are rare but do occur, most commonly after exposure to infected poultry (Bird-to-human spread). Limited person-to-person spread of bird flu is thought to have occurred rarely in the past, most notably with avian influenza A (H5N1). Based on this previous experience, some limited human-to-human spread of this H7N9 virus would not be surprising. Most important, however, is that this transmission not be sustained (ongoing).
Influenza viruses constantly change and it’s possible that this virus could become able to easily and sustainably spread between people, triggering a pandemic.