"The World Health Organization says that at least 135 people in China have been sickened by the H7N9 flu strain, and 44 have died. Most likely, these victims got the virus from chickens sold in live poultry markets. But where did the chickens get it? From ducks, who got it from wild migratory birds, scientists now say."
"In fact, migratory birds that spent time in Hong Kong probably transferred the key N9 influenza genes to domestic ducks at least twice before the H7N9 outbreak began in March of this year, according to a report published Wednesday by the journal Nature.
In addition, wild migratory birds from Eurasia carried an H9N2 flu strain that contributed some genes to the H7N9 strain that went on to infect humans.
But the researchers emphasized the key role of ducks in bringing all the ingredients together to create H7N9."