Virologists infected five 10-week-old pigs with the human strain of virus and housed them with three uninfected pigs. Within four days, the three pigs had become infected and all pigs were showing flu symptoms. But five chickens that were housed, uncaged, with the pigs in the same room did not become infected, which eases fears that the virus can pass to poultry and pick up genes from avian microbes.
The authors of the study say the remarkably swift and easy way in which the three pigs became infected highlights the risk that the virus could become endemic in pig farms through people in close proximity. Pigs are touted as a mix-and-match breeding vessels for dangerous new viruses, as they are able to simultaneously house human, avian and swine strains.