Bloomberg If a pig infected with human flu got infected with the H5N1 bird flu, a new virus could emerge with parts of both. That’d be bad. When the USDA issued an announcement on Oct. 30 that the worrisome H5N1 bird flu turned up in a pig, I dropped what I was doing to read it. The situation didn’t quite match the nightmare scenario some experts described to me last spring, in which this virus starts rampaging through commercial pigs. But it’s worrisome.
Spreading through big, industrial pig farms would give the virus ample opportunity to evolve into a form capable of causing a pandemic in humans. Pigs remain at the center of scientists’ nightmare scenario because commercial swine carry lots of human flu viruses. Their cells share enough features with ours that flu viruses can use some of the same entry ports, known as receptors.