PING!
Mom, feel free to refine my comments re: reassortment.
When I read this a couple of days ago I was hoping you didn’t have any backyard chickens or ducks. We do have a lot of wild turkeys in our yard on a daily basis. Interesting to see how this spreads.
Your comments about reassortment are accurate, as far as they go.
Two influenza A viruses can easily co-infect the same host. Since they each have 8 gene cassettes on separate pieces of RNA, those pieces of RNA tend to get mixed up, or reassort. As long as the new virus has one of each gene cassette, it is potentially infective.
Not every reassorted virus is equally pathogenic or infective; some of them are duds. But others can be more deadly than either parent.
Influenza virus RNA also mutates, which can cause an avian influenza virus to slightly change from preferring to attach to bird cells to preferring to attach to human cells. The controversial “gain of function” experiments (Kawaoka and Fouchier) were looking at exactly which mutations cause that shift.
Many emerging influenza viruses are a result of both processes, reassortment and mutation. Swine are an ideal host for influenza, because bird and mammal adapted viruses can both attach within the pig upper respiratory tract, where they can reassort and mutate to become more infective to humans.
Influenza is a particularly nasty virus. Even a mild flu can kill. I just read about a healthy teenage girl who died in days from influenza. She had not been vaccinated.
Oh, and there is a completely new influenza in livestock, influenza D. So far, it has only infected pigs and cattle.