I’m sure lots of other people will point to the new Nature paper on the history and evolution of the new H1N1 influenza.1 (I believe this is an open-access paper, so check it out for yourself.)  Key points include:

  • it was derived from several viruses circulating in swine
  • the initial transmission to humans occurred several months before recognition of the outbreak.
  • the reassortment of swine lineages may have occurred years before human emergence
  • the nature and location of the genetically closest swine viruses reveal little about the immediate origin of the epidemic

A key conclusion: “Our results highlight the need for systematic surveillance of influenza in swine.”  This seems to be becoming fairly widely accepted, though I don’t know what is being done to make it happen.

They include a really helpful diagram, by far the best I’ve seen for clarifying the evolutionary history:

Flu recombination history

(Sorry for the lack of updates this week, by the way.  It’s been a rough week, nothing has gone well except for the Red Sox beating the Yankees in the first two games of their series.)


  1. Smith, G., Vijaykrishna, D., Bahl, J., Lycett, S., Worobey, M., Pybus, O., Ma, S., Cheung, C., Raghwani, J., Bhatt, S., Peiris, J., Guan, Y., & Rambaut, A. (2009). Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic Nature DOI: 10.1038/nature08182[]