Rhiza Labs FluTracker Forum

PLoS Pathog. 2011 Jun;7(6):e1002077. Epub 2011 Jun 9.
Spatial dynamics of human-origin h1 influenza a virus in north american Swine.
Nelson MI, Lemey P, Tan Y, Vincent A, Lam TT, Detmer S, Viboud C, Suchard MA, Rambaut A, Holmes EC, Gramer M.
SourceDivision of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America.

Abstract
The emergence and rapid global spread of the swine-origin H1N1/09 pandemic influenza A virus in humans underscores the importance of swine populations as reservoirs for genetically diverse influenza viruses with the potential to infect humans. However, despite their significance for animal and human health, relatively little is known about the phylogeography of swine influenza viruses in the United States. This study utilizes an expansive data set of hemagglutinin (HA1) sequences (n = 1516) from swine influenza viruses collected in North America during the period 2003-2010. With these data we investigate the spatial dissemination of a novel influenza virus of the H1 subtype that was introduced into the North American swine population via two separate human-to-swine transmission events around 2003. Bayesian phylogeographic analysis reveals that the spatial dissemination of this influenza virus in the US swine population follows long-distance swine movements from the Southern US to the Midwest, a corn-rich commercial center that imports millions of swine annually. Hence, multiple genetically diverse influenza viruses are introduced and co-circulate in the Midwest, providing the opportunity for genomic reassortment. Overall, the Midwest serves primarily as an ecological sink for swine influenza in the US, with sources of virus genetic diversity instead located in the Southeast (mainly North Carolina) and South-central (mainly Oklahoma) regions. Understanding the importance of long-distance pig transportation in the evolution and spatial dissemination of the influenza virus in swine may inform future strategies for the surveillance and control of influenza, and perhaps other swine pathogens.

_________________
www.twitter.com/hniman

_________________
www.twitter.com/hniman

A large number of H1 swine sequences from North America were released at Genbank in association with the above paper. Many of these sequences were closely related to swine sequences from Hong Kong, adding the evidence demonstrating the spread of "North American" swine sequences to Asia over a decade ago, which is why scientists reference pandemic H1N1 in geographically neutral terms. The calling of pandemic H1N1 sequences "mexican" or "mex" or "mx' is largely limited to clueless internet babblers.

_________________
www.twitter.com/hniman

I posted this paper because it was asscoiated with the release of a large number of swine sequences. The paper itself really doesn't say anything new. The fact that H1N1 and H1N2 was circulating in humans isn't new, and the fact that the human H1 moved into swine isn't new.

The paper is an excuse for the release of the sequences, but really doesn't say much about pandemic H1N1 origins.

_________________
www.twitter.com/hniman