# 4656
During the last week of February we learned that a sample taken from a pig in a Hong Kong slaughterhouse tested positive for a reassorted influenza virus (see Hong Kong: Swine Flu Reassortment).
This hybrid between a regular swine influenza virus and the human-adapted novel H1N1 virus caused quite a stir at the time, although we’ve not heard of any more detections out of Hong Kong.
Pigs are believed to make excellent `mixing vessels’ for influenza viruses because they are susceptible to human, swine, and avian flu strains.
That increases the odds that a pig could be infected by two different flu strains at the same time, a situation that makes it possible for two flu viruses to swap genetic material (reassort) and potentially create a new hybrid virus.
While `biologically fit’ hybrids don’t happen often, when they do, they have the potential to jump to humans. Which is exactly what happened with `swine flu’ in early 2009.
Today University of Hong Kong Virologist Malik Pieris and Microbiology Professor and co-author Yi Guan – both genuine heroes of the SARS epidemic of 2003 – published a paper entitled:
“Reassortment of Pandemic H1N1/2009 Influenza A Virus in Swine,” by D. Vijaykrishna, L.L.M. Poon, H.C. Zhu, S.K. Ma, O.T.W. Li, C.L. Cheung, G.J.D. Smith, J.S. M. Peiris, Y. Guan. Science, Vol. 328 No. 5984, June 18, 2010.
They report on this reassorted virus detected at a slaughterhouse in Hong Kong. As they point out, the novel H1N1 story is not over.
Although this article is behind a pay wall (which, alas, I don’t have access to) Wired Science has a helpful write up on the paper today.
Swine Flu Jumps Back to Pigs and Keeps Evolving
By Brandon Keim June 17, 2010 | 2:00 pm
A new strain of swine flu shows that the pandemic version has jumped from humans back to pigs, where it’s evolving in new and unpredictable ways.
The new strain, identified in a Hong Kong slaughterhouse, isn’t especially virulent. But the findings emphasize the need for continued vigilance. Swine flu isn’t going away.
“Hoping for the best while preparing for the worst seems a sensible strategy,” said University of Hong Kong virologist Malik Peiris. The strain is described June 18 in Science.
UPDATE: While I was posting the above, another report emerged from CBCNEWS which contains additional information.
H1N1 swaps genes with other pig viruses: study
Last Updated: Thursday, June 17, 2010
Swine herds should be watched closely for changes in the pandemic H1N1 virus, say scientists who found the virus has swapped genes with other viruses in pigs.
The genetic reassortments have not made the virus more virulent or caused pork to be unsafe to eat, the researchers stressed.
But Dhanasekaran Vijaykrishna of the University of Hong Kong and colleagues said in Friday's issue of the journal Science that global surveillance of H1N1 should be heightened because another flu strain could emerge from swine that is harmful to humans.
