H1N1 Reassortment in Swine

[indigo girl]

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.

More at: H1N1 Reassortment In Swine

[indigo girl]

Branswell on the Reassortment Story

Unsettling information...

Scientists from Hong Kong are calling for ramped-up surveillance of pig populations after discovering a new swine flu virus that is a hybrid of the pandemic H1N1 virus and viruses previously found in pigs.

The discovery of the virus, found early this year in a pig taken to slaughter in Hong Kong, suggests what experts have feared: the H1N1 virus may reassort easily with other viruses in pigs.

That's a process that could generate new flu viruses that might have the capacity to sicken humans, they warned, noting two viruses high on the pandemic watch list-H5N1 and H9N2-are occasionally found in swine in Asia.

Inherent in their report is a message flu experts know the world doesn't want to hear at this point: the mild H1N1 pandemic may be the opening act of a longer play.

More at: Branswell On The Reassortment Story

[indigo girl]

The Swine Flu Virus Is Evolving. Are We Paying Enough Attention?

The Swine Flu Virus Is Evolving. Are We Paying Enough Attention? | 80beats | Discover Magazine

The scientists led by virologist Malik Peiris say the flu virus that the world feared last year has gone back into pigs in China, where it's laying down and recombining its genetics with other flu strains. And, they say, we're not sufficiently monitoring the danger of a new strain jumping back to people.

"Just because we've just had a pandemic does not mean we've decreased our chances of having another," said Dr. Carolyn B. Bridges, an epidemiologist in the flu division of the Centers for Disease Control and Prevention. "We have to stay vigilant" [The New York Times].

Re-assortment, in which a virus picks up new genetic material, is scientists' major worry. As I wrote during the swine flu scare last year, RNA viruses like the flu are especially prone to mixing. That's what happened to produce the new strain Peiris and colleague Yi Guan found.

Peiris says we don't know exactly what mixing is happening or if and when a new virus will jump back to people. But we can count on the fact that Hong Kong isn't the only place it's happening. That's why we need to keep a closer eye on the world's pigs than we are now.

(hat tip pfi/pixie)