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

By Andrew Moseman | June 18, 2010 2:14 pm

swine-flu-virus1It’s still out there, you know.

A study out today in the journal Science tracks the path of swine flu, which may have receded from the forefront of humanity’s attention but hasn’t quit mixing and moving and making ready. 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 and Guan found the new strain in January in a Hong Kong slaughterhouse, where they regularly sample pigs arriving from farms in southeast China. It contains a gene from the pandemic swine flu, plus genes from the two strains that originally mixed to create the pandemic flu. Having sequenced the new strain’s genes, the researchers recreated it in a laboratory and exposed it to pigs. The strain proved contagious but only mildly virulent [].

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.

“We’re not saying this particular virus is a huge threat or that people should stop eating pork,” he said, “but that this is likely happening in other places in the world. And there could be other combinations arising that could pose a threat to human health” [National Geographic].

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Related Content:
DISCOVER Video: No Swine Flu Parties! (They don’t do any good)
80beats: Killer Flu Strains Lurk & Mutate for Years Before They Go Pandemic
80beats: Swine Flu Goes Deeper Into the Body Than Regular Flu–Even Into Intestines
DISCOVER: Swine Flu Was a Warning Shot. How Can We Do Better Against the Next Pandemic?

Image: CDC

CATEGORIZED UNDER: Health & Medicine
  • nick

    I’d like to point out that these viruses, genetically, are probably well older than mankind. And they haven’t got us yet.

  • Angela

    Actually, many of them have “got us”. The flu of 1918 killed millions, syphilis decimated whole populations in the new world, and bugs like measles, smallpox and mumps continued to kill thousands or millions until we developed effective vaccines. Bacterial infections like the Black Death, bubonic/ pneumonic plague caused by Y. pestis, wiped out between 1/4 to 1/3 of Europe’s population during the Middle Ages. These are only a couple of examples from within the last thousand years – we don’t know how many previous outbreaks there were before our history was recorded (written). We do have to be vigilant and prepared for viruses and bacteria that can kill us.

  • Ryan

    A not so small thing to consider, though, is that it wasn’t simply the viral or bacterial infections that killed us then either – it was poor nutritional intake, poor hygiene and overall poor civil service/management. So I wouldn’t say that “they” got us, so much as I would say that a confluence of factors “got some people who were at the epicenter of such a confluence”.

    Still, it’s always important to keep track of what’s going on out there; that’s just common sense.

  • Kyle

    The biggest mordern concern for any flu virus outbreak is our global transportation system. Someone infected with a flu virus strain of high virulance and low contageous factor can fly to an area with people infected with a different strain of low virulance and high contageous factor. This senerio is what the WHO and CDC are fearing and is called antigenic shift. A person infected with both strains has to possiblity to produce a high virulance and high contageous factor srain, a great example is the 1918 outbreak during WW1. It will happen sooner or later!

  • Idlewilde

    I’m not worried. I live in a family of six and we have only had the flu once. We only catch maybe 2 colds a year. I guess we have natural cold resist.

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  • http://ALLISON4U.NET Zackary Torset

    How about the methodology of the counting? Has that changed or did it change from 07-08? Why doesn’t anyone talk about the major increase from 07-08 followed by years with decreases. Every time someone mentions increases in cycling they use 07 as the low reference.


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