Wednesday, September 12, 2012

CDC & ICAAC Updates On H3N2v

 

 

# 6550

 

 

A bit of a twofer today, as we’ve two videos featuring the CDC’s Dr. Lyn Finelli discussing the recent emergence of the H3N2v swine-origin virus, and how to reduce the risk of it spreading.

 

First stop, a 6-minute  podcast, released earlier this week by the CDC, called:

 

CDC Recommendations to Reduce the Risk of H3N2v Flu Virus Infection for Fairgoers and Swine Exhibitors

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You’ll find a video of this podcast, and the transcript, available at the above link.

 

The second video comes from the closing day of 2012’s ICAAC conference in San Francisco, where Dr. Finelli is interviewed by Jeff Fox in a 30 minute presentation.

 

 

Dr. Finelli indicates that, out of the 300 or so new human cases of H3N2v infection this summer, about 10 instances of human-to-human transmission have been detected.  


So far, the vast majority of cases have had direct, and prolonged contact with swine.

 

Complicating matters, we now have four cases of a different swine variant virus – H1N2v – recently detected in Minnesota. 

 

And much like the newly emergent H3N2v virus – this reassortant swine flu has picked up the M gene segment from the 2009 H1N1 virus (see CDC Updates Minnesota H1N2v Cases).

 

 

In another related story, on Monday we learned (see PNAS: Virulence & Transmissibility Of H1N2 Influenza Virus In Ferrets) that Korean researchers had detected a swine flu H1N2 strain that produced serious (even lethal) illness in ferrets, and spread easily among then. 

 

For more on this story, Robert Roos of CIDRAP wrote last night:

 

Ferret study underlines persistent threat of swine flu viruses

Robert Roos * News Editor

Sep 11, 2012 (CIDRAP News) – A Korean-US research team has identified an H1N2 strain of swine influenza capable of killing ferrets and spreading among them by respiratory droplets, underlining the continuing threat of swine flu to humans amid a wave of swine-origin flu cases in Americans exposed to pigs at agricultural fairs.

(Continue . . . )

 

 

The concern has long been that swine are highly susceptible to the influenza virus, and are capable of serving as `mixing vessels’, allowing them to reassort into new hybrid strains. 

 

Since end of  the 2009 H1N1 pandemic we’ve begun to see reassortments of other swine flu viruses (H3N2 & H1N2) with genetic elements picked up from the previously `humanized’ H1N1 pandemic strain.

 

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For now, these reassortant viruses haven’t evolved into efficiently transmitted human flu strains, and so their public health impact is limited. 

 

The caveat being, that as this virus jumps to humans it could begin to `figure us out’, and become more easily transmissible.

 

Which is why the CDC, along with local & state health departments, plan to remain vigilant this fall and winter as they look for any signs of increased human transmission.