Friday, 31 January 2014

If not poultry then what? [UPDATED]

Maybe China needs to look at other
animals, both within market 

environments and at the source farms 
(using sensitive molecular tools as they 
have been), to find the "smoking chicken" 
(shamelessly stolen from Mike Coston)...
which may not be a chicken at all.
Mike Coston has written a nice post about the Chinese MOA denying that there is any proof of direct transmission of H7N9 from poultry to humans. 

Technically, they are of course correct. 

We have yet to see a human put in a cage downwind, but separated from, a flock of infected chickens or duck or geese to see if the human acquires H7N9 infection and disease. Nor have we seen any card-playing lockdown transmission scenarios to investigate aerosol, droplet and direct transmission routes. 

Nonetheless - if you take a look at a snippet of my list of H7N9 cases compiled from various public sources, "poultry" contact is mentioned...a lot; 72% of those rows (if you exclude the 19 awaiting WHO notification data; see below for update). 

Of course it may be a "poultry" euphemism or a translation error (I'm asking @WHO) for contact with any feathery creatures, so song birds and wild birds may be the source in the markets....or another animal altogether of course but I think something non-feathery would have shown up as a pattern by now.

[UPDATE] Gregory Härtl notes..
Only one way to tell what's happening now; get more samples and RT-PCR them. Serology is historically solid and well relied upon, particularly in the world of influenza surveillance. See expert comments on this in a recent CIDRAP article here. I'm just not convinced its providing enough sensitivity at a suitable speed to feed the needs of rapid response and control measures for an emerging virus like an influenza. A virus which is spilling into humans from somewhere not yet convincingly defined to everyone's satisfaction. 

But I'm new to flu and am coming at this from an endemic human virus detection and characterization angle. I may be waaay off point.