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Pausing to look at the data on H7N9 infections

The situation over the past two days has pretty much been the same.  New cases, all located in the areas previously identified for H7N9 infection. 

Blessedly, there are those who are looking at the data and coming up with some pretty interesting analysis.  First, I refer you to Mike Coston's blog of today. Titled "Three graphic descriptions of China's H7N9 outbreak," this post collects some great information from informed sources.


The first chart comes from Dr. Ian Mackay.  Dr. Mackay runs a flu blogsite in Australia.  The chart shows the current (as of yesterday, and LOL on the word "Current" right now! I cannot even tell you what the current counts are.) individual H7N9 cases.  As you can see, only seven of the 28 cases had definable, confirmed contact with poultry in wet markets or the actual preparation of fowl.  This is problematic, because it seems to run counter to the prevailing theory that wet markets are the spawning place for H7N9 bird flu. It may suggest adaptation to a different host, mammilian in nature, as Dr. Richard Webby of St. Jude has theorized by looking at the makeup of the virus itself.

We just don't know enough yet on this front.  We assume and can pretty safely state that poultry is or has been a vector.  But the culling of 111,000 birds in Shanghai and adjacent wet markets has yielded little virus. If this cull had yielded virus, I have to believe the Chinese government would have trumpeted this fact and declared the outbreak over.


The second set of charts comes from veteran Flutrackers poster Laidback Al.  Laidback Al is a Jedi Master of the highest order when it comes to charts and maps of bird flu outbreaks.  His analysis and ability to see The Big Picture are impatiently sought and happily received when he weighs in.

His current geospacial analysis can be found at this link. I reproduce one key map below:

Name:  H7N9 China cases 20130409 dots.jpg Views: 306 Size:  119.4 KB

Look at the geographic dispersion of human cases.  If this were limited to wet markets, perhaps, we would not see this level of dispersion.  Of course, travel needs to be accounted for. But we are talking a huge area here. There are other charts in Laidback Al's post worth poring over.  The other chart that got my eye was the mortality - versus - morbidity chart. The ratio of deaths to cases, while admittedly a very small sample, shows the virus is killing young adults and the very old.  This seems to fit the mold of pandemic candidate viruses, whose proclivity is toward young adults and the elderly with their assorted contributing ailments.

We must look forward while looking back.  Only testing will determine how widespread H7N9 truly is in China.  A nice place to look would be the downstream rivers, streams and tributaries shown in another Laidback Al map.  Looking at those areas downstream from Shanghai, and matching up those principalities with any unexplained reports of respiratory failure, might prove quite useful.

In the meantime, everyone continues to monitor the developing situation.

Reader Comments (1)

Thanks for the citation. Finding info on animal contact is increasingly hard (its now rarely listed in preliminary case info from Chinese Provincial Health sites so my graph is likely to be under-estimating this aspect.

April 11, 2013 | Unregistered CommenterIan Mackay

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