Weekly Article: It's Nearly Flu Season Again

by Caleb Ward
Children's National

Another summer draws to an end, time for another animal related flu scare... This week the BBC (for all the other expats out there!) flagged an upcoming article in the American Journal of Pathology that caught my eye.

The article references work from a Dutch group (van Riel et al) doing histochemical analysis on H7N9. The key findings seem to be:

H7N9 can attach to the epithelium of both the upper and lower respiratory tracts

Attaching to upper respiratory tract cells theoretically gives risk for high transmissibility (like H1N1)

Attachment to lower respiratory tract cells theoretically gives risk for high virulence (like H5N1)

The combination of high transmissibility and virulence would indicate theoretical concerns for a pandemic are not that far fetched

For further background on H7N9, the WHO has some great resources, in particular the following links to total case numbers and an overview of H7N9. These show that cases thus far peaked in April 2013, when Chinese authorities moved to shut down outdoor bird markets in affected cities. Most affected individuals thus far have had direct contact with poultry. I think this raises obvious questions about whether the in vitro finding of attachment to upper respiratory tract cells necessarily means high transmissibility. Provisional case fatality was an alarming 25%.