Avian influenza A(H7N9) virus re-emergence risk factors...

Hard to believe it was over 6-months ago that we heard so much about H7N9. Papers are still coming out thick and fast describing all manner of aspects of the virus, its impact, transmission and ways to intervene in its replication.

There have been no new cases reported since July and the tally remains at 136 (including Taiwan case) with 44 deaths.

In a recent article in Scientific Reports, Fang and colleagues from China look into risk factors. 

It's hard to know how broadly applicable these data can be given the massive area and population covered and the relatively few cases identified.

Nonetheless the authors main predictors of re-emergence of H7N9 infections in humans are:

1. Poultry markets and their environments
2. Human population density
3. Irrigated lands (exposed to waterfowl; carried by waterfowl)
4. Built-up areas (see #2)
5. High humidity
6. Temperature around 15°C (citing drop in cases with rise in temperatures)