Friday, 23 December 2016

H7N9:2016 has been the most quiet year to date...

Influenza A(H7N9) virus, or 'H7N9', has had a quiet year when compared to past outbreaks.

All human cases to date have been linked to China. The majority of human cases have had some link with poultry - chickens or ducks - although we do hear of human-to-human transmission, this seems to be limited. H7N9 has been found in poultry from backyard farms and in live poultry markets (LPMs) in China - sometimes in the company of other influenza viruses, like H9N2.[1]

Cases and deaths each month over the 4 years we have known
about human cases of H7N9 infection.
Click on image to enlarge.

Despite the slow year,the 2016 graph above shows the usual December uptick in human cases. It will be what happens next that matters. Will be see a big January surge as in 2014, or a later Feb-April surge as in 2013 and 2015? Will live LPMs be quickly closed, disinfected, the animals destroyed and any outbreaks in 2017 squashed or will they remain open allowing more human cases as the virus spreads among market animals?

Time, and testing data - which China generates lots of but does not seem to enjoy publicly reporting - will tell.

In 2016 - 2 new regions were added for the first time - Tianjin municipality and Liaoning province - both in the north-eastern coastal region of China. 

In 2013, no sustained human-to-human transmission had been reported [2] - this remains true up until today.

References...

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4911810/pdf/nihms749408.pdf
  2. http://www.nature.com/news/mapping-the-h7n9-avian-flu-outbreaks-1.12863