
# 10,876Since it first emerged in the winter-spring of 2013, avian H7N9 has proved exceptionally difficult to control because - unlike the HPAI H5 viruses we monitor (H5N1, H5N6, H5N8, etc.) - the H7N9 virus is benign in most birds (including poultry). HPAI H5 viruses - at least in unvaccinated birds - produce significant morbidity and mortality in poultry, and that provides...