In April 2017, three avian influenza (H7N9) viruses were isolated from chickens in southern China. Each virus had different insertion points in the cleavage site of the hemagglutinin protein compared to the first identified H7N9 virus. We determined that these viruses were double or triple reassortant viruses.

In order to determine the prevalence of Newcaste Disease Virus (NDV) in ducks in Guangdong province of China, 10 NDVs were isolated in domestic ducks. Eight isolates were pathogenic as determined by MDT, ICPI and cleavage site of F protein. The F genes of 10 isolates were sequenced, all the genes and their deduced amino acids were compared with 32 reference strains. 5 isolates were clustered in genotype VII (VIId), 3 isolates were classified as genotype IX and 2 isolates were classified as genotype. The subgenotype VIId isolates possessed the motif 112R-R-Q-K-R-F117, and the genotype IX isolates possessed the motif 112R-R-Q-R-R-F117. The 8 NDV isolates exhibited a high ICPI, they were classified as velogenic type of NDVs and were collected between the years of 2006 and 2010. The genotype I isolates possessing the motif 112G-K-Q-G-R-L117 were collected in 2005, they were exhibited a low ICPI and were classified as lentogenic type of NDVs. The NDVs of subgenotype VII are now dominant and have been implicated in most of the recent ND outbreaks in duck farms in Guangdong province. These findings provide data on genetics and molecular evolution of NDV in ducks in China and emphasize importance of NDV surveillance for improving of strategies for the control of the disease.