Phylogenetic analysis and assessment of the pathogenicity and transmissibility of the H13N6 subtype AIV firstly isolated from China

GAO Xiao-long;FAN Sheng-tao;LI Sheng-nan;GUO Jiao;WANG Ai-rong;SUN Wei-yang;LI Xue;YU Yi-cong;WANG Tie-cheng;LI Yuan-guo;SANG Xiao-yu;YU Zhi-jun;ZHANG Kun;GAO Yu-wei;XIA Xian-zhu;Animal Influenza Key Laboratory of the Ministry of Agricultural, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences;Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Institute of Military Veterinary, Academy of Military Medical Sciences;

H13N6;;transmissibility;;pathogenicity;;chicken;;mice;;guinea pigs

The emergence of a new serotype of H13N6 avian influenza virus(AIV) in China was firstly isolated from mallard environmental samples in Dalian and the biological characteristics of the H13N6 isolate were identified. The sequence analysis indicated that the H13N6 isolate showed a cleavage site(PAISNR↓G) consistent with a low pathogenic AIV characterization. The phylogenetic analysis of all eight viral genes revealed that NA segment of H13N6 belonged to the North American lineage, the remaining segments were grouped with the Eurasian lineage; In addition, the NA, NP, M and NS segments were similar to AIVs from gulls and the HA, PB2, PB1, PA segments showed highly similarity with the AIVs isolated from waterfowl. Furthermore, the pathogenicity and transmissibility experiments showed that the isolate was unable to efficiently replicate in chicken and mice, and also unable to shed and efficiently transmit in guinea pigs and chicken. The study indicated that the novel reassortant H13N6 isolate probably had already spreaded into China through wild birds migratory. The H13N6 isolate seems to be transmitted exclusively in wild waterfowl and still do not aquired the ability of crossing the species barrier to transmitting in mammals and domestic avian.