Figure 1

Ling Tang

and 7 more

The H10-H12 subtypes are designated as the “waterfowl-associated” subtypes and are not frequently detected in nature, but these viruses can highly reassort with other subtypes of AIVs. It has shown that very few H10-H12 subtypes were isolated from wild birds in China, it is essential to conduct the extensive surveillance of these rare subtypes in wild birds to narrow this knowledge gap in this region. In this study, 12 AIVs of H10-H12 subtypes were identified with the routine surveillance in wild birds in Shanghai, China from 2016 to 2019. There were 2 H10 subtypes, 3 H11 subtypes and 7 H12 subtypes, and the HA-NA combinations were H10N4, H11N2, H11Nx, H11N9, H12N2, H12N5 and H12N8. Sequence and phylogenetic analysis showed these gene segments of the 12 strains had high levels of genetic diversity among them, and most of them were closely related to the Eurasian lineage, and shared high sequence identity with those isolated from wild birds and domestic ducks in Japan, Korea, Bangladesh, Vietnam and China located at the East Asian-Australasian Flyway route. However, part of the gene segments of the two H12N2 strains (NH112319-H12N2 and NH101807-H12N2) were belonged to the North American lineage, which indicated that the gene flow and reassortment had occured between the Eurasian and American lineages in H12 subtypes. To better understand the ecological and phylodynamic features of these H10-H12 subtypes in wild birds, it is necessary to continuously conduct large-scale surveillance of wild birds in future.