Epidemiology and genotypic diversity of duck hepatitis B virus identified from waterfowl in partial areas of Guangdong province, Southern China.

Duck Hepatitis B virus (DHBV) infection model is extensively utilized as an animal model for studying human hepatitis B virus infection and for comparative research. 557 liver samples from geese and ducks were collected in parts of Guangdong province, southern China. The overall prevalence of DHBV was 45.6% (254/557) in all samples. And the 27 complete genome sequences of DHBV strains in this study share 89.6%-100% genome-wide pairwise identity with previously identified DHBV genomes. Notably, DHBV-1, DHBV-2 and DHBV-3 of were found co-circulating among the waterfowl population in parts of Guangdong. More importantly, seven out of the 16 recombination events were determined involved DHBV sequences obtained in this study as major parent and minor parent, suggesting DHBV strains from Guangdong province play an important role in recombination events. Additionally, purifying selection was the dominant evolutionary pressure acting on the genomes of DHBV.