Epidemiology and Genetic Variation of Duck Hepatitis A Virus Type 1 Circulating in Some Regions of China

The epidemic prevalence and molecular variation of duck hepatitis A virus type 1 (DHAV-1) were investigated. Three-hundred-twenty-seven clinical samples collected in 2015-2016 from Fujian and surrounding provinces were used for the virus detection and isolation. Thirty-five of these samples (10.7%)were found to be pusitive for DHAV-1. From the 35 positive specimens, 23 strains were isolated, mainly from shelducks and mule ducks of less than 30-day-old. The sequence analysis on VP1 gene of the 23 isolates showed 93.3%-99.9% homology, and the strains could be divided into 2 subgroups with a genetic distance of 0.06. Among them, 18 isolates clustered in a currently prevalent subgroup which contains the virus (MPZJ1206)causing yellowed-pancreas in ducklings. On the other hand, all 23 isolates shared merely 91.3-96.2% nucleotide sequence homology with the strain used for vaccination abroad and domestically. It appeared that genetic variations existed among the various DHAV-1 strains.