Isolation and identification of muscovy duck adenovirus and genetic variation of hexon gene

Objective This study aims to investigate the pathogen characteristics, epidemiological features, and genetic variations of the Muscovy duck white-hepatitis disease in Fujian Province

Methods Clinical samples were collected from 9 cases of suspected white liver disease in Muscovy ducks from Fuzhou, Sanming, Putian, Zhangzhou in Fujian Province, and were tested for the presence of duck adenovirus (DAdV) using pathogen detection methods. The isolated pathogens identified, and their hemagglutination characteristics, pathogenicity, and hexon gene sequences were analyzed.

Result duck Adenovirus infection occurred in 9 farms, mainly in spring and autumn, with an incidence of 15%～40% and a mortality of 5%～15%. The virus was isolated from muscovy duck adenovirus infection. All the virus isolates could cause death of muscovy duck embryos. The morbidity and mortality of muscovy duck infected with the virus were 60% -100% and 20%～40% respectively. The nucleotide homology of hexon gene of 9 DAdV isolates was over 99.9%, and the sequence was consistent with that of CH-GD-12-2014 strain. Among them, 9 DAdV isolates shared 99.9%～100% homology with Guangdong isolate CH-GD-12-2014, and 76.6%～76.7% homology with French isolate DAdV-GR The homology between FAdV and other serotypes was 64.1% ～ 66.8%. Phylogenetic tree analysis showed that the 9 isolates belonged to the same branch as GD-12-2014 and GR, but not the same branch as Adv.

Conclusion Tthe Muscovy duck adenovirus strain circulating in 2022 is adenovirus type 2. The results of this study provide important clinical information and basic data for further study on the pathogenesis of duck adenovirus type 2, vaccine development and integrated control measures.