Isolation, identification and genome analysis of an avian hepatitis E virus from white-feathered broilers in China

Avian hepatitis E virus (HEV) is the major causative pathogen of the big liver and spleen disease, hepatitis-splenomegaly syndrome, and hepatic rupture hemorrhage syndrome. Until now, there are 6 different avian HEV genotypes that infect chickens have been reported worldwide. Epidemiologic investigations of the avian HEV demonstrated that avian HEV has been widely spread in China in recent years. In this study, an avian HEV named YT-aHEV was obtained from white-feathered broilers using LMH cells by virus isolation assay in Shandong province, China. The complete genome consists of 6656-nt excluding the poly(A) tail. The isolate was highly similar to the CaHEV strain and segregated into the same branch belonging to avian HEV genotype 3. Indirect immunofluorescence using capsid protein-specific polyclonal antibodies confirmed that YT-aHEV could establish productive infection and replicate stably in LMH cells. Furthermore, an in vivo avian HEV infection model was established successfully in specific pathogen-free chicken embryos by intravenous experiments. In the present study, we demonstrate an avian HEV infection associated with liver lesions of hemorrhage and swelling by LMH cells for the first time in a white-feather broiler flock in China. This research also provides a new diagnosis method for detection of avian HEV, which laid a foundation for the understanding of pathogenicity and molecular biology of this virus for further study.