Identification and pathogenicity of avian hepatitis E virus from quail

Avian hepatitis E virus (HEV) has caused economic losses in the poultry industry and has shown a broad spectrum of infections. In 2022, a quail farm (YangLing, China) exhibited a decrease in egg production, an increase in mortality and hepatosplenomegaly. These characteristics were similar to those of avian HEV infection. To determine whether avian HEV existed on this farm and further clarify the pathogenicity caused by avian HEV under experimental conditions, the livers and spleens were collected from the diseased quails in the field for gross lesion observation and avian HEV detection; then, the pathogenicity was characterized.

In the field, the results showed enlargement of the liver and spleen and hemorrhage spots on the liver, and the amplified fragment (330-bp length) of HEV shared 100% identity with the Chinese avian HEV strain. The pathogenicity of this virus in quail was characterized by decreased egg production, seroconversion, viremia, fecal virus shedding, liver lesions and HEV antigen in the liver under experimental conditions. These differences indicated that there may be other pathogens or factors causing this disease together on the quail farm in addition to avian HEV, and further detection should be performed.

Overall, this is the first study to detect HEV RNA in quails, and an avian HEV strain can successfully infect quails under experimental conditions.