The diagnosis and molecular epidemiology investigation of avian hepatitis E in Shandong province, China

Abstract

Background Avian hepatitis E virus (HEV) is the pathogenic agent of big liver and spleen disease (BLS) and of hepatitis-splenomegaly syndrome (HSS) in chickens, which have caused economic losses to the poultry industry in China. In this study, 18 samples of BLS chickens were collected to reveal the molecular epidemiological characteristics of avian HEV in the province of Shandong, China. Results Gross and microscopic lesions of clinical samples were observed; then, virology detection and genetic analysis of avian HEV were performed. The results showed that there was significant swelling and rupture in the liver and that the spleen was enlarged. Microscopic lesions demonstrated obvious hemorrhage in the liver, with infiltration of heterophilic granulocytes, lymphocytes, and macrophages, as well as the reduction of lymphocytes in the spleen. Eleven of the 18 samples were positive for avian HEV, with a positive rate of 61.11%. More importantly, all avian HEV-positive samples were mixed infections: among these, the mixed infections of avian HEV and chicken infectious anemia virus (CIAV) and avian HEV and fowl adenovirus (FAdV) were the most common. Furthermore, the genetic evolution analysis showed that all avian HEV strains obtained here did not belong to the reported 4 genotypes, thus constituting a potential novel genotype. Conclusions These results of this study further enrich the epidemiological data on avian HEV in Shandong, prove the genetic diversity of avian HEV in China, and uncover the complex mixed infections of avian HEV clinical samples.

Research Note: The prevalence and vertical transmission of avian hepatitis E virus novel genotypes in Tai'an city, China

“…Different genotypes of avian HEV have been reported worldwide ( Kwon et al, 2012 ; Liu et al, 2022 ), including strains of different genotypes widely reported in China's Shandong, Jiangxi, and Guangdong Provinces ( Li et al, 2020 ; Liu et al, 2020 ; Su et al, 2020 ; Liu et al, 2022 ). To further determine the molecular characteristics of avian HEV from layer farms and breeder farms, the positive samples were sequenced and analyzed, 14 partial sequences of ORF2 genes of avian HEV strains were obtained, and the genetic evolution showed that all strains except ON457637 and ON457638 belong to the same branch as the potential novel genotypes that we reported earlier, as shown in Figure 1 ( Liu et al, 2022 ), which indicated that potentially novel genotypes might be widespread in some chicken farms in Shandong Province. However, the ON457637 and ON457638 strains were of the same branch as the representative strain of a novel genotype isolated from Gansu Province in 2020 (accession number: MN562265), as reported by Liu et al ( Liu et al, 2020 ), with a nucleotide homology of 91.3% and an amino acid homology of 100%.…”

“…Genotype 1 isolates were from Australia and Korea, while genotype 2 had been detected from the United States, Central Europe, and Spain ( Su et al, 2020 ). Genotypes 3 and 4 have been reported in Europe, China and Hungary, Taiwan Province, respectively ( Li et al, 2020 ; Liu et al, 2020 ; Liu et al, 2022 ). In addition, some new genotypes of avian HEV have been reported but not yet categorized ( Liu et al, 2020 ; Su et al, 2020 ; Liu et al, 2022 ).…”

“…Genotypes 3 and 4 have been reported in Europe, China and Hungary, Taiwan Province, respectively ( Li et al, 2020 ; Liu et al, 2020 ; Liu et al, 2022 ). In addition, some new genotypes of avian HEV have been reported but not yet categorized ( Liu et al, 2020 ; Su et al, 2020 ; Liu et al, 2022 ).…”

Retrospective Investigation and Genetic Variation Analysis of Chicken Infectious Anemia in Shandong Province, 2020–2022

“…The Simply P Virus DNA/RNA Extraction Kit (Bioer, Hangzhou, China) was used to obtain the nucleic acid of each sample, following the manufacturer's instructions. In our previous study, the PCR primers of CAV, fowl adenovirus (FAdV), reticuloendotheliosis virus (REV), avian leukosis virus (ALV), Marek's disease virus (MDV), and avian hepatitis E virus (HEV) were reported [12]; primer sequences are shown in Table 1. The total volume of the reaction system was 25 µL.…”

Inflammatory response triggered by avian hepatitis E virus in vivo and in vitro

“…The chickens had severe hepatosplenomegaly syndrome, many bleeding spots, and apparent bleeding clots in the livers ( 16 ). In 2022, a study described cases of aHEV associated with hepatosplenomegaly, rupture, and hemorrhage from several cities in Shandong ( 17 ).…”