Avian hepatitis E seroprevalence and its association with production parameters in layer hens

Big Liver and Spleen (BLS) disease in poultry is caused by avian Hepatitis E virus (aHEV) and has been reported in poultry flocks across the world including Australia. BLS was first characterised in Australia in the 1980s but currently the prevalence of aHEV in commercial egg layer flocks is not known. How aHEV effects production performance has also not been investigated. In this study, a cross-sectional epidemiological survey was conducted across several commercial egg producing flocks. Two rearing (5 flocks) and five production farms (19 flocks) were included in the study. Blood samples were collected from 20 birds from each flock. Serum was used to evaluate the seroprevalence of aHEV. The production parameters were also investigated by comparing weekly mean egg production, weekly mortality as well as food and water consumption between seropositive and seronegative sheds. The seroprevalence of aHEV for birds sampled was 14.5 % in production and 1 % in rearing flocks. A decrease in weekly egg production (p < 0.001), increased mortality (p < 0.001) as well as food (p = 0.003) and water (p < 0.001) intake were associated with seropositive sheds. The detection of anti-avian HEV antibodies in this study and its associated influence on production parameters in layer hen flocks highlights the importance of continued surveillance and impacts of aHEV in the egg industry. Further research is required to investigate the pathophysiology of avian hepatitis E viral infection and its impact on egg production and mortality.