Identification and characterization of avian hepatitis E virus in 2013 outbreaks of hepatitis-splenomegaly syndrome in two US layer operations

Figures & data

Figure 1. Egg production and mortality rates for Farm A (1a) and Farm B (1b). Egg production was compared with the breed standard. Dashed line, threshold of a weekly mortality above 0.15%; black arrow, onset of clinical signs. HD = Hen-day.

Figure 2. Macroscopic lesions in affected 23-week-old Farm A chickens. 2a: Diffusely enlarged liver. 2b: Congested enlarged liver and yellow foci. 2c: Pectoral muscles; normal (on left) and pale carcass on affected bird (on right).

Figure 3. Microscopic liver lesions in affected 23-week-old Farm A chickens. 3a: Intrahepatic haemorrhage (bar = 250 µm). 3b: Necrosis and fibrin deposition within hepatic parenchyma (bar = 450 µm). 3c: Heterophils in a portal triad area (bar = 75 µm). 3d: Vasculitis in a portal triad area (bar = 90 µm).

Figure 4. Phylogenetic tree based on 361-base-pair regions of the helicase gene of aHEV isolates. Sequences that were obtained in this study are underlined. The phylogenetic tree was constructed by the neighbour-joining method. Significant bootstrap values are indicated as a percentage for 1000 replicates. Genotype classification represented as proposed by Marek et al. (2010) and Hsu & Tsai (2014).