Histopathology and cytopathology associated with IN-05 RHDVa infection. A. A liver section from one of the fatally infected rabbits (day 2 post infection) is shown (H&E stain, 40× objective). Note the acute hepatocellular necrosis characterized by destruction and disassociation of hepatocytes, loss of cellular organization, and evidence of acidophilic bodies (white arrow head), karyorrhexis (white arrow), and necrotic or apoptotic hepatocytes (black arrow head). B. A liver section from the surviving infected rabbit (day 21 post infection) exhibited normal liver morphology (H&E staine, 40× objective). C. Transmission electron micrograph showing the ultrastructure of a hepatocyte from a fatally infected rabbit revealed the presence of 26.5 nm +/- 1.9 diameter viral particles with morphology characteristic of caliciviruses. D. An example of ultrastructural changes to a hepatocyte from one of the fatally infected rabbits. Note the margination of chromatin (Ch) in the nucleus (Nu), and disruption of cristae in mitochondria (Mt). Often, an abnormal condensation of the endoplasmic reticulum (ER) was observed. The inset shows an abnormally dense reticular network.