Fig. 5

Histological (a-f) and immunohistochemical (g-h) examination of the infected neonatal mice in the moribund state. a The skeletal muscle of the mock-infected control mice. b The section of infected mice skeletal muscles exhibited severe necrotizing myositis (arrow). c The small intestine of the mock-infected control mice. d The section of infected mice small intestine exhibited intestinal villus interstitial edema and epithelial cell vacuolar degeneration. e The lung of the mock-infected control mice. f The section of infected mice lung exhibited severe alveolar shrinkage, vascular dilatation and congestion. g and h are based on immunohistochemical examination of the infected neonatal mice in the moribund state. g No viral antigen was detected in skeletal muscles of the mock control mice. h In contrast, distinct viral antigen was observed in skeletal muscles fibers of infected mice (arrow)