Figure 6.

Three (two females and one male) of eleven tested mice were positive for virus infection in the stomach tissues. Representative stomach tissues were examined for histology. (A) Within the glandular stomach there is a focally extensive plaque lesion of mild to moderate hyperplasia with atypia. There is abundant hyperkeratosis (likely parakeratotic), with what appear to be crypt formation. There are occasional positive nuclei within the stratum spinosum and granulosum, with abundant positive staining of the cornified layers. There is multifocal cytoplasmic hybridization with parietal cells in the glandular stomach. (E) A small isolated (possibly pedunculated) focus of mild hyperplasia with cytologic and nuclear atypia (low grade) in the non-glandular stomach with scattered individual nuclear positive cells. These tissues were positive for viral DNA by in situ hybridization (ISH, B, F, 20×, in blue), viral capsid protein L1 (IHC, C, G, 20×, in red), and E4 protein (IHC, D, H, 20×, in red) by immunohistochemistry.