2.5. Morphometric analysis
Eight pieces of formalin-fixed mid- to distal jejunum were
taken from each virus-infected and control pigs for morphometric
analysis. Only well-orientated, H&E- or IHC-stained jejunal
sections were measured and care was taken to ensure that only
transverse sections cut perpendicularly from villous enterocytes to
the muscularis mucosa were included as described previously
(Jung et al., 2006). Villous height, crypt depth, and number of PEDV
antigen-positive cells were estimated by measuring at least 10 villi
and crypts throughout the section. Mean ratios of jejunal villous
height to crypt depth (VH:CD) were calculated as previously
described (Jung et al., 2006).