Localization of the anti-rEnGAM22 antibodies to the endogenous developmental stages of E. necatrix . The micrographs of endogenous stages of E. necatrix in histological sections, stained with H&E (A-F) and immuno-stained with anti-rEnGAM22 and visualised with FITC (green) and counter stained with DAPI (blue) (G-L). Abbreviations: M, mature meront; MAG, macrogamont; O, oocyst. Bar represents 10 μm, or images photographed at × 1 000 magnification. (A, G) Meronts with distinct merozoites in the crypt epithelial cells of the midintestinal area at 132 h PI. (B, H) Mid-stage macrogametocytes in the crypt epithelial cells of the caeca at 156 h PI. (C, I) Mature macrogametes at 168 h PI. (J) Enlargement of macrogametes of Figure 4I. (D) The third generation mature meront at 168 h PI. (E, K) A macrogamete to initiate the formation of the first layer of the wall at 168 h PI. (F, L) Mature oocysts located in cecal contents at 168 h PI.