Complete disruption of all intestinal layers due to the deep penetration of the proboscis of Pomphorhynchus laevis. Evident features include the slender neck (N) of the acanthocephalan,
the muscle layer (m), and, the tunica mucosa (tm),whilst the arrows highlight the intestinal folds close to the site of acanthocephalan attachment. Scale bar 400 μm; b. Section of
the intestinal folds sampled from an uninfected specimen of Squalius cephalus showing several mucous cells containing acidic (alcian blue, thin arrows), neutral (periodic-acid-Schiff,
arrowheads), and mixed (thick arrows) glycoconjugates. Scale bar 200 μm; c. In the intestine of a chub infected with the acanthocephalan P. laevis (A), mucous cells are more numerous
and most of them contain alcian blue positive (thin arrows) and mixed (thick arrows) glycoconjugates. Scale bars 200 μm; d. An uninfected intestinal section stained with the high iron
diamine/alcian blue sequence reveals the presence of predominantly alcian blue reactivemucous cells (thin arrows). Scale bar 200 μm; e.When an acanthocephalan (A) is present, then a
high density of intestinal mucous cells is observed, most of which contain alcian blue glycoconjugates (thin arrows). Arrowheads indicate mucous cells containing sulphated
glycoconjugates (HID reactive). Scale bars 200 μm.