Fig. 3.

Occupation of the fish brain by Cardiocephaloides longicollis in fresh (A, B) and histological samples (C–F). Cardiocephaloides longicollis metacercariae within (A) the PGZ and (B) the medulla oblongata in experimentally-infected fish one month after infection. Asterisks indicate the position of metacercariae. Cardiocephaloides longicollis metacercariae are found at 6 dpi in the tectal ventricle (C), and as they grow (D, 21 dpi; E, 8 mpi; F, 15 mpi) they occupy larger part of the tectal ventricle, and also the PGZ. The representations of brains indicate the sections and positions (yellow square) where metacercariae have been found. Legend: TeO striped, cerebellum in dots and Mo squared. ICL, inferior cerebellar lobe; Mo, medulla oblongata; PGZ, periventricular gray zone of optic tectum; TeO, tectum opticum; TV, tectal ventricle. Scale bars: A = 300 μm; B = 450 μm; C–F = 200 μm. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)