Infestations expérimentales de crabes juvéniles par la sacculine. Ultrastructure des racines parasitaires en croissance et relations avec la niasse ganglionnaire ventrale de l'hôte

Experimental infestations of young Carcinus with Sacculina carcini indicate that the ventral ganglionic mass (VGM) is the first "target" of the parasite roots into the host tissues. As in pubescent crabs naturally parasitized, either with or without an external visceral sac, the roots penetrate and invade that area of the central nervous system during the first month of infestation.Ultrastructural study of the developing roots, in contact with the VGM, leads to the conclusion that apart from a few embryonic characters, the root cells show a cytostructure similar to the one that has been observed in the roots naturally parasitizing pubescent crabs, whether the external visceral sac is present or not.In the two cases of infestation the roots which cross the neurolemma bring about a marked disorganization of ganglia in consequence of the alteration of the neuroglia, neuropiles and neurosecretory areas.An action of the parasite at a distance, i.e. in the absence of contact of the roots with the ganglia, also ...