"Proctoeces maculatus" "(Trematoda: Digenea)", paràsit del musclo "Mytilus edulis": Estructura, desenvolupament i ultrastructura de la cercària

Resum

About 1 % of the mussel beds of the Galician coast are affected by the so called «orange sickness», a disease detected for the first time by COLE (1935) and caused by Proctoeces maculatus (Trematoda: Digenea), whose sporocysts, approximately one thousand in number, infect different organs of the host, amongst the most important of which are the pallium and the gonads. The sporocist has the shape of an oval bag in which sporocysts in formation as well as cercariae in different developping phases dwell; some morphological differences between the latter and the former appear already during the early phases.
The acetabulum of the cercaria differenciates itself as a spherical cavity whose wall presents muscular fibres in radial and circular directions. At the same time, the cercaria's own teguments are being developped and the tegumentary cover that surrounds it degenerates during development, which originated in the sporocyst's wall.
Cells of a connective tissue nature form the parenchyma of the cercaria, which present very well defined boundaries and scarcity of intercellular matter.