Histopathological survey of the yellow clam Mesodesma mactroides from southern Brazil.

摘要

The yellow clam Mesodesma mactroides has historically been an important economic resource from dissipative sandy beaches in southern Brazil, Uruguay and Argentina. The current study analysed the yellow clam Mesodesma mactroides (Mesodesmatidae) from southern Brazil. A sample of 30 clams was collected in the tidal zone of Cassino Beach (32 degrees 24'S - 52 degrees 20'W, Rio Grande do Sul State, Brazil) in January 2012, and tissue samples, including siphons, gills, gonads, digestive glands and foot, were processed for histological examination. Microscopical examination revealed the presence of three parasitic or commensal taxa: ciliates cf. Trichodina on the gills, turbellaria cf. Paravortex mesodesma in the intestinal lumen and digenean trematodes (sporocysts and metacercariae) in the inhalant siphon and digestive gland. No pathology was apparent with the trichodinid or turbellarian infections whilst limited pathological changes were associated with both digeneans. This is the first report on the identification of digenean trematodes in M. mactroides, in addition to the first histopathological report in yellow clams from Brazil.