Temporal dynamics of infection of cockles Cerastoderma edule with the protistan parasite Minchinia tapetis (Rhizaria: Haplosporida) in Galicia (NW Spain).

Uninucleate and binucleate cells and multinucleate plasmodia of a haplosporidan-like protist associated with heavy haemocytic infiltration were observed in histological sections of cockles, Cerastoderma edule, from the Ría de Noia (Galicia, NW Spain) in the course of a cockle health surveillance programme. Molecular assays provided identification of this protist as Minchinia tapetis, which we thus record from a new host. Prevalence of M. tapetis as high as 93% was recorded but infection intensity was low to moderate, never heavy, and abnormally high cockle mortality was not observed in the ria by shellfishers. A significant positive correlation was found between M. tapetis prevalence and sea water temperature. Sea water temperature increase associated with climate change might contribute to increase the prevalence of this infection in cockles and, as a consequence, this parasite may be considered a threat for cockle production.