Steinhausia mytilovum in Mytilus galloprovincialis (The Case of Atlantic Northwest Africa-Morocco)

Steinhausia mytilovum (Field, 1924) is a microsporidian parasite that infects female individuals of Mediterranean mussel, Mytilus galloprovincialis. The aim of this work was to evaluate the incidence and histopathological effect of the microsporidian in the host from the Atlantic coast of northwest Africa. Samples were collected monthly during two years (March 2009 - March 2011) at three sites; north, middle and south, along the Moroccan coast. The prevalence showed to be the highest in the north (0% - 26.66%) and south (0% - 75%), respectively, while mussels from the middle sampling site showed no infection of S. mytilovum. The seasonality of S. mytilovum was investigated as well, although no significant variation of its incidence was observed in respect to season. The most usual histopathological characteristic of the S. mytilovum infection was hemocytic infiltration in gonads, showing a statistically significant relationship to the S. mytilovum infection (P<.001). Further investigation is recommended to study influences of the biological and physical parameters on the infections of S. mytilovum in the natural populations of the Mediterranean mussel along the Moroccan coast.