Unusual Localization of Sp. in Swordfish () Hearts.

The genus comprises hematophagous parasites of marine aquatic species, including cephalopods, marine mammals, and pelagic fish. Nine species have been officially included in the genus plus another six . They are most often found in the host's musculature, without penetrating internal organs. For the present study, 83 hearts from swordfish () caught in the Mediterranean Sea were sampled and immediately fixed in formalin for histopathological analysis. In total, 10 (12.05%) hearts were found to be parasitized by copepods of the genus . Macroscopically, there was mild-to-severe fibrinous pericarditis with atrial wall thickening and multiple parasitic nodules. Histologically, the parasitic nodules were surrounded by an inflammatory-necrotizing reaction. Parasitic infestation by spp. is common in pelagic fish and in swordfish, in particular. Here, however, we report atypical cardiac localization. A future area of focus is the evaluation of cardiac spp. infestation by histopathology and genetic identification of the parasites.