Morphological and molecular identification of the fish-borne metacercaria of Ascocotyle (Phagicola) longa Ransom, 1920 in Mugil liza from Argentina

This is the first report of Ascocotyle (Phagicola) longa Ransom, 1920 (Digenea: Heterophyidae) in Argentina confirmed by morphological and molecular studies. The metacercaria was found encysted in myotomal musculature, heart and mesentery of the mullet Mugil liza (Pisces: Mugilidae) from Samborombon bay. We provide a morphological description of the metacercaria which we identified using species-specific primers for A. (Phagicola) longa and nucleotid sequence. This worldwide parasite has been reported as one of the causative agents of heterophyiosis, an emerging fish-borne disease of humans, contracted by the consumption of raw mullet. The discovery of A. (Phagicola) longa in Argentina represents a warning of the potentially great impact of this parasite on public health.