Originals

VALIDATION OF A METHOD FOR TREMATODE METACERCARIAE DETECTION IN FRESHWATER FISH THROUGH THE HELMINTHOLOGICAL ANALYSIS OF STRIPED CATFISH, PANGASIUS HYPOPHTHALMUS, FILLETS
Angela L. Debenedetti1, Sandra Hernández1, Marta Baquedano1, Màrius V. Fuentes

Fish-borne zoonotic trematodes are recognized as a serious health problem for humans. These parasites are particularly prevalent in South East Asia, but the high demand for fih on a global scale together with increasing aquaculture in Asian countries increase the risk of infection for exporter and importer countries. Spain is the main importer of freshwater fih, potential hosts for these parasites. The aim of this study is to validate an artifiial pepsic digestion method for trematode metacercariae detection in freshwater fih filets, based on WHO and the European Union Reference Laboratory for Parasites procedures. Deep frozen striped catfih, Pangasius hypophthalmus, filets acquired at various supermarket chains were used for the study and helminthologically analysed. Artifiial infection with 50 trematode metacercariae was carried out in 5 fih filet samples, previously shown to be negative for other metacercariae. All metacercariae were recovered after studying the total decantation volume, obtaining a sensitivity of 100%, and minimizing the sample (20 g) and reagents (1 g pepsin powder, 2 ml HCl 37% and 100 ml water) with respect to the reference methods. Therefore, this method is proposed to be used routinely for epidemiological studies on trematode metacercariae detection in freshwater fih. Moreover, none of the striped catfih filets was found to be parasitized by any kind of helminth. Considering this negative result, as well as the deep frozen conservation of fih for many months, it can be ascertained that the striped catfih does not pose a helminthological risk for consumers in Spain.

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