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Norovirus (NoV) is the most important cause of seafood-borne gastroenteritis worldwide, mainly associated with the consumption of raw oysters. NoV is often present in oysters that comply with existing control standards for shellfish. Therefore, the improvement of post-harvest treatments and practices can represent one of the main strategies to reduce the incidence of viral diseases related to shellfish. This study aimed to investigate long-term relays for the reduction of NoV levels in live oysters, during the high-risk cold months, by transferring the oysters from a more contaminated site to two sites with lower NoV levels. The efficacy of relaying was evaluated by analyzing oyster samples collected at days 0 (T0) and 30 (T30) for NoV levels using a real-time quantitative PCR (RT-qPCR). The NoV level at the relay sites was consistently lower than at the harvest site. The relay process for 30 days in seawater with a lower NoV level resulted in a decrease in the NoV load compared to day 0 with significant reductions depending on the site and genogroup of NoV considered. These results suggest that long-term relaying of oysters to reduce NoV levels is promising and could help growers to improve oyster safety; however, further investigations are needed.

Scanning electron microscopy (SEM) techniques can highly contribute to the knowledge of body structures in order to differentiate between different species or between varieties within the same species. This is particularly important in extreme environments, such as in Antarctic waters, where the evolution efforts have promoted the development of endemisms. In this work the external anatomy of Metridia gerlachei (Copepoda, Calanida) adult females, sampled during the Italian Oceanographic Campaign in Antarctica 1987-88, was described by SEM, particularly considering some swimming legs and the genital abdominal joint. The descriptions already reported have been verified and some morphological details have been better emphasized. As concerns the P2, the hook process of the first segment of endopod and a series of spines vaguely indicated, but not defined, in previous descriptions have been clearly evidenced. In the P5 the occurrence of three well separated free segments and the location of a marginal sets have been shown. The ultrastracture of the genital segment showed that a clear areola surrounds the genital field.