Evaluation of Extraction Methods to Detect Noroviruses in Ready-to-Eat Raw Milk Minas Artisanal Cheese.

This study aimed to assess two homogenization methods to recover norovirus from Minas artisanal cheese (MAC) made with raw bovine milk obtained from four microregions of the Minas Gerais state, Brazil, with different ripening times and geographical and abiotic characteristics. For this purpose, 33 fiscal samples were artificially contaminated with norovirus GI and GII, and Mengovirus (MgV), used as an internal process control (IPC). TRIzol® reagent and Proteinase K homogenization methods were evaluated for all samples were then subjected to RNA extraction using viral magnetic beads and RT-qPCR Taqman® for viral detection/quantification. Proteinase K method showed better efficiency results for both norovirus GI and GII, with means recovery efficiency of 45.7% (95% CI 34.3-57.2%) and 41.4% (95% CI 29.1-53.6%), respectively, when compared to TRIzol method (16.6% GI, 95% CI 8.4-24.9%, and 12.3% GII, 95% CI 7.0-17.6%). The limits of detection for norovirus GI and GII for this method were 101GC/g and 103GC/g, respectively, independent of cheese origin. MgV was detected and revealed in 100% success rate in all types of cheese, with mean recovery efficiency of 25.6% for Proteinase K, and 3.8% for the TRIzol method. According to cheese origin, Triangulo Mineiro MAC had the highest mean recovery rates for the three viral targets surveyed (89% GI, 87% GII, and 51% MgV), while Serro MAC showed the lowest rates (p < 0.001). Those results indicate that the proteinase K adapted method is suitable for norovirus GI and GII detection in MAC and corroborated MgV as an applicable IPC to be used during the process.

Assessment of Gastroenteric Viruses in Marketed Bivalve Mollusks in the Tourist Cities of Rio de Janeiro, Brazil, 2022.

This study investigated the prevalence and genetic diversity of gastroenteric viruses in mussels and oysters in Rio de Janeiro, Brazil. One hundred and thirty-four marketed bivalve samples were obtained between January and December 2022. The viral analysis was performed according to ISO/TS 15216, and the screening revealed the detection of norovirus GII/GI (40.3%), sapovirus (SaV; 12.7%), human mastadenovirus (7.5%), and rotavirus A (RVA; 5.9%). In total, 44.8% (60) of shellfish samples tested positive for one or more viruses, 46.7% (28/60) of the positive samples tested positive for a single viral agent, 26.7% (16) tested positive for two viral agents, 8.3% (5) for three viral agents, and 13.3% (8) for four viral agents. Additionally, three mussel samples were contaminated with the five investigated viruses (5%, 3/60). Norovirus GII showed the highest mean viral load (3.4 × 105 GC/g), followed by SaV (1.4 × 104 GC/g), RVA (1.1 × 104 GC/g), human mastadenovirus (3.9 × 103 GC/g), and norovirus GI (6.7 × 102 GC/g). Molecular characterization revealed that the recovered norovirus strains belonged to genotypes GII.2, GII.6, GII.9, GII.17, and GII.27; SaV belonged to genotypes GI.1 and GIV.1; RVA to genotypes G6, G8, P[8]-III, and human mastadenovirus to types F40 and F41. The GII.27 norovirus characterized in this study is the only strain of this genotype reported in Brazil. This study highlights the dissemination and diversity of gastroenteric viruses present in commercialized bivalves in a touristic area, indicating the potential risk to human health and the contribution of bivalves in the propagation of emerging pathogens.