Absence of norovirus contamination in shellfish harvested and commercialized in the Northeast coast of Brazil

Norovirus (NoV) is the main cause of gastroenteritis outbreaks worldwide. Although NoV spreads mainly from person to person, it is estimated that a large proportion of NoV outbreaks are caused by foodborne transmission. Bivalve mollusks are one of the most important foods involved in NoV transmission to humans. Little is known about NoV prevalence in shellfish harvested and commercialized in Brazil. The aim of this study was to map, for the first time, the distribution of NoV contamination in oysters and mussels harvested and commercialized in the coast of Pernambuco state, northeast Brazil. A total of 380 mollusks (260 oysters and 120 mussels) were collected between February and August 2017 either directly from harvesting areas or obtained from beach vendors at 17 sites in Pernambuco. Samples were processed and tested for NoV contamination using a SYBR Green real-time PCR assay. All samples were negative for NoV GI or GII contamination, suggesting a low risk of NoV contamination from this food source during the study period. Additional surveys in different areas of the Brazilian coast are warranted to monitor the risk of NoV infection upon seafood consumption.

Determinação de bactérias do grupo dos coliformes no tecido mole de Mytella guyanensis extraídas em Cananéia/SP, Brasil / Detecting bacteria of the coliform group in the soft tissue of Mytella guyanensis extracted in Cananéia/SP, Brazil

Esta pesquisa teve por objetivo avaliar a qualidade microbiológica de amostras da água e do tecido de Mytella guyanensis (Mollusca: Bivalva) espécie de relevante interesse comercial e que faz parte direta da renda e alimentação das comunidades tradicionais em regiões litorâneas. Este estudo foi realizado em duas comunidades do Estuário de Cananeia conhecidos como Retiro e Itanhoapina. Durante o período de 2017, onde a espécie é coletada para consumo humano, as amostras de água e do bivalve foram coletadas nas localidades a fim de determinar as concentrações de coliformes totais e termotolerantes. As Amostras de água e de M. guyanensis foram analisadas para determinar o Número Mais Provável de Coliformes (NMP), baseado na Técnica de Tubo Múltiplo. Os resultados das analises, demonstraram baixas concentrações de coliformes nas amostras de água, tendo ocorrido resultado semelhante para as amostras de tecidos dos indivíduos coletados. A análise da água apresentou média geométrica de 34,81 coliformes totais e 20,70 MPN 100 mL-1 de coliformes termotolerantes. As médias de coliformes nos tecidos moles de M. guyanensis foram de 190 MPN g-1 para coliformes totais e 174 MPN g-1 para coliformes termotolerantes. As concentrações de coliformes no tecido dos espécimes coletados, apresentaram correlação positiva com a temperatura e negativa com a salinidade. Houve diferenças significativas entre a sazonalidade em relação à concentração de coliformes totais e termotolerantes no tecido. O verão período de chuvas, apresentou a maior média sazonal de coliformes em M. guyanensis. Todas os valores obtidos para NMP de coliformes estiveram abaixo do limite estabelecido pela legislação.

This study aimed to evaluate the microbiological quality of water and tissue samples of Mytella guyanensis (Mollusk: Bivalve), a species of relevant commercial interest and is a direct part of the income and food of traditional communities in coastal regions. This study was carried out in two communities in the Cananeia Estuary known as Retiro and Itanhoapina. During the period of 2017, where the species is collected for human consumption, water and bivalve samples were collected in the localities in order to determine the concentrations of total and thermotolerant coliforms. The samples of water and M. guyanensis were analyzed to determine the Most Probable Number (MPN) of Coliforms, based on the Multiple Tube Technique. The results of the analyses showed low concentrations of coliforms in the water samples, with a similar result for the tissue samples of the individuals collected. The water analysis showed a geometric mean of 34.81 total coliforms and 20.70 MPN 100 mL-1 of thermotolerant coliforms. The averages of coliforms in the soft tissues of M. guyanensis were 190 MPN g -1 for total coliforms and 174 MPN g -1 for thermotolerant coliforms. The concentrations of coliforms in the tissue of the collected specimens showed a positive correlation with temperature and a negative correlation with salinity. There were significant differences between seasonality in relation to the concentration of total and thermotolerant coliforms in the tissue. The summer rainy season showed the highest seasonal average of coliforms in M. guyanensis. All values obtained for MPN of coliforms were below the limit established by the legislation.

Spatiotemporal appraisal of TBT contamination and imposex along a tropical bay (Todos os Santos Bay, Brazil).

A spatiotemporal evaluation of butyltin contamination was performed between 2010 and 2012 along Todos os Santos Bay (Northeast Brazil) using surface sediments, bivalve tissues (Anomalocardia brasiliana and Mytella guyanensis), and imposex occurrence (Stramonita rustica). The spatial study detected high tributyltin (TBT) levels (maximum values of 262 ng Sn g (-1) - 21,833 ng Sn g(-1) of total organic carbon - for surface sediments and 421 ng Sn g(-1) for bivalve tissues) in the innermost part of the bay. The TBT levels detected in M. guyanensis tissues might cause human health risk since local population consumes these organisms. These high concentrations observed in the bivalves might result in ingestions higher than the safe limits established by European Food Safety Authority (250 ng TBT kg(-1) day(-1)). Considering the temporal evaluation, no difference (p > 0.05) was observed between TBT concentrations in sediments obtained during the two sampling campaigns (2010/2011 and 2012). However, the increasing predominance of TBT metabolites (butyltin degradation index (BDI) >1) in more recent sediments indicates further degradation of old TBT inputs. In spite of that, recent inputs are still evident at this region. Nevertheless, a reduction of imposex parameters in S. rustica over the last decade suggests an overall decline in the TBT contamination, at least in the outermost and possible less impacted region of the bay. The TBT contamination is probably reducing due to the national and international legislative restrictions on the use of TBT as antifouling biocide. The contamination levels, however, are still relevant especially in the inner part of Todos os Santos Bay since they are above those that are likely to cause toxicity to the biota.

Linking environmental heavy metal concentrations and salinity gradients with metal accumulation and their effects: A case study in 3 mussel species of Vitória estuary and Espírito Santo bay, Southeast Brazil.

The present study was conducted to link the heavy metal load in three species of mussels (Perna perna, Mytella falcata and Mytella guyanensis) from the estuaries and bays around Vitória island, south-east of Brazil, with the salinity gradient and the heavy metal levels in the abiotic environment (including water, suspended particulate matter (SPM) and sediment). Primarily based on the salinity gradient, a total of 26 sites around Vitória Island were selected for sampling of water, SPM, sediments and organisms. Besides tissue metal levels, the condition index and energy stores (glycogen, lipid and protein) were quantified as an indicator of fitness in response to metal pollution. Dissolved metals in water indicate that Cd and Mn content was higher along Espírito Santo Bay, while Al, Co, Cu, Cr and Fe were elevated in the sites with low salinity such as river mouths, estuarine and sewage canals. Likewise, suspended matter sampled from low salinity sites showed a higher heavy metal load compared to moderate and high salinity sites. Though mussels were sampled from different sites, the contamination for Cd, Cu, Fe and Mn was higher in mussels inhabiting low salinity sites (M. guyanensis and M. falcata) compared to P. perna, a high saline water inhabitant. However, a higher Zn body burden was observed for P. perna compared to Mytella species. Tissue Fe accumulation (but not Mn and Zn) correlated with heavy metal levels in suspended material for all three species, and for M. falcata this correlation also existed for Cd and Cu. Energy store and condition index in all mussels varied depending on the sampling sites and correlated with salinity gradient rather than tissue metal concentration. Overall, metal concentration in mussels did not exceed the safe levels as per the international standards for metals, and would be of no risk for human consumption.

Antioxidant defense responses in Mytella guyanensis (Lamarck, 1819) exposed to an experimental diesel oil spill in Paranaguá Bay (Paraná, Brazil).

We evaluated the effects of diesel oil on the bivalve Mytella guyanensis using biomarkers of oxidative stress (glutathione S-transferase, glutathione peroxidase, and reduced glutathione) after an experimental in situ spill in a mangrove area in southern Brazil. A linear model was developed for the Multiple Before-After Control-Impact (MBACI) experimental design to assess the significance of biological responses. Control and impacted sites were sampled seven and two days before as well as two and seven days after the spill. With the exception of a late response of reduced glutathione (GSH) levels on day seven, none of the biomarkers were significantly altered by the impact. This result was attributed to the high environmental variability of the experimental sites combined with a low sensitivity of Mytella guyanensis to diesel oil at short time-scales. The high resistance of M. guyanensis suggests that its antioxidant response is triggered only after a medium- to long-term exposure to contaminants.

Parasites of economically important bivalves from the southern coast of Bahia State, Brazil / Parasitos de bivalves de interesse econômico no Litoral Sul do Estado da Bahia, Brasil

This study investigated the parasites of three commercially important bivalve species (Crassostrea rhizophorae, Mytella guyanensis and Lucina pectinata) from the southern coast of Bahia, Brazil. A total of 540 specimens were collected in August 2009 and February 2010, at three localities. The bivalve specimens were measured on their longest axis, opened, and macroscopically examined for the presence of parasites or signs of disease. They were then fixed in Davidson' solution and subjected to routine histological processing, with paraffin embedding and H&E staining; next, the specimens were examined under a light microscope. No parasites were observed associated with L. pectinata. Rickettsia-like organisms (RLOs), Sphenophrya sp. (Ciliophora), Nematopsis sp. (Apicomplexa), Urastoma sp. (Turbellaria) and Bucephalus sp. (Digenea) were observed in both C. rhizophorae and M. guyanensis, as well as Ancistrocoma sp. (Ciliophora) and Tylocephalum sp. (Cestoda) in the former. A high prevalence of Nematopsis sp. was seen, but caused no apparent damage to the host. Bucephalus sp. caused the destruction of tissues, with castration, but showed low prevalence. The other parasites occurred in low prevalence and intensity, without causing significant damage.(AU)

Neste estudo foram investigados os parasitos de três espécies de bivalves de interesse econômico (Crassostrea rhizophorae, Mytella guyanensis e Lucina pectinata) da Bahia. Foram analisados 540 exemplares, obtidos em duas coletas (agosto-2009 e fevereiro-2010), em três localidades. Os bivalves foram medidos quanto ao seu maior eixo, abertos e examinados macroscopicamente quanto à presença de parasitos ou sinais de enfermidades. Depois disso, foram fixados em solução de Davidson e processados por rotina de histologia, com inclusão em parafina e coloração com H&E. O material foi examinado ao microscópio de luz. Nenhum parasito esteve associado a L. pectinata. Bactérias do tipo RLOs (organismos assemelhados a Rickettsia), Sphenophrya sp. (Ciliophora), Nematopsis sp. (Apicomplexa), Urastoma sp. (Turbellaria) e Bucephalus sp. (Digenea) foram observados tanto em C. rhizophorae quanto em M. guyanensis, sendo que a primeira apresentou ainda Ancistrocoma sp. (Ciliophora) e Tylocephalum sp. (Cestoda). Nematopsis sp. ocorreu em alta prevalência, porém, aparentemente, não causou danos aos bivalves. Bucephalus sp. causou destruição de tecidos, com castração, mas foi pouco prevalente. Os demais parasitos ocorreram em baixa prevalência e intensidade de infecção e sem causar danos.(AU)

Maintenance of filtering molluscs in aquaria for sub-chronic studies

This work determined the best survival conditions for the clam Mytella guyanensis and the mussel Perna perna in the estuary and sea aquaria respectively over at least 12 days, which could enable their use in the ecotoxicological studies. The aquaria were set up with the appropriate water and sedimen, and allowed to establish for a minimum of one month before adding the organisms. The best survival conditions for M. guyanensis required more time for the aquarium stabilization, addition of inocula and more frequent water changes than for P. perna. The organisms' lipid contents increased and their condition index was maintained indicating the good conditions of the aquaria, hence, their possible use in the sub-chronic studies.

Estudos sobre a dinâmica de contaminação de organismos marinhos devem ser feitos sob condições controladas pelo tempo necessário para que os organismos possam responder à presença do agente contaminante. No entanto, a manutenção de organismos em aquários por determinado período pode ser difícil porque todas as outras variáveis do ambiente precisam ser próximas às condições naturais. Este trabalho determinou as melhores condições de sobrevivência do marisco Mytella guyanensis e do mexilhão Perna perna, respectivamente em aquários de estuário e de mar, por período de até 12 dias. Os aquários foram montados com água e sedimento de estuário ou de mar e estabilizados por, no mínimo, um mês antes da colocação dos respectivos organismos. As melhores condições de sobrevivência de M. guyanensis requisitaram mais tempo de estabilização do aquário, adição de inóculos e trocas de água mais freqüentes do que para os P. perna. Os conteúdos de lipídios aumentaram com o tempo e o índice de condição dos organismos foi mantido, indicando as boas condições dos aquários e, conseqüentemente, a possibilidade de uso em pesquisas ecotoxicológicas.

Nematopsis sp. (Apicomplexa: Eugregarinida) em Mytella guyanensis (Lamarck, 1819) (Bivalvia:Mytilidae) da Região Estuarina do Rio Cachoeira, Ilhéus, Bahia, Brasil / Nematopsis sp. (Apicomplexa: Eugregarinida) in Mytella guyanensis (Lamarck, 1819) (Bivalvia: Mytilidae) from estuarine region of the Cachoeira river, Ilhéus, Bahia, Brazil

Exemplares do molusco Mytella guyanensis (Bivalvia: Mytilidae) da região estuarina do Rio Cachoeira (Ilhéus, Bahia) foram investigados quanto à freqüência de ocorrência e sítios de infecção por protozoários do gênero Nematopsis Schneider, 1892 (Apicomplexa: Eugregarinida: Porosporidae), no período entre agosto de 2005 e julho de 2006. Em 480 animais analisados, medindo entre 34,5 e 74,9 mm de altura (Média: 55,4 mm; DP ± 6,7), 387 apresentaram em seus tecidos o parasito e nestes, os locais com maior freqüência de ocorrência do Nematopsis foram as brânquias (298 animais) e o manto (248). O parasito foi também observado na glândula digestiva e na musculatura. Alguns indivíduos gravemente infectados apresentaram modificações na conformação das brânquias e do manto

Individuals of the clam Mytella guyanensis (Bivalvia: Mytilidae) from the estuarine region of the Cachoeira river (Ilhéus, Bahia) have been analyzed to detect the frequency of occurrence and infected sites by protozoans of the genus Nematopsis Schneider, 1892 (Apicomplexa: Eugregarinida: Porosporidae), in the period between August 2005 and May 2006. A total of 480 individuals were analyzed, measuring between 34.5 and 74.9 mm of height (Average: 55.4 mm; DP ± 6.7). Nematopsis were found in 387 of them, occurring more frequently within the gills (298 animals) and the mantle (248). The parasite was also observed in the digestive gland and the musculature. Some severely infected individuals presented modifications in the conformation of the gills and the mantle