Complex genetic structure of a euryhaline marine fish in temporarily open/closed estuaries from the wider Gulf of Aden

Temporarily open/closed estuaries (TOCEs) are major ecosystems of the Indian Ocean coastal zones. Their functioning is tightly linked to climatic events such as monsoons and storms, and their mouth can close up for prolonged and variable periods of time, thus limiting their connectivity with the marine environment. Two types of genetic markers (i.e., mitochondrial cytochrome c oxidase I (COI) gene and microsatellites) were used to assess the genetic structure of 288 individuals of Terapon jarbua, a widely distributed fish species in the wider Gulf of Aden. Firstly, the hypothesis of panmixia was tested. Then, alternative hypotheses were investigated to explain the population genetic structure of T. jarbua: could it be shaped by (1) regional biogeographic barriers (i.e., Socotra Island vs. mainland Yemen) and/or (2) the particular functioning of TOCEs in relation to the species life cycle and particular physical ocean parameters? On one hand, the polymorphism of the COI inferred (1) a high haplotype diversity and a reduced nucleotide diversity over the whole data set and (2) a “star-like” shape of the haplotype network, thus suggesting a population expansion after local extinctions during the Pleistocene glaciations. On a second hand, the genotyping of eight microsatellites showed a significant genetic differentiation between T. jarbua populations in the wider Gulf of Aden (F _ST = 0.035, p < 0.01), and thus, the panmixia hypothesis was rejected. Analyses of molecular variance results did not show any significant structure between Socotra Island and mainland Yemen and thus did not support the role of biogeographic barriers in structuring T. jarbua populations. Significant multi-locus deficits in heterozygotes at particular locations displaying high levels of F _IS were recorded. It was suggested that a possible Wahlund effect took place in those TOCEs which could gather several cohorts of larvae stemming from different marine subpopulations over the sampled area. The present study emphasized the uniqueness of each TOCE as a potential reservoir of biodiversity and the urgent need for a better conservation program of those estuaries in the region, in order to avoid habitat fragmentation and permanent closure of those nursery areas by human activities.     

How wave exposure, group size and habitat complexity influence foraging and population densities in fishes of the genus Halichoeres (Perciformes: Labridae) on tropical rocky shores

Wave exposure and habitat complexity have been used to explain variations in the distribution patterns and behavior of many reef fishes. This study analyzed the influence of both factors on density and foraging activity, and the influence of group size on foraging in three species of the genus Halichoeres (Labridae) on tropical rocky shores. It was shown that initial phases (IP) and terminal phases (TP) Halichoeres, were influenced by wave exposure, although foraging in Halichoeres brasiliensis TP was not influenced by wave exposure. The IP in all three species were positively associated with rugosity and algal cover while the TP was positively associated with depth. Habitat complexity also influences foraging in these species. Group size influenced foraging activity, except in H. brasiliensis TP. We also found variations in microhabitat patches used for foraging between species and differences in the stomach contents between species and phases, showing that functional roles change in response to ontogenetic shifts.     

Environmental Surveillance of Polioviruses in Rio de Janeiro,Brazil, in Support to the Activities of Global Polio Eradication Initiative

Wild polioviruses still remain endemic in three countries (Afghanistan, Pakistan, and Nigeria) and re-emergency of wild polio has been reported in previously polio-free countries. Environmental surveillance has been used as a supplementary tool in monitoring the circulation of wild poliovirus (PVs) and/or vaccine-derived PVs even in the absence of acute flaccid paralysis cases. This study aimed to monitor the presence of polioviruses in wastewater samples collected at one wastewater treatment plant located in the municipality of Rio de Janeiro, Brazil. From December 2011 to June 2012 and from September to December 2012, 31 samples were collected and processed. RD and L20B cell cultures were able to isolate PVs and non-polio enteroviruses in 27/31 samples. Polioviruses were isolated in eight samples (type 1 Sabin = 1, type 2 Sabin = 5, and type 3 Sabin = 2). Vaccine-derived polioviruses were not detected nor evidence of recombination with other PVs or non-polio enterovirus serotypes were observed among the isolates. The Sabin-related serotypes 2 and 3 presented nucleotide substitutions in positions associated with the neurovirulent phenotype at the 5′-UTR. Changes in important Amino acid residues at VP1 were also observed in the serotypes 2 and 3. Environmental surveillance has been used successfully in monitoring the circulation of PVs and non-polio enteroviruses and it is of crucial importance in the final stages of the WHO global polio eradication initiative. Our results show the continuous circulation of Sabin-like PVs and non-polio enteroviruses in the analyzed area during the study period.     

Adhesion of Norovirus to Surfaces: Contribution of Thermodynamic and Molecular Properties Using Virus-Like Particles

Food and Environmental Virology - The aim of the study was to assess human norovirus and feline calicivirus (FCV) surface free energy, hydrophobicity, and ability to interact with fresh foods and...     

Prenatal diagnosis of congenital Chagas' disease (American trypanosomiasis)

The prenatal diagnosis of congenital transmission of Chagas' disease in a pregnant woman with the indeterminate form of the disease is reported. Sonography revealed fetal hydrops at 31 weeks' gestation. Anti-Trypanosoma cruzi IgM and IgG antibodies were negative in the fetal blood sampled by cordocentesis, but T. cruzi trypomastigotes were found in its buffy coat. Owing to anemia, in utero exchange transfusion was undertaken, but fetal demise ensued. Labor was induced and a stillborn infant weighing 2030 g was delivered. The pathological examination revealed placentitis and meningoencephalitis, myocarditis and splenitis in the stillborn fetus. Amastigotes were found in the myocardium, brain and placenta. Copyright © 2004 John Wiley & Sons, Ltd.     

Soleidae macroparasites along the Portuguese coast: latitudinal variation and host–parasite associations

Parasite assemblages are increasingly being used as indicators of their hosts’ biology and ecology, especially for economically important marine species such as the Soleidae. In this study, seven species inhabiting Portuguese coastal waters were examined for external and internal macroparasite infections using standard procedures: Dicologlossa cuneata, Microchirus azevia, Microchirus variegatus, Solea lascaris, Solea senegalensis, Solea solea and Synaptura lusitanica. Despite being closely related, these species present different life history patterns and ecological preferences which were expected to be mirrored by their macroparasite assemblages. The aim of the study was, therefore, to study the variation of these assemblages, within and between host species, along the Portuguese coast in order to evaluate the importance of the hosts’ features and environmental factors in the assemblage compositions. Flatfish were obtained seasonally from commercial fishing vessels operating in three areas (northern, central and southern) along the Portuguese coast. Prevalence and mean abundance were calculated and tested for differences between host sex, areas and seasons. The host specificity index and the importance of the host–parasite relationship were computed based on mean abundance. The total number of parasite individuals, species richness, total prevalence, total mean abundance, diversity and evenness were also calculated. A canonical correspondence analysis (CCA) was performed using prevalence and mean abundance data. A total of 44 macroparasite species were found. No significant differences were observed in prevalence and mean abundance between sexes and sampling seasons but, for three of the parasite species, significant differences were found between areas. The highest values of the parasitological and ecological indices were generally registered in the hosts S. lascaris and S. senegalensis and in the southern area. The CCA using the prevalence data revealed the differentiation of S. lascaris samples, which was mainly related to the total prevalence and to the number of important species of macroparasites. When using mean abundance data, the CCA revealed the differentiation of D. cuneata from the south, S. lascaris from the three areas and S. senegalensis from the south, mainly related to total prevalence and richness. The differences found between infection levels and assemblages’ composition were mainly due to differences in hosts’ diet, namely prey type consumption, given that most macroparasites found were transmitted through the food web. However, environmental factors were also important given that they regulate the distribution of ectoparasites and the availability of prey, and therefore the infections’ pattern. These findings were in agreement with the ones from similar studies performed in other species, revealing the importance of parasites as indicators of their hosts’ ecology.