We provide a global overview of the intestinal bacteriome of Litopenaeus vannamei in two rearing systems and after an oral challenge by the White spot syndrome virus (WSSV). By using a high-throughput 16S rRNA gene sequencing technology, we identified and compared the composition and abundance of bacterial communities from the midgut of shrimp reared in the super-intensive biofloc technology (BFT) and clear seawater system (CWS). The predominant bacterial group belonged to the phylum Proteobacteria, followed by the phyla Bacteroidetes, Actinobacteria, and Firmicutes. Within Proteobacteria, the family Vibrionaceae, which includes opportunistic shrimp pathogens, was more abundant in CWS than in BFT-reared shrimp. Whereas the families Rhodobacteraceae and Enterobacteriaceae accounted for almost 20% of the bacterial communities of shrimp cultured in BFT, they corresponded to less than 3% in CWS-reared animals. Interestingly, the WSSV challenge dramatically changed the bacterial communities in terms of composition and abundance in comparison to its related unchallenged group. Proteobacteria remained the dominant phylum. Vibrionaceae was the most affected in BFT-reared shrimp (from 11.35 to 20.80%). By contrast, in CWS-reared animals the abundance of this family decreased from 68.23 to 23.38%. Our results provide new evidence on the influence of both abiotic and biotic factors on the gut bacteriome of aquatic species of commercial interest.

Animal and human wastewater can potentially contaminate water sources and the treatment of drinking water may not effectively remove all contaminants, especially viruses. The purpose of the present study was to evaluate the viral contamination of water used for human and animal consumption in the city of Concórdia, located in southern Brazil. Porcine circovirus type 2 (PCV2), porcine adenovirus (PAdV), human adenovirus (HAdV) and human norovirus (NoV) were searched for using quantitative polymerase chain reaction (qPCR). HAdV-positive samples were tested for viral infectivity by plaque assay. The qPCR results showed that PAdV, PCV2 and HAdV genetic material were present in all sampling sites. NoV was absent in all samples. The presence of genetic material from PAdV and PCV2 was detected in 30% and 45% of the 36 analyzed samples, respectively, with an average of 102 gc mL–1 for PAdV and 104 gc mL–1 for PCV2. HAdV was present in 100% of the samples, with an average of 104 gc mL–1. However, in plaque assay, only 36% of the samples were positive. As viable particles of HAdV were found in drinking water, these results confirm that swine manure and human sewage impact surface water and groundwater, endangering water quality and indicating a potential risk to public health.