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| Author(s): |
Samara Rita de Lucca Maganha
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Pirassununga. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT) |
| Defense date: | 2016-08-12 |
| Examining board members: |
Ricardo Luiz Moro de Sousa;
Simone de Carvalho Balian;
Adriano de Oliveira Torres Carrasco
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| Advisor: | Ricardo Luiz Moro de Sousa |
| Abstract | |
Viral fish disease caused by viruses of Iridoviridae and Alloherpesviridae families are distributed globally and represent a real threat to the expansion of world aquaculture system. Thus, improvement and application of current diagnostic techniques in order to control or stop the spread of these infections among countries become necessary. Virus of Megalocytivirus (MV) gender and the Cyprinid herpesvirus (CyHV), types 1, 2 and 3, induce diseases in fish with high mortality rate. Virus of Lymphocystivirus (LCDV) gender, despite their lower pathogenicity, cause severe economic losses by reducing the commercial value of infected animals. Due to the paucity of data available on the circulation of these viruses in Brazil, this study aimed to prospecting, including the detection and characterization through the use of molecular techniques, MV, LCDV, CyHV-1, CyHV-2 and CyHV-3 in ornamental fish come from the city of São Paulo, as well as in fish species of free and commercial life from 5 Brazilian states. For this purpose, 306 samples of 43 different species of fish were collected and characterized, all of which were processed to CyHV-3 and 81 were subjected to the diagnosis of other viruses, yielding a positivity rate of 47% for MV, 1.2% for LCDV and 2% for CyHV-3. All positive samples were from ornamental fish of São Paulo municipality. The only LCDV-nucleotide sequence obtained was grouped phylogenetically in the genotype VII clade, showing 44.8-91.1% similarity to other homologous sequences. Sequences of MV grouped into clade with Asian sequences, displaying 47.2-99.2% similarity to other homologous sequences. For CyHV-3, the similarity among the sequences obtained in this study and the similarity to homologous sequences was equal or superior to 97.4%, grouping into 2 distinct clades. Evolutionary analysis indicated weak or relaxed negative selection for all the sequences from the 3 studied virus groups. In this sense, it can highlight the novelty of the obtained results for a better understanding of the molecular epidemiology of these viruses in Brazil. (AU) | |
| FAPESP's process: | 14/04327-7 - Molecular diagnosis of infections caused by Cyprinid herpesvirus 3 in fish from Northeastern and Central-Eastern regions of São Paulo State |
| Grantee: | Samara Rita de Lucca Maganha |
| Support Opportunities: | Scholarships in Brazil - Master |