Genetic differentiation of Megalocytivirus by real time PCR and sequencing.

BACKGROUND: Megalocytiviruses (MCV) are double-stranded DNA viruses that infect fish. Two species within the genus are epidemiologically important for fish farming: red sea bream iridovirus (RSIV) and infectious spleen and kidney necrosis virus (ISKNV). The objective of this work was to study regions that allow the differentiation and correct diagnosis of RSIV and ISKNV. METHODS: The regions ORF450L, ORF342L, ORF077, and the intergenic region between ORF37 and ORF42R were sequenced and compared with samples from the database. RESULTS: The tree constructed using the sequencing of the PCR product Megalocytivirus. ORF077 separated the three major clades of MCV. RISV genotypes were well divided, but not ISKNV. All qPCRs tests showed acceptable repeatability values, that is, less than 5%. CONCLUSION: Two qPCRs for ISKNV detection and two for RSIV were considered suitable for use in the diagnosis and typing of MCV. The results of this study demonstrate the importance of an accurate evaluation of methodologies for the differentiation of MCV.

Phylodynamics of Alagoas vesiculovirus in Brazil.

The vesicular stomatitis virus belongs to the Rhabdoviridae family, genus Vesiculovirus. Four species (New Jersey, Indiana, Cocal, and Alagoas) are responsible for disease outbreaks in Western Hemisphere countries. In Brazil, the Alagoas virus is responsible for the main outbreaks of the disease, mainly in the states of the Northeast, Midwest, and Southeast regions of the country. The present study aimed to perform the genetic characterization of 41 vesicular stomatitis virus samples. RNA was extracted using Trizol and used to amplify part of gene P. Amplicons were sequenced using the Sanger method. The phylogenetic trees generated showed that Alagoas vesiculoviruses were positioned into three groups: group A formed by the first virus isolate; group B by isolates from states in the Northeast region; and group C by isolates from the states of Bahia, Goiás, and Tocantins. Their divergence to date has generated the formation of two genotypes evolving independently in regions that until the present study had little geographic overlap.

Phylodynamics of classical swine fever virus in Brazil.

The classical swine fever virus is the etiologic agent of one of the diseases with the greatest impact on swine farming worldwide. An extensive area of Brazil is considered free of the disease, but some states in Northeast Brazil have registered outbreaks since 2001. The objective of this study was to analyze the genetic variations of the virus and its spread over time and space. Partial sequences of the viral E2 protein obtained from samples collected during the Brazilian outbreaks were compared with sequences from the GenBank database (NCBI). The results demonstrated the continuous presence of the virus in the state of Ceará, with diffusion to at least two other states. The Brazilian Northeast virus presents specific polymorphisms that separate it from viruses isolated in other countries.