Genetic differentiation of Megalocytivirus by real time PCR and sequencing

BackgroundMegalocytiviruses (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.MethodsThe regions ORF450L, ORF342L, ORF077, and the intergenic region between ORF37 and ORF42R were sequenced and compared with samples from the database.ResultsThe 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%.ConclusionTwo 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.

Automated summary

The objective of this study was to differentiate and correctly diagnose red sea bream iridovirus (RSIV) and infectious spleen and kidney necrosis virus (ISKNV) in fish farming. The sequencing of ORF450L, ORF342L, ORF077 and the intergenic region between ORF37 and ORF42R showed that ORF077 separated the three major clades of Megalocytivirus (MCV), while ISKNV could not be differentiated. All qPCRs tests showed acceptable repeatability values, less than 5%. Therefore, two ISKNV qPCRs and two RSIV qPCRs are considered suitable for the diagnosis and typing of MCV.