Detection of megalocytivirus in Oreochromis niloticus and Pseudoplatystoma corruscans in Brazil

The infectious spleen and kidney necrosis virus (ISKNV) belongs to the genus Megalocytivirus (MCV), a group of double-stranded DNA genome viruses. The aim of this study was to retrospectively analyze samples from suspected foci of MCV infection in freshwater fish in Brazil. Samples were collected from infected fish between 2017 and 2021. Phylogenetic analysis revealed 2 groups of MCV circulating in the country. A genetically homogeneous group formed a clade with ISKNV samples from different parts of the world. Only 2 of the sequences from the state of Goias showed a small genetic distance when compared to the larger group in the same clade. This study describes the validation of 3 qPCR methods and the presence of MCV in Brazil since 2017, including a genotype not previously described.

Automated summary

This study retrospectively analyzed suspected foci of Megalocytivirus (MCV) infection in freshwater fish in Brazil. Results revealed two circulating groups of MCV in Brazil, with one group forming a clade related to ISKNV samples worldwide. Additionally, two sequences from the state of Goias showed a small genetic distance compared to the larger group in the same clade. The study also validated three qPCR methods and described the presence of MCV in Brazil since 2017, including a previously undescribed genotype.