Molecular Investigation of Aquatic Reoviruses in Rainbow Trout in Northern Türkiye: The First Molecular Detection of Aquareovirus A in Türkiye

Abstract

Aquareovirus A (AqRV A) has been known to cause low or intermediate diseases among various salmon species and mollusks. Additionally, Piscine orthoreovirus (PRV), divided into subtypes PRV-1, PRV-2 and PRV-3, has been reported in rainbow trout, coho salmon and Atlantic salmon. In this study, we investigated the presence of these aquatic reoviruses in rainbow trout in Turkiye. For this purpose, fish were collected from 5 cities (Sinop, Samsun, Ordu, Trabzon and Rize) in Turkiye`s Black Sea Region. In total, 150 fresh rainbow trout (30 fish per city) of 25–35 cm were collected from fishmongers. All the genotypes of Piscine orthoreoviruses (PRV) and Aquareovirus A were investigated using RT-PCR with degenerated pan-specific primers. No PRV genotypes were detected, but 4 pools of 30 pools were positive for AqRV A. According to phylogenetic analyses of segment 10 (VP7), all viruses were closely related to the Chum salmon reovirus (CSRV) belonging to AqRV A (GeneBank Accession number: NC_007590.1). This is the first report of AqRV A in naturally infected rainbow trout cultivated in sea cages in the world, necessitating further investigation of the pathobiology of AqRV A in rainbow trout.