Novel viruses discovered in metatranscriptomic analysis of farmed barramundi in Asia and Australia.

Barramundi aquaculture is at risk of severe disease outbreaks and massive production losses. Here we used bioinformatics to screen 84 farmed barramundi transcriptomes to identify novel viruses that could threaten barramundi aquaculture and to establish a barramundi aquaculture virome. We discovered five novel viruses: latid herpesvirus 1 (LatHV-1) from the Alloherpesviridae family, barramundi parvovirus 1 (BParV1) from the Parvoviridae family, barramundi calicivirus 1 (BCaV1) from the Caliciviridae family, and barramundi associated picorna-like virus 1 and 2 (BPicV1 and BPicV2) from the Picornaviridae family. LatHV-1, BCaV1, and BParV1 are closely related to pathogenic viruses found in other fish species that can cause mass mortality in farms. To aid in future viral surveillance, we also designed and successfully tested an RT-PCR assay for the detection of BCaV1. Overall, we discovered a range of pathogenic viruses in barramundi aquaculture, paving the way for developing effective detection methods to assist early outbreak management.