Viral metagenome analysis uncovers hidden RNA virome diversity in juvenile largemouth bass (Micropterus salmoides).

The largemouth bass (Micropterus salmoides) is a well-known freshwater fish species that is commonly bred in aquaculture. Unfortunately, this species faces a significant threat from viral diseases, and there is currently no available vaccine to combat them. In this study, we have conducted viral metagenome analysis to explore the RNA virome of largemouth bass, which refers to the collection of all RNA viruses present in the fish. It revealed the existence of 69 known viruses and 117 novel viruses in the liver, spleens, and kidneys of largemouth bass. The diverse range of viruses suggests that their host range may be wider than previously believed. Interestingly, many of the viruses identified in largemouth bass bear similarities to known pathogens found in nonaquatic animals, such as bovine viral diarrhea virus 1 and 2, porcine endogenous retrovirus, feline sarcoma virus, avian sarcoma virus 16, mouse mammary tumor virus, and mammalian orthoreovirus 5. This finding indicates the potential for these viruses to be transmitted across different species to largemouth bass. To confirm the presence of these viruses, reverse PCR and Sanger sequencing were employed to explore the authenticity of the identified RNA viruses. The discovery of this hidden diversity within the RNA virome of juvenile largemouth bass brings attention to the latent viruses that pose a serious threat. Further investigation is crucial to understanding the pathogenicity of these viruses and developing effective measures for disease prevention in largemouth bass aquaculture. • 117 distinct viruses were identified in the liver, spleens, and kidneys of largemouth bass. • Many viruses bear similarities to pathogens found in non-aquatic animals. • Reverse PCR was employed to explore the authenticity of identified RNA viruses. [ABSTRACT FROM AUTHOR]