Rainbow trout (Oncorhynchus mykissis) is a North Pacific salmonid species, which, in the Western hemisphere, is the principal inland-farmed fish. In terms of production, global rainbow trout reached 600,000 tons in 2012; by 2019, it had exceeded 950,000 tons. Recently, we discovered a novel and ongoing disease in farmed rainbow trout, the hallmark of which is hepatic granulomatous-like lesions. Diseased fish were ill-thrift with stunted growth. Furthermore, we revealed the presence of a novel (Nido)virus, which we named ‘Trout Granulomatous Virus’ (TGV), in these lesions.

UNMET NEED
Assessing TGV distribution in rainbow trout aquaculture (diagnostics) and ways to control the disease (vaccination) are needed to limit the disease.

OUR SOLUTION
We sequenced the full-length RNA genome of TGV (consisting of ~29,000 nucleotides) and identified TGV’s genes. Importantly, among the different genes, we identified the gene encoding for the surface glycoprotein – the Spike (S) protein – of the virus.

APPLICATIONS
Decoding the TGV genome provides two essential directions for disease containment: 1. Diagnostics – Development of PCR and protein-based diagnostics to detect the virus. 2. Vaccination – Development of anti-TGV vaccines. For example, Spike-based vaccines.

STATUS
We developed PCR-based diagnostics. We are currently developing TGV-specific antibodies against TGV proteins suspected to be highly immunogenic. We are also constructing various vaccination platforms against TGV to be tested in trout.

INTELLECTUAL PROPERTY
A patent was filed

REFERENCES
Discovery of an unrecognized nidovirus associated with granulomatous hepatitis in rainbow trout. Karniely S, et. al., iScience. 2023 Mar 11;26(4):106370. doi: 10.1016/j.isci.2023.106370.