Aquabirnaviruses

Aquabirnaviruses are a genus of double-stranded RNA viruses belonging to the family Birnaviridae. These viruses infect a wide range of aquatic organisms, including fish, mollusks, and crustaceans. They are known for their potential to cause significant disease outbreaks in aquaculture.

The genome of aquabirnaviruses is divided into two segments, designated as segment A and segment B. Segment A encodes the viral protein (VP)1 and VP2, with VP2 undergoing post-translational cleavage to form VP2a and VP2b. Segment B encodes VP3, a protein involved in RNA silencing suppression. The viral particles are non-enveloped and have an icosahedral capsid structure.

Diseases caused by aquabirnaviruses can vary in severity. In fish, common diseases include infectious pancreatic necrosis (IPN) in salmonids, caused by infectious pancreatic necrosis virus (IPNV), and viral encephalopathy and retinopathy (VER) in various fish species. These diseases can manifest with symptoms such as lethargy, loss of appetite, darkening of the skin, and neurological signs.

Aquabirnaviruses are transmitted through various routes, including horizontal transmission via infected water, feces, or contaminated feed, and vertical transmission from parent to offspring. Diagnosis typically involves molecular methods like RT-PCR, as well as virus isolation and serological tests. Prevention strategies focus on biosecurity measures, vaccination, and selective breeding for resistant strains. Control relies on managing outbreaks and implementing strict hygiene protocols in aquaculture facilities.