Surveillance of aquatic animal viruses in seawater and shellfish in Korea

• Development of multiplex nested PCR assay for detection of aquatic animal viruses from seawater and shellfish
• A variety of viral agents co-existed in shellfish regardless of the sampling sites and time.
• Shellfish may act as bio-indicators or reservoirs of aquatic animal viral diseases.

Surveillance of aquatic animal viruses in hosts and seawater is very important to control and prevent the spread of aquatic animal diseases. And also the investigations for shellfish as play role in vector or carrier species, or a candidate host are required. Primer sets for multiplex nested polymerase chain reaction were developed to simultaneously detect aquatic animal viruses (megalocytivirus and white spot syndrome virus as DNA viruses, and viral hemorrhagic septicemia virus, viral nervous necrosis virus [VNNV], and marine birnavirus as RNA viruses) from seawater and shellfish. The multiplex nested PCR amplified each virus specifically with a detection limit of about 10 copies of viral particles and facilitated detection of several aquatic animal viruses from seawater and shellfish. The detection rates of viruses in shellfish samples were not significantly different between areas, except for VNNV which showed much lower positive results in eastern sea area. But, several viruses co-existed in shellfish regardless of the sampling site and time. These results revealed that shellfish might accumulate several viruses over the long-term and could play a role as a bio-indicator or reservoir of viruses derived from aquatic animals.Statement of relevanceThis article is related to field of aquatic animal disease. In this study, we developed multiplex nested PCR assay for detection of aquatic animal viruses from seawater and shellfish. And we found several viruses co-existed in shellfish for long-term, suggesting that shellfish may act as a bio-indicator or reservoir of viruses derived from aquatic animals.