Nervous necrosis virus viability modulation by water salinity and temperature

Area of Science:

• Aquatic Virology
• Fish Pathology

Background:

• Nervous necrosis virus (NNV) is a globally significant aquatic pathogen affecting various fish species.
• Environmental factors like temperature, salinity, and UV radiation influence viral persistence in aquatic environments.

Purpose of the Study:

• To investigate the viability and persistence of NNV strains under varying salinity and temperature conditions.
• To compare NNV survival in natural seawater versus cell culture medium.
• To assess the impact of UV light and oxygen exposure on NNV infectivity in aquarium settings.

Main Methods:

• NNV viability was tested in low- and high-salinity seawater at different temperatures (15°C, 20°C, 25°C, 30°C).
• Comparative analysis included incubation in cell culture medium and under simulated aquarium conditions with UV and oxygen exposure.
• Viral persistence was quantified over time under these controlled conditions.

Main Results:

• NNV exhibited highest viability in seawater at 15°C; higher temperatures reduced viral persistence.
• Seawater salinity significantly affected NNV survival at 15°C and 30°C, but not at 20°C or 25°C.
• UV light and oxygen exposure in aquarium settings accelerated NNV inactivation. NNV persisted longer in cell culture medium than in seawater.

Conclusions:

• Temperature is a critical factor influencing NNV persistence in seawater, with optimal survival at lower temperatures.
• Salinity plays a role in NNV viability, particularly at temperature extremes.
• Environmental factors like UV and oxygen, alongside storage medium, are crucial for understanding NNV transmission dynamics.