Epidemiological investigations inform Ostreid herpesvirus 1 disease control in Pacific oysters (Crassostrea gigas)

• Main Author: de Kantzow, Maximilian Clarence
• Format: Thesis
• Language: English
• Published: University of Sydney 2020
• Subjects: OsHV-1; Pacific oyster; Epidemiology; Virology; Disease control; Pacific; Crassostrea gigas
• Online Access: https://hdl.handle.net/2123/23494

The high mortality and economic loss in farmed Pacific oysters (Crassostrea gigas) caused by the virulent microvariant genotypes of Ostreid herpesvirus - 1 (OsHV-1) has spurred research into strategies to mitigate the impact of the disease. The two aims of this thesis are i) to examine the effect of farm management and other risk factors on mortality caused by OsHV-1 during a natural outbreak and ii) to use a laboratory infection model for OsHV-1 that provides control of the environment to examine the specific risk factors and there interactions on mortality due to OsHV-1. Water temperature has a strong effect on OsHV-1 pathogenesis in Pacific oysters that could be leveraged to develop ways to reduce mortality due to OsHV-1 in commercial oyster aquaculture. Exposing oysters to OsHV-1 at a low water temperature (18°C) reduced mortality when oysters were subsequently exposed to OsHV-1 at a higher water temperature (22°C). The different pattern of expression of some immune genes at 18°C compared to at 22°C suggested that the response to OsHV-1 is influenced by different water temperatures and provided an insight into Pacific oyster immune function.