Oyster herpes-type virus

Area of Science:

• Marine biology
• Invertebrate pathology
• Virology

Background:

• Herpes-type viruses are known pathogens in vertebrates.
• Oysters, such as Crassostrea virginica, are ecologically and economically important marine bivalves.
• Understanding viral diseases in oysters is crucial for aquaculture and ecosystem health.

Purpose of the Study:

• To report the first identification of a herpes-type virus infection in an invertebrate host.
• To investigate the prevalence of this viral infection in oysters at different water temperatures.
• To determine the association between the virus and oyster mortality.

Main Methods:

• Microscopic examination of oyster tissues for viral inclusions.
• Comparison of viral inclusion prevalence at ambient (18–20°C) versus elevated (28–30°C) water temperatures.
• Correlation of viral presence with observed disease and mortality rates.

Main Results:

• A herpes-type virus infection was identified in the oyster Crassostrea virginica.
• Intranuclear viral inclusions were significantly more prevalent in oysters exposed to elevated water temperatures (28–30°C).
• The presence of these viral inclusions was associated with a lethal disease in oysters at higher temperatures.

Conclusions:

• This study documents the first herpes-type virus identified in an invertebrate.
• Elevated water temperatures exacerbate herpes-type viral infections in oysters, leading to significant mortality.
• The findings highlight the potential impact of climate change on marine invertebrate diseases.