An investigation of ostreid herpes virus microvariants found in Crassostrea gigas oyster producing bays in Ireland

The variant μVar of OsHV-1 has been identified as the causative agent of an emerging disease in Europe affecting Crassostrea gigas oysters which has caused significant mortalities in C. gigas oyster stocks in France, Ireland, the UK, Spain, the Netherlands and Italy. Microvariants presenting some differences to the variant μVar have also been associated with mortalities in Australia and New Zealand.