Vibrio tapetis-like strain isolated from introduced Manila clams Ruditapes philippinarum showing symptoms of brown ring disease in Norway.

The Manila clam Ruditapes philippinarum was introduced to Norway in 1987 and was produced in 2 hatcheries until 1991. Clam seed was planted at 6 sites. Two sites were on the Island of Tysnes, south of Bergen.

Characterization by restriction fragment length polymorphism and plasmid profiling of Vibrio tapetis strains.

A total of nine Vibrio tapetis strains acquired from France, the United Kingdom and Norway were studied for their plasmid content. All the isolates contained from two to four large plasmids, ranging from approximately 60 to 100 kpb. in size.