An outbreak of botulism in rainbow trout, Salmo gairdneri Richardson, farmed in Britain

Abstract

Abstract. An outbreak of disease in a British trout farm was identified as fish botulism. The diagnosis was established by demonstration of toxin in the serum and intestinal contents of fish, and was confirmed by the production of experimental botulism in trout inoculated with toxin from a strain of Clostridium botulinum type E isolated from intestinal contents of a sick fish. The outbreak was controlled and eliminated within 1 month by conservative measures which comprised the emptying, cleaning and heavy liming of affected ponds; intensive examination of all ponds for immediate removal of dead and sick fish and, on public health grounds, the banning of movement of fish outwith the farm. This episode, although of considerable financial consequence to the farmer, was shown to have no public health significance.