Successful aquatic animal disease emergency programmes

The authors provide examples of emergency programmes which have been succes sful in eradicating or controlling certain diseases of aquatic animals. The paper is divided into four parts. The first part describes the initial isolation of viral haemorrhagic septic aemia (VHS) virus in North America in the autumn of 1988 from feral adult c hinook (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) returning fo r spawning. The fish disease control policies at both State and Federal lev els in the United States of America required quarantine and emergency eradi cation measures upon the finding of certain exotic fish pathogens, includin g VHS virus. The procedures for emergency plans, destruction of stocks and disinfection of facilities are described, as well as challenge experiments with the North American strains of VHS virus and the detection of the virus in marine fish species (cod [Gadus macrocephalus] and herring [Clupea hare ngus pallasi]) in the Pacific Ocean. The second part of the paper outlines the aquatic animal legislation in Gre at Britain and within the European Union, in regard to contingency plans, i nitial investigations, action on the suspicion of notifiable disease and ac tion on confirmation of infection. The legal description is followed by an account of an outbreak of viral haemorrhagic septicaemia in turbot (Scophth almus maximus) in Great Britain, including the stamping-out process at the affected farm and investigations conducted to screen other farms in the vic inity for possible infection. The third part provides a historical review of the build-up of infectious s almon anaemia (ISA) in Norway and the attempts to control the disease using legal measures in the absence of detailed knowledge of the aetiology, epiz ootiology, pathogenesis, etc. of the disease. The measures taken show that the spread of ISA can be controlled using restrictions on the movement of f ish, disinfection procedures, etc. However, acceptance and understanding of the chosen strategy by the fish farmers is a pre-requisite to reach that g oal. Finally, the paper summarises future needs for national and international l egislation, including the development of standard approaches for control, t he creation of appropriate infrastructures and a better understanding of th e epidemiology of aquatic animal diseases.