The role of epidemiology in the prevention, diagnosis, and control of infectious diseases of fish.

Epidemiologic methods are essential to understanding infectious diseases in aquaculture. Unfortunately, many of these methods are poorly understood or not utilized by fish-health scientists and aquaculturists -- often because of the lack of contact with epidemiologists who are willing to investigate fish diseases. In this paper, we describe direct interactions between epidemiologists and fish-health specialists that have resulted in an improved understanding of the causes and management of infectious diseases in aquaculture. We focus on risk-factor studies, risk analysis and infectious-disease modeling, evaluation of diagnostic tests and experimental studies. We also describe characteristics of confined fish populations that make them ideal for developing and testing epidemiologic models and the theoretical and practical challenges of designing and conducting epidemiologic studies in fish farms. Throughout our presentation, emphasis is given to characteristics, opportunities and problems associated mainly with conducting epidemiologic studies to intensive aquaculture systems. We conclude that the development of increased cooperation among epidemiologists, fish-health scientists and aquaculturists will be mutually beneficial and, therefore, efforts for such collaboration should be initiated from all parties involved.