PREVENTION AND MANAGEMENT OF INFECTIOUS DISEASES IN INTENSIVE MOLLUSC HUSBANDRY

Abstract

ABSTRACT Principles for management of infectious diseases in intensive mollusc husbandry are presented as derived from an evaluation of pertinent literature and general principles of health management. Both opportunistic pathogens and obligate agents of disease are managed in terms of finite entry points in husbandry systems: brood stocks, algal food stock and seawater source. Opportunistic bacterial diseases, particularly vibriosis, are presently the most significant diseases. Bacteria expand in the culture system in a preclinical phase and subsequently cause primary disease both by direct infection by bacteria and by toxin‐mediated processes. Primary disease involving direct infection and growth of bacteria in ligament and soft tissues appears to be the most significant mechanism of infection in metamorphosing and juvenile animals, the critical phase in intensive mollusc husbandry. Diagnosis and management of the disease depend on recognition of the disease and determination of the source of infectious organisms. Obligate intracellular diseases are prevented and managed by control of animal movements, prevention of cross contamination and sterilization of effluents from animal tanks.