To Measure the Immune Response, through Lysozyme Activity and Leucocyte Counts in Atlantic salmon infected with ADG, Neoparamoeba pemaquidensis
             Neoparamoeba pemaquidensis is an amoeboid protozoan that causes amoebic gill disease (AGD) in salmonids in several different countries (Mundy et., 2001). AGD is the main disease affecting the salmon industry in Australia (Powell & Clark 2004), and is the most important infectious disease affecting sea-caged salmon in Tasmania (Findlay & Munday 1998) it has been reported that pre-existing gill lesions and other amoebae may play a role in the pathogenesis of this disease (Munday et al. 1990), Little information is available on the epidemiology of AGD and the biology of Neoparamoeba pemaquidensis the aetiological organism of AGD. The disease appears as white mucoid patches on the surface of the gill lamellae, with pronounced mucous production (Mundy et al 1990). N. pemaquidensis has been associated with sever gill disease and significant mortalities among salmon reared in seawater (Bruno and Poppe, 1996). The immune response of a fish is strong and measurable (Kuby 1997). The non-specific, innate arm of the immune system exists to either prevent pathogens from entering the host or prevent multiplication and colonization of the microbe within the host (Kuby 1997). Innate immunity comprises four types of defensive barriers (Anatomic barriers, physiological barriers Phagocytic and endocytic barriers). Phagocytic and endocytic barriers consist of cells that phagocytose or endocytose foreign macromolecules and break them down, and specialized phagocytic cells (monocytes, macrophages, and neutrophils) (Kuby 1997). Leucocytes can be classed as neutrophils, lymphocytes, monocytes and thrombocytes. Lymphocytes can be broken down into two populations of both Band T lymphocytes which recognise antigens and therefore produce the reciprocal antibody and stimulants such as cytokines, which inturn stimulates t...