haemorrhagic septicaemias e.g. furunculosis and vibriosis
which may also be accompanied by enteritis (Fig. 4.4). Peritonitis, results from inflammation of the thin tissue that
covers most of the abdominal organs (Fig. 4.5), and an
inflammatory cardiomyopathy is also present in several fish
diseases (Fig. 4.6).
An early hyperaemia in the hypodermis and dermis can
be preceded by infiltration of macrophages and other inflammatory cells with a liquefactive necrosis within the centre of
the lesion. Lesions may also be designated as degenerative
or proliferative. In the former, intracytoplasmic vacuolation,
cysts, hyalinization and spongiosis may be seen, whereas
Fig. 4.1 (continued)
4.1 Inflammation and Proliferation
35