Glomerular disease in cultured rainbow trout, Salmo gairdneri Richardson, suffering from presumptive chronic viral haemorrhagic septicaemia

Abstract

Severe glomerular changes in the kidney of rainbow trout suffering from presumptive chronic viral haemorrhagic septicaemia are described. The pathological changes, as revealed by light-and electron microscopy, resembled those of membranous glomerulonephritis in mammals. Large electron-dense subendothelialmesangial deposits were present in most glomeruli. A lattice-like arrangement of macromolecules was observed. Monocytes and macrophages were observed in the capillary convolute. The possibility of post-infectious disease nephropathy with aggregation of immunocomplexes in the capillary wall in fishes is discussed.

An immune‐complex glomerulonephritis of Chinook salmon, Oncorhynchus tshawytscha (Walbaum)

“…Despite several reviews of fish immunology published in the intervening period, this work and its potential significance appears to have been neglected. Morphologically similar glomerular changes have been noted in a population of wild Chinook salmon returning to fresh water with high mortality (Meyers & McPherson 1985), in brook trout, Salvelinus fontinalis (Mitchell), infected with R. salmoninarum (Young & Chapman 1978), and in rainbow trout associated with severe nephrocalcinosis (Roberts 1989), with viral haemorrhagic septicaemia (VHS) infection (Elger & Hentschel 1983) or with extensive oedema (Hinton, Jones & Herman 1976). Finally, Chinook salmon in New Zealand with gastric dilation and air sacculitis (GDAS) were identified to have a glomerulopathy (Lumsden, Clark, Hawthorn, Minamikawa, Fenwick, Haycock & Wybourne 2002).…”

“…These Chinook salmon presumably also had antibody to R. salmoninarum although serum was not collected from these fish. The ultrastructural descriptions of glomeruli with thickened basement membranes presented here, and in rainbow trout with VHS (Elger & Hentschel 1983), brook trout (Young & Chapman 1978) and rainbow trout with BKD (Sami et al 1992), and wild white perch with glomerulonephritis (Ferguson et al 1982), do vary in some respects. The one common finding, however, is the presence of electron-dense material between the lamina densa and the endothelium.…”

“…The ultrastructural descriptions of glomeruli with thickened basement membranes presented here, and in rainbow trout with VHS (Elger & Hentschel 1983), brook trout (Young & Chapman 1978) and rainbow trout with BKD (Sami et al. 1992), and wild white perch with glomerulonephritis (Ferguson et al.…”

“…While the quality of our tissues for ultrastructure was somewhat limiting, we have noted here the presence of cytoplasmic processes, perhaps of mesangial cells, between the endothelium and lamina densa. Mesangial cell processes in this location have been described in trout with VHS (Elger & Hentschel 1983) but were not noted in the glomeruli of trout with BKD in which immunoglobulin was detected (Sami et al. 1992).…”

“…Salmonids in particular have been observed to have glomerular lesions consistent with those described in mammals due to immune‐complex mediated glomerulonephritis (Meyers & McPherson 1985; Sami, Fischer‐Scherl, Hoffman & Pfeil‐Putzein 1992; Reimschuessel & Ferguson 2006). Specific investigations into the pathogenesis of glomerular lesions are relatively few (Yokote 1970; Young & Chapman 1978; Ferguson, Moccia & Down 1982; Elger & Hentschel 1983; Sami et al. 1992).…”