Hematological changes in cryptobia infected rainbow trout salmo gairdneri
Lowe Jinde, L.
Canadian Journal of Zoology 64(6): 1352-1355
Rainbow trout, Salmo gairdneri, were experimentally infected with Cryptobia salmositica and total and differential erythrocyte and leucocyte abundances were examined. Total erythrocyte counts were profoundly reduced and were lowest at 4 weeks postinoculation during the peak of infection. Differential erythrocyte number showed significant reduction in mature erythrocytes, degenerating erythrocytes, and erythroblasts. The reduction in mature erythrocytes number were observed from 3 through 8 weeks postinoculation, while erythroblast reduction occurred at 1 through 5 weeks postinoculation. Subsequently, the number of erythroblasts increase and reach control values at 6, 7 and 8 weeks post inoculation. Although the total leucocyte count was not significantly changed, the differential leucocyte abundance showed that granulocytes were significantly increased. Similarly, the rarely seen, circulating, immature granuloblasts were increased. Both granuloblast and granulocyte numbers returned to control values by 8 weeks postinoculation. Thus, the pattern of differential erythrocytic and leucocytic changes reflect and acute parasitemia and a subsequent partial recovery of the infected fish to the parasitemia.