CARP COCCIDIOSIS - ACTIVITY OF PHAGOCYTIC-CELLS FROM COMMON CARP INFECTED WITH GOUSSIA-CARPELLI

Pronephric phagocytes from common carp Cyprinus carpio L, infected wit h the gut-dwelling coccidian Goussia carpelli showed enhanced phagocyt ic activity during the period of merogonic and gamogonic development o f the parasite from Days 10 to 15 post exposure (PE) to the parasite. The respiratory burst activity was enhanced during excretion of oocyst s at Days 15 to 25 PE. The addition of parasite lysates to assays resu lted in an increase of phagocyte activity in cells from carp infected with gamogonic and sporogonic stages of the parasite and from carp whi ch, at Day 35 PE, had recovered from a G. carpelli infection. The addi tion of immune serum sampled from fish at Days 5, 10, 15, 20, and 25 P E had no clear stimulatory effect on phagocyte activity. This suggests an activation of pronephric phagocytes on infection with the parasite . In carp with gamogonic and sporogonic parasite stages, activated mac rophages show an increased cytotoxic reactivity, and activated macroph ages rather than non-activated resident macrophages can be enhanced by opsonization with parasite molecules.