Brooklynella hostilis (hartmannulidae), a pathogenic ciliate from the gills of maricultured sea bream

Brooklynella hostilis Lom and Nigrelli, 1970 is recorded for the first time from the gills of cultured sea bream, Sparus aurata. The infection was found in 150-200g fish reared in a sea cage farm in Eilat (northern Red Sea). The ciliates obliterate the respiratory epithelium and feed on erythrocytes and tissue debris producing branchial hemorrhages, telangiectasis, lamellar fusion and severe epithelial desquamation, exacerbating the condition of stressed fish with additional respiratory and osmotic distress. As B. hostilis is a nonspecific parasite of warmwater marine fish, brooklynellosis may be expected to appear in other fish species in Mediterranean mariculture in the future.