Host response to the chondracanthid copepod Chondracanthus goldsmidi, a gill parasite of the striped trumpeter, Latris lineata (Forster), in Tasmania

The chondracanthid copepod, Chondracanthus goldsmidi is an ectoparasite of gills, inner opercula and nasal cavities of cultured striped trumpeter, Latris lineata (Forster). Whilst often present in high numbers (up to 60 parasites per host), little is known about its effect on striped trumpeter. In this study C. goldsmidi was associated with extensive epithelial hyperplasia and necrosis. Pathological changes were most pronounced near the parasite's attachment site, with papilloma-like growths surrounding the entire parasite resulting in deformation of the filament. The number of mucous cells increased near the parasite attachment sites on both the opercula and gills. Mast cells were absent in healthy gills; in contrast numerous mast cells were identified in the papilloma-like growths. Immunostaining identified piscidin-positive mast cells in the papilloma-like growths, presenting the first evidence of piscidin in the family Latridae.