Response of striped trumpter to the infection with chondracanthid copepod

The chondracanthid copepod, Chondracanthus goldsmidi Tang, Andrews & Cobcroft, 2007, was recently identified as an ectoparasite on gills, inner opercula and in nasal cavities of cultured striped trumpeter, Latris lineata (Forster), and is the first member of this genus known to parasitise a cultured host. While often present in high numbers (up to 60 parasites per host), little is known about its effect on striped trumpeter. Adult 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. Mast cells were absent in healthy gills, in contrast numerous mast cells were identified in the papilloma-like growths. The number of mucous cells increased near the parasite attachment sites on both the opercula and gills. A significant up-regulation of three pro-inflammatory cytokines, TNF-a, IL-l ~ and IL-8 was found in the gills. Examination of head kidney cells revealed a significant up-regulation of TNF-a, but not IL-l~ or IL-8. Conversely, the spleen cells showed significant up-regulation of both IL-l~ and IL-8, but not TNF-a. These findings allow for more detailed investigation of the striped trumpeter immune response, in addition to providing insight into possible mitigation strategies for large scale infestation of C. goldsmidi on commercially cultured striped trumpeter.