Gross and microscopic pathology of West Indian sea eggs (Tripneustes ventricosus)

In this study, we performed comprehensive pathology examinations on 83 Tripneustes ventricosus from 11 locations on St. Kitts to build baseline data necessary for disease diagnosis in this species. Gross abnormalities were observed in 23/83 (28%) urchins and included spine loss, visceral hyperpigmentation, test discoloration, and test ulceration. Ciliates were the only protists identified in this study via examination of tissue wet mounts and histology, documented in 50/83 (60%) urchins. Microscopic observations associated with visibly abnormal status included muscle necrosis, test and appendage inflammation, appendage (tube feet, spines, and pedicellariae) degeneration, severe coelomocytosis, and generalized hypermelanosis. Enterocyte intranuclear inclusion bodies, microbial aggregates, nerve pigmentation, enteric pigmentation, integument-associated crustaceans, and encysted metazoan parasites were of uncertain pathological significance. The etiology for any lesion was not microscopically apparent, contrasting literature implicating common marine bacteria in urchin diseases. This study highlights the importance of histopathology in urchin disease investigations and facilitates the recognition of disease in T. ventricosus.