Lymphocystis in Indian oil sardine, Sardinella longiceps (Valenciennes 1847)

ObjectiveTo analyse the prevalence and pathology of lymphocystis disease in Sardinella longiceps of three different landing centers in Tamil Nadu of southeast coast of India for a period of three years from January 2013 to December 2015.MethodsTumourous sardines were sourced from three different landing centers (Cuddalore, Parangipettai and Nagapattinam) in Tamil Nadu, southeast coast of India. The prevalence of lymphocystis, and its gross pathology, histopathology and ultra-structure were investigated.ResultsA total of 369 individuals were affected with lymphocystis. The overall prevalence was 0.11% among the three stations. The uncircumscribed, translucent white, pink and reddish and jelly-like nodules of cell growths scattered on the both sides of eyes and operculum plates. Histopathological and ultra-structural studies of the white masses showed abundant hypertrophied cells with cytoplasmic vacuoles and basophilic intra-cytoplasmic inclusion bodies. The hypertrophied cells had pleomorphic, hypertropic and hyperchromatic nuclei and contained basophilic marginated chromatin. The hypertrophied nuclei had high numbers of viral particles. Here we mentioned viral particle morphology for morphological diagnosis.ConclusionsThe histological and ultra-structural findings, the lesions were diagnosed as the hypertrophied cells containing iridovirus-like particles. The lesions were confirmed the lymphocystis disease in Sardinella longiceps.