By H&E staining and immune-histochemistry, histopathological changes in target organs (the lymphoid organ, gill and hepatopancreas) of Gill-associated virus (GA V) infected with white leg shrimp. Overall, histopathological features of GAV infection in the lymphoid organ were characterized and developed by spheroid formation, pyknosis, karyorrhexis and cellular vacuolization. The appearance and development of lymphoid organ spheroid could result in distortion and disorganization and loss of normal structure of adjacent lymphoid organ tubule. Few histopathological features distinguished the other target organs of GAV-infected shrimp such as gills and hepatopancreas from those of negative control shrimp. Pyknotic and karyorrhectic nuclei were infrequently detected in connective tissue of the hepatopancreas and gill.