Lymphocystis disease, caused by the iridovirus lymphocystis disease virus (LCDV), is
characterized by the appearance of tumour-like lesions on the skin of affected animals associated
with several environmental factors and/or with stress due to the intensive culture conditions of fish
farms. In a previous study, the genomes of a new LCDV species, LCDV-Sa, were detected, together
with 2 previously unknown viruses, Sparus aurata papillomavirus 1 (SaPV1) and Sparus aurata
polyomavirus 1 (SaPyV1). Gilthead seabream from 17 fish farms in Spain, Italy and Turkey were
sampled between 2009 and 2015 to investigate the role of the newly described SaPV1 and SaPyV1
viruses in lymphocystis disease development. Our results show that in diseased fish, either or both
of the new viruses are almost invariably detected together with LCDV (98%). In asymptomatic
fish, these viruses were detected in a much lower percentage (28%) and mostly in concurrence
with LCDV (24%). These data confirm the suspected association among the 3 different viruses
during lymphocystis disease development in gilthead seabream and warrant future studies to
establish their respective contributions.
