ABSTRACT: The replication of the turbot aquareovirus TRV in turbot tissues was studied in vitro in excised turbot tissues, and in vivo, following the evolution of viral titers in organs and tissues from experimentally infected turbot fry. Replication of TRV in vitro was demonstrated in kidney (with an increase of viral titer of more than 2 logs in 5 d), but also in liver and heart (increasing more than 1 log). Viral replication was also demonstrated in vivo, with the kidney being the apparent target organ. The virus was detected in most tissues of turbot fry 2 h post infection, which suggests involvement of the circulatory system in the rapid spreading of the virus to all fish organs and tissues. It appears that stress conditions, and/or simultaneous occurrence of bacterial infections, can enhance the replication of TRV in turbot, and the virus is more efficiently released to the environment. Our results suggest that, under normal conditions, TRV shows low levels of replication in turbot tissues, and thus infected fish may behave as asymptomatic carriers, spreading the virus to the environment and healthy fish.

KEY WORDS: Aquareovirus . Replication

Published in DAO Vol. 25, No. 3 (1996) on June 6
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1996