Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Pathogenesis study of sleeping disease in rainbow trout based on experimental disease reproduction

Until the project started by the end of 2001, experimental Sleeping Disease (SD) had only been performed by immersion of rainbow trout fry (<10g) in SDV contaminated water. The fish size was then a limiting factor to a consistent study of the pathogenesis of SD.

During the project, the experimental reproduction of SD in 1 year-old trout (100g) by intraperitoneal injection of a high concentration of SDV allowed partner 3 to get a better understanding of the development of the disease after some techniques had been developed. A full histological study performed on organs of trout sampled at regular intervals post-infection was completed and demonstrated the sequential lesions in pancreas, heart and muscle respectively. The concentration of virus in plasma, kidney and brain was optimal 7 days post-infection and then decreased to reach an undetectable level 6 weeks after infection. Neutralising antibodies were detected in the plasma of all the fish sampled 3, 6 and 10 weeks post-infection. The neutralising titre of the plasma increased within the time.

During this experiment different stages of SD have been described, acute, sub-acute, chronic and recovering, which will be used by laboratories involved in fish diagnostic to evaluate the phases of the disease in affected trout farms.

Reported by

Afssa-site de Brest, Technopole Brest-Iroise BP70
29280 Plouzane