[A study of the cause of massive mortality among marine-cultured rainbow trout (Oncorrhynchus mykiss, Walbaum) in a fish farm in the southwestern Netherlands].

The present study investigated the mass mortality of marine cultured young rainbow trout (Oncorhynchus mykiss, Walbaum) in the Netherlands. The course of the disease, the clinical symptoms, and bacteriological and virological investigations lead to the diagnosis: 'primary infectious pancreatic necrosis virus (IPNV) infection followed by secondary vibriosis'. Treatment with flumequine seemed to be effective. The trout were possible infected with IPNV at the trout hatchery and nursery from which they originated.