Detection and quantification of Chilean strains of infectious pancreatic necrosis virus by real-time RT-PCR assays using segment B as a target

Abstract

Infectious pancreatic necrosis virus (IPNV) is the causal agent of a highly prevalent disease that affects salmonid fish, mostly during their fresh water life period. Like many other viruses, IPNV produces highly heterogeneous populations. Therefore, diagnostic methods need to be checked constantly so that no variants of the virus escape detection. The IPNV genome is composed of two double-stranded RNA segments: A and B, polymerase chain reaction (PCR) methods normally use segment A as a target. In order to develop an optimized protocol to diagnose IPNV, we present a real-time RT-PCR (reverse transcription) technique, using primers designed to recognize segment B of the virus. To validate the ubiquity of the primers used, the IPNV isolates tested were sequenced and compared with previously published cladograms, which include a wide spectrum of genogroups. These primers made it possible to detect viral isolates belonging to genogroups 1 and 5, which were obtained from different locations linked to fish farming. As expected, we were able to detect the virus from distant Aquabirnavirus genogroups.