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

Comparative evaluation of diagnostic tests

Comparative evaluation of diagnostic tests have been carried out on both experimentally- and field-derived material within the project by Partners 1, 3, 4 and 5. Following development of the viraemia and virus neutralizing (VN) antibody tests, these methodologies were transferred to other partners within the consortium. In particular, partner 4 applied these assays, albeit in a modified format. Comparative evaluation of results generated with sera obtained from sequential sampling o f Atlantic salmon experimentally infected with an Irish strain of SAV indicated a good correlation (96.7%) between results, with one partner scoring two sera positive that were found negative by the other. Evaluation of end point titres indicated that these were typically within a two-fold dilution either way. There was 100% agreement between virus isolation results on serum. Both sera and heart were also tested by (different) real time RT-PCR tests by partners 1 and 4. In both tests, sera became negative after 14 days, corresponding to the development of VN antibodies. In contrast, both assays on heart found the majority of samples up to day 35 to be positive, with individual positive results thereafter as late as day 140.

The comparative evaluation also encompassed comparing the performance of different diagnostic tests. This evaluation was done where possible by using samples obtained from the same individual fish. Typically the results obtained with histology (pancreas, heart and muscle) were compared with immunohistochemistry (IHC), virology, serology and RT-PCR. Results showed that early acute infections could be diagnosed using histology, IHC (pancreas), detecting viraemia and detecting virus RNA in serum and heart tissue. Later chronic-stage infections could be diagnosed by histology, antibody detection and virus RNA detection.

Informazioni correlate

Reported by

Queen's University of Belfast
Veterinary Sciences Division, Stormont
BT4 3SD Belfast
United Kingdom