Comparative analysis of lethal and non-lethal (blood and mucus) sampling for isolation and identifi cation of infectious hematopoietic necrosis virus (IHNV) in rainbow trout

   Objective: To comparatively evaluate the effectiveness of classical lethal and non-lethal (blood and mucus) sampling methods for the diagnosis of infectious hematopoietic necrosis in rainbow trout.

   Methods: Virus isolation was performed on the EPC cell line followed by RT-PCR identifi cation; statistical analysis was carried out using the OpenEpi software.

   Novelty: For the first time in a Russian rainbow trout sample set, a comprehensive comparative assessment of non-lethal (blood and mucus) and lethal (kidney and spleen) sampling methods has been performed using two diagnostic approaches – virus isolation on EPC cell culture and direct RT-PCR.

   Results: Blood was shown to be the most informative non-lethal sample, comparable to the classical lethal method. In cell culture testing, blood sensitivity reached 90.9 %, while mucus sensitivity was 77.3 %. In direct RNA detection by RT-PCR, blood sensitivity was 88.5 %, mucus – 82.8 %; however, mucus specifi city was low (25 %), indicating the need for further optimisation of sample fi xation and storage protocols.

   Practical significance: The use of blood serum as an alternative non-lethal sample for IHNV isolation is sub-stantiated. The method reduces economic costs and avoids lethal sampling when examining valuable brood-stock.

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