engleski

Molecular detection and characterization of Croatian Infectious Pancreatic Necrosis Virus isolate from reared rainbow trout fry

Infectious pancreatic necrosis virus (IPNV) is the prototype species of the genus Aquabirnavirus within the family Birnaviridae. This pathogen causes serious pancreatic necrosis disease, with high mortality rate among rearing salmonids and huge economic losses in fish industry. IPNV is a non-enveloped virion containing the bisegmented, double-stranded RNA genome. Although IPNV has not been previously reported in trout aquaculture in Croatia, its broad distribution and continuous spreading to the non-infected areas encouraged us to carry out investigation of IPNV occurence in Croatia. Rainbow trout fry were sampled at three Croatian fish farms. One step RT-PCR combined with "nested" PCR was applied directly on pooled and individual (liver, spleen, heart, kidney and brain) tissue samples for IPNV detection. Determination of VP2/NS region sequence was performed for comparison with the known aquabirnavirus sequences. Physico-chemical and microbiological analysis of water from farms was accomplished. Our results confirmed IPNV occurence at one Croatian trout farm. Infected fish were asymptomatic, without increased mortality. Determined nucleotide VP2/NS sequence enabled Croatian isolate genotyping and designated its relationship to European, American and Japanese isolates. This study presents the first record of IPNV in trout aquaculture in Croatia. Nucleotide sequence analysis of IPNV short region proved to be a valuable method in molecular characterization of Croatian IPNV isolate. Infected fish farm had poor water quality, indicating that disturbed environmental conditions are important predisposing factors for IPNV occurence.

IPNV; rainbow trout fry; molecular epidemiology

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