First Record of Infectious Haematopoietic Necrosis Virus in Rainbow Trout Fry in Croatia

The paper describes the first diagnosis of infectious haematopoietic necrosis virus (IHNV) in Croatia. The viral causative agent was detected in pooled organ samples from the imported rainbow trout fry on the fish farm. Reverse transcriptase - semi-nested polymerase chain reaction (RT- snPCR) was applied directly on the infected tissue for rapid virus detection. After isolation on cell cultures, IHNV isolate was characterised on the basis of the 303 nt region of the glycoprotein gene (Mid-G) sequence. Phylogenetic comparison to North American and European IHNV isolates revealed that this Croatian isolate belongs to the M genogroup, confirming the prediction of the M genogroup origin of European IHNV isolates. The introduction of the virus presents a threat of further spreading of the disease in Croatia, as the infected farm is in a direct contact with the open waters