Sequences comprising the "mid-G" region of the glycoprotein (G) gene of Austrian isolates of infectious hematopoietic necrosis virus (IHNV) form two lineages within European isolates and are clearly separated from American and Asian lineages

Zoonoses and Emerging Infections Group, Clinical Virology, Clinical Department of Diagnostic Imaging, Infectious Diseases and Clinical Pathology, Clinic for Avian, Reptile and Fish Medicine, Clinical Department for Farm Animals and Herd Health Management, University of Veterinary Medicine, Vienna, A-1210 Vienna, Austria; and Impfstoffwerk Dessau-Tornau GmbH (IDT), Rodleben, Germany

^* To whom correspondence should be addressed. Email: Norbert.Nowotny{at}vu-wien.ac.at.

	Abstract

Infectious hematopoietic necrosis virus (IHNV) is one of the most important pathogens of salmonid fish. In this study a comprehensive phylogenetic analysis of the genetic evolution and variety of Austrian IHNV strains as well as selected strains ensuring worldwide coverage is presented. The phylogenetic investigation is based on sequences comprising the "mid G" region of the G gene, and it includes all to-date available IHNV sequences of the G gene with a length of at least 615 bp. Austrian IHN viruses are located - together with other European IHNV isolates - in two clusters of genogroup M (M-Eur1 and M-Eur2), and are clearly separated from American and Asian lineages. The genetic clustering, however, could not be linked to certain clinical symptoms or significant differences in the mortality rates.