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Gael Kurath, Ph.D.

Viruses and infectious diseases are natural components of every ecosystem. In aquatic ecosystems of the Pacific Northwest infectious hematopoietic necrosis virus (IHNV) is a significant viral pathogen of many salmonid fish populations. Studies of IHNV molecular biology, pathogenesis, field ecology, and evolution contribute to understanding and management of viral disease in salmon and trout.

Research Interests:                        

Our research involves viral diseases in finfish, with an emphasis on the rhabdovirus IHNV in Pacific salmon and trout of Pacific Northwest ecosystems. We conduct landscape-scale genetic typing of IHNV as it occurs across Western North America and use phylogenetic analyses and molecular epidemiology to identify patterns of virus occurrence, transmission, and disease impacts across large geographic regions, and over many years.  This has revealed divergence of IHNV into three major genetic groups (U, M, or L) with distinct host specificities and geographic ranges in North America. There is also clear evidence for viral host jumps, displacement events, and evolution of both specialist and generalist virus lineages. Potential drivers of these evolutionary events are tested in controlled wet laboratory challenge studies in salmonid fish, providing sound scientific data on the biological basis of patterns observed in the field. In a recent project we demonstrated evolution of increasing virulence as a driver of viral genotype displacements in steelhead trout of the Columbia River Basin and worked with collaborators to develop the first landscape-scale transmission model for IHNV.  We also explore the biological basis of specialist (adapted to single host species) and generalist (adapted to multiple host species) viruses, using naturally evolved subgroups of IHNV. This has potential to explain changes in virus types and disease impacts observed in the Columbia River Basin, and it also serves as a tractable research model for empirical testing of predictions of basic specialist-generalist theory for pathogens.  Finally, we collaborate with other researchers to investigate the evolution of IHNV virulence after a historical host jump from sockeye salmon to farmed rainbow trout using a historical panel of over 60 IHNV isolates collected over the last 50 years. Long-term interests include understanding drivers of viral evolution and ecology, host and virus factors that define virus transmission and transmission models, and how human activities can be modified to avoid unintended disease consequences.

*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government