Publications

Viral hemorrhagic septicemia (VHS) is one of the most important viral diseases of finfish worldwide. In the past, VHS was thought to affect mainly rainbow trout Oncorhynchus mykiss reared at freshwater facilities in Western Europe where it was known by various names including Egtved disease and infectious kidney swelling and liver degeneration (Wolf 1988). Today, VHS is known as an...

In 2011, the final year class of adult salmon Oncorhynchus spp. returned from smolt groups released for a multi-year study to evaluate an alternate release site for transported fish. Smolts were collected and tagged at Lower Granite Dam, transported, and released at the alternate site near Astoria, Oregon (river kilometer 10) or at the traditional release site near Skamania Landing (rkm...

The gene encoding IgH δ has been found in all species of teleosts studied to date. However, catfish (Ictalurus punctatus) is the only species of fish in which a secretory form of IgD has been characterized, and it occurs through the use of a dedicated δ-secretory exon, which is absent from all other species examined. Our studies have revealed that rainbow trout (Oncorhynchus mykiss) use...

Infection with the aquatic rhabdovirus Viral hemorrhagic septicemia virus (VHSV) genogroup IVa results in high mortality in Pacific herring (Clupea pallasii) and is hypothesized to be a potential limiting factor for herring recovery. To investigate anti-viral immunity in the Pacific herring, four immune response genes were identified: the myxovirus resistance (Clpa-Mx), a major...

Previously, we demonstrated that a representative M genogroup type strain of infectious haematopoietic necrosis virus (IHNV) from rainbow trout grows well in rainbow trout‐derived RTG‐2 cells, but a U genogroup type strain from sockeye salmon has restricted growth, associated with reduced genome replication and mRNA transcription. Here, we analysed further the mechanisms for this growth

The integument or skin is the envelope that not only separates and protects a fish from its environment, but also provides the means through which most contacts with the outer world are made. It is a large organ and is continuous with the linings of all body openings, and also covers the fins. Fish integument is a multifunctional organ, and its components may serve important roles in...

Surveys of pathogens in Pacific herring from 2007 – 2010 indicated that Ichthyophonus, viral hemorrhagic septicemia virus, and erythrocytic necrosis virus are endemic in Prince William Sound and throughout the NE Pacific. Laboratory studies with VHSV indicated that multiple herring stocks are equally susceptible to the resulting disease, Pacific herring shed copious levels of VHSV (as...

A key facet of the innate immune response lays in its ability to recognize and respond to invading microorganisms and cellular disturbances. Through the use of germ-line encoded PRRs, the innate immune system is capable of detecting invariant pathogen motifs termed pathogen-associated molecular patterns (PAMPS) that are distinct from host encoded proteins or products released from dying...

The relationship between pathogen fitness and virulence is typically examined by quantifying only one or two pathogen fitness traits. More specifically, it is regularly assumed that within-host replication, as a precursor to transmission, is the driving force behind virulence. In reality, many traits contribute to pathogen fitness, and each trait could drive the evolution of virulence in...

Viral hemorrhagic septicemia (VHS) is a disease caused by a virus (VHSV). There are different strains of the virus that can infect marine and freshwater fish species, and the different strains may affect species differently. VHSV has recently invaded the Great Lakes, resulting in many large-scale fish die-offs and new regulatory restrictions for aquaculture throughout the region.

Some circumstances IHNV infection can cause acute disease with mortality ranging from 5-90% in host populations. Genetic typing of IHNV field isolates has shown that three major genetic groups of the virus occur in North America. These groups are designated the U, M, and L virus genogroups because they occur in the upper, middle, and lower portions of the geographic range of IHNV in...

Real-time, or quantitative, polymerase chain reaction (qPCR) is quickly supplanting other molecular methods for detecting the nucleic acids of human and other animal pathogens owing to the speed and robustness of the technology. As the aquatic animal health community moves toward implementing national diagnostic testing schemes, it will need to evaluate how qPCR technology should be...