Infectious Diseases of Importance to Wild and Cultured Fishes

NON-TECHNICAL SUMMARY: Fishes represent various important economic commodities in the Pacific Northwest. As with terrestrial animals, diseases may severely impact the well-being and economic viability of fish industries. This study investigates the host and geographic range, pathogenesis, taxonomy, modes of transmission, and treatment of infectious diseases of importance to wild and cultured fishes, particularly those afflicting fishes in the Pacific Northwest region. The ultimate goal of this research is to provide information to assist fish health managers and veterinarians to minimize the impact of these diseases. <P>
APPROACH: 1.Diseases of importance in these fishes will be determined by complete necropsy and subsequent laboratory analyses, including pathology, bacteriology, and virology. Conducting in vivo transmission studies will elucidate the pathogenesis of various pathogens. 2.Molecular systematic approaches will lead studies on identifications and phylogenetic relationships of the pathogens in study. In addition, traditional morphology and culture characteristics will be included. 3.For bacteria and parasites, will focus on using ribosomal DNA sequences for the development of sensitive and specific PCR based tests.

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PROGRESS: 2002/10 TO 2007/09 <BR>
Over the time period of the project (2001 - 2007), Dr. Kent has conducted extensive investigations on diseases of fishes in the following topics: 1) impacts of pollution on fishes in high mountain lakes in western U.S., 2) impacts of parasites on coho salmon in coastal streams in Oregon, 3) characterization of mycobacteriosis in cultured hybrid striped bass, 4) determination of the cause of skeletal deformaties in cyprinid fishes in the Willamette River, 5) description of diseases in zebrafish used in laboratory research, and development of control measures for these diseases, and 6) molecular characterization of myxozoan parasites of fishes. He has also lead other, most short term projects as follows: 1) development of a non-lethal test for Ichthyophonus in for salmon in Alaska, 2) studies on diseases in rockfish in the Pacific Northwest, and 3) description of diseases afflicting wild and cultured fishes in Hawaii. These projects involved the mentoring of 4 PhD and 1 masters students. Findings were presented at XXXX symposia by Dr. Kent or his students since 2001. In addition, Dr. Kent lead three 2-5 day workshops on disease of zebrafish for laboratory animal veterinarians. Services over this time period was largely through providing diagnostic consultation on diseases of fishes and parasite indentifications for the OSU Veterinary Diagnostic Laboratory and the Zebrafish International Resource Center. Regarding products, the PCR tests developed in Kent lab for Ichthyophonus is now being used routinely by government laboratories in Alaska, and the PCR test for Pseudoloma in zebrafish is being used by several research laboratories to screen their fish.
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IMPACT: 2002/10 TO 2007/09<BR>
Kent's findings that the cause of skeletal deformaties in the Willamette River were caused by parasites, rather than pollutants, has saved millions of dollars to the state of Oregon for drinking water as this allowed for certain municipalities to continue to use the Willamette River for drinking water. Findings by Kent, and his colleagues Kent and Simonich that trout from high mountain lakes have elevated concentrations of certain pollutants derived from air and demonstration that they have pathological and physiological effects on these fish has profoundly changed are view of what were thought to be pristine lakes in high mountains in western U.S. As stated above, two PCR tests developed in Kent's lab are now routinely used by government or university research labs. Studies of mycobacteria from fish have demonstrated dramatic differences in virulence between species and strains, and we have provided tools to separate these bacteria. With this information in hand, biologists overseeing fish facilities (e.g., hybrid striped bass or zebrafish) can now make appropriate decisions on how to act depending on which type of bacteria is present.