MEPS 400:187-193 (2010)  -  DOI: https://doi.org/10.3354/meps08420

Kinetics of viral shedding provide insights into the epidemiology of viral hemorrhagic septicemia in Pacific herring

Paul Hershberger1,*, Jacob Gregg1, Courtney Grady1, Rachael Collins1, James Winton2

1US Geological Survey, Western Fisheries Research Center, Marrowstone Marine Field Station, 616 Marrowstone Point Road, Nordland, Washington 98358, USA
2US Geological Survey, Western Fisheries Research Center, 6505 NE 65th Street, Seattle, Washington 98115, USA

ABSTRACT: Losses from infectious diseases are an important component of natural mortality among marine fish species, but factors controlling the ecology of these diseases and their potential responses to anthropogenic changes are poorly understood. We used viral hemorrhagic septicemia virus (VHSV) and a laboratory stock of Pacific herring Clupea pallasii to investigate the kinetics of viral shedding and its effect on disease transmission and host mortality. Outbreaks of acute disease, accompanied by mortality and viral shedding, were initiated after waterborne exposure of herring to concentrations of VHSV as low as 101 plaque-forming units (pfu) ml–1. Shed virus in flow-through tanks was first detected 4 to 5 d post-exposure, peaked after 6 to 10 d, and was no longer detected after 16 d. Shedding rates, calculated from density, flow and waterborne virus titer reached 1.8 to 5.0 × 108 pfu fish–1 d–1. Onset of viral shedding was dose-dependent and preceded initial mortality by 2 d. At 21 d, cumulative mortality in treatment groups ranged from 81 to 100% and was dependent not on challenge dose, but on the kinetics and level of viral shedding by infected fish in the tank. Possible consequences of the viral shedding and disease kinetics are discussed in the context of epizootic initiation and perpetuation among populations of wild Pacific herring.


KEY WORDS: Viral shedding · VHSV · Pacific herring · Clupea pallasii · Disease ecology


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Cite this article as: Hershberger P, Gregg J, Grady C, Collins R, Winton J (2010) Kinetics of viral shedding provide insights into the epidemiology of viral hemorrhagic septicemia in Pacific herring. Mar Ecol Prog Ser 400:187-193. https://doi.org/10.3354/meps08420

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