Identifier

etd-04072016-123535

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

The red swamp crayfish, Procambarus clarkii, represents an important aquaculture species responsible for over half of all commercial aquaculture profits in Louisiana. White spot syndrome virus (WSSV) is highly pathogenic and induces mass mortality in crustacean aquaculture operations worldwide. Crayfish lack the adaptive ability of the vertebrate immune system, and must depend on primitive, innate immune responses to combat viral infections. This study aims to investigate the dose-response of WSSV in P. clarkii and to examine viral-host interactions by examining the biochemical and immunological changes induced by WSSV infection in this species. Viable viral particles were isolated from naturally infected P. clarkii gill tissue, quantified using a novel digital PCR approach, and inoculated into P. clarkii to determine a median lethal dose (LD50) value of WSSV particles. After estimating an LD50 value, crayfish were inoculated at this nominal concentration of viral particles, and biological tissues were sampled across time to observe physiological and immunological changes throughout the course of WSSV infection. Antioxidant activity increased over time, while immunological gene expression was downregulated in the gill tissue of WSSV-infected crayfish. Knowledge of the infectivity of WSSV in native crayfish is of critical importance to the management of the commercial aquaculture industry in Louisiana. Examination of the viral-host interactions in crayfish can be used to facilitate future investigations towards WSSV prevention and management, and serve to develop the use of P. clarkii to model innate immune responses to WSSV infection in other decapod crustaceans. This is the first study to investigate dose-response and immunological changes induced by the Louisiana strain of WSSV in native crayfish.

Date

2016

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Green, Christopher

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