Theses and Dissertations

ORCID

https://orcid.org/0000-0002-2162-1530

Advisor

Griffin, Matt J.

Committee Member

Camus, Alvin C.

Committee Member

Wise, David J.

Committee Member

Colvin, Michael M.

Committee Member

Mischke, Charles C.

Date of Degree

5-16-2025

Original embargo terms

Visible MSU Only 6 months

Document Type

Dissertation - Campus Access Only

Major

Veterinary and Biomedical Sciences (Veterinary Medical Research)

Degree Name

Doctor of Philosophy (Ph.D.)

College

College of Veterinary Medicine

Department

Department of Pathobiology and Population Medicine

Abstract

Catfish aquaculture is a critical industry in the United States and Mississippi in particular. The industry is beset by depredation, rising feed costs, competition with imports, and loss to disease. Chief among these is the myxozoan parasite and causative agent of proliferative gill disease, Henneguya ictaluri. In chapter 2, novel molecular markers for greater resolution in species identification of these parasites are provided, allowing more robust life cycle inference, species-level identifications, and inference of evolutionary relationships through molecular phylogenetic analyses. Chapters 3–5 apply the approaches developed in Chapter 2 to a broad array of taxa beyond catfish-infecting Henneguya spp. These included the marine parasites Kudoa hypoepicardialis from wild-caught lionfish Pterois volitans and Enteromyxum leei from Creole wrasse Clepticus parrae from a display aquarium in Mississippi, USA. Chapter 6 uses metagenomic analyses of fish, pond water, and feces from piscivorous birds and alligators to elucidate the effects of stocking rotations on myxozoan communities and potential mechanical vectors for transmission of myxozoans between environments. These data show that despite hybrid catfish being likely dead-end hosts for Henneguya ictaluri and contrary to studies in controlled experimental conditions, this parasite persists regardless of stocking strategy. This underscores the need for greater biosecurity and the development of treatment and prophylactic measures for addressing this devastating myxozoan parasite.

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