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Dana Rausch

Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)


Veterinary and Biomedical Sciences

First Advisor

Weiping Zhang


Enterotoxigenic Escherichia coli (ETEC) are the main cause of diarrhea in young animals (and humans). Neonatal and post-weaning diarrhea causes significant economic losses to swine and other livestock producers worldwide. Currently, there is no effective vaccine to protect young animals, such as pigs, against ETEC diarrhea. Enterotoxins, including heat-labile (LT), heat-stable type I (STa), heat-stable type II (STb) and shiga-like toxin Stx2e, produced by ETEC strains are the virulence determinants in porcine ETEC-associated diarrhea. These enterotoxins enzymatically disrupt fluid homeostasis in pig small intestinal epithelial cells that leads to fluid and electrolyte hyper-secretion and diarrhea. A protective antitoxin vaccine that induces host immunity to neutralize enterotoxicity of LT, STa, STb and Stx2e would protect against diarrhea and is urgently needed. In this study, a fusion antigen was genetically constructed which consists of antigenic epitopes from LT, STa, STb and Stx2e, antigen safety and immunogenicity of this fusion antigen was examined in a murine model, and potential application in vaccine development against ETEC diarrhea was assessed. Results showed that mice intraperitoneally immunized with this fusion antigen developed antitoxin antibodies specific to each toxin. Furthermore, induced antitoxin antibodies exhibited some neutralizing activities against these enterotoxins. These data indicated this fusion antigen induced broad antitoxin immunity, and suggested this fusion antigen could be used in future development of protective antitoxin vaccines against ETEC diarrhea in pigs and likely other livestock animals.

Library of Congress Subject Headings

Escherichia coli
Viral diarrhea -- Vaccination


Includes bibliographical references (pages 56-66)



Number of Pages



South Dakota State University


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