Document Type

Dissertation - Open Access

Award Date


Degree Name

Doctor of Philosophy (PhD)


Veterinary and Biomedical Sciences

First Advisor

Weiping Zhang


Bovine diarrhea is economically one of the most important problems in cattle industry. Enterotoxigenic Escherichia coli (ETEC), particularly strains expressing K99 (F5) fimbriae and heat-stable type I (STa) enterotoxin is the predominant bacterial cause of diarrhea in calves; whereas bovine viral diarrhea virus (BVDV) causes diarrhea and other illness to cattle at all ages. A vaccine that prevents against both K99 fimbrial ETEC and BVDV could benefit greatly to cattle producers worldwide. We hypothesized that a novel multivalent vaccine composed of K99, STa and BVDV E2 antigens could induce immunity for broad protection against bovine diarrhea. In this study we applied FanC, the major fimbrial subunit of K99, as a backbone to have a STa toxoid and the most immunogenic E2 epitopes embedded to construct ‘FanC-STa-E2’ fusion antigen, and examined this ‘FanC-STa-E2’ fusion antigen for immunity against ETEC and BVDV in a murine model for vaccine potential assessment. Adult female BALB/C mouse intraperitoneal (i.p.) immunized with 200 μg purified antigen with equal volume of adjuvant. Developed systemic and mucosal immune responses to K99, STa, and BVDV E2. Moreover, those antibodies showed abilities to block the E. coli K99 bacterial adhesion by K99-receptor positive INT-407 and IPEC-J1 cells, neutralized the STa enterotoxin, and also neutralized the BVDV infection. This suggests that this fusion antigen has the potential to be developed as a broadly protective vaccine against bovine diarrhea.

Library of Congress Subject Headings

Bovine viral diarrhea virus -- Vaccination.
Cattle -- Virus diseases -- Vaccination.
Escherichia coli.


Includes bibliographical references (pages 73-93).



Number of Pages



South Dakota State University


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