Newswise — Professor emeritus David Francis retired four years ago, but the expertise the SDSU veterinary and biomedical sciences researcher developed is still in demand. Francis will be one of the session keynote speakers at the 24th International Pig Veterinary Society Congress in Dublin, Ireland, June 7-10. He will talk about his research on colibacillosis, an intestinal disease that affects newborn and weanling pigs. During his 34-year career at SDSU, Francis examined how the toxin-producing E. coli bacterium establishes itself in the host and causes the diarrheal disease. “A similar organism causes traveler’s diarrhea in humans,” he noted.
“It’s the diarrhea that can kill you,” Francis said, but the question remains whether the body is trying to flush out the bacteria or whether the diarrhea benefits the toxin-producing bacteria by eliminating competing organisms. Though data suggests the toxin helps the organism effectively colonize the intestine, he added, “we don’t know—the answer may be both.”
Though the mortality rate among infected baby pigs is very high, Francis explained, a vaccine given to the sow has greatly reduced cases of colibacillosis in pigs infected shortly after birth. “The antibodies come through the mother’s milk,” he said.
However, no major vaccine company has a vaccine for the postweaning form of the disease.
Francis’ research showed that an effective post-weaning vaccine has to target at least two antigens—the fimbrae or hairlike structures on the bacteria that identify the host cells, and the toxins the bacteria produces. “If there are not antibodies against both, the protection will be incomplete,” he explained.
“Being asked to be the keynote speaker signals that you’re considered an authority in the area,” said Francis, who continues work on funded research projects, including collaborations with Vanderbilt University and Ohio State University. “If you’ve done your career well, people around the world will recognize you have something to offer.”
About South Dakota State UniversityFounded in 1881, South Dakota State University is the state’s Morrill Act land-grant institution as well as its largest, most comprehensive school of higher education. SDSU confers degrees from eight different colleges representing more than 175 majors, minors and specializations. The institution also offers 32 master’s degree programs, 15 Ph.D. and two professional programs. The work of the university is carried out on a residential campus in Brookings, at sites in Sioux Falls, Pierre and Rapid City, and through Cooperative Extension offices and Agricultural Experiment Station research sites across the state.
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