NC-1041, Enteric Diseases of Swine and Cattle: Prevention, Control and Food Safety

NON-TECHNICAL SUMMARY: Food-borne illness has been a prominent public health concern in the United States in recent years due to the occurrence of large-scale outbreaks which receive intense media scrutiny. Most of the known bacterial, viral and parasitic food-borne disease agents are primarily zoonotic in nature. Therefore, investigation and control in the animal reservoir are required to fully understand their epidemiology and biology in order to maximize the opportunities for their control. Several of these agents are also severe pathogens of animals or have close relatives that are animal pathogens, such that investigation of the host-parasite relationship in animal models or in fact in the animal populations themselves will be informative regarding the host-parasite interactions in humans. This project addresses swine and cattle pathogens that impact food safety, and cause enteric disease in the host species. It contributes to efficient pork and beef production by identifying and characterizing emerging and newly identified agents associated with enteric disease in cattle and swine. Particular attention is paid to those pathogens with zoonotic potential. The project addresses development and testing of interventions and preventative measures for reduction of animal carriage of these pathogens and their transmission to humans. Approaches include the development of new and improved vaccines and non-antibiotic therapies. Dissemination of information from the committee to possible users is also addressed.

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APPROACH: Escherichia coli O157:H7 isolates from beef cattle and environmental samples from feedlots will be genotyped for the purpose of better understanding whether specific ones persist or predominate in cattle populations, and also are more likely to cause epizootics. This information will be gathered by pulse-field gel electrophoresis (PFGE), octomer-based genome scanning (OBGS), six-marker lineage-specific polymorphism assay (LSPA-6), amplified fragment-length polymorphism assay (AFLP), and multilocus sequence typing (MLST). E. coli O157:H7 isolates from feedlot cattle and their environments will continue to be archived for future studies. Nebraska will continue to collaborate with the South Dakota and Kansas stations on studies of the role of Escherichia coli enterotoxins in bacterial colonization of the intestine and causation of disease in swine. Enterotoxin gene deletion mutants will be constructed and tested in ligated intestinal loops and orally-inoculated gnotobiotic piglets. Nebraska will also continue studies on Brachyspira pilosicoli and B. hyodysenteriae in swine in collaboration with the Iowa, Minnesota and North Carolina stations. The antimicrobial sensitivity of clinical isolates will be monitored. Methods for identification of pathogenic Brachyspira in clinical specimens will be developed. The complete genomic nucleotide sequences of representative B. hyodysenteriae and B. pilosicoli will be determined. MLST will be used for allelic profiling of pathogenic Brachyspira obtained from different hosts in different regions in the US. <P>In conjunction with the other stations participating in NC1041, Nebraska will provide: <ol>
<Li> training to college undergraduate and graduate students <li>information to livestock producers and/or professionals <li> knowledge and continuing education to station representatives and collaborating scientists <li> a forum for scientific exchange among colleagues of the international scientific community, and dissemination of knowledge to the biologics industry. </ul>