<ol> <LI>Focus on emerging diseases- Identify, characterize and develop improved detection methods related to newly recognized, novel or emerging causes of zoonotic enteric disease and enteric pathogens of cattle and swine. <LI>Focus on effective interventions- Develop and improve interventions and preventative measures to reduce the incidence and prevalence of infections of cattle and swine with enteric and food borne disease agents. <LI>Focus on disseminating knowledge- Provide training and continuing education opportunities and dissemination of information to students, producers, veterinarians and diagnostic laboratories. </ol>
NON-TECHNICAL SUMMARY: Enteric diseases of swine and cattle lead to major economic losses. This project focuses on better ways to diagnose and preventthese problems and on enhancement of safety of food of bovine or porcine origin. Food-borne illness has been a prominent public health concern in the US in recent years due to the occurrence of large-scale outbreaks and enormous incidence of sporadic food-borne disease problems. The latter resulted in estimates of more than 75 million cases of infectious and noninfectious food borne illness annually in the US during the 1990s, resulting in 325,000 hospitalizations and 5,000 deaths. The President, Congress, and the USDA have made food safety a high priority. FoodNet surveillance programs show: 1) Most food-borne illness events are of undefined etiology, stressing the need for identification and characterization of novel, emerging, or previously unrecognized agents, 2) 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. 3) 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.<P>
APPROACH: <BR> Objective 1: Focus on emerging diseases: <BR> A. Enteric viruses. We will identify bovine enteric calicivirus and porcine enteric calicivirus isolates from bovine and porcine fecal samples or waste lagoon or processed manure samples supplied by diagnostic laboratories. We will genetically characterize these isolates and investigate their ability to cause diarrhea and viremia, and to cross-protect against other strains. We will survey shellfish, environmental water sources or unprocessed foods for potential food borne enteric pathogens. <BR> B: Bacterial diseases. We will 1) distribute pathogen typing tools for enteric agent surveillance among cooperating stations; 2) monitor pathogen genotypes to identify trends in prevalence and to detect the emergence of new types; 3) archive strains for comparison with future isolates and for historic assessment of prevalence of virulence determinants yet to be discovered. <BR> <BR> Objective 2: Focus on effective interventions. <BR> A. For ETEC, EAEC, and EHEC, we will examine enterotoxins, colonization, virulence and secretory response. Several stations will pursue subunit vaccine development utilizing E. coli LT as an adjuvant. <BR> B: Pathogenesis and molecular typing of Lawsonia. Infection and transmission of L. intracellularis will be investigated using VNTR genetic typing. <BR> C: Campylobacter intervention strategies. We will study a novel pilus expressed by C. jejuni to ascertain its role on colonization of abiotic and biotic surfaces during biofilm formation . <BR> D: Brachyspira spp. We will 1) closely monitor the antimicrobial sensitivity of clinical isolates, 2) improve methods for identification of pathogenic Brachyspira in clinical specimens, and 3) determine the complete genomic nucleotide sequences of representative B. hyodysenteriae and B. pilosicoli. <BR> E. Viral receptors and intervention. We will improve the efficacy of current rotavirus vaccines and develop new rotavirus and calicivirus vaccines for use in animals to reduce the presence of animal rotaviruses and caliciviruses in unprocessed food or as environmental contaminants. <BR> F: Parasitology. We will continue to define the mechanism of Cryptosporidium parvum sporozoite interaction with and invasion of host cells <BR> <BR> Objective 3. Focus and dissemination of knowledge: <BR> We will provide 1) training to college undergraduate and graduate students; 2) information to livestock producers and/or professionals; 3) knowledge and continuing education to station representatives and collaborating scientists and 4) a forum for scientific exchange among colleagues of the international scientific community, and dissemination of knowledge to the biologics industry.