Diagnostic and characterization of Y. enterocolitica-infection in poultry

Vaccination constitutes a cost-effective tool for theprophylaxis of infectious diseases. The potency toprevent colonization with salmonellae as well as clinicalsymptoms of salmonellosis were evaluated afterimmunization with an attenuated live oral Salmonella(S.) typhimurium vaccine. Twenty 4-week-old malehybrid piglets were immunized orally with singleinocculation. A control group was treated with aplacebo. The animals were challenged orally with ahighly virulent S. typhimurium DT104 strain threeweeks post immunization. All pigs were controlled dailyfor clinical symptoms of salmonellosis~ Additionally,fecal samples were investigated daily for salmonellae.At day ten post vaccination, all pigs were euthanized.For Salmonella sp. examination, tissue samples (n=13)were collected aseptically and quantitatively andqualitatively examined. In addition, the systemicantibody response was investigated by ELISA.The clinical investigations revealed that the vaccinationprotected against symptoms of salmonellosis. While allplacebo animals revealed moderate to severe clinicalsymptoms, the majority of vaccinated pigs did notdevelop disease. Furthermore, the bacteriologicalinvestigation showed also marked effects ofvaccination. It could be demonstrated that vaccinestrain invaded the gut and gut-associated lymph nodes.Furthermore, vaccinated pigs showed a significantlydecreased rate of colonization (42.5 % versus 87.5 %at the placebos) of the inner organs. Particularly inorgans, which were used for human consumption(muscle, liver and spleen), the rate of colonizing wassignificantly increased. The challenge strain could notbe detected in liver, spleen, and muscle.