Nosicielstwo i siewstwo Salmonella typhimurium u eksperymentalnie zakażonych kur niosek

The experiments were done on 60 laying hens (Astra S) aging 26 weeks and of an egg production about 50°/». The birds were inoculated perorally for 3 consecutive days using 2 ml of 18h borth culture of S. typhimurium. The following examinations were performed: clinical observa­tions, egg laying, weekly bacteriological examinations of fecal swabs and eggs, serological examinations of blood sera and egg yolks by the tube agglutination test (OA) and by antiglobulin test (OAG). Moreover every 1—3 weeks 5 randomely chosen birds were sacrified and bacteriolo- gically examined. Hens infected perorally with S. typhimurium were clinically normal. The infections does not affected egg laying. S. typhimurium was isolated from internal organs only after 7 (100%' of birds) and 14 (40% of birds) after infection, and from intestines after 1 (80%), 2 (40%), 3 (40%) and 4 (20%) weeks after infection. The greates number of positive results for fecal swabs was noted after 1 (66%) and 6 (48%) weeks and from eggs after 1 (32%), 4 (32.5%), 5 (82.1%), 6 (81.4%), 7 (44.4%) and 8 (10.7%) weeks after infection. Diagnostically significant titres of serum antibodies in the OA test persisted for 3—8 weeks, and in the OAG test from 3 to 20 week. Similar tendencies but at low titres were noted for egg yolks. It was found that in laying hens perorally infected with S. typhimurium the bacterium persists in the organism and that it is disseminated for about 4 months. In bacteriological diagnosis better results are obtained in egg examinations than in fecal swabs examinations.