Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/9/2003
Publication Date: 11/9/2003
Citation: ROSTAGNO, M.H., HURD, H.S., MCKEAN, J.D., GAILEY, J.K. EVALUATING CECAL CONTENT AND ILEOCECAL LYMPH NODE SAMPLING TO DETERMINE SALMONELLA ENTERICA PREVALENCE IN SWINE. CONFERENCE OF RESEARCH WORKERS IN ANIMAL DISEASES. 2003. ABSTRACT P. 59. Interpretive Summary:
Technical Abstract: The objective of this study was to compare the prevalence of Salmonella enterica in swine populations by testing cecal contents versus ileocecal lymph nodes. In each of two abattoirs, four groups of pigs were studied. From each studied group, individual samples were collected from 30 animals randomly selected in the slaughter line. Overall, the S. enterica prevalence in abattoir A, determined by cecal contents and ileocecal lymph nodes was 36.7% and 27.5% (p < 0.05), respectively. In abattoir B, the prevalence found was 43.3% and 18.3% (p < 0.05), respectively. Combining results from both sample types, the prevalence found was 47.5% for abattoir A, 53.3% for abattoir B, and 50.8% overall. A total of 13 different S. enterica serovars was isolated (11 from cecal contents and 9 from ileocecal lymph nodes). Four serovars were isolated only from cecal contents, whereas 2 serovars were only isolated from ileocecal lymph nodes. S. enterica serovars isolated from both samples included: Typhimurium var. Copenhagen, Typhimurium, Derby, Anatum, Agona, Newport, and Heidelberg. The relative sensitivity of cecal content sampling was 79.3%, whereas for ileocecal lymph node sampling it was only 45.5%. The agreement (Kappa statistic) between both sample types was 13.1%, indicating that both sample types are complementary. We hypothesize that the invasiveness of a serovar, as well as the period of time elapsed between exposure and sample collection constitute determinant factors to the prevalence and serovar diversity found in each sample. This study demonstrates that sampling either cecal contents or ileocecal lymph nodes affects quantitative (prevalence), as well as qualitative (serovar diversity) results of S. enterica epidemiological studies. It is recommended that both samples be simultaneously used to achieve a better understanding of S. enterica ecology and epidemiology in swine populations.