PATHOGENESIS STUDY OF PORCINE SALMONELLOSIS IN MOUSE MODEL

A study was undertaken to isolate the Salmonella serovars from gastroenteritic lesions of piglets and to assess the pathogenic effect of porcine Salmonella in gastrointestinal tract of mice. Tissue samples were collected from piglets showing varying degrees of gastroenteritis. The tissue samples were subjected to different conventional culture methods and biochemical tests for Salmonella serovar identification. Ten sample isolates were isolated from 90 samples and were identified as Salmonella Choleraesuis. The major virulent Salmonella isolate with infective dose of 2.7 x 107 CFU/ml was administered orally for pathogenesis study to 48 mice based on the pilot study along with a control group of six mice. Six mice each were sacrificed by cervical dislocation at 6, 12, 24, 36, 48, 60, 72 and 96 h, post-inoculation. Detailed postmortem examination was conducted and gross lesions particularly of gastrointestinal tract (GIT) were recorded. Gross lesions of mice revealed severe catarrhal enteritis, hepatic degeneration and pulmonary emphysema at varying intervals. The representative tissue samples of gastrointestinal tract were collected in 10 percent neutral buffered formalin and processed for histopathological examination.