SUMMARY
The present study was carried out to assess the degree of pathogenicity of E.coli, isolated fromthe GI tract of piglets . All the mice inoculated with E.coli isolates died within 36 hours. Post-mortemexamination of the mice revealed lesions similar to that observed in most of the natural infectioncases in piglets. The E.coli were re-isolated from the dead mice by streaking on EMB agar. Thusin the present study E.coli isolated from the GI tract of piglets was found to be highly pathogenicto mice and was also re-isolated from the dead mice indicating that E.coli could be responsiblefor mortality in piglets.