Which one of the following gives strong evidence of Typhoid Fever carrier status

Typhoid Labarotary Diagnosis : 'BASU' Mneumonic Test of diagnosis Time of diagnosis Remarks Blood culture 1st Week Mainstay of diagnosis Antibodies (Widal test) 2nd Week Moderate, sens, spec Stool culture 3rd Week Urine test 4th Week Newer tests IDL Tubex test Detects IgM antibodies TYPHI DOT Detects IgM and IgG Ab TYPHI DOT-M Detection IgM antibodies DIPSTICK TEST Detects IgM antibodies Isolation of Vi Ag Detects carriers In chronic cases of Typhoid, organisms persist in : Gall Bladder and Biliary Tract Typhoid Mary, who gave rise to 1300 cases, was a chronic carrier VI antibodies are in 80% Most successful approach to treatment : Cholecystectomy + Ampicillins therapy Immunization doesn't give 100% protection Ref: Park 25th edition Pgno : 251-252