10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 2 2013 (April - June) Typhoid fever caused by lessThan i greaterThan Salmonella enterica serovar typhi (S. enterica serovar typhi lessThan /i greaterThan ) is one of the important public health problems in many developing countries. Conventional blood culture is currently the gold standard for diagnosis of typhoid fever by this bacterium, but it is time-consuming requiring several days for isolation of bacterium resulting in delay to initiate proper antibiotic therapy and often they are not cultivable. Early diagnosis of the disease is required since 2 to 5% of all deaths in India are due to typhoid fever. Semi-nested polymerase chain reaction (Sn-PCR) specific for the lessThan i greaterThan S. enterica serovar typhi lessThan /i greaterThan targeting flagellinC ( lessThan i greaterThan fliC lessThan /i greaterThan ) gene was standardized and applied onto 100 blood specimens. Sn-PCR was specific to lessThan i greaterThan S. enterica serovar typhi lessThan /i greaterThan and sensitivity is 10fg/10μl of peripheral blood DNA. Positivity rate was 62% in culture negative specimens and 100% in culture positives (p=0.001). Sn-PCR was highly reproducible and could detect lessThan i greaterThan S. enterica serovar typhi lessThan /i greaterThan in less than 12-24 hours after the receipt of the specimen in the laboratory and thus helping in rapid initiation of antibiotic treatment. M. SOWMIYA , J. MALATHI , P. AARTHI , T. VAIDEHI AND H. N. MADHAVAN Salmonella typhi, Typhoid fever, Semi-nested PCR, Flagellin gene 284-291