Abstract

Enteric fever remain as an important public health problem globally and it is a major cause of morbidity in the developing world. Typhoid fever is caused by Salmonella typhicc and a less severe disease, paratyphoid fever is caused by Salmonella paratyphi A, B and C. widal test is a tube agglutination test done in most of the clinical laboratories used for the diagnosis of enteric fever. Antibodies against O antigen of Salmonella typhi and H antigens of Salmonella typhi and paratyphi A and B are defeated and antibody titre is measured by doing this test in cases with clinical suspicion. In India where enteric fever is endemic, the serum of a proportion of healthy people contain antibodies capable of reacting to a variable titre, in widal test. A study was conducted by the Department of Microbiology at Sri Mookambika Institute of Medical Sciences (SMIMS), Kulasekharam, Tamil Nadu during a period of one year from November 2011 to October 2012 to find out the basal antibody titres against O and H antigens of Salmonella typhi and AH and BH antigens of Salmonella paratyphi A and B respectively in a healthy population between the age group of 15 to 45 years of age in the local area. A proportion of Medical and paramedical Staff and students of the Institute were also included in the Study. A total number of 250 samples of blood collected from the persons in the study group and widal test was performed in the clinical Microbiology laboratory with the serum seperatated from the samples after centrifugation. Of the 250 sera tested, 137 (54.8%) showed agglutination in the dilution of <1:20, for Salmonella O antibody, 176 (70.4%) showed H antibody titre in 1:20 dilution, 234 (93.6%) and 232 (92.8%) showed H antibodytitre in 1:20 dilution for Salmonella paratyphi A and B respectively. None of the samples showed antibody titres above 1:80 for TO, 1:160 for TH, AH and BH antibodies. The cut off limit was similar to the values reported from many other students conducted in different endemic areas in India.

Keywords: Typhoid fever, paratyphoid fever, widal test, Antibody titre, Salmonella typhi and Salmonella paratyphi.