An Epidemiological Study to Estimate the Baseline Titres of Widal Test in Apparently Healthy Individuals of Bhubaneswar, Odisha DC42-DC45
Dr. Surya Narayan Mishra
Assistant Professor, Department of Microbiology, Kalinga Institute of Medical Sciences, Bhubaneswar, Odisha, India.
E-mail : firstname.lastname@example.org
Introduction: Enteric fever is one of the most prevalent community acquired infection especially in the developing countries; caused by Salmonella enterica serovar Typhi, Paratyphi A and Paratyphi B. The Widal test is a well-known test to detect the serological evidences of presence of Salmonella groups. As the baseline Widal titre varies substantially region wise; updating the baseline Widal titre among the healthy individuals is a must for the proper interpretation of the Widal test.
Aim: To determine the baseline Widal titre (titre of the antibodies to the O and H antigens of Salmonella enterica serovar Typhi and the H-antigens of S. Paratyphi A and Paratyphi B) amongst apparently healthy individuals of Bhubaneswar, Odisha.
Materials and Methods: To determine the baseline Widal titre among apparently healthy individuals of Bhubaneswar; a prospective study covering 500 blood samples was conducted using tube Widal test. Healthy young individuals who were neither vaccinated nor have a recent hospitalization history were included in the study.
Results: Out of the total 500 serum samples, 340 were positive for agglutinins (1 = in 20) and 160 serum samples were negative for agglutinin (1 = in 20). The distribution of the samples with an antibody titre = 1:20 against different serotypes of Salmonella enterica subspecies enterica showed an antibody to anti O antigen in 340 samples (68%), an antibody to anti H antigen in 292 samples (58.4%), an antibody to anti AH antigen in 268 (53.6%), an antibody to anti BH antigen in 224 samples (44.8%) out of the total 500 samples. The baseline titre for Widal test in apparently healthy individuals of Bhubaneswar was calculated to be: 1:40 for the anti TO antibodies and of 1:20 each for the anti- TH, anti AH and anti BH antibodies.
Conclusion: It is clear that Salmonella agglutinins are common among apparently healthy people and as endemicity of typhoid in an area may change over time, information of baseline titre will help a better clinical diagnosis and treatment to the deserving patients.