1Assistant Professor, Department of Microbiology, Andhra Medical College, Visakhapatnam, Andhra Pradesh, India
2Senior Resident, Department of Orthopaedics, Andhra Medical College, Visakhapatnam, Andhra Pradesh, India
3Assistant Professor, Department of Community Medicine, Rajiv Gandhi Institute of Medical Sciences (RIMS), Srikakulam, Andhra Pradesh, India
(*Corresponding author) email id: *aruna_8182@yahoo.com; 2clickonsantu@gmail.com; 3drnagnaidu@gmail.com
Background: Enteric fever is an endemic problem in Srikakulam and Widal agglutination test is widely used for its diagnosis Aim and objective: The interpretation of the Widal test depends upon the baseline titre among healthy individuals in a particular geographical area. This study was undertaken to determine the baseline titre in apparently healthy individuals in Srikakulam District, Andhra Pradesh. Materials and methods: The average baseline antibody titres against O and H antigens of Salmonella enterica serotype typhi and H antigens of serotypes paratyphi A and B among apparently healthy blood donors (n=250) were determined by using Standard Widal confirmatory Quantitative tube test. Results: Among the 250 serum samples which were tested, 182 (72.8%) serum samples were positive for agglutinins against Salmonella serotypes (≥1:20). Among 182 samples with an anti-O titre ≥1:20, 60 (24%) samples had titres of 1:80. Among the 50 samples demonstrating anti- H titres of >1:20 to Salmonella serotype, 25 (10%) had a titre of 1:80. For Salmonella paratyphi A and B, anti -H titres of 1:20 were found in 8 (3.2%) and 8 (3.2%) respectively, for all samples tested. Conclusion: When a single Widal agglutination titre is used for diagnosis of enteric fever,it will be more appropriate to change the currently used cutoff levels against Salmonella enterica serotype typhi to >1:80 for anti- O and H of S. typhi and >1:20 for S. paratyphi A and B for Srikakulam district.
Enteric fever, Widal test, Blood donors, Baseline titres, S. typhi, S. paratyphi A, S. paratyphi B
