| Summary: | <p>Abstract</p> <p>Background</p> <p>Enteric fever is an endemic problem in Nepal and Widal agglutination test is widely used for its diagnosis but a normal baseline titer in healthy population and cutoff values have not been established.</p> <p>Methods</p> <p>We measured average baseline antibody titers against "O" and "H" antigens of <it>Salmonella enterica </it>serotype <it>Typhi </it>and "H" antigens of serotypes <it>Paratyphi A </it>and <it>Paratyphi B </it>among apparently healthy blood donors in Nepal. The antibody titers were measured using Standard Widal Confirmatory Quantitative Tube test.</p> <p>Results</p> <p>Among the 100 blood samples collected from healthy volunteers, 62 individuals had significant antibody titers (≥ 1:20) against one of the four antigens against <it>S. enterica</it>. Among 54 samples with an anti-O titer against serotype <it>Typhi</it>, 15 and 36 samples had titers of ≥ 1:60 and ≥ 1:40, respectively. A significant proportion (12% of all) had anti-O titer of ≥ 1:80. Similarly, among the 59 samples demonstrating anti-H titers of ≥ 1:20 to <it>S. enterica </it>serotype <it>Typhi</it>, 29 had a titer of ≥ 1:80 and 12 had 1:160. For <it>S. enterica </it>serotypes <it>Paratyphi A </it>and <it>B</it>, anti-H titers of ≥ 1:20 were found only in 12% and 3%, respectively, of all samples tested.</p> <p>Conclusion</p> <p>When a single Widal agglutination titer is used for the diagnosis of enteric fever, it will be more appropriate to change the currently used cutoff levels against <it>S. enterica </it>serotype T<it>yphi </it>to > 1:80 for anti-O and > 1:160 for anti-H titers for Nepal.</p>
|
|---|
