Determination of baseline antibody titre to S.typhi/paratyphi in Ile-Ife, Nigeria

Abstract

The aim of the study is to determine the baseline antibody titres to Salmonella typhi / paratyphi , in healthy individuals with a view to estabishing the sIgnifIcant titre for Widal agglutination test in Ile-lfe. Western, Niger.a. Three hundred and ten healthy volunteers were= admitted .Mo the study and forty-eight clinically diagnosed and culture positive cases of Enteric fever were used as purposeful controls. Widal test was performed on each serum. Slide agglutination test was first done then positive samples were further subjected to tube agglutination for quantitative titration. Of the 310 healthy volunteers 274 (97 had reciprocal antibody titre of <_80 to 0 antigen and2 6 (95.0%) had reciprocal antibody titre of < 80 to H. antigen of S. typhi. On the other hand, in 4 8 control cases, 43 (89 6%) had reciprocal antibody titre of > 160 to O antigen and 38 <78 2%1 ' had reciprocal t.tre of >16 0 to H. antigen. The sensitivity and specificity of the test were 89.9% and 94.2% for O antibody and 79.2% and 92.3% for H. antibody respectively. The baseline titre to 5 typhi /paratyphi for both O & H antibody is 1:80 whilst the significant titre for O & H antibodies is 1:160 and above in Ile-lfe, Nigeria.