Antibody levels to Salmonella typhi and paratyphi in Nigerians

Objective: To determine the antibody titre levels to typhoid/paratyphoid fe ver organisms among apparently healthy volunteers. Design: Cross sectional study. Setting: General community and University Teaching Hospital. Participants: Volunteer sample of 323 apparently healthy individuals with b ody temperatures less than or equal to 37.8 degrees C. Main outcome measures: Questionnaire administration to classify volunteers into three socio-economic status (SES). Results: There were 35.29% of the apparently healthy population in Jos comm unity with antibodies to typhoid/paratyphoid fever organisms, The presence of these antibodies were neither sex nor SES related. Normal antibody titre s were up to 1:40 and 1:80 for O and H Salmonella antigens respectively. Co ntrary to the general belief, typhoid/paratyphoid fevers have not affected virtually everybody in Nigeria. The difference between those without previo us history and those with previous history was significant (p < 0.05) with those in the former category having a higher percentage. Conclusion: For a single sere-diagnosis to have any diagnostic value in Jos community and its environs, only a four-fold rise to what has been found t o be normal should be significant. This means that only titres of 1:160 and 1:320 and above for O and H antigens should be considered significant.