Anti-typhoid agglutinins in school aged African children.

OBJECTIVES

To determine baseline antibody responses to H and O antigens of Salmonella typhi and Salmonella paratyphi (A, B and C) in school aged Nigerian children.

DESIGN

Cross-sectional study involving 175 children. Using both rapid slide and tube agglutination techniques in dilutions of sera (1:20 to 1:320), agglutination reactions with various antigens were determined.

SETTING

Community based study involving primary school pupils in Benin City.

SUBJECTS: Apparently healthy school children (5-16 years) selected systematically, using multistage sampling technique.

RESULTS

No subject demonstrated agglutination to any of antigens at 1:320 dilution. Two (1.1%), 26 (14.9%), 85 (33.1%) and 51 (29.1%) pupils respectively had reactions to either antigens of Salmonella typhi at dilutions of 1:160, 1:80, 1:40 and 1:20. At 1:40 dilution 1 (0.6%) and 3 (2.3%) each had reactions to HB, OB and HC respectively. Sixteen per cent had reactions at higher dilutions of > or = 1:80 and this occurred more significantly in older children (chi2(y) = 15.50; p < 0.001), those with low maternal socio-economic status (chi2(y) = 22.06, p < 0.001), those from poor apartments (chi2 = 4.49; p < 0.05) and those who used predominantly none pipe-borne water (chi2 = 5.40; p < 0.02). Against OD and HD, about 50.0% seroconverted at 1:40 dilution with antibodies against H being more prevalent.

CONCLUSION

Interpretation of single widal reaction in endemic areas must take into cognisance age, clinical and socio-cultural characteristics of the child.