RESUMO
We examined the association between socioeconomic status and the level of serum antibodies to selected faeco-orally transmitted pathogens among Israeli adolescents. Random samples of eighty volunteers aged 12-15 years from high (HSL), medium (MSL) and low (LSL) standard of living towns were included in the study. Serum samples were examined by radioimmunoassay for HAV and by in-house-developed ELISA systems for IgA and IgG antibody levels against Shigella sonnei, S. flexneri, E. coli O157:H7 lipopolysacchride and Cryptosporidium parvum antigens. Seropositivity to HAV was highest (98.8%) in the LSL towns and lowest (25%) in the HSL towns, showing a statistically significant linear trend. Antibody levels to the other enteropathogens had gender variation, with higher titres in females. Significantly lower titres in the HSL towns were found for: IgA anti-S. sonnei in females (P<0.001); IgG anti-S. sonnei in females (P=0.024) and males (P=0.033); IgG anti-S. flexneri in females (P=0.016). Inverse linear association with socioeconomic status was found for IgA anti-C. parvum in females (P<0.001); IgA anti-E. coli O157:H7 in females (P<0.001) and males (P=0.024). A statistically significant association between HAV seropositivity and higher titres of IgA anti-S. sonnei and E. coli O157:H7 was shown. In conclusion, exposure to enteropathogens transmitted via the faecal-oral route in communities of lower socioeconomic status is reflected in a higher prevalence of lifelong lasting antibodies to HAV, and higher levels of antibodies to bacterial and protozoan enteropathogens. Among females, the levels of specific serum antibodies are higher and more strongly associated with low socioeconomic status.
