IMMUNOEPIDEMIOLOGY OF HUMAN NECATORIASIS - CORRELATIONS BETWEEN ANTIBODY-RESPONSES AND PARASITE BURDENS

In this paper,ye describe the relationship between antibodies to Necat or americanus stage-specific antigens and parasite burden in an endemi cally-infected population in Papua New Guinea. Using an age-structured analysis, rye show that the correlation coefficient between levels of IgG against adult worm excetory-secretory (ES) antigen and parasite b urden declined significantly with host age from positive in younger ho sts to significantly negative in older hosts. A trend towards similar. patterns was present for anti-larval IgG both pretreatment and after reinfection, and for anti-ES IgM and anti-ES IgE pretreatment, These p atterns are consistent,vith a role for these isotypes in a protective immune response, although parasite-induced immunosuppression may provi de an alternate explanation. This is another demonstration of possibly protective responses to N, americanus infection.