Immunologic diagnosis of schistosomiasis. III. The effects of nutritional status and infection intensity on intradermal test results in St. Lucian children

ABSTRACT

The question of the insensitivity of immediate and delayed skin testing in children was studied with respect to both nutritional status and intensity of infection. Ninety-seven children on the island of St. Lucia, 5 to 11 years of age, with almost equal malefemale distribution, all excreting eggs of Schistosoma mansoni were tested as follows qualitatively and quantitative stool examinations; anthropometric measurements (height, weight, mid-arm circumference and triceps skinfold thickness); hematocrit; fluorescent antibody test; and skin tests with control material, S. mansoni adult worm antigen (both Puerto Rican and St. Lucian strains), and intermediate strenght PPD tuberculin. The anthropometric measurements revealed marginal malnutrition among the children. The overall positive intradermal response rate for each of the two antigens was similar, being 56 percent for the immediate and 37 percent for the delayed test. There was no relationship discernible between relative over- and under-nutrition and the skin test responses. A striking and highly significant positive association was revealed, however, between the intensity of infection, as shown by quantitative egg counts, and the sensitivity and extent of both the immediate and delayed skin test reactions.(AU)