ABSTRACT
As there appeared to be no data available on Toxocara canis infection in the children of Swaziland, a serological survey of T. canis infection was recently conducted among 92 children aged 3-12 years from rural slums in the low- and middle-veld. A child was considered seropositive if, in western blots based on the excretory-secretory antigens of larval T. canis, his or her serum gave a positive result when diluted 1 : 64. Forty-one (44.6%) of the children were found seropositive. There were no statistically significant differences in seroprevalence between the 49 boys and 43 girls investigated (46.9% v. 41.8%) or between the eight subjects aged 12 years and the 47 aged < or = 5 years (62.5% v. 38.3%); the corresponding odds ratios were 0.81 (95% confidence interval=0.36-1.86; P=0.62) and 2.69 (95% confidence interval=0.57-12.62; P=0.20), respectively. The 66 subjects from the middleveld were, however, significantly more likely to be seropositive than the 26 subjects from the lowveld (54.5% v. 19.2%; odds ratio=5.04, with a 95% confidence interval of 1.70-14.98; P<0.01). It seems likely that T. canis infection is common among the children who live in slums in Swaziland, particularly in the country's middleveld, probably as the result of poor hygiene and poor sanitation.
Subject(s)
Antigens, Helminth/immunology , Helminth Proteins/immunology , Toxocara canis/immunology , Toxocariasis/epidemiology , Adult , Age Distribution , Animals , Antigens, Helminth/isolation & purification , Blotting, Western , Child , Child, Preschool , Cross Reactions , Dog Diseases/parasitology , Dog Diseases/transmission , Dogs , Enzyme-Linked Immunosorbent Assay/methods , Eswatini/epidemiology , Female , Helminth Proteins/isolation & purification , Humans , Male , Poverty Areas , Sanitation/standards , Seroepidemiologic Studies , Toxocariasis/immunology , Toxocariasis/transmission , Urban PopulationABSTRACT
BACKGROUND: The protein composition of red cell (RBC) eluates has not been extensively studied. The purpose of this study was to determine the IgG content and protein composition of RBC eluates prepared by the acid and xylene elution methods. STUDY DESIGN AND METHODS: Six samples of group O R1R1 RBCs sensitized with anti-D in vitro, six nonsensitized samples of the same group O R1R1 RBCs, and six samples from patients with warm autoimmune hemolytic anemia (WAIHA) were studied. The eluate protein composition was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunoglobulin concentrations were estimated by an immunoblot technique using horseradish peroxidase-conjugated anti-IgG and 3,3' diaminobenzidine. RESULTS: The protein concentrations of the xylene eluates were significantly greater than those of the acid eluates (37.3 +/- 10.7 and 3.0 +/- 0.4 [SD], respectively; p < 0.005). In all samples, the proportion of IgG was less than 0.13 percent of the total protein content. The acid eluates of sensitized RBCs contained more IgG than the xylene eluates. The antibody titers of eluates from WAIHA RBCs were significantly lower than eluates of in vitro sensitized RBCs (p < 0.005). The estimated molecular weights of the Coomassie blue-stainable protein bands from xylene eluates were 97, 78, 63, 45, 31, 23, and 16 kDa, and those of bands from acid eluates were 97, 78, and 55 kDa. No periodic acid-Schiff reagent-stainable bands were detected. CONCLUSION: These data indicate that IgG represented only a small fraction of the proteins in the eluates and that the protein composition varies with the elution procedure.
