ABSTRACT
The aim of this study, carried out in 1993, was to evaluate diphtheria immunity in Siena. Diphtheria antitoxin levels were measured by means of the immunoenzymatic test (ELISA) in serum samples of 602 apparently healthy subjects (239 males and 363 females) of all ages residing in Siena. According to widely used criteria, 6% of the total population were susceptible to diphtheria (antibody levels < 0.01 IU/ml), 71% had basic protection (0.01-0.09 IU/ml) and 23% were fully protected (> or = 0.1 IU/ml). The results suggested that a high proportion of young population had a protective level of immunity against diphtheria, that susceptibility increased with age and a smaller proportion of males (2.9%) than females (8.3%) were unprotected; this difference was statistically significant. Our results suggest that it may be useful to revaccinate adults with low levels of diphtheria toxoid so that the percentage that remains unprotected does not put the community at risk of an outbreak of diphtheria.
Subject(s)
Diphtheria Antitoxin/blood , Diphtheria/immunology , Urban Health , Adolescent , Adult , Age Distribution , Child , Child, Preschool , Diphtheria/prevention & control , Disease Susceptibility , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunization, Secondary , Infant , Infant, Newborn , Italy , Male , Middle Aged , Prevalence , Seroepidemiologic Studies , Sex DistributionABSTRACT
Antibodies to Plasmodium falciparum sporozoites represent a serological transmission indicator, which can be applied in epidemiological studies to estimate the intensity of malaria transmission. An ELISA method has been developed as an industrial kit to detect these antibodies, using a chemically synthesized (NANP)40 peptide as antigen. The results obtained with this kit are compared in the present paper with those obtained by an ELISA test already applied in epidemiological studies. In testing sera from individuals living in endemic areas, a high diagnostic concordance (92.1%) was obtained between the two assays. The absorbances of these sera correlated well, as shown by a correlation coefficient r = 0.877. Sera from individuals never exposed to malaria gave very low absorbances with the kit. This minimum non-specific binding increases the probability of comparable results in different studies. When the two ELISAs were evaluated for analytical sensitivity and precision, similar satisfactory results were achieved. The test can be performed not only with sera but also with eluates from filterpaper bloodspots. Modifications of the kit to reduce its cost and suggestions regarding distribution and funding are also proposed.
Subject(s)
Antibodies, Protozoan/analysis , Enzyme-Linked Immunosorbent Assay/methods , Plasmodium falciparum/immunology , Animals , Evaluation Studies as Topic , Humans , Malaria/blood , Malaria/epidemiology , Peptides , Reagent Kits, DiagnosticABSTRACT
In the determination of plasma fibrinogen by electroimmunodiffusion, commercial sodium heparin, previously included in the agarose gel, by interacting with fibrinogen molecules, enhances their anodic mobility more strongly than after carbamylation with potassium cyanate. The proposed method provides an increase in sensitivity and specificity which practically eliminates the influence of fibrinogen degradation products.
