An evaluation of the dot-ELISA procedure as a diagnostic test in an area with a high prevalence of human Toxocara canis infection

Abstract

The aim of this work was to evaluate a dot-enzyme-linked immunosorbent assay (dot-ELISA) using excretory-secretory antigens from the larval stages of Toxocara canis for the diagnosis of toxocariasis. A secondary aim was to establish the optimal conditions for its use in an area with a high prevalence of human T. canis infection. The dot-ELISA test was standardised using different concentrations of the antigen fixed on nitrocellulose paper strips and increasing dilutions of the serum and conjugate. Both the dot-ELISA and standard ELISA methods were tested in parallel with the same batch of sera from controls and from individuals living in the problem area. The best results were obtained with 1.33 µg/mL of antigen, dilutions of 1/80 for the samples and controls and a dilution of 1/5,000 for the anti-human IgG-peroxidase conjugate. All steps of the procedure were performed at room temperature. The coincidence between ELISA and dot-ELISA was 85% and the kappa index was 0.72. The dot-ELISA test described here is rapid, easy to perform and does not require expensive equipment. Thus, this test is suitable for the serological diagnosis of human T. canis infection in field surveys and in the primary health care centres of endemic regions

A Lateral Flow Rapid Test for Human Toxocariasis Developed Using Three Toxocara canis Recombinant Antigens

“…Akao et al 24 were the first group to develop a rapid test based on the direct flow-through principle (called Toxocara-CHEK) for serodiagnosis of Toxocara infection. Bojanich et al 25 developed a dot-test ELISA and suggested that the several advantages it offered when compared with standard ELISA (i.e., test stability, low cost, and ease of use without the need for specialized equipment) made it the most suitable assay for epidemiological surveillance studies. More recently, Lim et al 26 reported on the development and evaluation of a lateral flow rapid test based on rTES-30, which they called iToxocara.…”

Latent and AsymptomaticToxocaraInfection among Young Population in Northwest Iran: The Necessity of Informing People as a Potential Health Risk

“…In comparison, ELISA method is much simple, with easier performance and does not require any complicated equipment. It has commercially available kit with appropriate sensitivity and specificity and it is recommended as effective and useful method in seroepidemiological studies of human toxocariasis [ 28 , 29 ]. In the present study, we used ELISA kit to recognize anti- Toxocara IgG antibody in serum samples and also stool exam was performed to prevent cross-reactions.…”

Field evaluation of a rapid diagnostic test to detect antibodies in human toxocariasis

“…Additionally, the specificity and sensitivity of the RDT method (sensitivity = 85.7%; specificity = 90.1%) was comparable to those of 30-35 kDa dot-ELISA (sensitivity = 89.3%; specificity = 89.4%) (Bojanich et al, 2012) and immunoblot (sensitivity = 85-100%; specificity = 96.6-100%) (Roldán and Espinoza, 2009). Significant correlation between the RDT rating and ELISA reading further suggested that the band intensity was well correlated to the amount of antibody detected by the recTES-ELISA.…”

“…Further, there is also a lack of consensus in the reportable cutoff for ELISA reading to define positive toxocariasis. Due to these shortcomings, several rapid and portable field detection kits had been developed over the recent years (Akao et al, 1997;Lim et al, 1999;Bojanich et al, 2012;Yamasaki, 2012).…”