Electrochemical detection of Toxocara canis excretory-secretory antigens in children from rural communities in Esmeraldas Province, Ecuador: association between active infection and high eosinophilia.
Parasit Vectors
; 13(1): 245, 2020 May 12.
Article
em En
| MEDLINE
| ID: mdl-32398157
BACKGROUND: The diagnosis of active Toxocara canis infections in humans is challenging. Larval stages of T. canis do not replicate in human tissues and disease may result from infection with a single T. canis larva. Recently, we developed a nanobody-based electrochemical magnetosensor assay with superior sensitivity to detect T. canis excretory-secretory (TES) antigens. Here, we evaluate the performance of the assay in children from an Ecuadorian birth cohort that followed children to five years of age. METHODS: Samples were selected based on the presence of peripheral blood eosinophilia and relative eosinophil counts. The samples were analyzed by the nanobody-based electrochemical magnetosensor assay, which utilizes a bivalent biotinylated nanobody as capturing agent on the surface of streptavidin pre-coated paramagnetic beads. Detection was performed by a different nanobody chemically labelled with horseradish peroxidase. RESULTS: Of 87 samples tested, 33 (38%) scored positive for TES antigen recognition by the electrochemical magnetosensor assay. The average concentration of TES antigen in serum was 2.1 ng/ml (SD = 1.1). The positive result in the electrochemical assay was associated with eosinophilia > 19% (P = 0.001). Parasitological data were available for 57 samples. There was no significant association between positivity by the electrochemical assay and the presence of other soil-transmitted helminth infections. CONCLUSIONS: Our nanobody-based electrochemical assay provides highly sensitive quantification of TES antigens in serum and has potential as a valuable tool for the diagnosis of active human toxocariasis.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Toxocaríase
/
Proteínas de Helminto
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Eosinofilia
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Técnicas Eletroquímicas
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Anticorpos de Domínio Único
/
Antígenos de Helmintos
Tipo de estudo:
Diagnostic_studies
/
Risk_factors_studies
Limite:
Animals
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Child, preschool
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Humans
/
Infant
País/Região como assunto:
America do sul
/
Ecuador
Idioma:
En
Revista:
Parasit Vectors
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Bélgica
País de publicação:
Reino Unido