Dados do Trabalho

Título

A high performance rapid test for Chagas disease utilizing the multi-epitope synthetic protein DxCruziV3

Introdução

Current diagnostic tests for chronic Chagas disease (CCD) require laboratory infrastructure, which compromises diagnosis in neglected populations living in remote areas.

Objetivo (s)

An in-field evaluation for the specificity and sensitivity of a LF-RT using DxCruziV3 RT conducted in a difficult to access endemic area of Brazil.

Material e Métodos

Although the DxCruzi V3 protein sensitivity and specificity have already been evaluated in the previous steps of this study, the DxCruzi V3 Prototype LF-RT were evaluated against a panel with 95 serologically known samples from LACENs of Ceará, Maranhão, Paraíba and Sergipe (55 positives and 40 negatives for CCD) showing sensitivity 94.5% and specificity 100%. The negative panel is composed of positive Leishmania spp. and dengue samples, which ruled out cross-reactivity with these diseases. Prototype LF-RTs were independently manufactured in our lab (LPR&M) and BioManguinhos (BM) that included recombinant protein production. A total of 167 participants from the city of Barcelos, AM, Brazil and six surrounding riverside communities were tested by digital puncture. A whole blood sample was also collected by venipuncture from all participants for confirmatory testing under laboratory conditions by indirect immunofluorescence assays (IFA), two commercial ELISAs (BioClin and Wiener 3.0), and in-house ELISAs (DxCruzi V3).

Resultados e Conclusão

By LF-RT, 43 samples were reactive both in the open-air environment and in controlled environments (hospital and laboratory) with an 84% agreement with the IFA results. For the BioClin ELISA, the agreement rate was 77% and 86% with Wiener. The in-house DxCruziV3 ELISA agreed with 95% of the LF-RTs. Using the Wiener ELISAs and IFA as “reference”, the sensitivity for the LF-RT LPR&M in field was 97.6% and specificity 99.2%. For BM LF-RT in field sensitivity was 95.3% and specificity 96.8%. LPR&M and BM tests were concordant with the “reference tests”, respectively, 98.8% and 96.4%. Thus, we can conclude that DxCruzi shows excellent promise as the critical reagent for building lateral flow rapid tests for Chagas disease in endemic and hard-to-reach areas, that showed stability at varying temperatures and humidity.

Palavras-chave

Chagas disease. Neglected diseases. Rapid test. Synthetic Protein.

Agradecimentos

Dr. Carlos Médicis Morel (CDTS-Fiocruz); Dr. Pedro Albajar Viñas (PAHO); Dr. Pedro Hernan Cabello (LGH/IOC/Fiocruz); Dr. José Borges Pereira, Tec. Júlio César Miguel (LDP/IOC/Fiocruz); DSEI-ARN; LESM/IOC/Fiocruz; CGLAB/DAEVS/SVS/MS. Fiocruz. CDTS. Capes. INCT-IDNP