Dados do Trabalho

Título

Assessment of indirect immunofluorescence assay performance for Chagas disease in dogs using a reference array of four chimeric proteins

Introdução

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi, represents a significant public health concern in Latin America. Domestic dogs act as sentinel animals in endemic regions, predicting human infection risk. However, no commercial tests are available to diagnose CD in dogs. 

Objetivo (s)

This study assesses the diagnostic performance of an indirect immunofluorescence assay (IIF) for detecting anti-T. cruzi IgG in canine sera, using a latent class analysis (LCA) model with chimeric T. cruzi antigens as a reference standard.

Material e Métodos

The study protocol was approved by the Committee on Animal Ethics and Experimentation at Maranhão State University, Brazil (protocol 09/2018). Sampling was performed by venipuncture in households after guardians signed a free and informed consent. A panel of 330 serum samples from dogs in a non-endemic Amazonian area in Brazil was tested for anti-T. cruzi antibodies using IIF with glass slides coated with T. cruzi F90 and Y88 epimastigotes, and LCA based on a reference array using four T. cruzi chimeric recombinant antigens: IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4. These synthetic antigens were obtained by genetic engineering techniques and purified using chromatographic assays.

Resultados e Conclusão

LCA classified 284 samples as T. cruzi-negative and 46 as T. cruzi-positive. IIF showed a sensitivity of 43.5%, specificity of 70.1%, overall accuracy of 66.4%, and positive and negative likelihood ratios of 1.45 and 0.81, respectively. The diagnostic odds ratio was 1.79, and Cohen's kappa was 0.08, indicating poor agreement between IIF and LCA. The poor performance of IIF, particularly in sensitivity, renders it unsuitable for serologic screening and laboratory diagnosis of CD in dogs. Improved diagnostic tools for CD in dogs are essential for effective epidemiological surveillance and public health interventions.

Palavras Chave

Chagas disease; dogs; diagnosis; Indirect immunofluorescence; Latent Class Analysis; Chimeric recombinant proteins