Dados do Trabalho

Título

ANALYSIS OF RISK FACTORS AND CROSS-REACTIVITY BETWEEN T. CRUZI E TOXOPLASMOSE USING STRUCTURAL EQUATION MODELS

Introdução

Visceral Leishmaniasis and Chagas disease are characterized by parasitic diseases of wide worldwide distribution caused by protozoa of the genus Leishmania spp. and Trypanosoma cruzi, and that, due to phylogenetic homogeneity, share surface antibodies, which may cause cross-reactions in the face of serological tests used in the routine diagnosis of diseases. Serological reactions should not be used as an isolated criterion for diagnosis, as they may present a cross-reaction with other Trypanosomatids. The Structural Equation Modeling is a set of techniques that allows correlation between data.

Objetivo (s)

The present study aimed to analyze the occurrence of cross- seroreactivity between Leishmania spp. and Trypanosoma cruzi antigens in serum samples from dogs, verifying the possible correlations and associations between the multiple variables observables and risk factors on seroreactivity using mathematical modeling.

Material e Métodos

A total of 266 serum samples from dogs were used and  tested for Leishmania spp.  Trypanosoma cruzi antigens when submitted IFAT, DPP and Elisa serological tests. In the study, the concordance in the serological diagnoses was calculated using Cohen & Kappa index, based on the contingency table. analysis between the IFAT for Leishmania spp. and T. cruzi was evaluated using the Spearman correlation test (ρ). To verify the occurrence of association between the variables: sex, race , and clinical signs, in view of the serological tests (IFAT - Leishmania spp. and IFA - T. cruzi) the  Q- square tests and continuity correction were applied.

Resultados e Conclusão

Of the 266 samples used for the study, 226 (85%) were reactive and 40 (15%) non- reactive against the DPP tests and the qualitative ELISA test, for Leishmania spp.  In the Indirect Immunofluorescence Reaction (IFAT) for Leishmania spp and T. cruzi  156 (59%) reactive samples and 110 (41%) non-reactive; 141 (53%) samples simultaneously presented anti-Leishmania spp. and anti-T. cruzi antibodies, with cross-reactivity, in both serological . Was concluded that there was cross-seroreactivity between the antigens of parasite. The Elisa test, the neighborhood and the clinical signs constituted risk factors for the presence of anti-Leishmania spp. and anti-T. cruzi antibodies. The latent variable had a greater influence for IFRS T. cruzi than for IFRS Leishmania spp. There was a correlation between the observable variable and the results ; seroreactivity,  and the structural equation model proved to be an excellent tool for data analysis.

Palavras Chave

Antibodies; dogs; Visceral Leishmania; Chagas disease; Factor Risck