Resumen

ROSSI S, Marcello S; SIGALES, Leonardo  y  ZAPATA, Danny. Thin layer immunoassay (TIA) for the serodiagnosis of cattle Trypanosomiasis caused by trypanosoma vivax. Rev. Fac. Cienc. Vet. [online]. 2008, vol.49, n.2, pp.81-89. ISSN 0258-6576.

Trypanosoma vivax is the aethiological agent of bovine trypanosomiasis. The low parasitic burden and typical fluctuations, limit the direct diagnosis of the disease. The ELISA is a serological technique that has been used for the detection of trypanosomiasis. However, despite its good sensibility, specificity and predictive value, the high cost of this test has restricted its applicability under field conditions. Given the previous standardization of the ELISA assay for the detection of bovine antibodies against T. vivax using T. evansi antigens, the aim of this work was to standardize the Thin Layer Immunoassay (TIA) and apply it in conjunction with the ELISA test in a serological and epidemiological comparative study. Briefly, T. evansi antigens were sensitized in Petri dishes at different protein concentrations in 0.05 M carbonate buffer (pH 9.6). Subsequently, the Petri dishes were incubated in the presence of problem and reference sera, which were either positive or negative to T. vivax. The excess antigen and sera was eliminated by washes in distilled water and the antigen-antibody reactions were developed with a water steam in the TIA, followed by incubation with secondary antibodies (anti-bovine IgG) conjugated to Horseradish Peroxidase (HRP) and a chromogenic substrate in the ELISA. Results show that the values of seroprevalence obtained by both techniques were similar (38.66% and 36% for ICF and ELISA, respectively). Also, seroprevalence distribution in each locality was similar for both tests. The relative trustability of TIA was demonstrated with a sensibility of 89.36% and a specificity of 75%, respectively. These results suggest that TIA has a high correlation with ELISA and is suitable to be used in serological and epidemiological studies of bovine trypanosomiasis.

Palabras clave : Cattle; Trypanosoma vivax; Immunological techniques; antibodies.

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