Evaluation of a commercial double-recognition ELISA for caprine tuberculosis diagnosis: sensitivity, specificity, and correlation to macroscopic and microscopic lesions

Abstract

Ante-mortem diagnosis of caprine tuberculosis, as in other ruminant species, is a complex process. Therefore, it is sometimes necessary to apply a combination of methods that increases the sensitivity of diagnosis while maintaining adequate specificity. In the present study, we analysed the use of ELISA based on a double-recognition methodology for the diagnosis of goat tuberculosis. Serum samples from animals with tuberculosis, confirmed by histopathological studies and presence of Ziehl-Neelsen-positive bacteria in the lesions, were used to assess sensitivity. Sera from flocks without tuberculosis were used to assess diagnostic specificity. The relationship between ELISA results and the type of tuberculous lesions, both macroscopic and microscopic, was analysed. The sensitivity and specificity of ELISA test were 69.9% and 97.9%, respectively. Sensitivity was higher in animals with macroscopic lesions, indicating more advanced forms of the disease. Similarly, a higher sensitivity was found in animals with microscopic lesions associated with active tuberculosis, such as cavitary lesions.