Evaluation of immunohistochemical technique for the diagnosis of Leishmania spp. in canine tissues samples

Abstract

In Brazil, leishmaniasis represents a major public health problem due to its high incidence, wide distribution and remarkable increase in transmission associated with the disease urbanization. Dogs are considered as the main reservoirs of visceral leishmaniasis (VL) in the urban environment and diagnosis improvement was fundamental in this species. This study aimed at evaluating the immunohistochemical technique (IHC) for diagnosing Leishmania spp. in differents tissues samples collected from dogs. This investigation was performed at the Quantitative Pathology Center of the Institute Adolfo Lutz (NPQ-IAL). Tissue samples collected from 134 dogs, derived from municipalities of São Paulo State, positive for VL by rapid testing (TR DPP® - Bio-Manguinhos), enzyme-linked immunosorbent assay (EIA/ELISA - Bio-Manguinhos), and polymerase chain reaction, were analyzed by specific IHC in duplicate. These dogs were previously diagnosed as VL. IHC showed sensitivity of 98.51 %, specificity of 100.00 %, positive predictive value of 100.00 %, negative predictive value of 83.33 % and accuracy of 98.61 %. The major positivity was detected in spleen samples. Kappa index between the tissues duplicate results was of 0.84. IHC technique, standardized and implemented at NPQ-IAL, showed to be suitable to be used as routine test for diagnosing canine leishmaniasis effectivelly.