Anatomomopathological and immunohistochemical analyses of the spleen and lymph node of dogs seropositives for leishmaniasis in serological tests

Abstract

Canine leishmaniasis (CanL) is a zoonosis caused by the protozoan of the species Leishmania infantum. The spleen and lymph nodes undergo morphological changes during CanL. This research aimed to perform an anatomopathological and immunohistochemical study of these organs in dogs reactive to leishmaniasis in the Dual-path Platform chromatographic immunoassay (DPP®) and Enzyme Immunoabsorption Assay (ELISA). Twenty-seven dogs were evaluated for anatomopathological examination with 92.6% having clinical signs. Splenomegaly and lymphadenomegaly were the main macroscopic changes. All dogs showed changes in the spleen, unrelated to the parasitic load, with granulomatous splenitis being the most severe change. Diffuse cortical and paracortical hyperplasia and spinal cord hyperplasia and hypertrophy were observed in the lymph nodes. Amastigote forms of Leishmania spp. were found in the spleen and lymph node during histopathological and immunohistochemical evaluations, with good agreement between these evaluations (k = 0.55, p = 0.00124), but no difference was observed in the parasitic intensity of these organs (p = 0.23) . Thus, the spleen and lymph node reactive to leishmaniasis on the DPP® and ELISA tests show histomorphological changes resulting from the disease. In addition, the spleen and lymph node have a parasitic load similar to those found by direct diagnostic methods.