Immunohistochemistry in myocardium of dogs naturally infected with Leishmania chagasi / Imunohistoquímica em miocárdio de cães naturamente infectados por Leishmania chagasi

ABSTRACT

Background: Canine visceral leishmaniasis is a chronic and endemic disease, widespread zoonotic infection with a greatimpact on public health. The domestic dog is the main reservoir and also a source of infection for humans in the urbanenvironment. Canine visceral leishmaniasis is a multisystem disease that affects several organs, mainly the heart. The aimof this study was to verify the presence of amastigotes of Leishmania chagasi in myocardium of dogs naturally infectedby immunohistochemistry. In addition, to correlate the number of parasitized cells with the intensity of the inflammation,the macroscopic and microscopic lesions.Materials, Methods & Results: It were used 52 dogs positive for leishmaniasis diagnosed by clinical examination, IndirectImmunofluorescence (RIFI), ELISA and cytological analysis of popliteal lymph nodes. The positive animals were euthanized and submitted a necropsy. Following necropsy, the macroscopic analysis was done, and samples from the region ofthe cardiac apex were collected at the transition between the two ventricles. Fragments of heart tissues were fixed in 10%neutral formalin for histopathological and immunohistochemistry analysis. The inflammatory process of the myocardiumand lesions semi-quantitatively scored for myocardial injury on a scale of 0 to 3 (0) absent, (1) mild = small focal lesions,(2) moderate = larger, multifocal lesions and (3) severe = affecting most areas with coalescence. On immunostaining,the animal was classified according to the parasite load - (no microorganism), mild (1-100 microorganisms), moderate(101-300), intense parasitism (> 300). At the macroscopically analysis, 33 animals (63.46%) had at least one lesion. Theconcentric hypertrophy left ventricular was the most...(AU)