Alterações clínicas e cardíacas em cães sintomáticos com leishmaniose visceral na cidade de Montes Claros, Minas Gerais, Brasil

Abstract

Infections caused by Leishmania spp. represent one of the major causes of public health problems in the world related to the protozoan community. Dogs and humans are the individuals most frequently infected by visceral leishmaniasis agents, which correspond to the most severe form of the disease. However, little is known about the cardiac alterations associated with this protozoonosis. In this study, the objective was to identify cardiac alterations in symptomatic dogs with naturally infected visceral leishmaniasis. Twenty adult male dogs, symptomatic and positive for visceral leishmaniasis, were selected through clinical examination and ELISA test. Among the clinical signs, there was a higher occurrence of skin lesions, splenomegaly and peripheral lymphadenopathy. After sedation and anesthesia, evaluating cardiac electrophysiology, followed by measurement of blood pressure. Blood was collected in a vial with EDTA for measurement of the MB collection of creatine phosphokinase (CK-MB). the animals were subsequently euthanized. Then, a segment of the heart muscle of the right ventricle and the complete removal of the mitral valve were collected for histopathological evaluation. Slides, in duplicate, were prepared, one silanized stained by picrosirius, for analysis of the presence of collagen fibers, and another in a conventional slide, stained with HE for the study of cellular and proliferative alterations and research of amastigotes of Leishmania infantum. When evaluating the electrocardiograms, the QT segment had an average duration above the maximum physiological limit and the R wave had an amplitude greater than the normality indices for all evaluated animals. Eleven dogs (55%) had systemic blood pressure above the expected mean. The CK-MB dosage was high in all of them. Eighty percent (16/20) of the dogs showed cardiac alterations on histopathological examination. In stained with HE, lipid infiltrate or isolated associated with inflammatory infiltrates and necrosis of the contraction band were the most frequently detected lesions (80%), followed by necrosis of the contraction band, alone or associated with other lesions in 66.66% of the sections of the animals. Amastigotes were identified in the cardiac tissues of two animals. Under the colors picrosirius tolerated increased collagen fiber in 95% of dogs. Nine of the animals had nodules on the mitral valve and of these, in eight, valvulopathy was confirmed by histolopathology, with valve fibrosis and adipose metaplasia being the most frequent. Therefore, in this study, canine visceral leishmaniasis probably triggered cardiac alterations.