Diagnóstico coproparasitológico e histopatológico de infecção por Aelurostrongylus abstrusus em gatos domésticos de Araguaina Tocantins

Abstract

Aelurostrongylus abstrusus is a nematode of worldwide occurrence, which causes parasitic pneumonia in felines. Infection occurs by ingestion of gastropod molluscs, which are intermediate hosts, and the clinical presentation of the disease varies sub clinically to severe pneumonia, with risk of death. Thema in part of this study was to describe the frequency of A. abstrusus infection in a domestic cat (Felis silvestris catus) from Araguaína, Tocantins, by means of stool exam and histopathological examination, to compare diagnostic techniques and to analyze the morphological alterations observed in the lungs of parasitized cats. Samples of 62 cat lungs were histologically examined and stool exam al examinations of 210 animals were performed. For stool exam evaluation, the direct examination by smear was used; Faust's method and Baermann’s method. For microscopic analysis, histological slides of the lungs were made, coraofhematoxylin-eosin. From each slide, 30 fields were photographed in a 40-fold objective, which were analyzed in the Image J program, regarding the presence and quantity of evolutionary forms of the parasite and the tissue alterations were evaluated qualitatively and semi quantitatively. The observed frequency of A. abstrusus in cats evaluated by stool exam examinations was 8.1% (17/210) and 20.97% (13/62) was obtained by histopathological examination. The sensitivity and specificity of the histological technique was 100%, demonstrating perfect agreement in the result with the Baerman method (Kappa=)1, and the Faust method presented sensitivity of 88.2%, specificity of 99.5% and Kappa coefficient=0.9. The Direct Examination had low sensitivity (5.9%). Themost errant nimais were 5.5 times more likely to be infected by A. abstrusus (P<0.001), as well as cats that manifested sneezing as a respiratory clinical sign that presented a 5.77 times higher chance (P=0.005). Macroscopically there were focal or multifocal lesions, characterized as firm nodules, of color ranging from white to grayish yellow, of various sizes, In histopathology the presence of inflammatory infiltrate in areas affected by the presence of eggs, hypertrophy of thesmooth musculature of the ducts and alveolar septa, hypertrophy and hyperplasia of the musculature of the arteries and inflammatory infiltrates eosinophilic and lymphocytic were the most observed changes in cats positive for A. Abstrusus. The comparison of histopathological findings between positive and negative animals showed that positive animals presented significantly higher organ alteration index (Iorg)(P<0.001), demonstrating greater pulmonary involvement in cats parasitized by A. abstrusus.