Caracterização patológica da candidíase em animais

Abstract

Superficial or invasive candidiasis is the most common fungal disease in humans and is among the most diagnosed ones in animals. Despite this, there is a gap in the literature of systematic studies that approach the characteristics of this infection in animals and offer diagnostic alternatives in paraffinized tissues. Thus, this study aims to characterize 56 cases of candidiasis in domestic mammals and birds, from 32 years of diagnostic routine at the Laboratory of Veterinary Pathology (LPV) of the Federal University of Santa Maria (UFSM). The evaluation of these cases resulted in two scientific articles that are part of this Dissertation. The first article (Article 1) board 56 cases of candidiasis, where the main predisposing factors, macroscopic and histopathological changes were characterized. Of the 56 cases, the highest number of cases was in birds (23/56; 41.1%), followed by dogs (22/56; 39.3%), cats (4/56; 7.1%), swine (3/56; 5.4%), cattle (2/56; 3.6%) and sheep (2/56; 3.6%). Among the organic systems, the most affected ones were the alimentary (35/56; 62.5%) and integumentary systems (15/56; 26.8%). Candidiasis was observed associated mainly with viral diseases in dogs and cats. In birds, a large number of cases did not present concomitant diseases, so candidiasis was related to other predisposing factors. Macroscopically, it was evident that candidiasis is a difficult disease to recognize. Because, in most cases of all species, gross lesions were caused by concomitant diseases or were not specific to this infection. Histologically, it was possible to characterize and quantify the morphological forms (yeasts, pseudohyphae, and hyphae) associated with different morphological diagnoses. The second article (Article 2) is a case report of a disseminated Candida albicans infection in a cat. This case was approached separately because it is uncommon and there are few reports of this condition in felines. The animal has a clinical history of corticosteroids and antibiotic use. At necropsy, it was diagnosed with chronic pancreatitis, and was found extensive and sometimes nodular areas of yellowish, opaque, and friable material in organs of the abdominal and thoracic cavity. Histopathology showed necrosuppurative or pyogranulomatous inflammation associated with yeasts, pseudohyphae and hyphae in the omentum, intestinal serosa, kidney, liver, lung, heart and brain. In both articles, histochemical techniques such as periodic acid Schiff (PAS) and Grocott silver impregnation (GMS) were used for better visualization of the intralesional agent and in Article 1, these helped to quantify it. In addition, the use of the immunohistochemistry (IHQ) technique with an anti-Candida albicans monoclonal antibody to confirm the etiology was a highlight in the two scientific articles.