Causas de mortes em gatos no sul do Brasil

Abstract

A intensificação da criação de felinos em todo o mundo demandam uma ampliação e aprofundamento dos conhecimentos da clínica e patologia de doenças infecciosas que acometem os gatos. Entretanto, existe uma escassez de informações sobre doenças infecciosas que acometem os gatos do Brasil, especialmente da região sul. Esta tese de doutorado teve como objetivo realizar um levantamento das principais causas de morte em gatos, além da caracterização anatomopatológica e identificação de agentes infecciosos em tecidos e células de gatos através da técnica de imuno-histoquímica (IHQ) e imunocitoquímica (ICQ). O primeiro artigo teve como objetivo determinar as principais causas de morte em gatos na região Sul do Brasil, através de um estudo retrospectivo, de 2000 a 2015. Foram realizadas um total de 1753 necropsias de felinos domésticos, destas 1364 (77,8%) foram conclusivas e 389 foram inconclusivos (22,2%). As categorias mais prevalentes foram: neoplasmas (20%), doenças infecciosas/parasitárias (17,8%), doenças do sistema digestório (14,1%), traumatismos (13,4%), doenças do sistema urinário (11,4%), doenças do sistema cardiovascular (6,9%), doenças do sistema respiratório (5,8%) e outras (8,5%). As causas de morte mais frequentes incluíram: politraumatismo (13,4%), linfoma (8,8%) e peritonite infecciosa felina (7,9%). O segundo artigo teve como objetivo fazer a identificação por ICQ dos antígenos do coronavírus felino (FCoV) em macrófagos e monócitos fixados em formol e embebidos em parafina a partir de derrame e sangue como alternativa diagnóstica ante mortem da peritonite infecciosa felina. Foram selecionados para o estudo gatos com pelo menos um dos seguintes sinais clínicos: derrame em cavidades abdominal e/ou torácica e/ou pericárdica, temperatura retal acima de 40oC, icterícia, linfoadenomegalia, e sinais clínicos oftálmicos e neurológicos. Foram recebidas 25 amostras provenientes de derrames. Dessas, 16 tiveram marcação positiva no interior de macrófagos. Nove desses casos, foram confirmados pela necropsia. De 17 amostras de sangue total, 3 amostras tiveram marcação positiva no interior de monócitos; dois desses casos foram confirmadas na necropsia. O teste de ICQ anti-FCoV foi sensível e específico como método diagnóstico ante mortem da PIF. O terceiro artigo teve como objetivo descrever cinco casos de gatos apresentando cardiomiopatia hipertrófica e miocardite associadas ao vírus da imunodeficiência felina (FIV). Na necropsia, os cinco gatos apresentaram o coração acentuadamente aumentado de tamanho, por hipertrofia ventricular esquerda, e múltiplos focos brancacentos coalescentes no miocárdio e no epicárdico. Microscopicamente, no miocárdio, havia infiltrado multifocal acentuado composto por linfócitos, alguns macrófagos, neutrófilos e plasmócitos. Na IHQ para FIV houve intensa imunomarcação no citoplasma e no núcleo, principalmente de linfócitos e no citoplasma de ocasionais macrófagos no miocárdio. O infiltrado inflamatório caracterizou-se por linfócitos T e macrófagos, o que foi evidenciado por imunomarcação específica para essas células. Este trabalho demonstra a importância das doenças infecciosas/parasitárias, consideradas como causa de morte em gatos, demonstra a utilidade da técnica técnica ocorrência de infecção pelo do vírus da imunodeficiência felina em células inflamatórias no miocárdio de gatos com miocardite e cardiomiopatia hipertrófica.

The increase of cat breeding worldwide demands an expansion in qualified information on clinic clinical and pathological aspects of feline infectious diseases. There is, however, a lack of information on the infectious diseases that affect cats in Brazil, especially in the Southern region. This doctoral thesis aimed to survey of the main causes of death caused in cats, as well as the anatomopathological characterization of tissue response and identification of infectious agents in the tissues and cells through immunohistochemistry (IHC) and immunocytochemistry (ICH). Three articles were written. The first one aimed to determine the main causes of death in cats in southern Brazil, through a retrospective study, from 2000 to 2015. A total of 1,753 domestic feline necropsies were reviewed, from which 1,364 (77.8%) had a conclusive diagnosis and 389 were inconclusive (22.2%). The most prevalent categories were neoplasms (20%), infectious/parasitic diseases (17.8%), diseases of the digestive system (14.1%), traumatisms (13.4%), diseases of the urinary system (6.9%), diseases of the respiratory system (5.8%) and others (8.5%). The most frequent causes of death included multiple trauma (13.4%), lymphoma (8.8%) and feline infectious peritonitis (7.9%). lymphoma (8.8%) and feline infectious peritonitis (7.9%). The second article aimed to tests and alternative antemortem diagnostic method to identified cats with feline infectious peritonitis feline coronavirus (FCoV) antigens; the method consists of applying ICH to macrophages and monocytes sampled from effusion and blood, fixed in formalin and embedded in paraffin. Cats with at least one of the following clinical signs were selected for being tested: cavitary (abdominal and/or thoracic and/or pericardial) effusion, rectal temperature above 40 ° C, jaundice, enlargement of lymph nodes, clinical ophthalmic and neurological signs. Twenty-five samples from effusions were received, of which 16 had positive marking within macrophages, 9 of which were confirmed by necropsy examination. Seventeen samples consisted of whole blood, from these, 3 samples had positive staining within monocytes and two cases were confirmed by postmortem examination. The anti-FCoV ICQ test was sensitive and specific as a PIF antemortem diagnostic method. The second article aimed to identify by ICQ the feline coronavirus (FCoV) antigens in macrophages and monocytes fixed in formalin and embedded in paraffin from effusion and blood as a diagnostic alternative antemortem of feline infectious peritonitis. Cats with at least one of the following clinical signs were selected: cavitary (abdominal and/or thoracic and/or pericardial) effusion, rectal temperature above 40°C, jaundice, enlargement of lymph nodes, clinical ophthalmic and neurological signs. Twenty-five samples from effusions were received, of which 16 had positive marking inside macrophages, 9 of which were confirmed by necropsy examination. 17 samples were also received from whole blood, these 3 samples had positive staining within monocytes and in 2 cases confirmed by postmortem examination. The anti-FCoV ICQ test was sensitive and specific as a PIF antemortem diagnostic method. The third article aimed to describe five cases of cats presenting hypertrophic cardiomyopathy and myocarditis associated with feline immunodeficiency virus (FIV). At necropsy, the five cats presented a markedly enlarged heart, marked left ventricular hypertrophy, multiple myocardial and epicardial whitening foci. Microscopically, in the myocardium, there was marked multifocal infiltrate composed of lymphocytes, macrophages, neutrophils and plasma cells. In the IHC for FIV there was intense immunostaining in the cytoplasm and nucleus, mainly of lymphocytes and occasional macrophages cytoplasm in the myocardium. The inflammatory infiltrate was predominantly composed of T lymphocytes and macrophages, evidenced by immunostaining. This work demonstrates the importance of 8 infectious/parasitic diseases, as the cause of death in cats, demonstrate the use of the IHC technique as an alternative antemortem diagnostic tool for FIP and the occurrence of feline immunodeficiency virus infection in inflammatory cells in the myocardium of cats with myocarditis and hypertrophic cardiomyopathy.