Piroplasmídeos em canídeos e procionídeos

Parasitos da ordem Piroplasmorida causam doenças em animais silvestres e de companhia. Devido a isso, nessa tese estão incluídos três artigos científicos acerca do tema, com destaque para a espécie Rangelia vitalii e para espécies do gênero Babesia. O primeiro trabalho teve por objetivo relatar detecção molecular de parasitismo por R. vitalii em uma população uruguaia de Cerdocyon thous. Amostras de sangue e/ou baço de C. thous e Lycalopex gymnocercus encontrados atropelados nas principais vias do Uruguai foram submetidos à Reação em Cadeir de Polimerase (PCR) amplificando um gragmento de 551 pb do gene rRNA 18S para R. vitalii. Foram analisados 62 canídeos, sendo 38 C. thous e 24 L. gymnocercus. Cinco C. thous (13,16%) foram positivos para R. vitalii, com 99,5% a 100% de similaridade entre cada sequência, e nenhum dos L. gymnocercus amostrados foram positivos. Quando comparadas às amostras de R.vitalii disponíveis no GenBank, uma similaridade de 98,9% a 100% foi revelada. Os resultados da análise molecular sugerem que R. vitalii está circulando na população de raposas comedoras de caranguejo no Uruguai; no entanto, sua relevância veterinária para essas raposas permanece desconhecida. O segundo estudo objetivou detectar e quantificar a carga parasitária de R. vitalii em diferentes orgãos de canídeos domésticos e silvestres a fim de elucidar as distintas apresentações da infecção nestas espécies. Fragmentos de 22 órgãos coletados de cães domésticos (n=7) e silvestres (n=8) foram utilizados para quantificação histológica e molecular, através de PCR em tempo real do gene hsp70. Na histologia os vacúolos parasitóforos foram detectados nos tecidos de todos os cães que morreram com rangeliose, e em somente dois C. thous. A carga parasitária foi significativamente maior em cães domésticos nos tecidos do sistema digestivo, cardiorrespiratório, endócrino, genitourinário e músculo esquelético. No sistema hematopoiético, C. thous apresentou carga parasitária significativamente menor em linfonodos e tonsilas do que cães, enquanto no baço, medula óssea e sangue as detecções foram similares. No sistema nervoso central a detecção foi semelhante. Tanto em cães como em C. thous, o agente possivelmente se mantém de forma assexuada (merogonia). No entanto, C. thous provavelmente desenvolva uma fase esquizogônica limitada e/ou de curta duração, o que conferiria ao mesmo o possível caráter de reservatório do agente, em contrapartida com o cão, um provável hospedeiro acidental. O terceiro artigo é sobre espécies do gênero Babesia em procionídeos, e tem como objetivo de detectar e caracterizar filogeneticamente o parasitismo por piroplasmídeos em P. cancrivorus de vida-livre do Sul do Brasil. Amostras de baço e/ou pool de órgãos de quatro P. cancrivorus atropelados em estradas do sul do Brasil (#1 a #4), além de uma amostra de sangue de P. cancrivorus de vida livre (#5), foram submetidas a PCR para os genes 18S rRNA, hsp70 e cox1. Paralelamente à coleta de sangue, foi realizado esfregaço sanguíneo de ponta de orelha e cauda para análise citológica em busca de hemoparasitos. Duas amostras de P. cancrivorus foram positivas para o gene 18S rRNA, e uma dessas amostras foi positiva, também, para os genes hsp70 e cox1. À análise filogenética, uma dessas apresentou alta similariadade (99,75%) com Babesia sp. obtida em P. cancrivorus do Uruguai, pertencente ao clado das Babesia sensu stricto, enquanto a outra amostra se enquadrou no clado I, do grupo de Babesia microti-like, agrupando-se monofileticamente com as sequências de B. microti isoladas de Procyon lotor. Pelo conhecimento dos autores, essa é a primeira detecção de parasitismo por Babesia sp. em P. cancrivorus no Brasil; no entanto, análises filogenética mais amplas são necessárias em relação a B.microti- like a fim de elucidado se a espécie pertence a um genótipo zoonótico.Piroplasmida parasites cause a wide range of diseases in wild and domestic animals. The thesis presented herein includes three scientific papers regarding this subject, with an emphasis on Rangelia vitalii and Babesia sp. The first manuscripts aimed to detect R. vitalii parasitism in the Uruguayan wild fox population. DNA extracted from the blood and/or spleen samples of road-killed C. thous and L. gymnocercus found in northern Uruguay were subjected to polymerase chain reaction (PCR) to amplify a 551-bp fragment of the Rangelia 18S rRNA gene. A total of 62 wild canids, including 38 C. thous and 24 L. gymnocercus, were analyzed. Five crab-eating fox samples (13.2%) were positive for R. vitalii, with 99.5–100% identity between the sequences. All samples from pampas fox tested negative for R. vitalii. When compared with the R. vitalii sequences available in GenBank, a similarity of 98.9– 100% was revealed. Molecular analysis results suggest that R. vitalii is circulating in the crabeating fox population in Uruguay; however, its veterinary relevance for these foxes remains unknown.The second study aimed to detect and quantify the parasitic load of R. vitalii in different organs of domestic and wild canids in order to elucidate differences in clinical and pathological presentations of rangeliosis in these species. Fragments of 22 organs were collected from domestic (n = 7) and wild (n = 8) canids and later used for histological and molecular quantification, which was performed through real-time hsp70 PCR. Histologically, parasitophorous vacuoles were detected in tissues of all dogs that died due to rangeliosis, and only in two Cerdocyon thous. The parasitic load was significantly higher in domestic dogs in tissues of the digestive, cardiorespiratory, endocrine, genitourinary systems, and skeletal muscle. Regarding the hematopoietic system, C. thous had a significantly lower parasitic load in the lymph nodes and tonsils compared to dogs, while in the spleen, bone marrow, and blood the parasitic load was similar, as in the central nervous system. In domestic and wild canids (C. thous), the agent possibly maintains a prolonged asexual phase (merogony), but it probably develops a limited and/or short schizogonic phase in the C. thous, which would characterize the host as a reservoir, in contrast to the dog, a probable accidental host. In the third investigation, aimed to detect and phylogenetically characterize the parasitism by piroplasmids in free-living P. cancrivorus from Southern Brazil. Samples of spleen and/or organ pool of four P. cancrivorus killed by motor vehicle collision on highways of Rio Grande do Sul state, Southern Brazil (# 1 to # 4), in addition to a blood sample of free-living P. cancrivorus (# 5), were subjected to PCR for the 18S rRNA, hsp70 and cox1 genes. During clinical evaluation of P. cancrivorus #5, a sample of peripheral blood (tip of the ear and tail) was collected and a blood smear was made for cytological analysis in search of hemoparasites. Two samples of P. cancrivorus were positive for the 18S rRNA gene, and one of these samples was also positive for the hsp70 and cox1 genes. On phylogenetic analysis, one of these showed high similarity (99.75%) with Babesia sp. obtained previously from P. cancrivorus in Uruguay, belonging to the Babesia sensu stricto clade, while the other sample fell into clade I, Babesia microti –like group, grouping monophyletically with the B. microti sequences isolated from Procyon lotor. To the knowledge of the authors, this is the first detection of parasitism by Babesia sp. in P. cancrivorus in Brazil; however, more wide phylogenetic analyses are necessary for B. microti-like, in order to elucidate whether the species belongs to a zoonotic genotype

Aspectos anatomopatológicos e o uso da imuno-histoquímica em suínos abatidos com lesões cutâneas de erisipela

Swine erysipelas is a disease of worldwide distribution, responsible for causing economic losses in swine and considered an occupational zoonotic disease. It is estimated that 30% to 50% of pigs are carriers and stress can predispose the appearance of clinical disease. The diagnosis of erysipelas in slaughter pigs becomes a challenge for pathologists, since scalding and dehairing, routine procedures in slaughterhouses, generate histological artifacts that often make the final diagnosis impossible. This study describes the anatomopathological aspects and evaluate the use of immunohistochemistry as a diagnostic tool in these cases. Forty-three cases of erysipelas in slaughter pigs were analyzed. Grossly, the cutaneous lesions were characteristic pink, red, or purple raised rhomboid, rectangular or square lesions (“diamond skin”). Histologically, in the dermis and subcutaneous tissue, there were suppurative vasculitis, hidradenitis and folliculitis, as well as degeneration and necrosis of the vessel wall, thrombosis and multifocal areas of necrosis. Suppurative vasculitis and damage to the blood vessel wall were observed in all cases, with varying degrees of severity. The immunohistochemical technique proved to be an effective complementary method of diagnosis, with positive immunostaining in 93%. In most cases, we observed mild immunostaining (57.5%), moderate in 22.5% and marked in 20%.A erisipela suína é uma doença de distribuição mundial, responsável por causar prejuízos econômicos na suinocultura, além de ser uma doença zoonótica com caráter ocupacional. Estima-se que 30%-50% dos suínos sejam portadores e fatores estressantes podem predispor o aparecimento da doença clínica. O diagnóstico de erisipela em suínos de abate torna-se um desafio aos patologistas, uma vez que os processos de escaldagem e depila, rotineiros em abatedouros frigoríficos, geram artefatos histológicos que muitas vezes impossibilitam o diagnóstico final. Este trabalho descreve os aspectos anatomopatológicos e avalia o uso da imuno-histoquímica como uma ferramenta diagnóstica nestes casos. Foram analisados fragmentos de pele de 43 casos de erisipela em suínos de abate. Macroscopicamente, eram múltiplas lesões cutâneas romboides, retangulares ou quadradas rosa, vermelho ou roxo característicos (“pele de diamante”). Histologicamente, na derme e subcutâneo, havia vasculite, hidradenite e foliculite supurativas, bem como degeneração e necrose da parede de vasos, trombose e áreas de necrose multifocais. A vasculite supurativa e a lesão na parede de vasos sanguíneos foram observadas em todos os casos, em diferentes graus de severidade. A técnica imuno-histoquímica se mostrou um eficaz método complementar de diagnóstico, com imunomarcação positiva em 93%. Na maior parte dos casos observamos marcação discreta (57,5%), moderada em 22,5% e acentuada em 20%

Pet pyometra : correlating bacteria pathogenicity to endometrial histological changes

Pyometra is a life-threatening infectious disease that frequently affects bitches and queens. Although histopathological patterns of pyometra have been extensively explored, the microbiological aspects, such as bacteria pathogenicity, have not been correlated to microscopy endometrial lesions so far. In this study, these two pathological aspects of pyometra were analysed and correlated. Uterus fragments and intrauterine content samples were collected from pets diagnosed with pyometra (30) and submitted to histopathology analysis and bacterial culture, respectively. The degree of endometrial histopathological lesions in pyometra cases were classified as mild, moderate and severe. Thirty different bacteria isolates were identified from intrauterine content culture. Escherichia coli(E. coli) was pure isolated in 57.7% and highly related to severe endometrial lesions. Immunohistochemistry assay revealed the adhesion and invasion of this bacteria agent to the injured endometrium. Virulence aspects of these E. coli strains were explored, demonstrating biofilm formation ability and a set of virulence genes in most isolates. These results support the adaptive genetic and phenotypic advantages of E. coli for uterus infection, and justify the high frequency of this agent involved in pyometra cases

Colesteatoma e hidrocefalia associados a meningioma em terceiro ventrículo em um gato

Meningiomas are neoplasms that commonly involve the central nervous system of cats, while cholesteatomas are nodular granulomatous chronic lesions within the choroid plexus that are rarely reported in cats. This study described a case of cholesteatoma and non-communicating hydrocephalus associated to a third ventricle meningioma in a cat. Clinically, the cat had a 2-year history of behavioral changes, photophobia and motor incoordination. At the necropsy, a tan-brown mass totally occluded the third ventricle, causing a severe dilation of the lateral ventricles (non-communicating hydrocephalus). Microscopically, the mass was composed by a neoplastic proliferation of spindle cells arranged in bundles, containing in the center psammomatous bodies (meningioma), while in the adjacent areas a cholesteatoma was observed, which was characterized by multiple cholesterol cleft formation, hemosiderosis and associated granulomatous inflammation. At immunohistochemistry (IHC), neoplastic cells had a marked immunostaining for vimentin, while were negative for cytokeratin and S100. The diagnosis of transitional meningioma occurring in association to cholesteatoma and non-communicating hydrocephalus in a cat was obtained mainly by the histological and IHC features. These are important methods to distinguish this condition from other neurological disorders in cats.Meningiomas são neoplasias que comumente envolvem o sistema nervoso central de gatos, enquanto colesteatomas são formações nodulares granulomatosas raramente descritas nessa espécie e que resultam de lesões crônicas em plexo coroide. O objetivo desse trabalho é descrever um caso de meningioma em terceiro ventrículo culminando com a formação de colesteatoma e hidrocefalia não comunicante em um gato. Clinicamente, o gato apresentava alteração de comportamento, fotofobia e incoordenação motora durante dois anos. À necropsia apresentava uma massa acastanhada no terceiro ventrículo que provocava oclusão total do mesmo e acentuada dilatação de ventrículos laterais (hidrocefalia não comunicante). Microscopicamente, havia proliferação neoplásica de células fusiformes arranjadas em feixes com a formação de corpos psamomatosos (meningioma), e em área adjacente havia múltiplas fendas de colesterol e hemossiderose com infiltrado granulomatoso (colesteatoma). À imuno-histoquímica (IHQ), foi observada marcação positiva para vimentina e negativa para citoqueratina e S100 nas células neoplásicas. Os exames histológicos e de IHQ contribuíram para a confirmação do diagnóstico de meningioma transicional associado à formação de colesteatoma e hidrocefalia não comunicante, e são métodos importantes para diferenciar de outras afecções que cursam com quadro clínico neurológico em felinos

Neoplasmas gastrointestinais primários não linfoides em cães no Rio Grande do Sul

Gastrointestinal neoplasms (GIN) are uncommon in dogs, but they mainly show malignant behavior and poor prognosis. The types of GIN in dogs and their frequency, as well as their epidemiological and histopathological characteristics were analyzed through a retrospective study of biopsies from 24.711 dogs from 2005 to 2017. Additionally, histological sections of neoplasms were subjected to immunohistochemistry (IHC) using antibodies against pancytokeratin, vimentin, smooth muscle actin, c-Kit, S-100, CD31, CD79αcy, and neuron specific enolase. Of the total samples from dogs analyzed, 88 corresponded to GIN. Neoplasms occurred more frequently in purebred dogs (64.8%, 57/88), males (53.4%, 47/88), with a median age of 10 years. The intestine was affected by 84.1% (74/88) of the cases. Of these, the large intestine was the most affected (67.6%, 50/74). Most of the neoplasms had malignant behavior (88.6%, 78/88). Regarding the classification of neoplasms, 46.6% (41/88) of the diagnoses corresponded to epithelial, 46.6% (41/88) were mesenchymal, 5.7% (5/88) were hematopoietic, and 1.1% (1/88) was neuroendocrine. The most frequently diagnosed neoplasms were papillary adenocarcinoma (19.3%, 17/88), leiomyosarcoma (17.0%, 15/88), gastrointestinal stromal tumors (GISTs) (12.5%, 11/88), and leiomyoma (5.0%, 8/88). Adenocarcinomas were located mainly in the rectum, whereas leiomyosarcomas and GISTs developed mainly in the cecum. Epithelial neoplasms showed a greater potential for lymphatic invasion whereas mesenchymal neoplasms appeared to be more expansive with intratumoral necrosis and hemorrhage. Immunohistochemistry was found to be an important diagnostic technique for the identification of infiltrating cells in carcinomas and an indispensable technique for the definitive diagnosis of sarcomas.Neoplasmas gastrointestinais (NGI) são pouco comuns em cães, mas possuem principalmente comportamento maligno e prognóstico reservado. Os tipos de NGI em cães e sua frequência, bem como características epidemiológicas e histopatológicas foram analisados por meio de um estudo retrospectivo dos exames de biópsias de 24.711 cães entre os anos de 2005 a 2017. Adicionalmente, cortes histológicos de NGI foram submetidos à técnica de imuno-histoquímica (IHQ), utilizando os anticorpos anti-pancitoqueratina, vimentina, actina de músculo liso, c-Kit, S-100, CD31, CD79αcy e enolase neurônio específica. Do total de cães analisados, 88 corresponderam a NGI não linfoides. Os neoplasmas ocorreram com maior frequência em cães de raça pura (64,8%, 57/88), machos (53,4%, 47/88), com mediana de idade de 10 anos. O intestino foi acometido em 84,1% dos casos (74/88). Destes, o intestino grosso foi o segmento mais afetado (67,6%, 50/74). A maior parte dos neoplasmas tinha comportamento maligno (88,6%, 78/88). Quanto à classificação, 46,6% (41/88) dos diagnósticos corresponderam a neoplasmas epiteliais, 46,6% (41/88) mesenquimais, 5,7% (5/88) hematopoiéticos e 1,1% (1/88), neuroendócrino. Os neoplasmas mais frequentemente diagnosticados foram adenocarcinoma papilar (19,3%, 17/88), leiomiossarcoma (17,0%, 15/88), tumor estromal gastrointestinal (GIST) (12,5%, 11/88) e leiomioma (12,5%, 8/88). Adenocarcinomas localizavam-se principalmente no reto, enquanto leiomiossarcoma e GISTs desenvolveram-se principalmente no ceco. Os neoplasmas epiteliais demonstraram um potencial maior de invasão linfática enquanto que os mesenquimais aparentaram ser mais expansivos, com necrose e hemorragia intratumorais. A imuno-histoquímica mostrou ser uma técnica diagnóstica importante para a identificação de células neoplásicas infiltravas no caso dos carcinomas e uma técnica indispensável para o diagnóstico definitivo de sarcomas

Emphysematous and Granulomatous Submucosal Rumenitis in a Feedlot Nellore Steer.

Background: Emphysematous rumenitis is a condition characterized by gas filled bubbles or cysts in the ruminal mucosa. Although a similar pathology is reported from swine and humans, the incidence of this disease in cattle seems to be scarce. The etiology of emphysematous rumenitis is uncertain once many factors can be involved in its pathogeny, a single cause is difficult to ascertain. This lesion usually fails to display specific clinical signs; however, some degree of malabsorption and weight loss is expected. We described a case of emphysematous granulomatous submucosal rumenitis in a 2.5-yearold feedlot Nellore steer that presented reduction on daily weight gain.Case: Rumen fragments of a 2.5-year-old Nellore steer were submitted for histopathological evaluation at the Sector of Pathological Anatomy (SAP) of the Rural Federal University of Rio de Janeiro, Brazil. The specimens were part of an experimental trial to evaluate the effect of phosphorus (P) supplementation on nutrient intake, performance and P balance in fifty feedlot Nellore steers. Following a short adaptation period, in which behavioral observations were made twice daily to assess possible adverse factors, all steers were fed with balanced diet for one hundred and sixteen days. The steers were then slaughtered in order to evaluate macroscopic changes in the gastrointestinal system. Rumen and abomasum of each steer was emptied, washed with tap water and grossly examined. One steer presented ruminal lesion, while the other forty-nine did not show any ruminal injury. Throughout the experiment the affected steer showed reduction of daily weight gain; but during clinical examination no additional clinical sign was seen. At gross inspection, a reduction in the amount of muscular and adipose tissue was seen. Multiple coalescent bullous elevated structures measuring three to ten mm diameter were covering about 40% of the ruminal surface. The affected ruminal mucosa showed irregular and atrophic papillae. Rumen samples were processed routinely and stained with Hematoxylin and Eosin, Period Acid Schiff (PAS), Grocott’s Methenamine Silver (GMS), Ziehl-Neelsen (ZN), Brown-Hopps (Gram), Giemsa and Toluidine Blue (TB) stains. Additionally formalin-fixed, paraffin wax-embedded sections were stained with a primary polyclonal rabbit antibody for Escherichia coli. Histologically the submucosa was largely replaced by cyst-like enlarged lymphatic vessels filled with gaseous content and the ruminal submucosa was infiltrated by macrophages, multinucleated giant cells, eosinophils, lymphocytes and plasma cells. Special stains were negative for granules within the mast cells, fungi, acid-fast bacilli, bacteria and protozoa. E. coli was immuno-labeled only at the ruminal epithelial surface.Discussion: This paper provided a description of a rare and possible underdiagnosed condition in cattle to highlight the necessity of recognizing ruminal changes during slaughterhouse inspection. The spontaneous and extensive emphysematous rumenitis described in this paper showed histological similarities with the analogous condition documented in the small and large intestine, mesentery and mesenteric lymph node of swine. The etiology and pathogenesis of emphysematous submucosal rumenitis remain unknown. We believe that the lesion described was the reason for the decrease of weight gain of the steer; therefore it should be considered as a differential diagnosis for conditions that affect weight gain and performance of cattle.Keywords: cattle, veterinary pathology, feedlot, emphysema, rumen

Neoplasmas hepáticos primários de bovinos

Primary hepatic neoplasms are mostly detected in cattle as incidental findings in slaughterhouses or diagnosed at the necropsy, wherein it may be related to the cause of death. A proper characterization of primary hepatic neoplasms is essential to provide an accurate diagnosis, especially at the slaughter lines, in order to reduce erroneous condemnations. This work aimed to characterize the gross, histological, and immunohistochemical features of primary liver neoplasms detected in slaughtered cattle in Southern Brazil. Nineteen primary hepatic neoplasms were identified. Grossly, these lesions were classified according to their distribution, as focal, multifocal, or diffuse. Histologically, the shape and arrangement of the cells, as well as possible malignant features were evaluated. Immunohistochemistry (IHC) was also performed for biliary epithelium (anti-CK7) and hepatocytes (anti-Hep Par-1) markers. Hepatocellular carcinoma (84.2%) was the most frequently detected hepatic neoplasm, followed by cholangiocarcinoma (15.8%), and these were only identified in adult cows. Hepatocellular carcinomas occurred as solitary masses or multifocal nodules, which on the cut surface were often green. Cholangiocarcinomas occurred as multifocal nodules, occasionally showing an umbilicated appearance. Histologically, hepatocellular carcinomas had mostly trabecular and solid patterns, while cholangiocarcinomas presented mostly a solid arrangement. Upon IHC, all hepatocellular carcinomas were immunolabeled for anti-Hep Par-1, ranging from mild (25%), moderate (31.2%) to marked (43.7%), while immunolabeling for anti-CK7 was detected only in one case of cholangiocarcinoma.Os neoplasmas hepáticos primários são detectados em bovinos principalmente como achados incidentais em matadouros ou diagnosticados na necropsia, quando podem estar relacionados à causa da morte. A caracterização adequada dos tumores hepáticos primários é essencial para obter diagnósticos precisos, especialmente nas linhas de abate, com o propósito de reduzir condenações errôneas. Este trabalho teve o objetivo de determinar as características macroscópicas, histológicas e imuno-histoquímicas dos neoplasmas primários do fígado de bovinos abatidos em um matadouro-frigorífico no Sul do Brasil. Dezenove neoplasias hepáticas primárias foram identificadas. Macroscopicamente, os tumores hepáticos foram classificados de acordo com sua distribuição, como focais, multifocais ou difusos. Histologicamente, a forma e o arranjo das células e possíveis características malignas foram avaliados. Também foi realizada imuno-histoquímica (IHQ) para marcadores de epitélio biliar (anti-CK7) e hepatócitos (anti-Hep Par-1). O carcinoma hepatocelular (84,2%) foi o neoplasma hepático mais frequentemente detectado, seguido pelo colangiocarcinoma (15,8%). Esses tumores foram identificados apenas em vacas adultas. Os carcinomas hepatocelulares eram vistos como massas solitárias ou nódulos multifocais que na superfície de corte geralmente eram esverdeados. Os colangiocarcinomas foram observados como nódulos multifocais, ocasionalmente com aspecto umbilicado. Histologicamente, os padrões mais observados nos carcinomas hepatocelulares foram trabeculares e sólidos, enquanto nos colangiocarcinomas o arranjo sólido foi o mais frequente. Na IHQ, todos os carcinomas hepatocelulares foram marcados por anti-Hep Par-1, com marcação que variou de leve (25%), moderada (31,2%) a acentuada (43,7%); imunomarcação para anti-CK7 foi detectada em apenas um caso de colangiocarcinoma

Nocardiosis in Cats - Clinical, Anatomopathological and Morphotintorial Characteristics

Background: Nocardiosis is an infectious bacterial disease that can cause cutaneous/ subcutaneous, pulmonary and systemic lesions in different species of domestic animals. The type of transmission occurs through mechanical lesions on the skin or contamination of wounds, in cases of skin involvement, inhalation of aerosols and ingestion of contaminated materials are involved in the pathogenesis of the respiratory and digestive form of the disease. This paper described 4 cases of nocardiosis in cats, addressing the clinical, anatomopathological and morphotintorial characteristics of Nocardia sp.Cases: Four cases of nocardiosis in cats were reviewed, in which data related to breed, sex, age, origin, clinical signs, macroscopic and histological lesions described in necropsy protocols were evaluated. The histological tissue sections stained with Hematoxylin and Eosin (HE) were evaluated in order to characterize the inflammatory response in each case. In addition, paraffin blocks of fragments from affected organ were selected to perform special histochemical staining techniques of Grocott Methenamine Silver (GMS), modified Ziehl-Neelsen, Gram Brown-Brenn and Giemsa stain which are the most characterized techniques used for histopathological diagnoses and it was also used an immunohistochemical test with polyclonal antibody anti-Nocardia sp. (non-commercial). The animals were adults of both sexes, mixed breed, not castrated and semi-domesticated. Neither immunosuppressive factors nor concomitant diseases were identified in the cases studied. The main clinical signs were apathy, anorexia, dehydration, phlegmon and draining tracts. Macroscopically, skin / subcutaneous tissue (3/4), skeletal muscle (2/4), lymph nodes (2/4), liver (2/4), omentum (1/4), spleen (1/4) were affected. In addition, it could be noted that mandibular bone (1/4), pleural tissue (1/4), left testicle (1/4) and Central Nervous System (CNS) (1/4) were also affected by this disease. Microscopically, regarding all cases, there was a pyogranulomatous inflammation in the affected organs. With respect to cases 1, 3 and 4, filamentous, branched, slightly basophilic structures in loose or individual aggregates in the interior of the pseudo-rosettes and in the necrotic areas were observed in the HE-stained tissue sections. In all cases submitted to special histochemical techniques, filamentous, branched, individual or loose aggregate structures were observed, the samples were impregnated with silver, and bacteria appear as blue using the Brown-Brenn Gram technique, and stained red in the modified Ziehl-Neelsen, and stained faintly pink in Giemsa stain. The bacteria were observed mainly in the border of the pyogranulomas, in the center of the pseudo-rosettes and in the necrotic areas, being compatible with the infection by Nocardia sp. All cases were positive for immunohistochemistry (IHC).Discussion: Nocardiosis was diagnosed in all cats in this study based on the anatomopathological findings associated with the visualization of the agent and its morphotintorial characteristics by using special histochemical stains and being confirmed by IHC. It occurs mainly in the cutaneous and/or subcutaneous tissues, with systemic involvement and death of the affected animals, in addition to affecting bone tissue considered an uncommon site for the disease. The diagnosis can be established based on the anatomopathological findings associated with the morphotintorial characteristics by using special histochemical stains, which are important for evidencing and morphologically characterizing the agent, as well as being confirmed by IHC.Keywords: disease in cat, pyogranulomatous inflammation, Nocardia sp.Título: Nocardiose em gatos - achados clínicos, anatomopatológicos e morfotintoriais Descritores: doença de gato, inflamação piogranulomatosa, Nocardia sp.