Pesq. Vet. Bras. 39(2):134-141, fevereiro 2019 DOI: 10.1590/1678-5150-PVB-5942 Original Article Small Animals Disease ISSN 0100-736X (Print) ISSN 1678-5150 (Online)
PVB-5942 SA Clinical and pathological aspects of idiopathic pulmonary fibrosis in cats1 Fernanda G. Cony2, Fernando F. Argenta2, Lilian C. Heck2, Leticia F. Moreira3, Fernanda V.A. Costa3, Luciana Sonne2 and Saulo P. Pavarini2*
ABSTRACT.- Cony F.G., Argenta F.F., Heck L.C., Moreira L.F., Costa F.V.A., Sonne L. & Pavarini S.P. 2019 Clinical and pathological aspects of idiopathic pulmonary fibrosis in cats. Pesquisa Veterinária Brasileira 39(2):134-141. Setor de Patologia Veterinária, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves 9090, Agronomia, Porto Alegre, RS 91540‑000, Brazil. E-mail: [email protected] Interstitial lung diseases are a group of diffuse parenchymal lung diseases that include
interstitialagents through lung bacteriologicalfibrosis. The aim and of mycologicalthis study is exams to characterize and immunohistochemistry. the clinical and pathological All three findingscats were of female idiopathic and pulmonary aged from fibrosis10 to 14 in years three old, cats they and presentedto investigate with possible a clinical etiological history
increased pulmonary radiopacity with a mixed bronchointerstitial pattern progressing to an of weight loss and dyspnea. The radiographic changes were similar in all cats and included
alveolarappearance pattern. on the Two pleural cats died surface; during they lung failed biopsy to completely procedures. collapse At necropsy, when the the lesions thorax were was limitedopened. to In the the pulmonary pleural region, parenchyma there were and multifocalwere firm, star-shapedhypocrepitant scarring with a multinodularlesions, with
type II pneumocyte hyperplasia, hypertrophy or hyperplasia of the smooth muscle tissue of parenchymal retraction. Microscopically, all three cats had multifocal-to-coalescing fibrosis, was no growth on bacteriological or mycological cultures, and the immunohistochemical terminalevaluations bronchioles for the presence and an accumulation of viral etiological of macrophages agents (FIV, within FeLV, the FCoV, alveolar FCV spaces. and FHV-1) There were also negative.
immunohistochemistry, type II pneumocytes, cats. INDEX TERMS: Clinics, pathology, idiopathic pulmonary fibrosis, interstitial lung disease, dyspnea,
RESUMO.- [Aspectos clínicos e patológicos em felinos de idade e histórico clínico de emagrecimento e dispneia. com fibrose pulmonar idiopática.] As enfermidades As alterações radiográficas observadas foram similares, com pulmonares intersticiais são um grupo de doenças difusas aumento de radiopacidade difuso dos campos pulmonares do parênquima pulmonar, nas quais a fibrose pulmonar de padrão misto broncointersticial e eventualmente está incluída. O objetivo deste trabalho é caracterizar alveolar. Dois felinos morreram durante procedimento de os achados clínicos e patológicos da fibrose pulmonar biópsia pulmonar. No exame de necropsia as lesões eram idiopática em três gatas, e avaliar possíveis agentes exclusivas no parênquima pulmonar os quais estavam firmes, etiológicos através dos exames bacteriológicos, micológicos e hipocreptantes, com aspecto levemente multinodular em imuno‑histoquímicos. As três gatas tinham entre 10 e 14 anos superfície pleural e não colapsaram após a abertura da 1 Received on September 4, 2018. cavidade torácica. Em região pleural havia lesões cicatriciais Accepted for publication on September 18, 2018. de aspecto estrelar multifocais, com retração do parênquima. 2 Setor de Patologia Veterinária, Faculdade de Veterinária, Universidade Microscopicamente, todos os gatos apresentaram fibrose Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9090, multifocal a coalescente, hiperplasia dos pneumócitos Agronomia, Porto Alegre, RS 91540-000, Brazil. *Corresponding author: do tipo II e hiperplasia e hipertrofia do músculo liso de [email protected] 3 Setor de Medicina Felina, Hospital de Clínicas Veterinárias, Universidade bronquíolos terminais e acúmulo de macrófagos no interior Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9090, de espaços alveolares. Não houve crescimento nas culturas Agronomia, Porto Alegre, RS 91540-000. bacteriana e micológica, e os exames de imuno-histoquímica
134 135
Clinical and pathological aspects of idiopathic pulmonary fibrosis in cats para avaliação de possíveis agentes virais (FIV, FeLV, FCoV, FCV e FHV-1) foram negativos em todos os felinos. andThe stained cats were with necropsied hematoxylin and and fragments eosin from(HE). various Additionally, organs werelung collected, fixed in 10% formalin, routinely processed for histology intersticiais, dispneia, imuno-histoquímica, pneumócitos tipo II, felinos. TERMOS DE INDEXAÇÃO: Clínica, patologia, doenças pulmonares to the protocol described by the Armed Forces Institute of Pathology (Mcfragments Elroy 1992).were stained Lung samples with Masson’s were kept trichrome refrigerated (MT), accordingand were INTRODUCTION submitted to bacteriological and mycological examinations. A sample Interstitial lung diseases compose a group of diffuse diseases forof lung 72 hours. was inoculated Lung samples in 5% were sheep seeded blood in Mueller Sabouraud Hinton glucose Agar agar and (Cushley et al. 1999). It is a common pulmonary disease in within MacConkey chloramphenicol Agar. The and sample cycloheximide was aerobically followed incubated by incubation at 37°C at humans,of the pulmonary and recently parenchyma it has beenthat include seen in pulmonary domestic fibrosisfelines (Selman et al. 2010). It is suggested that in humans, the onset IHC analysis was performed by the peroxidase-labeled antibody of the condition is related to continuous pulmonary injuries method26°C for (MACH seven 4,days. Universal HRP-Polymer, Biocare Medical) to evaluate the disease in felines is not yet well elucidated; however, the virus (FeLV), feline herpesvirus type 1 (FHV-1), feline calicivirus microscopicassociated with characteristics a genetic predisposition. of type II pneumocytes The pathogenesis seen inof (FCV),lung sections feline coronavirus for feline immunodeficiency (FCoV), vimentin, virus pancytokeratin, (FIV), feline leukemia smooth cats with the condition are similar to the form of this disease muscle actin and lysozyme. IHC was also performed on bone marrow sections for to evaluate them for the presence of FIV and FeLV. shows the immunohistochemical antibodies and protocols yearsin humans old, and (Thomas there is et no al. sex 2002). or breed predilection (Evola et al. used. IHC positive controls included samples of skin (smooth muscle The disease affects adult cats that are an average of eight actin,Table vimentin1 and pancytokeratin) and previously tissues for FIV, treatment, the condition has an unfavorable prognosis, and FeLV, FHV-1, FCV, FCoV and lysozyme (Rolim et al. 2016). Negative 2014). Due to the progressive nature and thepost absence mortem of specific based controls consisted of tissue samples incubated with phosphate buffered saline (PBS) instead of primary antibody. ofthe this definitive study is diagnosis to characterize is usually the made clinical and pathological on anatomopathological findings (Cohn et al. 2004). The aim RESULTS to investigate possible etiological agents through bacteriological andfindings mycological of the idiopathic exams and pulmonary immunohistochemistry fibrosis in three cats (IHC). and Clinical findings Animal number 1 was a 10-year-old female spayed mixed breed cat that presented with a complaint of respiratory distress MATERIALS AND METHODS and anorexia for two days. On physical exam, the patient was moderately dehydrated and mixed restrictive dyspnea, evaluated at the Veterinary Clinical Hospital of the Federal University without any abnormalities on cardiopulmonary auscultation. ofThe Rio three Grande cats do that Sul were (HCV-UFRGS) included in and the had study a pathological (Cats 1, 2 and diagnosis 3) were Blood samples were collected for hematology and biochemical evaluation ( ), and chest radiography showed a moderate the Veterinary Pathology Department of the Federal University of Rio Grandeof idiopathic do Sul pulmonary (SPV-UFRGS). fibrosis All patients made betweenwere from 2016 the metropolitan and 2017 at bronchointerstitialTable 2 to alveolar pattern, with a predominant area of Porto Alegre, Rio Grande do Sul, Brazil. bronchialdiffuse increase pattern in ( Fig.1Aradiopacity in the lung fields and a mixed
Table 1. Antibodies and immunohistochemical protocols used in cats with idiopathic). The pulmonarypatient was fibrosis discharged home Antibody/code Clone Antigenic recovery Dilution Chromogen Vimentina Monoclonal (v9) 1:200 DABb (18-002) Pancytokeratinb Monoclonal (AE1/AE3) 3 min/125°C, plus citrate, pH 6.0 1:80 DABb (M3515) Alpha smooth muscle actinb Monoclonal (1A4) 3 min/125°C, plus citrate, pH 6.0 1:80 DABb (M0851) Lysozymeb Polyclonal 3 min/125°C, plus citrate, pH 6.0 1:80 DABb (A0099) FIVb Monoclonal (PAK32C1) 3 min/125°C, plus citrate, pH 6.0 1:100 Permanent redb (MCA 2278) FeLV b Monoclonal (C11D8) 40 min/96°C, 0.01 M, plus citrate, pH 6.0 1:500 Permanent redb (MCA 1897) FHV-1c Monoclonal (CM1) 40 min/96°C, 0.01 M, plus citrate, pH 6.0 1:100 AECb (FHV7-5) FCVc Monoclonal (FCV143) 40 min/96°C, 0.01 M, plus citrate, pH 6.0 1:50 AECb (FCV2-16) FCoVd Monoclonal (F1PV370) 40 min/96°C, 0.01 M, plus citrate, pH 6.0 1:300 AECd (MCA 2194) Acquisition sources: a Zymed, b Dako, c Custom Monoclonals, d Serotec; AEC = 3-amino-9-ethylcarbazole,40 min/96°C, 0.01 M, plus DAB citrate, = 3,3’-diaminobenzidine. pH 6.0
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Table 2. Hemogram results and biochemical evaluation of three cats with idiopathic pulmonary fibrosis Exams Cat number 1 Cat number 2 Cat number 3 Reference Hemoglobin (g/dL) 12.6 11.9 13.2 8 - 15 40 33.2 40 24 - 45 11.700 11.500 19.300 5.000 - 19.500 Hematocrit (%) Segmented neutrophils (/L) 7.722 9.775 16.019 2.500 - 12.500 Total leukocytes (/L) Albumin (g/L) 30 ---- 33 21 - 33 327 <10 2 <83 Creatinine (mg/dL) 1.0 1.4 0.78 0.8 - 1.8 ______ALT* (U/L)
*ALT= Alanine transaminase.
A) Chest radiography from Cat 1 showing a
Fig.1.pattern. Radiographic (B and macroscopic findings in 3 cats with idiopathic pulmonary fibrosis. ( moderate diffuse increase in radiopacity in the lung fields and a mixed bronchointerstitialC to) Chestalveolar radiography pattern, with from a predominant Cat 2 with a moderatebronchial ) Macroscopic features of the lungs of Cat 1 with idiopathic pulmonary fibrosis. The lungs show multifocal‑to‑coalescing (whitishD areas and were firm with a slightly nodular appearance on the pleural surface. ( E) Chest radiography from Cat 3 diffuse increase in radiopacity in the lung fields and a mixed bronchointerstitial to alveolar pattern, with a predominant bronchialF) Macroscopic pattern. ) Macroscopic features of the lungs of Cat 2 with idiopathic pulmonary fibrosis, similar to Cat 1. ( showing a severe diffuse increase in radiopacity in the lung fields and a mixed bronchointerstitial to alveolar pattern. ( features of the lungs of Cat 3. The thoracic cavity had serosanguinous effusion, and the lungs showed multifocal-to-coalescing whitish areas and were firm with a multifocal slightly nodular appearance on the pleural surface. Pesq. Vet. Bras. 39(2):134-141, fevereiro 2019 137
Clinical and pathological aspects of idiopathic pulmonary fibrosis in cats with prescriptions of analgesics, corticosteroids and protective organs. Cats 2 and 3 had mild to moderate pleural effusion medications in addition to force-feeding. Fourteen days (hydrothorax) (Fig.1F). Microscopically, the pulmonary parenchyma exhibited after the first consultation, the patient returned presenting distributed in a multifocal-to-coalescing pattern, with more withwas administeredthe same symptoms. Zoletil and She methadone was referred as preanesthetica fine-needle markedpronounced proliferation areas in the of subpleural fibrous connective region (Fig. tissue 2A that was aspiratemedications of the and lung propofol for cytological for induction, evaluation. and maintenance The patient marked hypertrophy of the terminal bronchiolar musculature and marked multifocal proliferation of type II pneumocytes). There was (Fig.2B,C), rarely forming syncytial cells. Occasionally, there was anesthesia was provided with inhaled isoflurane. During the procedure, fluid therapy rate of 5ml/kg/h was maintained. foamy, cytoplasm and cellular debris within the alveoli, as well Theneedleattached patient was to placeda 10mL insyringe lateral was recumbency inserted into and, the tenthafter a marked infiltration of macrophages with a broad, sometimes clippingdorsal intercostal and antisepsis space, with according 2% chlorhexidine, to previous a 25G planning x 7/8 after thoracic radiography was performed. Aspiration was aspleural discrete region, multifocal a proliferation interstitial of mesothelial lymphocytic cells inflammatory was observed, performed with repeated movements and negative pressure. infiltrates, moderate congestion and alveolar edema. In the On cytological analysis, the sample had low cellularity and the bronchi, moderate multifocal accumulation of mucinous was composed of rare well‑differentiated spindle cells and especiallymaterial and in areascellular with debris marked were subpleural observed. Multifocalfibrosis. Within areas of alveolar rupture (alveolar emphysema) that formed large the patient decompensated and progressed to death. yieldedAnimal an inconclusive number 2 was result. a 14-year-old After the fine-needle female spayed aspiration, mixed tissue proliferation stained was marked blue (Fig.2D), and breed cat. She presented with inappetence, weight loss and thevoids remainder were observed. of the pulmonaryOn MT staining, parenchyma, the fibrous stained connective red. On IHC, the proliferative spindle cells were remarkably two antimicrobials with no clinical improvement. On physical reactive for vimentin (Fig.3A) and actin, which was also mildexamination, respiratory she was distress. tachypneic The patient with slight had bilateral been treated pulmonary with observed in the hyperplastic smooth muscle (Fig.3B). On IHC crackles auscultated during cardiopulmonary auscultation. for pancytokeratin, there was an intense proliferation of Blood samples were collected for hematology and biochemical type II pneumocytes around the alveoli (Fig.3C), and on IHC analysis ( ), and chest radiography revealed a moderate for lysozyme, an accumulation of alveolar macrophages was observed (Fig.3D). bronchointerstitialTable 2 to alveolar pattern, with a predominant diffusebronchial increase pattern in (radiopacityFig.1C). She in was the referredlung fields for with pulmonary a mixed cultures, and immunohistochemical evaluations for the presence biopsy by thoracoscopy; she was administered Zoletil and of viralThere etiological was no growth agents on(FIV, bacteriological FeLV, FCoV, FCV or mycologicaland FHV-1) methadone as preanesthetic medications and propofol for was also negative. induction, and maintenance anesthesia was provided with DISCUSSION of 5ml/kg/h was maintained. Analgesics and corticosteroids inhaled isoflurane. During the procedure, a fluid therapy rate in this study was based on clinical, radiographic, pathological less than 24 hours after the surgical procedure. The diagnosis of idiopathic pulmonary fibrosis in the patients wereAnimal administered number after 3 was the a procedure.10-year-old The female patient spayed died withinmixed ranging in age from 10 to 14 years old, which is the common breed cat. She presented with a complaint of dyspnea, sneezing andage groupimmunohistochemical of cats affected findings.by this disease All three (Cohn cats were et al. females 2004). for two days and weight loss. On physical examination, she the insidious pathogenesis of the disease (Cohn et al. 2004). had a low body condition score, mixed dyspnea, pulmonary AsBecause in humans, the number cats with of pulmonary included fibrosiscats was are small, older, it reflecting was not wascrackles hypothermic auscultated (35°C) during and cardiopulmonary moderately dehydrated, auscultation. and possible to determine sex or breed predilection; however, Chest radiography demonstrated a severe diffuse increase in the three patients in this study were females, as previously described in several other studies (Le Boedec et al. 2014, to alveolar pattern (Fig.1E). Blood samples were collected for Evola et al. 2014, Pereira et al. 2016). radiopacityhematology andin the biochemical lung fields analysis and a mixed ( bronchointerstitial referred for hospitalization and treatment with bronchodilators, by anorexia, lethargy and respiratory distress with acute corticosteroids, analgesics, oxygentherapyTable and 2 ).nebulization The patient with was progression,These cats similar had tosimilar the previously clinical reportedsigns, characterized clinical signs (Cohn et al. 2004). Although this disease is characterized as a and dyspneic for two days and progressed to death. chronic condition, the clinical course of patients with idiopathic physiological saline solution. The cat remained hypothermic Pathological and immunohistochemical findings animals to mask pulmonary clinical signs (Cohn et al. 2004). At necropsy, in all three cats, the lungs had whitish areas pulmonary fibrosis may be short due to the ability of these pleural surface; they also failed to completely collapse when Themixed radiographic bronchointerstitial changes pattern were similar progressing in the to cats an alveolar in this andthe thoraxwere firm was withopened. a slightly In the nodular pleural appearanceregion, there on were the study,pattern; with however, adiffuse some increase authors in radiopacity have stated lung that fieldsdiffuse and and a multifocal star-shaped scarring lesions, with parenchymal retraction (Fig.1A-C). When the lung was cut, whitish multifocal (Le Boedec et al. 2014). However, the imaging features of areas were observed, and the parenchyma exhibited low heterogeneousthis disease are lesions variable pattern (Cohn are et atypicalal. 2004, in Evola cats with et al. fibrosis 2014) and may include a predominantly diffuse bronchointerstitial crepitation. No significant changes were observed in other Pesq. Vet. Bras. 39(2):134-141, fevereiro 2019 138 Fernanda G. Cony et al.
A) Pulmonary parenchyma showing marked proliferation of spindle cells, especially in the subpleural region, associated with smooth muscle hypertrophy and reactive mesothelial cells. HE, bar = 250µm. Fig.2.(B Histological) Marked hypertrophy features of idiopathicof the terminal pulmonary bronchiolar fibrosis musculature in felines. ( and marked multifocal proliferation of type II pneumocytes. HE, bar = 130µm. (C D) Pulmonary ) Marked multifocal proliferation of type II pneumocytes, infiltration of macrophages with a broad, sometimes foamy, cytoplasm and cellular debris within the alveoli, as well as proliferation of fibrous connective tissue. HE, bar = 130µm. ( parenchyma showing a marked proliferation of fibrous connective tissue, distributed in a multifocal-to-coalescing form. MT, bar = 500µm. to alveolar pattern, as seen in this study. Pleural effusion, However, because the treatment of the disease is limited, pulmonary nodules and mineralization are rarely observed patients usually die after such an invasive diagnostic procedure, (Evola et al. 2014); however, in the present study, two cats as occurred in two patients in this study (Cohn et al. 2004, had mild to moderate pleural effusion. In terms of blood test Le Boedec et al. 2014). Oxygen therapy, bronchodilators, antimicrobials, diuretics and immunosuppressive drugs are both cats and humans (Cohn et al. 2004). used with no success or with a very short therapeutic response. results, there are no significant hematological alterations in Usually, the disease progresses very fast, leading to worsening pulmonary diseases in felines and due to the variation in respiratory conditions despite therapeutic attempts, as in the The clinical presentation of this disease is similar to other cases reported (Cohn et al. 2004, Evola et al. 2014). biochemical alterations, the clinical diagnosis is challenging (Cohnradiographic et al. 2004). findings Procedures, and the absence such as of bronchoscopy, hematological were and they did not have a historic of previous pulmonary disease. not useful for diagnosis in a previous study (Cohn et al. 2004). The cats in this study were domesticated and healthy; Pulmonary aspiration may result in low cellularity samples were negative for FIV, FeLV, FHV-1, FCV and FCoV, and there Based on IHC examinations, it was confirmed that these cats cultures, excluding the possibility of these infectious agents ofbecause the lung fibroblasts is necessary are (Cohnjuxtaposed et al. cells,2004, as Pereira observed et al. in 2016). Cat 1. inwas the no disease. significant As in growth humans, on the bacteriological pathogenesis or of mycological the disease To achieve a definitive diagnosis histopathological evaluation
Pesq. Vet. Bras. 39(2):134-141, fevereiro 2019 139
Clinical and pathological aspects of idiopathic pulmonary fibrosis in cats
A) Intense intracytoplasmic diffuse staining of mesenchymal cells for vimentin. IHC and DAB, bar = 210µm. (B) Moderate and diffuse intracytoplasmic staining for smooth muscle Fig.3.actin. Immunohistochemical IHC and DAB, bar = 120µm.evaluation (C) Proliferationof idiopathic of pulmonary type II pneumocytes fibrosis in around felines. heavily ( immunoreactive alveoli for pancytokeratin. IHC and DAB, bar = 100µm. (D) Alveolar macrophages reactive for lysozyme. IHC and DAB, bar = 60µm. in domestic felines has not been well elucidated. It has been surfactant protein C, suggesting a genetic component to the suggested that, in humans, the onset of the condition is development of this disease (Van Moorsel et al. 2010). associated with pulmonary injury (Gross & Hunninghake 2001). Latent viral infection, particularly herpes viral infections, also Pulmonary fibrosis may be observed in others domestic animals,lung disease such of as unknown in West Highland etiology, White with Terrierspoor prognosis dogs. These and forhas cats;been however,reported theas possible animals causes in this of study pulmonary were negative fibrosis may present with a chronic progressive interstitial fibrosing for(Gross the &FHV-1 Hunninghake infection 2001). and were The not same previously has been diagnosedsuggested nothe responselung (Heikkilä to treatment et al. 2011), (Heikkilä which et is al. similar 2011). to Thethat mainseen with any pulmonary parenchymal diseases that could have findingin cats affected of this bycondition the same is condition.a diffuse interstitialMoreover, pulmonary fibrosis of caused injury, such as feline asthma, pneumonia or neoplasia. Moreover, chemotherapy with nitrosourea for the treatment the equine herpesvirus-5 (Panziera et al. 2014), popularly of intestinal lymphoma in felines has also been indicated as a fibrosis may be caused by specific etiological agents, such as none of the cats in this study had been treated with this calledof the lungequine in horses multinodular (Williams pulmonary et al. 2007). fibrosis, In humans, that isit isa cause of pulmonary fibrosis (Skorupski et al. 2008); however, chronicknown thatinfectious the inhalation disease characterized of silica and by asbestos interstitial may fibrosis result of type II pneumocytes observed in cats with the condition aremedication. similar toThe the microscopic familial form and of structural this disease characteristics in humans, which occurs because of a defect in the gene encoding the mayin the occur development in the lung of fibrotic of animals nodules subsequently (Oberdorster to chronic 1996). Interstitial fibrosis with concentric collagen deposition
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