Immunohistochemical detection of canine adenovirus in paraffin sections of liver

Prednisolone therapy for chronic hepatitis in English springer spaniels: a prospective study of 12 cases

Background

English springer spaniels (ESS) show an increased risk of chronic hepatitis (CH). In a previous study of 68 ESS with CH, in which only one dog received corticosteroids, a median survival time of 189 days was noted. Some ESS with CH appear to improve with prednisolone treatment; therefore, we aimed to investigate the response to prednisolone in this breed.

Participants

ESS with histologically confirmed idiopathic CH were treated with prednisolone 1–2 mg/kg/day. Nine female and three male ESS were enrolled (median age at diagnosis of five years). Patients were monitored clinically and had biochemistry samples taken to assess markers of hepatocellular damage and function.

Results

The mean starting dose of prednisolone was 1.1 mg/kg/day. All symptomatic patients showed an initial clinical improvement. Two cases were euthanased while receiving prednisolone. The median time since diagnosis is 1715 days (range: 672–2105 days) and the remaining patients are clinically well, with seven patients still receiving a mean dose of 0.4 mg/kg prednisolone every other day. Statistical analysis demonstrated significant (P<0.05) reductions in serum alkaline phosphatase, alanine aminotransferase and bilirubin following 2–4 weeks of prednisolone treatment.

Conclusion

This study demonstrates improved clinical and biochemical parameters when some ESS with CH are managed with prednisolone and standard supportive treatments.

ACVIM consensus statement on the diagnosis and treatment of chronic hepatitis in dogs

This consensus statement on chronic hepatitis (CH) in dogs is based on the expert opinion of 7 specialists with extensive experience in diagnosing, treating, and conducting clinical research in hepatology in dogs. It was generated from expert opinion and information gathered from searching of PubMed for manuscripts on CH, the Veterinary Information Network for abstracts and conference proceeding from annual meetings of the American College of Veterinary Medicine and the European College of Veterinary Medicine, and selected manuscripts from the human literature on CH. The panel recognizes that the diagnosis and treatment of CH in the dog is a complex process that requires integration of clinical presentation with clinical pathology, diagnostic imaging, and hepatic biopsy. Essential to this process is an index of suspicion for CH, knowledge of how to best collect tissue samples, access to a pathologist with experience in assessing hepatic histopathology, knowledge of reasonable medical interventions, and a strategy for monitoring treatment response and complications.

Canine morbillivirus (canine distemper virus) with concomitant canine adenovirus, canine parvovirus-2, and Neospora caninum in puppies: a retrospective immunohistochemical study

A retrospective immunohistochemical study was designed to investigate the frequency of concomitant traditional infectious disease pathogens in puppies that died suddenly and review the aspects of associated pathogenesis. Fifteen puppies were evaluated; the pathology reports and histopathologic slides of these animals were reviewed to determine the pattern of histopathologic lesions. The intralesional identification of antigens of canine (distemper) morbillivirus (CDV), canine adenovirus-1 and -2 (CAdV-1 and -2), canine parvovirus-2 (CPV-2), Toxoplasma gondii, and Neospora caninum was evaluated by IHC within the histopathologic patterns observed. All puppies contained CDV nucleic acid by molecular testing. The most frequent histopathologic patterns were intestinal crypt necrosis (n = 8), white matter cerebellar demyelination (n = 7), necrohaemorrhagic hepatitis (n = 7), interstitial pneumonia (n = 7), and gallbladder oedema (n = 5). All puppies contained intralesional antigens of CDV in multiple tissues resulting in singular (n = 3), and concomitant dual (n = 3), triple (n = 5) and quadruple (n = 4) infections by CAdV-1, and -2, CPV-2, and N. caninum; T. gondii was not identified. Concomitant infections by CDV was observed with N. caninum (100%; 1/1), CPV-2 (100%; 8/8), CAdV-1 (100%; 8/8), and CAdV-2 (100%; 8/8). Intralesional antigens of CDV and not CAdV-1 were identified in cases of gallbladder oedema. The “blue eye” phenomenon was histologically characterized by corneal oedema and degenerative lesions to the corneal epithelium, without inflammatory reactions.

Canine hepacivirus is not associated with chronic liver disease in dogs

Canine hepacivirus (CHV) has recently been identified in liver and respiratory tract samples from dogs, and comparative phylogenetic analysis has confirmed it to be the closest genetic relative of hepatitis C virus (HCV) described to date. CHV offers great potential as a model system for HCV, but only if the underlying processes of infection and pathogenesis are similar for both viruses. However, it is not yet clear if CHV is hepatotrophic. Canine chronic hepatitis (CH) is a common and usually idiopathic disease that shares similar histological features to that of HCV infection of humans. To date, no study has attempted to determine whether CHV is involved in the aetiology of liver disease in dogs. We employed two nested PCR assays, using primers targeting regions of the helicase domain of CHV NS3, to identify viral nucleic acids in liver samples from 100 dogs with CH of unknown cause in the UK. We also used a sensitive luciferase immunoprecipitation system (LIPS) assay to screen serum samples from these dogs for the presence of anti-CHV antibodies. Surprisingly, there was no evidence of exposure to, or a carrier state of, CHV in this large cohort, suggesting that the virus is not associated with CH in UK dogs. Future work, including transmission studies, is required to understand the pathogenesis of CHV in canids before it can be proposed as a surrogate model for HCV-induced liver disease in man.

The immunopathogenetic role of autoantibodies in canine autoimmune hepatitis: lessons to learn from human autoimmune hepatitis

Autoimmune hepatitis (AIH) is not a disease entity restricted to man, but it can be found in other animals including canines. An increasing number of studies have focused on the immunopathogenesis of human autoimmune hepatitis (hAIH), but little is known of what triggers canine autoimmune hepatitis (cAIH). Several drugs, toxins, microbial and viral agents are able to induce autoantibodies and indeed immune-mediated chronic canine hepatitis with immunological and serological features similar of those seen in the human disease. We discuss the features of cAIH paying attention to the autoantibody profile of the disease in comparison to that seen in hAIH. We also discuss the immunomodulatory role of specific molecular signaling pathways such as those mediated by tumor growth factor and p38 mitogen-activated kinase in the induction of AIH, and the potential of these molecules to act as targets of specialized immunotherapeutic interventions. Review of the literature indicates that we have more to learn for the delineation of autoantibody profile and the antigen-specific immunoregulatory mechanisms involved in the pathogenesis of cAIH from the human disease, rather than the other way around.

Chronic hepatitis in the English springer spaniel: clinical presentation, histological description and outcome

Medical records and liver histology of 68 English springer spaniels (ESS) with a histological diagnosis of CH were reviewed retrospectively. PCR was performed on liver tissue for canine adenovirus-1 (CAV-1), canine parvovirus, canine herpesvirus and pathogenic Leptospira species. Follow-up information was obtained to calculate survival times. Median age at presentation was three years seven months (range, seven months to eight years five months) and there were 48 female and 20 male dogs. Clinical signs were non-specific and five dogs were asymptomatic. All dogs had an increase in serum activity of one or more hepatobiliary enzymes. Histopathology demonstrated hepatocyte necrosis and apoptosis with varying amounts of fibrosis. A predominantly lymphoplasmacytic infiltrate throughout the hepatic parenchyma was found in all 68 dogs, but 45 of these dogs also had a neutrophilic component to the inflammatory infiltrate. There was no significant copper accumulation and no aetiological agent was identified by PCR. The median survival time was 189 days (range, 1 to 1211 days), 38 dogs died within three months and 12 dogs survived more than a year following diagnosis.

Hepatite infecciosa canina em cães naturalmente infectados: achados patológicos e diagnóstico imuno-histoquímico

Vinte e três cães com hepatite infecciosa canina (HIC) foram analisados com base nos seus dados gerais, achados clínicos, patológicos e imuno-histoquímicos. As principais lesões macroscópicas encontradas foram palidez do fígado (17/23), hepatomegalia (10/23) e hemorragia (21/23). Observou-se também edema da parede da vesícula biliar (11/23), malhas de fibrina cobrindo a superfície capsular hepática (8/23) e icterícia (6/23). Acentuada necrose hepatocelular foi encontrada associada à identificação de corpúsculos intranucleares anfofílicos e basofílicos em hepatócitos e células endoteliais (22/23) característicos de adenovírus. Identificou-se no baço e linfonodos necrose linfoide, hemorragia e menor ocorrência de corpúsculos intranucleares em células reticuloendoteliais. A imuno-histoquímica (IHQ) foi positiva para adenovírus canino tipo 1 em todos os animais analisados. Os principais órgãos positivos na IHQ foram fígado (23/23), telencéfalo (22/22), cerebelo (16/20) e rim (16/21). Maior marcação de antígenos viral foi observada em hepatócitos e no endotélio vascular do encéfalo e dos tufos glomerulares renais.

Primary hepatitis in dogs: a retrospective review (2002-2006)

BACKGROUND

Little is known about etiology, disease progression, treatment outcome, survival time, and factors affecting prognosis in dogs with primary hepatitis (PH).

OBJECTIVES

To review retrospectively different forms of hepatitis in a referral population, by the World Small Animal Veterinary Association Standardization criteria.

ANIMALS

One-hundred and one dogs examined for histologically confirmed PH between 2002 and 2006. Dogs with nonspecific reactive hepatitis were excluded.

METHODS

Retrospective study. Medical records were reviewed for prevalence, signalment, clinical and clinicopathologic manifestation, outcome, survival time, and prognostic factors for shortened survival.

RESULTS

PH occurred in 0.5% of dogs in this referral population. Acute (AH) and chronic hepatitis (CH) were diagnosed in 21 and 67 dogs, respectively. Progression from AH to CH occurred in 5/12 of the repeatedly sampled dogs. CH was idiopathic in 43 (64%) dogs, and was associated with copper accumulation in 24 (36%) dogs. Median survival time was longer in dogs with AH than in dogs with CH (either idiopathic or copper associated), and dogs with lobular dissecting hepatitis had the shortest survival time. Prognostic factors predicting shortened survival were associated with decompensated liver function and cirrhosis at initial examination.

CONCLUSIONS AND CLINICAL IMPORTANCE

The majority of PH in dogs is CH. Previous studies appear to have underestimated the etiologic role of copper in both AH and CH. Prognosis is reduced in dogs with hepatic cirrhosis or cirrhosis-related clinical findings. Further research into etiology and treatment effectiveness in all PH forms is needed.

Disease threats to the endangered Iberian lynx (Lynx pardinus)

The Iberian lynx, (Lynx pardinus), is the most endangered felid in the world. To determine whether sympatric carnivores are reservoirs of pathogens posing a disease risk for the lynx, evidence of exposure to 17 viral, bacterial and protozoan agents was investigated in 176 carnivores comprising 26 free-living lynx, 53 domestic cats, 28 dogs, 33 red foxes (Vulpes vulpes), 24 Egyptian mongooses (Herpestes ichneumon), 10 common genets (Genetta genetta) and 2 Eurasian badgers (Meles meles) in the areas inhabited by the last two populations of Iberian lynx, both in Andalusia (South-Western Spain).

The results indicated that the lynx had low rates of contact with viral pathogens, with one seropositive finding each for feline leukemia virus, parvovirus and canine adenovirus-1, whereas contact with bacteria and protozoa appeared more frequent. Active infections with parvovirus, Ehrlichia spp., Mycobacterium bovis, Leptospira interrogans and Cytauxzoon spp. were confirmed. In contrast, 53% of the domestic cats were exposed to some infectious agent (prevalence range 4.5–11.4%). Antibodies to canine distemper virus and parvovirus were frequently found in dogs (32% and 42%, respectively) and foxes (30% and 12%). Past or present infections with parvovirus, Ehrlichia spp., Chlamydophila spp., M. bovis, Salmonella enterica, L. interrogans, Toxoplasma gondii, and Neospora caninum were also detected in these and other species surveyed.

Questionnaires to owners revealed that 14% of the dogs but none of the cats had been vaccinated, and no cat had been neutered. Based on the apparent absence of acquired immunity of the lynx against infectious agents, the frequent detection of agents among sympatric carnivores, and the reported lack of immunocompetence of the Iberian lynx, a disease outbreak among the local abundant carnivores may pose a serious disease risk for lynx conservation.

Cirrose hepática em cães: 80 casos (1965-2003)

Foi realizado um estudo retrospectivo de 80 casos de cirrose em cães no Laboratório de Patologia Veterinária da Universidade Federal de Santa Maria, Rio Grande do Sul. Dos cães em que o sexo e a idade constavam dos protocolos de necropsia, 53,8% eram machos e 46,2% eram fêmeas; 50,0% foram incluídos como idosos, 48,6% como adultos e 1,4% como filhote. Os principais sinais clínicos observados incluíram: ascite (39/80 [48,8%]), icterícia (19/80 [23,8%]), anorexia (13/80 [16,2%]), distúrbios neurológicos (12/80 [15,0%]), dispnéia (12/80 [15,0%]) e edema subcutâneo (10/80 [12,5%]). Dos 63 cães em que a descrição macroscópica constava dos protocolos de necropsia, 76,2% tinham cirrose macronodular e 23,8% tinham cirrose micronodular. Nos 14 cães em que as lesões histológicas foram revistas pode-se observar diferentes graus de fibrose (leve [57,2%], moderada [21,4%] ou acentuada [21,4%]) e nenhuma relação entre as intensidades da fibrose e das outras lesões histológicas observadas (degeneração gordurosa, proliferação de ductos biliares, inflamação, bilestase, hemossiderose e necrose aleatória de hepatócitos). As alterações macro e microscópicas extra-hepáticas incluíram: ascite (39/63 [61,9%]), icterícia (19/63 [30,2%]), status spongiosus (15/63 [23,8%]), hidrotórax (12/63 [19,0%]), edema subcutâneo (10/63 [15,9%]), derivações portossistêmicas (11/63 [17,5%]), úlceras gástricas ou duodenais (11/63 [17,5%]) e nefrose colêmica (4/63 [6,3%]).

Hepatite infecciosa canina: 62 casos

Os protocolos de necropsias realizadas em 5.361 cães durante um período de 43 anos (1964-2006) foram revisados em busca de casos de hepatite infecciosa canina (HIC) e sessenta e dois (1,2%) casos foram encontrados. A maioria dos 62 cães afetados tinha dois anos de idade ou menos (91,9%). Os sinais clínicos foram anotados nos protocolos de necropsia de 45 cães afetados por HIC e incluíam anorexia (55,6%), apatia (35,6%), diarréia (35,6%), freqüentemente com sangue (43,8% dos casos de diarréia), distúrbios neurológicos (33,3%), vômito (26,7%), petéquias e equimoses nas membranas mucosas e/ou pele (24,4%), hipotermia (20,0%), dor abdominal (15,6%), icterícia (13,3%), aumento de volume e congestão das tonsilas (11,1%), febre (11,1%) e ascite (6,7%). A duração do curso clínico variou de poucas horas a 15 dias. Os principais achados de necropsia incluíram alterações hepáticas (87,1%), linfonodos edematosos, congestos e hemorrágicos (51,6%), líquido sanguinolento, líquido claro ou sangue na cavidade abdominal (35,5%), víbices, sufusões e petéquias sobre a pleura visceral (27,4%) e superfície serosa das vísceras gastrintestinais (24,2%). Em 12,9% dos casos a serosa do intestino tinha aspecto granular. Hemorragias cerebrais nas leptomeninges e na substância do encéfalo foram observadas em 9,7% dos casos. As alterações hepáticas macroscópicas incluíam fígados moderadamente aumentados de volume, mais friáveis, com acentuação do padrão lobular, congestos e com múltiplos focos de necrose pálidos ou hemorrágicos. Películas e filamentos de fibrina cobriam a superfície hepática em 20,4% dos casos e em 27,8% dos casos a parede da vesícula biliar estava espessada por edema. Necrose hepática zonal ou aleatória (93,5% dos casos) associada a corpúsculos de inclusão intranucleares foi a lesão histológica mais regularmente encontrada. Os corpúsculos de inclusão intranucleares ocorreram no fígado em todos os casos e esse foi o critério para confirmação do diagnóstico. As lesões histológicas extra-hepáticas mais importantes incluíram hemorragias e corpúsculos de inclusão em células endoteliais do tufo glomerular renal (50,0%) dos linfonodos (47,8%) , do encéfalo (27,8%), das tonsilas (25,0%) e do baço (10,0%).

Hepatitis with special reference to dogs. A review on the pathogenesis and infectious etiologies, including unpublished results of recent own studies

The causes of hepatitis in dogs are mostly unknown. Known causes of canine hepatitis are infectious (CAV-1), toxic (e.g. aflatoxin), and metabolic (copper accumulation). In order to understand the unknown causes, research in this field is necessary. Despite the marked progress in the knowledge on viral causes for human hepatitis, the involvement of infectious agents in the pathogenesis of hepatitis in the dog is still largely unknown. It is, like in human hepatitis, very likely that more than one causative infectious agent may cause hepatitis in the dog. This review presents the various forms of hepatitis in the dog, the known infectious and non-infectious causes of canine hepatitis, the infectious causes of hepatitis in man and other animals, and finally our recent infection and molecular studies to investigate possible infectious causes of canine hepatitis.

Chronic hepatitis in dogs: a review of current understanding of the aetiology, progression, and treatment

Chronic hepatitis is common in dogs in primary and referral practice but the cause is usually unknown. This paper reviews the literature on potential causes of chronic hepatitis in dogs (infectious, autoimmune, metabolic, toxic, and breed-associated) together with the literature on the progression of the disease and on treatments. This is compared with the current understanding of aetiology, progression, and treatment of chronic hepatitis in man. Unfortunately, little is known about the aetiology and progression of the canine disease and very few therapies have been subjected to critical trials. It is difficult therefore to draw conclusions about causes and effective treatment in dogs. Even the histological description for canine chronic hepatitis has yet to be standardised. Much research remains to be done and this review suggests some potential areas for future investigation.

Hepatic cirrhosis in a five-month-old dog

The clinicopathological features of an unusual case of a five-month-old male Spanish mastiff, which was presented with clinical signs indicative of severe hepatic failure, are reported. Fluid replacement therapy, colloid plasma expanders, antibiotics and diuretic drugs were unsuccessful in improving the animal's general condition, and euthanasia was elected by the owner. On necropsy, ascites and severe cirrhosis, with extensive periacinar necrosis, was found. Cirrhosis is a rare lesion in young dogs. The most common causes are circulatory disturbances, hereditary metabolic disorders or poisoning, such as aflatoxicosis and anticonvulsant therapy. The possible involvement of canine adenovirus in this case is discussed.

Use of polymerase chain reaction and immunohistochemistry for detection of canine adenovirus type 1 in formalin-fixed, paraffin-embedded liver of dogs with chronic hepatitis or cirrhosis

To assess the possible involvement of canine adenovirus type 1 (CAV-1) in naturally occurring cases of canine chronic liver disease, a polymerase chain reaction (PCR)-based assay was developed to detect a conserved region of the major core protein gene (pVII) of CAV-1 in formalin-fixed, paraffin-embedded liver sections. Results were compared with a standard avidin-biotin immunoperoxidase complex technique that detected CAV-1 antigens using a commercial monoclonal anti-adenovirus antibody. Seventeen cases of cirrhosis and 28 cases of chronic hepatitis with piecemeal necrosis and progressive fibrosis were selected for the study. Formalin-fixed, paraffin-embedded liver sections of 2 cases of infectious canine hepatitis (ICH) and crude DNA extract from CAV-1 (ATCC VR 293 Utrecht strain) served as positive controls. A 411-base-pair viral region was amplified and sequenced as CAV-1 pVII in both cases of infectious canine hepatitis and in the CAV-1 crude DNA extract. The 2 ICH cases were positive for CAV-1 antigens by the immunoperoxidase method. CAV-1 DNA or antigens were not detected by either technique in any of the 45 cases of chronic liver disease selected for the study. These results indicate that both PCR and immunohistochemistry are reliable and rapid techniques for detecting CAV-1 in formalin-fixed, paraffin-embedded liver sections of dogs with ICH. Several possibilities may explain the negative results obtained with both techniques in this study, including the noninvolvement of CAV-1 in canine chronic hepatitis and cirrhosis and the possibility that the virus causes initial damage, provokes a self-perpetuating chronic liver disease, and disappears.

Chronic hepatitis associated with leptospiral infection in vaccinated beagles

Sixteen juvenile Beagle dogs originating from a single breeding colony and regularly vaccinated against Leptospira interrogans (serogroups Canicola and Icterohaemorrhagiae) developed a clinical syndrome characterized by retarded growth, weight loss and often ascites. Over a 10-month period, post-mortem examinations were performed on all affected dogs. Gross lesions were confined to the liver which was often firm, tan-coloured and mottled. Microscopically, hepatic lesions ranged from those of severe chronic hepatitis to mild diffuse hepatocellular vacuolation, with bile stasis, occasional scattered lymphocytic aggregates and haemosiderin granulomas. Special stains and electron microscopy revealed spirochaetes within bile canaliculi. The genus Leptospira was recognized by immunohistochemical methods in nine dogs. Leptospires were isolated from six dogs, but serological tests failed to detect significant titres of antibody to L. interrogans in these animals. A serological survey of 37 kennelmates demonstrated that 20 dogs had high titres of serogroup Australis leptospiral antibody, which could not have resulted from vaccination. These findings strongly suggest a connection between the presence of leptospires and the hepatic lesions.

Cell-mediated immune responses to liver membrane protein in canine chronic hepatitis

Peripheral blood mononuclear cells from dogs with chronic inflammatory liver disease and dogs with noninflammatory liver diseases were evaluated for proliferative responses to pokeweed mitogen and canine liver membrane protein. Dogs with chronic hepatitis were selected based on histopathological evidence of periportal lymphocytic infiltrates with or without neutrophilic infiltrates, fibrosis and necrosis. Incorporation of tritiated thymidine was assessed 72 hours after addition of liver membrane protein or pokeweed mitogen. Peripheral blood mononuclear cell proliferation in response to liver membrane protein was significantly higher in chronic hepatitis dogs compared to control dogs. Eight of 12 dogs with chronic hepatitis and 2 of 7 dogs with noninflammatory liver disease had proliferative responses to liver membrane protein greater than 2 standard deviations above the mean of the control group. These data support the hypothesis that immune-mediated processes are involved in canine chronic hepatitis, but did not determine whether this is a primary disorder or occurred secondary to liver destruction.

Immunocytochemical detection of Ehrlichia platys antigens in canine blood platelets

An avidin-biotin immunoperoxidase complex (ABC) immunocytochemical (ICC) stain procedure was optimized for detection of Ehrlichia platys antigens. Positive immunoreactivity was detected with dilutions of canine immune serum on acetone-fixed smears of platelet-rich plasma from E. platys-infected dogs. No E. platys antigens were detected when this ICC stain was applied to frozen or paraffin-embedded formalin- or acetone-fixed tissue sections from dogs with acute E. platys infection. Acetone fixation and freezing preserved ICC staining of ehrlichial antigens in infected blood platelets, whereas formalin treatment of similarly preserved E. platys-infected platelets nullified positive immunoreactivity. Significant E. platys infection of cells and tissues other than platelets may not occur.