Resultado da pesquisa (10)
Termo utilizado na pesquisa pathogenicity
#1 - Phylogenetic and pathotypic characterization of newcastle disease virus in Tibetan chickens, China
Abstract in English:
Chickens are considered to be potential reservoirs of Newcastle disease virus (NDV). In this study, six Newcastle disease virus strains were isolated and characterized in Tibetan chickens. The HN gene was sequenced, and phylogenetic relationship to reference strains was studied. The phylogenetic analysis demonstrated that these six isolated strains were closely related to NDV isolates of the reference strains GQ245823, KT002186, KU527561, KJ563939, AY225110, EU305607, KM056357, Y18898, GQ245832, AF077761 and lasota strain. Among them, EU305607, KJ563939 and KM056357 were isolated from India, while lasota strain came from attenuated vaccine widely used in China. Then, mean death time (MDT) and intracerebral pathogenicity index (ICPI) were used to estimate the pathogenicity of the isolates. Pathogenicity experiment showed HNH1 and HN17 to be virulent. Our results indicated that genetically diverse viruses circulate in Tibetan chickens, and based upon the phlogeographic analysis, we estimated the origin of ancestral viruses of the isolates and its sister strains located in India and China (lasota strain). It indicates the importance of continuous surveillance to enhance current understanding of the genetic evolution of the NDV strains.
Abstract in Portuguese:
Chickens are considered to be potential reservoirs of Newcastle disease virus (NDV). In this study, six Newcastle disease virus strains were isolated and characterized in Tibetan chickens. The HN gene was sequenced, and phylogenetic relationship to reference strains was studied. The phylogenetic analysis demonstrated that these six isolated strains were closely related to NDV isolates of the reference strains GQ245823, KT002186, KU527561, KJ563939, AY225110, EU305607, KM056357, Y18898, GQ245832, AF077761 and lasota strain. Among them, EU305607, KJ563939 and KM056357 were isolated from India, while lasota strain came from attenuated vaccine widely used in China. Then, mean death time (MDT) and intracerebral pathogenicity index (ICPI) were used to estimate the pathogenicity of the isolates. Pathogenicity experiment showed HNH1 and HN17 to be virulent. Our results indicated that genetically diverse viruses circulate in Tibetan chickens, and based upon the phlogeographic analysis, we estimated the origin of ancestral viruses of the isolates and its sister strains located in India and China (lasota strain). It indicates the importance of continuous surveillance to enhance current understanding of the genetic evolution of the NDV strains.
#2 - Evaluation of the biofilm formation capacity of Pasteurella multocida strains isolated from cases of fowl cholera and swine lungs and its relationship with pathogenicity, 37(10):1041-1048
Abstract in English:
ABSTRACT.- Emery B.D., Furian T.Q., Pilatti R.M., Chitolina G.Z., Borges K.A., Salle C.T.P. & Moraes H.L.S. 2017. Evaluation of the biofilm formation capacity of Pasteurella multocida strains isolated from cases of fowl cholera and swine lungs and its relationship with pathogenicity. Pesquisa Veterinária Brasileira 37(10):1041-1048. Centro de Diagnóstico e Pesquisa em Patologia Aviária, Faculdade de Medicina Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 8824, Porto Alegre, RS 91540-000, Brazil. E-mail: brunnadeemery@hotmail.com
Pasteurella multocida is a Gram-negative bacillus that causes economic losses due to the development of respiratory diseases in several animal species. Among the mechanisms of virulence, the formation of biofilms is an important factor for bacterial survival in hostile environments. Studies of biofilm formation by P. multocida are needed because P. multocida is an important pathogen involved in respiratory infections. However, in contrast to other microorganisms, few studies of biofilm formation have examined P. multocida. Studies comparing the pathogenicity of microbial strains as a function of their biofilm production capacity are also rare. Consequently, the aim of this study was to evaluate the biofilm formation capacity of 94 P. multocida strains isolated from cases of fowl cholera and from swine lungs on polystyrene plates. The associations of the biofilm formation capacity with the pathogenicity index (PI) in vivo and with the presence of four genes (screened by PCR) of the tad locus (tadB, tadD, tadE and tadG), described as adhesion markers, were also determined. Strains from both animal origins were able to form biofilms. However, most of the specimens (52.13%) were classified as weak producers, and more than 40% of the strains of P. multocida (40.42%) did not produce biofilms. There was no significant difference (p>0.05) in the degree of biofilm production between the two sources of isolation. Of the analyzed strains, 56.52% contained all four genes (tadB, tadD, tadE and tadG). The PI arithmetic mean of the strains classified as non-biofilm producers was significantly different (p<0.05) from the PI of moderate-producer strains. The PI of specimens classified as weak biofilm producers also differed significantly (p<0.05) from that of the moderate-producer strains. The results indicate that even though the P. multocida strains isolated from cases of fowl cholera and swine lungs formed biofilms on polystyrene surfaces, adhesion was usually weak. The genes tadB, tadD, tadE and tadG were not significantly associated (p>0.05) with the production of biofilms and with the origin of a given strain. Finally, low virulence strains may suggest a higher biofilm formation capacity on polystyrene plates.
Abstract in Portuguese:
RESUMO.- Emery B.D., Furian T.Q., Pilatti R.M., Chitolina G.Z., Borges K.A., Salle C.T.P. & Moraes H.L.S. 2017. Evaluation of the biofilm formation capacity of Pasteurella multocida strains isolated from cases of fowl cholera and swine lungs and its relationship with pathogenicity. [Avaliação da capacidade de formação de biofilme por cepas de Pasteurella multocida isoladas de casos de cólera aviária e de pulmões de suínos e sua relação com a patogenicidade.] Pesquisa Veterinária Brasileira 37(10):1041-1048. Centro de Diagnóstico e Pesquisa em Patologia Aviária, Faculdade de Medicina Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 8824, Porto Alegre, RS 91540-000, Brazil. E-mail: brunnadeemery@hotmail.com
Pasteurella multocida é um bacilo Gram negativo que ocasiona perdas econômicas, geralmente associadas a doenças respiratórias em diversas espécies animais. Entre os mecanismos de virulência existentes, a formação de biofilmes demonstra ser um importante fator para a proteção e para a sobrevivência bacteriana em ambientes hostis. Estudos relacionados à formação de biofilmes por P. multocida são necessários, uma vez que este é um importante patógeno envolvido em infecções respiratórias. Entretanto, ainda são poucos os estudos desenvolvidos nesta área, quando comparados com aqueles envolvendo outros microrganismos. Também são os raros os estudos que comparam a patogenicidade das cepas com a sua capacidade de produção de biofilme. Neste contexto, o objetivo deste estudo foi avaliar a capacidade de formação de biofilme em placas de poliestireno de 94 cepas de P. multocida isoladas de casos de cólera aviária e de pulmões de suínos, associando-se com o índice de patogenicidade (IP) in vivo e com a presença de quatro genes do locus tad (tadB, tadD, tadE e tadG), descritos como marcadores de adesão e pesquisados através de PCR. As cepas de ambas as origens foram capazes de formar biofilme. Contudo, a maioria dos exemplares (52,12%) foi classificada como fracamente produtora e mais de 40% das cepas de P. multocida (40,42%) não produziram biofilme. Não foi observada diferença estatística (p>0,05) quanto ao grau de produção de biofilme entre as duas origens de isolamento. 56,52% das cepas analisadas apresentaram os quatro genes (tadB, tadD, tadE e tadG) concomitantemente. O IP médio das cepas classificadas como não produtoras de biofilme apresentou diferença estatística (p˂0,05) em relação ao IP das cepas moderadamente produtoras. Os exemplares classificados como fracamente produtores de biofilme diferiram significativamente (p˂0,05) do grupo de cepas moderadamente produtoras. Os resultados obtidos indicaram que, apesar de as cepas de P. multocida isoladas de casos de cólera aviária e do pulmão de suínos apresentarem capacidade de formar biofilme em superfícies de poliestireno, a adesão ocorreu geralmente de forma fraca. Os genes tadB, tadD, tadE e tadG, pertencentes ao locus tad, não apresentaram associação significativa com a produção de biofilme e nem com a origem de isolamento da cepa. Por fim, observou-se que as cepas de menor patogenicidade apresentaram uma maior capacidade de formação de biofilme em placas de poliestireno.
#3 - Isolation and characterization of Pythium species from swampy areas in the Rio Grande do Sul, Brazil, and evaluation of pathogenicity in an experimental model, 37(5):459-464
Abstract in English:
ABSTRACT.- Zambrano C.G., Fonseca A.O.S., Valente J.S.S., Braga C.Q., Sallis E.S.V., Azevedo M.I., Weiblen C., Santurio J.M., Botton S.A. & Pereira D.I.B. 2017. [Isolation and characterization of Pythium species from swampy areas in the Rio Grande do Sul, Brazil, and evaluation of pathogenicity in an experimental model.] Isolamento e caracterização de espécies de Pythium de ambientes aquáticos no Estado do Rio Grande do Sul e avaliação da patogenicidade em modelo experimental. Pesquisa Veterinária Brasileira 37(5):459-464. Laboratório de Micologia, Instituto de Biologia, Departamento de Microbiologia e Parasitologia, Universidade Federal de Pelotas, Campus Universitário s/n, Pelotas, RS 96160-000, Brazil. E-mail: danielabrayer@gmail.com
One hundred and eighty-six water samples from swampy areas were collected in 13 municipalities of South, Central and West regions of Rio Grande do Sul, Brazil, in order to isolate and characterize Pythium species and assess their pathogenicity using rabbits as experimental model. Different Pythium species were isolated from 22 (11.8%) water samples, including P. insidiosum (n=1), P. catenulatum (n=3), P. pachycaule voucher (n=1), P. rhizo-oryzae (n=3), P. torulosum (n=4) e Pythium spp. (n=10). Zoospores of these microorganisms were produced in vitro and inoculated subcutaneously into rabbits, which were assessed over 45 days. Only P. insidiosum showed pathogenicity, causing pythiosis in the experimental model.
Abstract in Portuguese:
RESUMO.- Zambrano C.G., Fonseca A.O.S., Valente J.S.S., Braga C.Q., Sallis E.S.V., Azevedo M.I., Weiblen C., Santurio J.M., Botton S.A. & Pereira D.I.B. 2017. [Isolation and characterization of Pythium species from swampy areas in the Rio Grande do Sul, Brazil, and evaluation of pathogenicity in an experimental model.] Isolamento e caracterização de espécies de Pythium de ambientes aquáticos no Estado do Rio Grande do Sul e avaliação da patogenicidade em modelo experimental. Pesquisa Veterinária Brasileira 37(5):459-464. Laboratório de Micologia, Instituto de Biologia, Departamento de Microbiologia e Parasitologia, Universidade Federal de Pelotas, Campus Universitário s/n, Pelotas, RS 96160-000, Brazil. E-mail: danielabrayer@gmail.com
Foram coletadas 186 amostras de água de ambientes pantanosos em 13 municípios das regiões Sul, Central e Oeste do Rio Grande do Sul, Brasil, com o objetivo de isolar e caracterizar espécies de Pythium e avaliar a sua patogenicidade empregando coelhos como modelo experimental. Em 11,8% (n=22) das águas coletadas foram isoladas diferentes espécies de Pythium incluindo: P. insidiosum (n=1), P. catenulatum (n=3), P. pachycaule voucher (n=1), P. rhizo-oryzae (n=3), P. torulosum (n=4) e Pythium spp. (n=10). Zoósporos desses micro-organismos foram produzidos in vitro e inoculados por via subcutânea em coelhos, os quais foram avaliados durante 45 dias. Dentre os oomicetos testados, apenas P. insidiosum evidenciou patogenicidade, causando pitiose no modelo experimental, evidenciando que, em nossas condições, apenas esta espécie de Pythium é patógena para mamíferos.
#4 - Research of Salmonella spp. and evaluation of pathogenicity, cytotoxicity of Escherichia coli isolates proceeding from sparrows (Passer domesticus), 32(9):931-935
Abstract in English:
ABSTRACT.- Vilela S.M.O., Pinheiro Júnior J.W., Silva J.S.A., Pace F., Silveira W.D., Saukas T.N., Reis E.M.F. & Mota R.A. 2012. Research of Salmonella spp. and evaluation of pathogenicity, cytotoxicity of Escherichia coli isolates proceeding from sparrows (Passer domesticus). Pesquisa Veterinária Brasileira 32(9):931-935. Departamento de Medicina Veterinária, Universidade Federal Rural de Pernambuco, Rua Dom Manuel de Medeiros s/n, Recife, PE 52171-900, Brazil. E-mail: rinaldo.mota@hotmail.com
The aim of this study was to research the occurrence of Salmonella spp. and Escherichia coli in feces samples of sparrows, as well as to identify the pathogenicity, cytotoxicity and sensitivity profile of the isolates to antimicrobial use. Two hundred and twenty eight sparrows were captured in eight farms. The in vitro pathogenicity test was performed by the isolates culture on congo red-magnesium oxalate Agar, whilst the in vivo pathogenicity test was performed in one day-old chicks. In order to study the cytotoxic effects of indicators, samples were inoculated into Vero cells. The results obtained for Escherichia coli isolation confirmed the presence of this microorganism in 30 (13.2%) of the evaluated samples. Out of those isolates, 10 (33.3%) presented the capacity of absorbing ongo red. As for in vivo pathogenicity a 68.0% of mortality rate of the evaluated samples was observed. Out of 20 isolates tested for cytotoxin production, none of them presented cytotoxic effect in the Vero cells. The Salmonella spp was isolated only in one sample (0.04%), and it was identified as Salmonella enterica subspecies houtenae. Results obtained through this research indicate the need for new studies to identify other virulence factors of E. coli samples and to delineate the phylogenetic profile of the isolates in order to establish a relation with colibacillosis outbreaks in chickens and broilers in the studied region, as well as to analyze the critical points in the aviculture productive chain to identify the source of Salmonella enterica subspecies houtenae.
Abstract in Portuguese:
RESUMO.- Vilela S.M.O., Pinheiro Júnior J.W., Silva J.S.A., Pace F., Silveira W.D., Saukas T.N., Reis E.M.F. & Mota R.A. 2012. Research of Salmonella spp. and evaluation of pathogenicity, cytotoxicity of Escherichia coli isolates proceeding from sparrows (Passer domesticus). Pesquisa Veterinária Brasileira 32(9):931-935. Departamento de Medicina Veterinária, Universidade Federal Rural de Pernambuco, Rua Dom Manuel de Medeiros s/n, Recife, PE 52171-900, Brazil. E-mail: rinaldo.mota@hotmail.com
Objetivou-se com este estudo pesquisar a ocorrência de Salmonella spp. e Escherichia coli em amostras de fezes de pardais, além de avaliar a patogenicidade, citotoxicidade e perfil de sensibilidade dos isolados frente a antimicrobianos. Foram capturados 228 pardais em oito granjas. O teste de patogenicidade in vitro foi realizado por meio do cultivo dos isolados em ágar oxalato de magnésio acrescido de vermelho de congo, enquanto o teste de patogenicidade in vivo foi realizado em pintos de um dia. Para o estudo dos indicadores dos efeitos citotóxicos, as amostras foram inoculadas em células Vero. Os resultados obtidos quanto ao isolamento de Escherichia coli confirmaram a presença deste microorganismo em 30 (13,2%) amostras analisadas. Destes isolados, dez (33,3%) apresentaram capacidade de absorção do vermelho congo. Quanto à patogenicidade in vivo observou-se uma taxa de mortalidade de 68,0% das amostras analisadas. Dos 20 isolados testados quanto à produção de citotoxina, nenhum apresentou efeito citotóxico nas células Vero. Obteve-se o isolamento de Salmonella spp. em apenas uma amostra (0,04%), sendo tipificada em Salmonella enterica subespécie houtenae. Os resultados obtidos nesta pesquisa indicam a necessidade da realização de novos estudos para identificar outros fatores de virulência das amostras de E. coli e traçar o perfil filogenético dos isolados para estabelecer uma relação com surtos de colibacilose em galinhas e frango de corte na região estudada, além de analisar os pontos críticos na cadeia produtiva da avicultura para identificar a origem da Salmonella enterica subespécie houtenae.
#5 - Genes associated with pathogenicity of avian Escherichia coli (APEC) isolated from respiratory cases of poultry, p.183-186
Abstract in English:
ABSTRACT.- Rocha A.C.G.P., Rocha S.L.S., Lima-Rosa C.A.V., Souza G.F., Moraes H.L.S., Salle F.O., Moraes L.B. & Salle C.T.P. 2008. Genes associated with pathogenicity of avian Escherichia coli (APEC) isolated from respiratory cases of poultry. Pesquisa Veterinária Brasileira 28(3):183-186. Centro de Diagnóstico e Pesquisa em Patologia Aviária, Departamento de Medicina Animal, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 8824, Porto Alegre, RS 91540-000, Brazil. E-mail: ana.crocha@terra.com.br
The virulence mechanisms of avian pathogenic Escherichia coli (APEC) have been continually studied and are believed to be multi-factorial. Certain properties are primarily associated with virulent samples and have been identified in avian isolates. In this study a total of 61 E. coli, isolates from chicken flocks with respiratory symptomatology, were probed by Polimerase Chain Reation (PCR) for the presence of genes responsible for the adhesion capacity, P fimbria (papC) e F11 fimbria (felA), colicin production (cvaC), aerobactin presence (iutA), serum resistance (iss), temperature-sensitive hemagglutinin (tsh), and presence of K1 and K5 capsular antigens (kpsII). The iss gene was detected in 73,8%, tsh in 55,7%, iutA in 45,9%, felA in 39,3%, papC in 24,3%, cvaC in 23% and kpsII in18%.
Abstract in Portuguese:
ABSTRACT.- Rocha A.C.G.P., Rocha S.L.S., Lima-Rosa C.A.V., Souza G.F., Moraes H.L.S., Salle F.O., Moraes L.B. & Salle C.T.P. 2008. Genes associated with pathogenicity of avian Escherichia coli (APEC) isolated from respiratory cases of poultry. Pesquisa Veterinária Brasileira 28(3):183-186. Centro de Diagnóstico e Pesquisa em Patologia Aviária, Departamento de Medicina Animal, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 8824, Porto Alegre, RS 91540-000, Brazil. E-mail: ana.crocha@terra.com.br
The virulence mechanisms of avian pathogenic Escherichia coli (APEC) have been continually studied and are believed to be multi-factorial. Certain properties are primarily associated with virulent samples and have been identified in avian isolates. In this study a total of 61 E. coli, isolates from chicken flocks with respiratory symptomatology, were probed by Polimerase Chain Reation (PCR) for the presence of genes responsible for the adhesion capacity, P fimbria (papC) e F11 fimbria (felA), colicin production (cvaC), aerobactin presence (iutA), serum resistance (iss), temperature-sensitive hemagglutinin (tsh), and presence of K1 and K5 capsular antigens (kpsII). The iss gene was detected in 73,8%, tsh in 55,7%, iutA in 45,9%, felA in 39,3%, papC in 24,3%, cvaC in 23% and kpsII in18%.
#6 - Pathogenicity of Rhodococcus equi in mice, isolated from environment, human and horse clinical samples
Abstract in English:
ABSTRACT.- Costa M.M., Machado S.A., Krewer C.C., Ilha M.R.S., Graça D.L., Guaraldi A.L.M. & Vargas A.C. 2006. Pathogenicity of Rhodococcus equi in mice, isolated from environment, human and horse clinical samples. Pesquisa Veterinária Brasileira 26(3):167-170. Laboratório de Bacteriologia, Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Avenida Roraima 1000, Santa Maria, RS 97105-900, Brazil. E-mail: agueda@ccr.ufsm.br
Rhodococcus equi is a facultative intracellular pathogen associated with bronchopneumonia, mesenteric lymphadenitis and enterocolitis in foals. Although R. equi is likely to be found in every horse-breeding farm, the clinical disease is unrecognized in most of them. Capsule components, equi factor, micolic acid and some products encoded by the large 85-90Kb plasmid were described as virulence factors. However, the pathogenesis of R. equi infections and the sensibility of foals are not completely understood. The aim of this study was evaluate the virulence of R. equi isolated from human, horses and environment for mices. Nine strains carrying the 85-90Kb plasmid isolated from foal clinical specimens, one from immunodeficient human patient and six plasmidless strains (four isolated from feces, one from pasture and one from immunodeficient human patient) were inoculated in cyclophosphamide immunossuppressed mice. The pathological changes and viability of R. equi cells in the liver of mice was verified after the 3rd, 6th an 10th day after inoculation for horse and environmental isolates and for R. equi isolates from human patients on the 1st, 3rd and 6th day. During the necropsy procedures, infiltrate of macrophages and pyogranulomatous lesions were detected after the sixth pos-inoculation day in the liver and spleen. In horse isolates, only plasmid positive strains were virulent, but in human isolates both strains (plasmid positive e plasmid negative) were virulent. Both groups of the immunossupressed mice inoculated with R. equi isolated from environment showed pathological changes. All R. equi strains were unable to kill non imunossuppressed mice.
Abstract in Portuguese:
ABSTRACT.- Costa M.M., Machado S.A., Krewer C.C., Ilha M.R.S., Graça D.L., Guaraldi A.L.M. & Vargas A.C. 2006. Pathogenicity of Rhodococcus equi in mice, isolated from environment, human and horse clinical samples. Pesquisa Veterinária Brasileira 26(3):167-170. Laboratório de Bacteriologia, Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Avenida Roraima 1000, Santa Maria, RS 97105-900, Brazil. E-mail: agueda@ccr.ufsm.br
Rhodococcus equi is a facultative intracellular pathogen associated with bronchopneumonia, mesenteric lymphadenitis and enterocolitis in foals. Although R. equi is likely to be found in every horse-breeding farm, the clinical disease is unrecognized in most of them. Capsule components, equi factor, micolic acid and some products encoded by the large 85-90Kb plasmid were described as virulence factors. However, the pathogenesis of R. equi infections and the sensibility of foals are not completely understood. The aim of this study was evaluate the virulence of R. equi isolated from human, horses and environment for mices. Nine strains carrying the 85-90Kb plasmid isolated from foal clinical specimens, one from immunodeficient human patient and six plasmidless strains (four isolated from feces, one from pasture and one from immunodeficient human patient) were inoculated in cyclophosphamide immunossuppressed mice. The pathological changes and viability of R. equi cells in the liver of mice was verified after the 3rd, 6th an 10th day after inoculation for horse and environmental isolates and for R. equi isolates from human patients on the 1st, 3rd and 6th day. During the necropsy procedures, infiltrate of macrophages and pyogranulomatous lesions were detected after the sixth pos-inoculation day in the liver and spleen. In horse isolates, only plasmid positive strains were virulent, but in human isolates both strains (plasmid positive e plasmid negative) were virulent. Both groups of the immunossupressed mice inoculated with R. equi isolated from environment showed pathological changes. All R. equi strains were unable to kill non imunossuppressed mice.
#7 - Comparative pathogenicity of bovine herpesviruses type 1 (BHV-1) subtypes 1 (BHV-1.1) and 2a (BHV-1.2a)
Abstract in English:
Spilki F.R, Esteves P.A., Lima M., Franco A.C., Chiminazzo C., Flores E.F., Weiblen R., Driemeier D. & Roehe P.M. 2004. Comparative pathogenicity of bovine herpesviruses type 1 (BHV-1) subtypes 1 (BHV-1.1) and 2a (BHV-1.2a). Pesquisa Veterinária Brasileira 24(1):43-49. Centro de Pesquisas Desidério Finamor, Fepagro Saúde Animal, Cx. Postal 47, Eldorado do Sul, RS 92990-000, Brazil. E-mail: proehe@ufrgs.br
The study aimed to examine the capacity of two bovine herpesvirus type 1 (BHV-1) isolates of different subtypes (EVI 123/96, BHV-1.1; SV265/98, BHV-1.2a) to induce respiratory disease in calves. These two isolates are representative of the BHV-1 subtypes prevalent in Brazil. Viral subtypes were confirmed by monoclonal antibody analysis and by restriction enzyme digestion of viral genomes. The viruses were inoculated intranasally into seven 3 months old calves (four with BHV-1.1, three with BHV-1.2a). Three other calves of identical age and condition were kept as uninfected controls. In both groups of infected calves, the clinical signs observed were consistent with typical infectious bovine rhinothracheitis (IBR), including pyrexia, apathy, anorexia, nasal and ocular mucopurulent discharges, erosions on the nasal mucosa, conjunctivitis, lachrymation, redness of nasal mucosa, dyspnoea, coughing, tracheal stridor and enlargement of retropharingeal, submandibular and cervical lymphnodes. No significant differences were observed between the clinical scores attributed to both groups. Virus shedding in nasal and ocular secretions were also similar, apart from a significant difference in nasal virus shedding on day 1 to 3 post-inoculation, which was higher for BHV-1.1 than for BHV-1.2a. Following corticosteroid induced reactivation of the latent infection, recrudescence of clinical signs was also observed, with no significant differences on both groups. It was concluded that both subtypes BHV-1.1 and BHV-1.2a were able to induce clinically undistinguishable respiratory disease in calves, either subsequent to a primary infection or following reactivation.
Abstract in Portuguese:
Spilki F.R, Esteves P.A., Lima M., Franco A.C., Chiminazzo C., Flores E.F., Weiblen R., Driemeier D. & Roehe P.M. 2004. Comparative pathogenicity of bovine herpesviruses type 1 (BHV-1) subtypes 1 (BHV-1.1) and 2a (BHV-1.2a). Pesquisa Veterinária Brasileira 24(1):43-49. Centro de Pesquisas Desidério Finamor, Fepagro Saúde Animal, Cx. Postal 47, Eldorado do Sul, RS 92990-000, Brazil. E-mail: proehe@ufrgs.br
The study aimed to examine the capacity of two bovine herpesvirus type 1 (BHV-1) isolates of different subtypes (EVI 123/96, BHV-1.1; SV265/98, BHV-1.2a) to induce respiratory disease in calves. These two isolates are representative of the BHV-1 subtypes prevalent in Brazil. Viral subtypes were confirmed by monoclonal antibody analysis and by restriction enzyme digestion of viral genomes. The viruses were inoculated intranasally into seven 3 months old calves (four with BHV-1.1, three with BHV-1.2a). Three other calves of identical age and condition were kept as uninfected controls. In both groups of infected calves, the clinical signs observed were consistent with typical infectious bovine rhinothracheitis (IBR), including pyrexia, apathy, anorexia, nasal and ocular mucopurulent discharges, erosions on the nasal mucosa, conjunctivitis, lachrymation, redness of nasal mucosa, dyspnoea, coughing, tracheal stridor and enlargement of retropharingeal, submandibular and cervical lymphnodes. No significant differences were observed between the clinical scores attributed to both groups. Virus shedding in nasal and ocular secretions were also similar, apart from a significant difference in nasal virus shedding on day 1 to 3 post-inoculation, which was higher for BHV-1.1 than for BHV-1.2a. Following corticosteroid induced reactivation of the latent infection, recrudescence of clinical signs was also observed, with no significant differences on both groups. It was concluded that both subtypes BHV-1.1 and BHV-1.2a were able to induce clinically undistinguishable respiratory disease in calves, either subsequent to a primary infection or following reactivation.
#8 - Genetic markers of pathogenicity in Yersinia enterocolitica 0:3 isolated from healthy pigs from Rio de Janeiro, 17(1):19-24
Abstract in English:
ABSTRACT.- Leal T.C.A., Leal N.C. & Almeida A.M.P. 1997. [Genetic markers of pathogenicity in Yersinia enterocolitica 0:3 isolated from healthy pigs from Rio de Janeiro.] Marcadores de patogenicidade em Yersinia enterocolitica 0:3 isoladas de suínos do Rio de Janeiro. Pesquisa Veterinária Brasileira 17(1):19-24. Depto Microbiologia, CPqAM-FIOCRUZ-MS, Cx. Postal 7472, Cidade Universitária, Recife, PE 50670-420, Brazil.
Sixteen Yersinia enterocolitica serotype 0:3 strains, isolated from pigs from Rio de Janeiro, have been analyzed for genetic and phenotypic markers of pathogenicity. lt was observed that only 6 strains harbored the p YV ( + 70 kb) plasmid and one strain harbored a small cryptic plasmid of about 8.6 kb. Accordingly only strains harboring pYV were calcium dependent in the MOX medium at 37°C. Twelve strains showed pesticin sensitivity and the esculin reaction was negative in 13 strains. PCR analysis of pathogenicity genes using specific primers showed the presence of the ail gene in 14 strains, the irp2 gene in one and the psaA in none. Most of the strains were resistant to ampicillin and carbenicillin, although they were susceptible to sulfazotrin and cefoxitin. For chloramphenicol, tetracycline, kanamycin, gentamicin and nalidixic acid the results varied among the strains.
Abstract in Portuguese:
SINOPSE.- Leal T.C.A., Leal N.C. & Almeida A.M.P. 1997. [Genetic markers of pathogenicity in Yersinia enterocolitica 0:3 isolated from healthy pigs from Rio de Janeiro.] Marcadores de patogenicidade em Yersinia enterocolitica 0:3 isoladas de suínos do Rio de Janeiro. Pesquisa Veterinária Brasileira 17(1):19-24. Depto Microbiologia, CPqAM-FIOCRUZ-MS, Cx. Postal 7472, Cidade Universitária, Recife, PE 50670-420, Brazil.
Foi realizada a caracterização genotípica e fenotípica de fatores de patogenicidade em 16 amostras de Yersinia enterocolitica 0:3 isoladas de suínos sadios do Rio de Janeiro. Foi observado que apenas 6 cepas possuíam o plasmídio de virulência, pYV ( + 70 kb) e apresentavam dependência ao cálcio no meio MOX a 37°C. Um plasmídio críptico de cerca de 8,6 kb foi encontrado em uma cepa. Doze cepas revelaram sensibilidade à pesticina enquanto que apenas três se revelaram capazes de hidrolisar a esculina. Através de PCR com "primers" específicos, foi constatada a presença dos genes ail em 14 cepas, irp2, em 1 cepa e a ausência de psaA em todas as cepas analisadas. Quanto aos quimioterápicos, a quase totalidade das cepas mostrou-se ao mesmo tempo resistente à ampicilina e carbenicilina e sensível ao sulfazotrin e à cefoxitina. As respostas foram variadas frente ao cloranfenicol, tetraciclina, kanamicina, gentamicina e ácido nalidíxo.
#9 - Virulence factors of Yersinia enterocolitica 0:3 isolated from healthy pigs, Rio de Janeiro
Abstract in English:
Virulence factors were determined in 43 cultures of Yersinia enterocolitica serotype 0:3, biotype 4, phagetype VIII, isolated from apparently healthy pigs. Twenty one isolates were from tonsils, twelve from feces, six from colon contents and four from tongues. The in vitro tests consisted of examining autoagglutination at 36ºC, and absorption of Congo Red. The virulence assays of Y. enterocolitica were conducted by in vivo tests, testing the invasiveness into guinea-pig eyes and detection of heat stable enterotoxin in suckling mice. The results revealed a higher positivity percentage of the autoagglutination test (76.7%), followed by absorption of Congo Red (53.5%), invasiveness into guinea-pig eyes (20.9%) and detection of heat-stable enterotoxin (7.0%). A higher correlation was found in vitro test as compareci to in vivo tests, which characterized 53.5% Y. enterocolitica isolates tested as virulent and which allowed the conclusion that the simultaneous utilization of autoagglutination and absorption of Congo Red tests may be relevant for the identification of pathogenic strains.
Abstract in Portuguese:
Foram pesquisados os fatores de virulência em 43 estirpes de Yersinia enterocolitica sorotipo 0:3, biotipo 4, lisotipo VIII isoladas de suínos sadios, sendo 21 amostras provenientes de amigdala, 12 de fezes, seis de conteúdo de cólon e quatro de língua. A avaliação da virulência foi verificada pela invasibilidade em olho de cobaia, detecção de enterotoxina termoestável em camundongo lactente, auto aglutinação a 36 ºC e absorção do vermelho Congo. Os resultados revelaram um maior percentual de positividade no teste de auto-aglutinação (76.7%), seguido da absorção do vermelho Congo (53,9%), invasibilidade em olho de cobaia (20,9%) e detecção de enterotoxina termoestável (7,0%). Evidenciou-se maior correlação entre os testes realizados "in vitro" quando comparados às provas "in vivo", caracterizando 53,5% das amostra testadas, como virulentas. A utilização simultânea dos testes de auto-aglutinação a 36°C e absorção do vermelho Congo na identificação de cepas patogênicas parecem ser importantes.
#10 - Pathogenicity of a strain of Marek's disease herpes virus
Abstract in English:
The objective of the present work was to study the pathogenicity of a Brazilian strain of Marek's disease herpes virus (MDV). Chicks experimentally infected at one day of age developed antibody which was detected by the agar gel precipitation test four weeks later. Contactexposed chickens developed antibody after eight weeks. Antibody persisted through the 12th week, when the last assay was performed. Uninoculated control chickens reared in isolation remained free of antibody during the sarne period. Viral antigens were detected in impression smears of spleen, thymus and bursa of Fabricius of inoculated chickens and in those of spleen and bursa of Fabricius of contact-exposed chickens by using a direct immunofluorescent technique. No fluorescence was observed in impression smears of brain, liver, gonads or kidney of all chickens tested. Impression smears of all tissues from uninoculated control chickens were negative. Precipitating antibody against the herpes virus of turkeys was demonstrated in the blood, and tissue extracts of kidney, feather tips, spleen, thymus, bursa of Fabricius and gonads of inoculated and contact-exposed chickens. No antibody was found in similar tissue extracts from uninoculated control chickens. Lymphoid infiltration corresponding to types A, B and C and their combination were observed in the vagus nerves and in the nerves of the brachial and sciatic plexus of chickens experimentally inoculated with MDV. Lymphoid infiltrations in the skin, kidney and gonads, as well as lymphoid depopulation with cystic degeneration of the thymus and bursa of Fabricius, were observed in the inoculated chickens. Similar lesions were observed in the kidney, skin, and nerves of contact-exposed chickens. No microscopic lesions were present in the uninoculated control chickens. It is concluded that the strain of MDV studied induces clinical symptoms, macroscopic and microscopic lesions characteristic of the neural form of Marek's disease, stimulates the development of antibody in the serum, spreads horizontally, and gives rise to viral antigens and antibody detectable in tissue extracts.
Abstract in Portuguese:
O objetivo do presente trabalho foi estudar a patogenicidade de uma cepa brasileira do vírus herpes da doença de Marek (VDM). Aves experimentalmente infectadas com um dia de idade, desenvolveram anticorpos os quais foram detectados pelo teste de precipitação em gel de ágar, após quatro semanas. Aves expostas por contato desenvolveram anticorpos após oito semanas. Tais anticorpos persistiram até a 12ª semana, quando o experimento foi encerrado. Aves testemunhas (não inoculadas) mantidas em isolamento, permaneceram livres de anticorpos durante o mesmo período. Antígenos virais foram detectados em impressões de baço, timo e bursa de Fabricius de aves inoculadas e em impressões de baço e bursa de Fabricius de aves expostas por contato, através da prova de imunofluorescência direta. Fluorescência não foi observada em impressões de cérebro, fígado, gônadas e rins de todas as aves testadas. Todas as impressões de tecidos de aves testemunhas foram negativas. Anticorpos precipitantes contra o vírus herpes de perus (HVT) foram demonstrados no sangue e nos extratos de tecidos renal, pontas de penas, baço, timo, bursa de Fabricius e gônadas de aves inoculadas ou expostas por contato. Anticorpos não foram encontrados nos extrados dos mesmos tecidos, de aves testemunhas. Infiltrações linfocitárias correspondentes aos tipos A, B e C e suas combinações, foram observadas nos nervos vagos e nos plexos braquial e ciático de aves inoculadas experimentalmente com o VDM. Infiltrações linfocitárias na pele, rins e gônadas, assim como, despovoamento linfóide com degeneração cística do timo e da bursa de Fabricius, foram encontradas nas aves inoculadas. Lesões semelhantes foram também observadas nos rins, pele e nervos das aves expostas por contato. Lesões microscópicas não foram visualizadas nas aves testemunhas. Conclui-se que a cepa do VDM estudada, induz sintomas clínicos, lesões macro e microscópicas características da forma neural da doença de Marek, estimula o desenvolvimento de anticorpos no soro, dissemina-se horizontalmente e dá origem a antígenos virais e anticorpos detectáveis nos extratos de tecidos.
