No description available.

No description available.

A Doença Infecciosa da Bolsa de Fabrício (DIB) é uma doença viral altamente contagiosa que afeta as galinhas nas primeiras semanas de vida. Ela pode causar altas taxas de morbidade e mortalidade dependendo da cepa viral envolvida no surto. Como o vírus é muito resistente no ambiente, a vacinação é requerida em alta pressão de infecção. Devido às variações no grau de virulência das vacinas disponíveis para o controle da DIB, o presente estudo objetivou avaliar a patogenicidade e imunogenicidade de três vacinas comerciais: as vacinas recombinante, complexo-imune e intermediária. Quatro grupos com 55 aves specific pathogen free (SPF) cada foram imunizadas no primeiro dia e desafiadas aos 25 dias com a cepa muito virulenta G11 para verificar o grau de proteção conferido pelas vacinas. As aves foram examinadas, sangradas, eutanaziadas e necropsiadas aos 25, 30 e 35 dias de idade. As bolsas de Fabrício (BF) foram coletadas, pesadas, mensurados seus diâmetros e pesos relativos e submetidas ao exame histopatológico para verificar a presença de lesões. Amostras de soro foram submetidas ao teste de ELISA para quantificação dos anticorpos contra a DIB. Aos 23 dias de idade, as aves SPF foram submetidas à prova de hipersensibilidade cutânea à fitohemaglutinina para avaliar o efeito das vacinas sobre a imunidade celular. Os resultados mostraram que a vacina complexo-imune induziu a maior redução no peso relativo e diâmetro e o maior grau de lesões nas BF. A vacina recombinante foi a que apresentou os melhores resultados, preservando a integridade tecidual e celular das BF. A vacina intermediária apenas induziu um discreto grau de atrofia nas BF. As análises sorológicas, antes do desafio, revelaram que as três vacinas testadas induziram com a mesma intensidade a imunidade humoral das aves SPF, apresentando semelhantes títulos de anticorpos. A avaliação da imunidade celular mostrou que a resposta à fitohemaglutinina das aves SPF imunizadas com as vacinas recombinante e complexo-imune foi menor do que as aves do grupo não vacinado. Nas condições em que o experimento foi conduzido verificou-se que a vacina complexo-imune é a mais patogênica, causando lesões em maior número e severidade nas BF. Todas as vacinas, quando administradas no primeiro dia, são eficazes em proteger as aves SPF contra o desafio com a cepa muito virulenta G11. / Infectious Bursal Disease (IBD) is a highly contagious viral disease that affects chickens in their first weeks of life. It may cause high morbidity and mortality depending on the strain involved in the outbreak. As the virus is very resistant to the environment, vaccination is required under high pressure of infection. Hence, due to variations in the degree of the virulence of vaccines available to control DIB, this study aimed to evaluate the pathogenicity and immunogenicity of three vaccines against Infectious Bursal Disease (IBD): recombinant, immune-complex and intermediate vaccines. Four experimental groups, with fifty-five specific pathogen free (SPF) chickens each, were vaccinated on the first day and challenged on the twenty-fifth day with the very virulent G11 strain in order to verify the protection conferred by the vaccines. The Chickens were examined, bled, euthanized and necropsied on the twenty-fifth, thirtieth and thirty-fifth days of age, and the Bursas of Fabricius (BF) were collected, weighed, having their diameter and relative weight measured, were subjected to histological examination to verify the presence of lesions, Serum samples were subjected to ELISA for the quantification of antibodies against IBD. On the twenty-third day of age, the chickens were submitted to cutaneous basophil hypersensitivity test at phytohemagglutinin to evaluate the immunosuppressive effect of the vaccines on the cell-mediated immunity. The results indicated that the immune-complex vaccine induced not only the greatest reduction in relative weight and diameter, but also the greatest lesion degree on the BF. The recombinant vaccine showed the best results, preserving the tissue and cellular integrity of the BF. The intermediate vaccine induced only a slight degree of atrophy on the BF. The intermediate vaccine induced only a slight degree of atrophy on the BF. The serological analyses, before the challenge, revealed that the three tested vaccines induced humoral immunity of SPF chickens with the same intensity, presenting similar antibody titers. In addition, the evaluation of the cellmediated immunity demonstrated that the cellular reaction to phytohemagglutinin of the immunized SPF chickens with the recombinant and immune-complex vaccines was smaller than the unvaccinated group. Thus, these results have indicated that, under the conditions of the experiment, the immune-complex vaccine is the most pathogenic, causing the highest atrophy degrees on the BF. Therefore, all vaccines, when administered on the first day, are considered effective to protect SPF chickens against the challenge with the very virulent G11 strain.

A Doença Infecciosa da Bolsa de Fabrício (DIB) é uma doença viral altamente contagiosa que afeta as galinhas nas primeiras semanas de vida. Ela pode causar altas taxas de morbidade e mortalidade dependendo da cepa viral envolvida no surto. Como o vírus é muito resistente no ambiente, a vacinação é requerida em alta pressão de infecção. Devido às variações no grau de virulência das vacinas disponíveis para o controle da DIB, o presente estudo objetivou avaliar a patogenicidade e imunogenicidade de três vacinas comerciais: as vacinas recombinante, complexo-imune e intermediária. Quatro grupos com 55 aves specific pathogen free (SPF) cada foram imunizadas no primeiro dia e desafiadas aos 25 dias com a cepa muito virulenta G11 para verificar o grau de proteção conferido pelas vacinas. As aves foram examinadas, sangradas, eutanaziadas e necropsiadas aos 25, 30 e 35 dias de idade. As bolsas de Fabrício (BF) foram coletadas, pesadas, mensurados seus diâmetros e pesos relativos e submetidas ao exame histopatológico para verificar a presença de lesões. Amostras de soro foram submetidas ao teste de ELISA para quantificação dos anticorpos contra a DIB. Aos 23 dias de idade, as aves SPF foram submetidas à prova de hipersensibilidade cutânea à fitohemaglutinina para avaliar o efeito das vacinas sobre a imunidade celular. Os resultados mostraram que a vacina complexo-imune induziu a maior redução no peso relativo e diâmetro e o maior grau de lesões nas BF. A vacina recombinante foi a que apresentou os melhores resultados, preservando a integridade tecidual e celular das BF. A vacina intermediária apenas induziu um discreto grau de atrofia nas BF. As análises sorológicas, antes do desafio, revelaram que as três vacinas testadas induziram com a mesma intensidade a imunidade humoral das aves SPF, apresentando semelhantes títulos de anticorpos. A avaliação da imunidade celular mostrou que a resposta à fitohemaglutinina das aves SPF imunizadas com as vacinas recombinante e complexo-imune foi menor do que as aves do grupo não vacinado. Nas condições em que o experimento foi conduzido verificou-se que a vacina complexo-imune é a mais patogênica, causando lesões em maior número e severidade nas BF. Todas as vacinas, quando administradas no primeiro dia, são eficazes em proteger as aves SPF contra o desafio com a cepa muito virulenta G11. / Infectious Bursal Disease (IBD) is a highly contagious viral disease that affects chickens in their first weeks of life. It may cause high morbidity and mortality depending on the strain involved in the outbreak. As the virus is very resistant to the environment, vaccination is required under high pressure of infection. Hence, due to variations in the degree of the virulence of vaccines available to control DIB, this study aimed to evaluate the pathogenicity and immunogenicity of three vaccines against Infectious Bursal Disease (IBD): recombinant, immune-complex and intermediate vaccines. Four experimental groups, with fifty-five specific pathogen free (SPF) chickens each, were vaccinated on the first day and challenged on the twenty-fifth day with the very virulent G11 strain in order to verify the protection conferred by the vaccines. The Chickens were examined, bled, euthanized and necropsied on the twenty-fifth, thirtieth and thirty-fifth days of age, and the Bursas of Fabricius (BF) were collected, weighed, having their diameter and relative weight measured, were subjected to histological examination to verify the presence of lesions, Serum samples were subjected to ELISA for the quantification of antibodies against IBD. On the twenty-third day of age, the chickens were submitted to cutaneous basophil hypersensitivity test at phytohemagglutinin to evaluate the immunosuppressive effect of the vaccines on the cell-mediated immunity. The results indicated that the immune-complex vaccine induced not only the greatest reduction in relative weight and diameter, but also the greatest lesion degree on the BF. The recombinant vaccine showed the best results, preserving the tissue and cellular integrity of the BF. The intermediate vaccine induced only a slight degree of atrophy on the BF. The intermediate vaccine induced only a slight degree of atrophy on the BF. The serological analyses, before the challenge, revealed that the three tested vaccines induced humoral immunity of SPF chickens with the same intensity, presenting similar antibody titers. In addition, the evaluation of the cellmediated immunity demonstrated that the cellular reaction to phytohemagglutinin of the immunized SPF chickens with the recombinant and immune-complex vaccines was smaller than the unvaccinated group. Thus, these results have indicated that, under the conditions of the experiment, the immune-complex vaccine is the most pathogenic, causing the highest atrophy degrees on the BF. Therefore, all vaccines, when administered on the first day, are considered effective to protect SPF chickens against the challenge with the very virulent G11 strain.

A Doença Infecciosa da Bolsa de Fabrício (DIB) é uma doença viral altamente contagiosa que afeta as galinhas nas primeiras semanas de vida. Ela pode causar altas taxas de morbidade e mortalidade dependendo da cepa viral envolvida no surto. Como o vírus é muito resistente no ambiente, a vacinação é requerida em alta pressão de infecção. Devido às variações no grau de virulência das vacinas disponíveis para o controle da DIB, o presente estudo objetivou avaliar a patogenicidade e imunogenicidade de três vacinas comerciais: as vacinas recombinante, complexo-imune e intermediária. Quatro grupos com 55 aves specific pathogen free (SPF) cada foram imunizadas no primeiro dia e desafiadas aos 25 dias com a cepa muito virulenta G11 para verificar o grau de proteção conferido pelas vacinas. As aves foram examinadas, sangradas, eutanaziadas e necropsiadas aos 25, 30 e 35 dias de idade. As bolsas de Fabrício (BF) foram coletadas, pesadas, mensurados seus diâmetros e pesos relativos e submetidas ao exame histopatológico para verificar a presença de lesões. Amostras de soro foram submetidas ao teste de ELISA para quantificação dos anticorpos contra a DIB. Aos 23 dias de idade, as aves SPF foram submetidas à prova de hipersensibilidade cutânea à fitohemaglutinina para avaliar o efeito das vacinas sobre a imunidade celular. Os resultados mostraram que a vacina complexo-imune induziu a maior redução no peso relativo e diâmetro e o maior grau de lesões nas BF. A vacina recombinante foi a que apresentou os melhores resultados, preservando a integridade tecidual e celular das BF. A vacina intermediária apenas induziu um discreto grau de atrofia nas BF. As análises sorológicas, antes do desafio, revelaram que as três vacinas testadas induziram com a mesma intensidade a imunidade humoral das aves SPF, apresentando semelhantes títulos de anticorpos. A avaliação da imunidade celular mostrou que a resposta à fitohemaglutinina das aves SPF imunizadas com as vacinas recombinante e complexo-imune foi menor do que as aves do grupo não vacinado. Nas condições em que o experimento foi conduzido verificou-se que a vacina complexo-imune é a mais patogênica, causando lesões em maior número e severidade nas BF. Todas as vacinas, quando administradas no primeiro dia, são eficazes em proteger as aves SPF contra o desafio com a cepa muito virulenta G11. / Infectious Bursal Disease (IBD) is a highly contagious viral disease that affects chickens in their first weeks of life. It may cause high morbidity and mortality depending on the strain involved in the outbreak. As the virus is very resistant to the environment, vaccination is required under high pressure of infection. Hence, due to variations in the degree of the virulence of vaccines available to control DIB, this study aimed to evaluate the pathogenicity and immunogenicity of three vaccines against Infectious Bursal Disease (IBD): recombinant, immune-complex and intermediate vaccines. Four experimental groups, with fifty-five specific pathogen free (SPF) chickens each, were vaccinated on the first day and challenged on the twenty-fifth day with the very virulent G11 strain in order to verify the protection conferred by the vaccines. The Chickens were examined, bled, euthanized and necropsied on the twenty-fifth, thirtieth and thirty-fifth days of age, and the Bursas of Fabricius (BF) were collected, weighed, having their diameter and relative weight measured, were subjected to histological examination to verify the presence of lesions, Serum samples were subjected to ELISA for the quantification of antibodies against IBD. On the twenty-third day of age, the chickens were submitted to cutaneous basophil hypersensitivity test at phytohemagglutinin to evaluate the immunosuppressive effect of the vaccines on the cell-mediated immunity. The results indicated that the immune-complex vaccine induced not only the greatest reduction in relative weight and diameter, but also the greatest lesion degree on the BF. The recombinant vaccine showed the best results, preserving the tissue and cellular integrity of the BF. The intermediate vaccine induced only a slight degree of atrophy on the BF. The intermediate vaccine induced only a slight degree of atrophy on the BF. The serological analyses, before the challenge, revealed that the three tested vaccines induced humoral immunity of SPF chickens with the same intensity, presenting similar antibody titers. In addition, the evaluation of the cellmediated immunity demonstrated that the cellular reaction to phytohemagglutinin of the immunized SPF chickens with the recombinant and immune-complex vaccines was smaller than the unvaccinated group. Thus, these results have indicated that, under the conditions of the experiment, the immune-complex vaccine is the most pathogenic, causing the highest atrophy degrees on the BF. Therefore, all vaccines, when administered on the first day, are considered effective to protect SPF chickens against the challenge with the very virulent G11 strain.

No description available.

The effects of vitamin E (VE) and Arginine (ARG) on humoral and cellular immunity in chickens were investigated in two experiments. The humoral immunity was measured by antibody responses to sheep red blood cells (SRBC) and maternal antibody titers to the infectious bursal disease virus (IBDV), while the cellular immunity was studied using the cutaneous basophil hypersensitivity test to phytogemagglutinin (PHA) and by counting subpopulations of T-lymphocytes. We used two levels of ARG: normal (NARG, 1.2% in feed) and high ARG (HARG, additional 0.3% in drinking water or 1% in feed in experiments 1 and 2, respectively); and three levels of VE were given: 40, 80, and 400 IU/kg feed in experiment 1, and 40, 80, and 200 in experiment 2. / HARG improved the antibody response to SRBC compared with NARG ( P<0.01 for experiment 1 and P<0.013 for experiment 2) 4 days after injection in both experiments. In experiment 1, the VE80 birds maintained higher antibody titers to SRBC (P<0.001) than the VE40 and VE400 birds 4, 8 and 16 d after inoculation. In experiment 2, the antibody titers to SRBC were higher in the VE80 birds compared with the VE200 birds at days 5, 8, and 12 after inoculation (P<0.001). Maternal antibody titers (log10) to the IBDV were higher in the HARG than in the NARG diet in 17-day-old birds (P<0.001) and higher in the VE80 than in the VE40 birds (P<0.001), yet similar to those of the VE200 birds. No interactions were found between ARG and VE. / Naive birds fed HARG exhibited a higher response than NARG birds (P<0.05) to PHA-P at d 17 and to PHA-M at d 41, but, after a second exposure, high ARG levels did not have an effect. Also, in naive birds, the effects of VE were not significant at d 17, but showed an influence after a second exposure in 41-d-old birds. / The percentage of T-helper (Th) and T-cytotoxic (Tc) cells in the blood of 29-d-old birds were not different between ARG levels (P=0.07 and P=0.06, respectively), but Th cells were higher in the VE80 and VE200 birds than in the VE40 birds, and Tc was higher in the VE80 than in the VE40 birds (P=0.02). The B-cell:T-cell ratio was higher in the HARG than the NARG birds (P=0.01) and in the VE40 compared with the VE80 and VE200 birds (P<0.001). Neither ARG nor VE had an effect on the ratio of Th:Tc cells, nor on the percentage of immature T-lymphocytes. / A combination of high levels of ARG and high levels of VE (80 IU/kg of BW) has an important immunomodulation effect on the cellular and humoral immune responses in broiler chickens, improving both maternal antibody titers against the IBDV and antibody titers against SRBC. A combination of ARG and VE increases the proportions of Th and Tc cells, the B-cell:T-cell ratio, and growth performance. The evidence suggests that ARG and VE play complementary and regulatory role on immune response and may enhance the resistance of broilers to infectious diseases. / Key words. Arginine, vitamin E, humoral immunity, cell-mediated immunity, lymphocyte, ELISA. / L'effet de la vitamine E (VE) et l'arginine (ARG) sur les systèmes hummoraireet cellulaire de l'immunité a était évalué chez la volaille dans deux recherches. Lesystème hummoraire de l'immunité a était évalué en utilisant les paramètres tels que laproduction d'anticorps après une injection des globules rouge provenant des moutons(SRBC) et le niveau d'anticorps maternelle après une infection avec les virus causantla maladie 'infectious bursal disease' (lBDV), tandis que les effets sur le systemcellulaire de l'immunité avaient aussi été évalués en utilisant les paramètres comme'cutaneous basophil hypersensitivity test to phytogemagglutinin (PHA)' et endéterminant la concentration des lymphocytes T. Deux concentrations de ARG avaientété utilisées: normale (NARG, 1.2 % de la diète) et une concentration élevée (HARG,additionel 0.3 % dans l'eau ou 1 % dans les diètes); et 3 concentrations de VE: 40, 80et 400 lU/kg dans les diètes dans la première recherche et 40, 80, et 200 lU/kg dans ladeuxième recherche.

No description available.

Empresa Brasileira de Pesquisa Agropecuária - EMBRAPA / Reusing litter is a common practice in broiler farming. However, it requires the adoption of efficient procedures for inactivating and controlling residual microorganisms during downtime between flocks to ensure sanitary control over the next flock and the quality of the broiler meat. The broiler production adopts a series of stringent precautionary measures to avoid sanitary emergencies and should be able to employ appropriate control measures. In addition, international consumer markets require proof of the efficiency of treatment methods for broiler litter reuse. The efficiency of broiler litter treatments on pathogens is variable and multifactorial and can be influenced by the treatment method and/or microorganisms evaluated. This study aimed to evaluate the efficiency of different strategies of treatment of broiler litter on Newcastle disease virus (NDV), Infectious bursal disease virus (IBDV) and Salmonella Heidelberg. Total enterobacteria counts were carried out as an indicator of microbiological quality of litter. First, the experimental contamination of the broiler litter by viruses was standardized, comparing the seeder birds inoculated versus the direct spray of the virus in the broiler litter. To evaluate the treatments, reused broiler litter was contaminated with the three microorganisms and submitted to the treatments (T): T1- shallow fermentation; T2- quicklime; T3- shallow fermentation followed by quicklime; and, T4- untreated. The broiler litter was submitted to bacteriological and physico-chemical analyzes during treatment. Sentinel chicks were housed on the broiler litter treated and further monitored by clinical evaluation, as well as microbiological, serological and molecular tests. The results demonstrated that seeder birds were efficient to stablish viral contamination in broiler litter. T1 was superior in reducing total enterobacteria in the broiler litter. The evaluation of sentinel chicks also indicated that T1 and T3 inactivated IBDV in the broiler litter. T2 was not able to reduce the microorganisms evaluated, and its association with T1 (T3) did not enhance the treatment action. NDV did not survive in broiler litter, regardless of the treatment applied. S. Heidelberg survived in broiler litter after all treatments evaluated and was also detected in the sentinel chicks. The antimicrobial activity of T1 and T3 was associated to ammonia levels present in the broiler litter. The results reveal that shallow fermentation is efficient to control residual IBDV and total enterobacteria in recycled broiler litter. However, other strategies should be considered in the presence of S. Heidelberg. / A reutilização da cama aviária é uma prática comum na avicultura de corte. Porém, o reuso da cama requer a adoção de procedimentos eficientes na inativação e controle de micro-organismos indesejáveis no intervalo entre os lotes, para preservar a saúde avícola e a qualidade do alimento produzido. A preocupação com as questões sanitárias na avicultura engloba a saúde dos frangos e do consumidor. A produção está sujeita às emergências sanitárias e deve estar preparada para empregar medidas adequadas de contenção e controle. Além disso, os mercados consumidores internacionais demandam comprovação da eficiência dos métodos de tratamento para o reuso da cama entre lotes de frangos. A eficiência dos tratamentos de cama sobre os patógenos é variável e multifatorial e pode ser influenciada pelo método de tratamento e/ou pelos micro-organismos avaliados. Deste modo, o objetivo desta pesquisa foi avaliar a eficiência de diferentes estratégias de tratamento da cama aviária sobre vírus da Doença de Newcastle (VDNC), vírus da Doença Infecciosa da Bursa (VDIB) e Salmonella Heidelberg. Enterobactérias totais foram analisadas como indicador da qualidade microbiológica da cama aviária. Inicialmente, a contaminação experimental pelos vírus aviários foi padronizada, comparando-se a excreção por aves inoculadas (seeder birds) versus a aspersão direta dos vírus na cama. Para avaliação dos tratamentos, cama aviária reutilizada foi contaminada com os três micro-organismos e submetida aos tratamentos (T): T1- fermentação plana; T2- cal virgem; T3- fermentação plana seguida de adição de cal virgem; T4- não tratado. A cama aviária foi submetida às análises bacteriológicas e físico-químicas durante o tratamento. Aves sentinelas foram alojadas sobre a cama tratada, sendo monitoradas por meio de avaliação clínica e análises microbiológicas, sorológicas e moleculares. Os resultados demonstraram que as seeder birds foram eficientes em estabelecer a contaminação viral da cama. O T1 foi superior na redução de enterobactérias totais na cama aviária. A avaliação das aves sentinelas indicou que ambos T1 e T3 inativaram VDIB na cama aviária. O T2 não foi eficiente sobre os micro-organismos avaliados e sua associação ao T1 (T3) não potencializou a ação do tratamento. O VDNC não sobreviveu na cama, independente do tratamento aplicado. S. Heidelberg permaneceu viável na cama de todos os tratamentos, sendo também detectada nas aves sentinelas. A atividade antimicrobiana dos T1 e T3 foi relacionada aos maiores teores de amônia presentes na cama aviária. Os resultados indicam que a fermentação plana é eficiente para o controle do VDIB e enterobactérias totais residuais na cama aviária reutilizada. Todavia, na presença de S. Heidelberg outras alternativas devem ser consideradas no controle deste agente de importância na saúde animal e pública.

Made available in DSpace on 2015-03-26T13:47:30Z (GMT). No. of bitstreams: 1 texto completo.pdf: 427044 bytes, checksum: 5c1651c701a5ae2b53e04e42782f989e (MD5) Previous issue date: 2007-09-24 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Infectious bursal disease (IBD) has been the major preoccupation for the poultry industry, especially in the past decade with the emergency of high virulent strains. Mutations in the gene that code the VP2 viral protein of pathogenic strains and the amiss use of attenuate vaccines by few passages have been responsible for the springing of new outbreaks. The purpose of this work was to analyze phylogenetically two different isolates of IBDV in Minas Gerais State by the comparison of the nucleotide sequence of the gene that code VP2 viral capside protein. In order to study the pathogen-host interaction, a subtractive library was constructed from VERO cells infected by IBDV (8 hours post-infection) aiming the identification of differential gene expression during this interaction. For the phylogenic analysis of the isolates, fragments of 251 bp amplified by RT-PCR were cloned and sequenced. The comparison of the sequences revealed that these isolates have 98-100% identity with classical vaccinal IBDV strains indicating that these outbreaks might have been caused by the vaccinal virus. To construct the subtractive library, two cDNA populations were hibridizated: one derived by IBDV infected VERO cells and other by non infected VERO cells. The hibridizated products were amplified for the posterior cloning and evaluation of the differential express products. Understanding of the replication characteristics of the IBDV associated to the study of the virus infection effects in the gene expression of the host cell, shown in this work, will allow the elucidation of the mechanisms involved in the pathogen-host interaction contributing, therefore, for the development of methods more effectives in the control and prevention of the IBDV. / A doença infecciosa bursal (IBD) tem sido, há muitos anos, uma grande preocupação para a indústria avícola, especialmente na década passada devido a emergência de cepas virais hipervirulentas. Mutações no gene responsável pela codificação da proteína viral VP2 de linhagens patogênicas e a má utilização de vacinas atenuadas por poucas passagens têm sido responsáveis pelo aparecimento de novos surtos. A proposta deste trabalho foi analisar filogeneticamente dois diferentes isolados de IBDV de Minas Gerais por meio da comparação da seqüência nucleotídica do gene que codifica a proteína do capsídeo viral VP2. Em razão da necessidade de se estudar melhor a interação patógeno-hospedeiro, objetivou-se ainda a construção de uma biblioteca subtrativa a partir de células VERO infectadas pelo IBDV, 8 horas após a infecção, com a finalidade de identificar genes diferencialmente expressos durante essa interação vírus-célula hospedeira. Para a análise filogenética dos isolados, fragmentos de 251 pb amplificados por RT-PCR foram clonados e seqüenciados. A comparação das seqüências revelou que os isolados possuem identidade de 98-100% com linhagens clássicas vacinais de IBDV, indicando que os surtos analisados podem ter sido causados pelo vírus vacinal. Para a construção da biblioteca subtrativa, duas populações de cDNA foram hibridizadas: uma derivada de células VERO infectadas por IBDV e a outra de células VERO não infectadas. Os produtos hibridizados foram amplificados para posterior clonagem e avaliação dos produtos diferencialmente expressos. O conhecimento das características replicativas do IBDV associado ao estudo das conseqüências da infecção pelo vírus na expressão gênica da célula hospedeira, iniciado neste trabalho, permitirá a elucidação dos mecanismos envolvidos na interação patógeno-hospedeiro, contribuindo assim para o desenvolvimento de métodos mais eficazes no controle e prevenção da IBD.