PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

D'Ávila da Silva A., Sortica V.A., Braga A.C., Spilki F.R., Franco A.C., Esteves P.A., Rijsewijk F., Rosa J.C.A., Batista H.B.C.R., Oliveira A.P. & Roehe P.M. 2005. [Antigenic and molecular characterization of eight samples of Aujeszky’s disease virus isolated in the state of Rio Grande do Sul, Brazil, in 2003.] Caracterização antigênica e molecular de oito amostras do virus da doença de Aujeszky isoladas no estado do Rio Grande do Sul em 2003. Pesquisa Veterinária Brasileira 25(1):21-24. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF), Fepagro Saúde Animal, Estrada do Conde 6000, Cx. Postal 47, Eldorado do Sul, RS 92990-000, Brazil. E-mail: proehe@ufrgs.br Pseudorabies or Aujeszky’s disease (AD), caused by pseudorabies virus (PRV) is a major concern in swine production. In the state of Rio Grande do Sul, Brazil, AD was only detected in 1954, in cattle. In 2003 two outbreaks of encephalitis occurred on the northern region of the state, close to the border with the state of Santa Catarina. Pseudorabies virus (PRV) was isolated from distinct farms within the region and subjected to antigenic and genomic analyses. These isolates were compared with prototype strains NIA-3 and NP. Antigenic characterization with a panel of monoclonal antibodies (Mabs) directed to viral glycoproteins (gB, gC, gD and gE,) was performed by an imunoperoxidase monolayer assay (IPMA) on infected cell monolayers. Genomic characterization was carried out by restriction enzyme analysis (REA) of the whole DNA viral genome with Bam HI. The antigenic profile of the eight isolates from Rio Grande do Sul as well as strains NIA-3 and NP were similar. REA analysis revealed that all isolates from Rio Grande do Sul displayed a genomic type II arrangement, a genotype often found in other outbreaks of AD previously reported in other Brazilian states. The results obtained suggest that the eight isolates examined here were similar.

• Aujeszky's disease epidemiology.

Abstract in Portuguese:

D'Ávila da Silva A., Sortica V.A., Braga A.C., Spilki F.R., Franco A.C., Esteves P.A., Rijsewijk F., Rosa J.C.A., Batista H.B.C.R., Oliveira A.P. & Roehe P.M. 2005. [Antigenic and molecular characterization of eight samples of Aujeszky’s disease virus isolated in the state of Rio Grande do Sul, Brazil, in 2003.] Caracterização antigênica e molecular de oito amostras do virus da doença de Aujeszky isoladas no estado do Rio Grande do Sul em 2003. Pesquisa Veterinária Brasileira 25(1):21-24. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF), Fepagro Saúde Animal, Estrada do Conde 6000, Cx. Postal 47, Eldorado do Sul, RS 92990-000, Brazil. E-mail: proehe@ufrgs.br Pseudorabies or Aujeszky’s disease (AD), caused by pseudorabies virus (PRV) is a major concern in swine production. In the state of Rio Grande do Sul, Brazil, AD was only detected in 1954, in cattle. In 2003 two outbreaks of encephalitis occurred on the northern region of the state, close to the border with the state of Santa Catarina. Pseudorabies virus (PRV) was isolated from distinct farms within the region and subjected to antigenic and genomic analyses. These isolates were compared with prototype strains NIA-3 and NP. Antigenic characterization with a panel of monoclonal antibodies (Mabs) directed to viral glycoproteins (gB, gC, gD and gE,) was performed by an imunoperoxidase monolayer assay (IPMA) on infected cell monolayers. Genomic characterization was carried out by restriction enzyme analysis (REA) of the whole DNA viral genome with Bam HI. The antigenic profile of the eight isolates from Rio Grande do Sul as well as strains NIA-3 and NP were similar. REA analysis revealed that all isolates from Rio Grande do Sul displayed a genomic type II arrangement, a genotype often found in other outbreaks of AD previously reported in other Brazilian states. The results obtained suggest that the eight isolates examined here were similar.

Abstract in English:

ABSTRACT.- Franco A.C., Spilki F.R., Esteves P.A., Lima M., Weiblen R., Flores E.F., Rijsewijk F.A.M. & Roehe P.M. 2002. A Brazilian glycoprotein E-negative bovine herpesvirus type 1.2a (BHV-1.2a) mutant is attenuated for cattle and induces protection against wild-type virus challenge. Pesquisa Veterinária Brasileira 22(4):135-140. [Um mutante gE-negativo de herpesvírus bovino tipo 1.2a é atenuado para bovinos e induz proteção frente ao desafio com vírus de campo.] Centro de Pesquisas Veterinárias Desidério Finamor, Fepagro-Saúde Animal, Cx. Postal 2076, Porto Alegre, RS 90001-970, Brazil. E-mail: proehe@ufrgs.br The authors previously reported the construction of a glycoprotein E-deleted (gE·) mutante of bovine herpesvirus type 1.2a (BHV-1.2a). This mutant, 265gE·, was designed as a vacinal strain for differential vaccines, allowing the distinction between vaccinated and naturally infected cattle. In order to determine the safety and efficacy of this candidate vaccine virus, a group of calves was inoculated with 265gE·. The virus was detected in secretions of inoculated calves to lower titres and for a shorter period than the parental virus inoculated in control calves. Twenty one days after inoculation, the calves were challenged with the wild type parental virus. Only mild signs of infection were detected on vaccinated calves, whereas nonvaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Six months after vaccination, both vaccinated and control groups were subjected to reactivation of potentially latent virus. The mutant 265gE· could not be reactivated from vaccinated calves. The clinical signs observed, following the reactivation of the parental virus, were again much milder on vaccinated than on non-vaccinated calves. Moreover, parental vírus shedding was considerably reduced on vaccinated calves at reactivation. In view of its attenuation, immunogenicity and protective effect upon challenge and reactivation with a virulent BHV-1, the mutant 265gE· was shown to be suitable for use as a BHV-1 differential vaccine vírus.

• BHV-1 differential vaccine gE deletion IBR vacina diferencial gE.

Abstract in Portuguese:

RESUMO.- Franco A.C., Spilki F.R., Esteves P.A., Lima M., Weiblen R., Flores E.F., Rijsewijk F.A.M. & Roehe P.M. 2002. A Brazilian glycoprotein E-negative bovine herpesvirus type 1.2a (BHV-1.2a) mutant is attenuated for cattle and induces protection against wild-type virus challenge. Pesquisa Veterinária Brasileira 22(4):135-140. [Um mutante gE-negativo de herpesvírus bovino tipo 1.2a é atenuado para bovinos e induz proteção frente ao desafio com vírus de campo.] Centro de Pesquisas Veterinárias Desidério Finamor, Fepagro-Saúde Animal, Cx. Postal 2076, Porto Alegre, RS 90001-970, Brazil. E-mail: proehe@ufrgs.br Em estudo prévio os autores reportaram a construção de um mutante do Vírus da Rinotraqueíte Infecciosa Bovina (IBR) ou Herpesvírus Bovino tipo 1.2a (BHV-1.2a), do qual foi deletado o gene que codifica a glicoproteina E. Esse mutante (265gE-) foi construído a partir de uma amostra autóctone do vírus, tendo como objetivo seu uso como amostra vacinai em vacinas diferenciais, capazes de permitir a diferenciação entre animais vacinados e infectados com vírus de campo. Para determinar a atenuação e eficácia do 265gE· como imunógeno, bezerros foram inoculados por via intranasal com 106,9 DICC50 do mesmo. O vírus foi detectado em secreções dos animais inoculados em títulos mais baixos e por um período mais curto do que a amostra virulenta parental, inoculada em animais controle. Vinte e um dias após, os animais inoculados com o vírus mutante foram desafiados com a amostra parental, apresentando somente sinais leves de infecção. Os animais controle apresentaram intensa rinotraqueíte e excretaram vírus em títulos mais elevados e por mais tempo do que os vacinados. Seis meses após a vacinação, foi examinada a capacidade de reativação da infecção nos bezerros, através da administração de corticosteróides. O mutante 265gE- não foi reativado dos animais vàcinados. Os sinais clínicos consequentes à reativação do vírus parental foram muito atenuados nos animais vacinados, em comparação com os não vacinados. Além disso, a excreção de vírus de campo foi consideravelmente reduzida nestes últimos. Em vista de sua atenuação, imunogenicidade e efeito protetivo frente ao desafio com uma amostra virulenta de BHV-1 e subseqüente reativação, o mutante 265gE- demonstrou apresentar grande potencial para ser utilizado como vírus vacinai em vacinas diferenciais contra o BHV-1.