RESUMO
Recombinant vaccines have low-cost manufacturing, regulatory requirements, and reduced side effects compared to attenuated or inactivated vaccines. In the porcine industry, post-weaning multisystemic disease syndrome generates economic losses, characterized by progressive weight loss and weakness in piglets, and it is caused by porcine circovirus type 2 (PCV2). We designed a chimeric antigen (Qm1) to assemble the main exposed epitopes of the Cap-PCV2 protein on the capsid protein of the tobacco necrosis virus (TNV). This design was based on the Cap-N-terminal of an isolated PCV2 virus obtained in Chile. The virus was characterized, and the sequence was clustered within the PCV2 genotype b clade. This chimeric protein was expressed as inclusion bodies in both monomeric and multimeric forms, suggesting a high-molecular-weight aggregate formation. Pigs immunized with Qm1 elicited a strong and specific antibody response, which reduced the viral loads after the PCV2 challenge. In conclusion, the implemented design allowed for the generation of an effective vaccine candidate. Our proposal could be used to express the domains or fragments of antigenic proteins, whose structural complexity does not allow for low-cost production in Escherichia coli. Hence, other antigen domains could be integrated into the TNV backbone for suitable antigenicity and immunogenicity. This work represents new biotechnological strategies, with a reduction in the costs associated with vaccine development.
Assuntos
Antígenos Virais/genética , Proteínas do Capsídeo/genética , Circovirus/imunologia , Vacinas Virais/genética , Animais , Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , Proteínas do Capsídeo/imunologia , Chile/epidemiologia , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/prevenção & controle , Infecções por Circoviridae/veterinária , Circovirus/classificação , Circovirus/genética , Epitopos , Fermentação , Filogenia , Síndrome Definhante Multissistêmico de Suínos Desmamados/epidemiologia , Síndrome Definhante Multissistêmico de Suínos Desmamados/prevenção & controle , Suínos , Tombusviridae/genética , Vacinação/veterinária , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Vacinas Sintéticas/metabolismo , Vacinas Virais/administração & dosagem , Vacinas Virais/imunologia , Vacinas Virais/metabolismoRESUMO
Porcine Circovirus Type 2 (PCV2) is one of the most important pathogens in pigs around the world. PCV2 is a non-enveloped virus and its capsid is formed by a single protein known as open reading frame 2 (ORF2). The aim of this study was to evaluate the antigenicity and immunogenicity of genetically-encoded protein nanoparticles (NPs) containing ORF2 from PCV2 fused to the first 110 amino acids of the N-terminus of polyhedrin from the insect virus Autographa californica nucleopolyhedrovirus (PH(1â¯-1â¯1â¯0)). Our group has previously described that some polyhedrin fragments self-aggregate forming polyhedra-like particles. We identified a self-aggregating signal within the first 110 amino acids from polyhedrin (PH(1â¯-1â¯1â¯0)). Fusing the ORF2 from PCV2 to the carboxyl terminus from PH(1â¯-1â¯1â¯0) results in the formation of NPs which incorporate the antigen of interest. Using this system we synthesized NPs containing PH(1â¯-1â¯1â¯0) fused to ORF2 (PH(1â¯-1â¯1â¯0)PCV2) and purify them to immunize pigs and evaluate the humoral immune response generated by these NPs comparing them to a commercially available vaccine. Pigs immunized with PH(1â¯-1â¯1â¯0)PCV2 NPs produced antibodies against ORF2 from PCV2 as indicated by western blot and ELISA analysis. Antibodies obtained with PH(1â¯-1â¯1â¯0)PCV2 NPs were comparable to those obtained using a commercial PCV2 vaccine. These antibodies neutralized the infection of a recombinant PCV2 expressing the green fluorescent protein (GFP). These results together suggest that the self-aggregating peptide PH(1â¯-1â¯1â¯0) can be used for the synthesis of subunit vaccines against PCV2.
Assuntos
Infecções por Circoviridae/veterinária , Circovirus/genética , Circovirus/imunologia , Nanopartículas , Fases de Leitura Aberta/imunologia , Síndrome Definhante Multissistêmico de Suínos Desmamados/prevenção & controle , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linhagem Celular , Ensaio de Imunoadsorção Enzimática , Feminino , Imunização , Masculino , Fases de Leitura Aberta/genética , Suínos , Vacinas de Subunidades Antigênicas , Vacinas Virais/química , Vacinas Virais/genéticaRESUMO
Worldwide Torque teno sus virus (TTSuV, genus Iotatorquevirus) species have been regarded as possible agents associated with porcine circovirus-associated disease. Iotatorquevirus species possess high genomic variability, suggesting that diverse genotypes are widely geographically distributed. In this study, we validated the genomic variability of Iotaroquevirus species in pigs with postweaned multisystemic wasting syndrome. Genomic DNA from nine TTSuV1a-positive tissues and 15 TTSuV1b-positive tissues was used to amplify the complete ORF2 of each species by nested PCR to perform a molecular characterization. It was found that Mexican TTSuV1a sequences belong to genotype B, sharing phylogenetic origin, high nucleic acid and amino acid sequence similarity and dominant epitope conformation with commercially linked countries, such as the United States, Canada and China, whereas the Mexican TTSuV1b sequences belong to genotype A, being more divergent among each other and displaying low nucleotide identity with worldwide genotype A sequences. In both Iotatorquevirus species, a PTPase-like signature motif was identified in the predicted amino acid sequence, being more conserved for Mexican TTSuV1b sequences than for Mexican TTSuV1a sequences, in which several substitutions were observed. These changes may influence the conformation of dominant epitopes as different arrays were determined among TTSuV1a genotypes. ORF2 variability may account for pathogenic differences by modifying viral replication and immune response, as depicted for human TTV.
Assuntos
Infecções por Vírus de DNA/veterinária , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Doenças dos Suínos/virologia , Torque teno virus/genética , Animais , Genótipo , México , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Suínos , Torque teno virus/isolamento & purificaçãoRESUMO
BACKGROUND: Porcine circovirus type 2 (PCV2) is a very small, non-enveloped and icosahedral virus, with circular single stranded DNA genome. This virus is the most ubiquitous and persistent pathogen currently affecting the swine industry worldwide. PCV2 has been implicated as the major causative agent of postweaning multisystemic wasting syndrome (PMWS), a disease which is characterized by severe immunosuppressive effects in the porcine host. Worldwide PCV2 isolates have been classified into four different genotypes, PCV2a, PCV2b, PCV2c and PCVd. The goal of this work was to conduct the first phylogenetic analysis of PCV2 in Chile. METHODS: PCV2 partial ORF2 sequences (462 nt) obtained from 29 clinical cases of PMWS in 22 Chilean intensive swine farms, covering over the 90% of the local pork-production, were analyzed. RESULTS: 14% and 52% of sequences belonged to the genotypes PCV2a and PCV2b, respectively. Surprisingly, 34% of sequences were PCV2a/PCV2d recombinant viruses. CONCLUSIONS: Our findings suggested that a novel cluster of Chilean sequences emerged resulting from intergenotypic recombination between PCV2a and PCV2d.
Assuntos
Circovirus/classificação , Circovirus/genética , Variação Genética , Genótipo , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Recombinação Genética , Animais , Chile , Circovirus/isolamento & purificação , Análise por Conglomerados , Fazendas , Fases de Leitura Aberta , Análise de Sequência de DNA , SuínosRESUMO
A SYBR Green-based real-time polymerase chain reaction (qPCR) was designed to detect Ungulate copiparvovirus 2, also known as porcine parvovirus 4 (PPV4). The test was applied to search for PPV4 DNAemia in sera from 1- to 4-month-old pigs displaying signs of postweaning multisystemic wasting syndrome (PMWS), as well as in sera from healthy swine at equivalent age and in sera from older healthy animals (>6 months old). High levels of PPV4 DNA were detected in PMWS-affected pigs. The mean viral DNA load in PMWS-affected pigs was 5.2 × 107 copies/mL, whereas in young healthy pigs it was 1.4 × 105 copies/mL (P ≤ 0.001). Although the copy numbers were lower in younger PMWS-affected individuals, this result sheds some light on the possible association between PPV4 viral load detection in this group and the immune impairment caused by PMWS.
Assuntos
Infecções por Parvoviridae/veterinária , Parvovirinae/isolamento & purificação , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Doenças dos Suínos/epidemiologia , Carga Viral/veterinária , Animais , DNA Viral/análise , Infecções por Parvoviridae/epidemiologia , Infecções por Parvoviridae/virologia , Parvovirus Suíno/fisiologia , Prevalência , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Suínos , Doenças dos Suínos/virologiaRESUMO
Porcine circovirus-2 (PCV2) is the etiologic agent of several diseases in pigs, including multi-systemic wasting syndrome (PMWS). In this work, a new mutant PCV2b was isolated from PMWS-affected pigs on a Brazilian farm. Its genome showed high sequence similarity (>99% identity) to those from a group of emerging mutants isolated from cases of PMWS outbreaks in vaccinated pigs in China, the USA and South Korea. Here, we show that these isolates share a combination of low-frequency substitutions (single amino acid polymorphisms with a frequency of ≤25%) in the viral capsid protein, mainly in regions of immunoprotective epitopes, and an additional lysine residue at position 234. These isolates were phylogenetically grouped in the PCV2b clade, reinforcing the idea of the emergence of a new group of mutants PCV2b associated with outbreaks worldwide. The identification of these polymorphisms in the viral capsid highlights the importance of considering these isolates for the development of more-effective vaccines.
Assuntos
Substituição de Aminoácidos , Proteínas do Capsídeo/genética , Infecções por Circoviridae/veterinária , Circovirus/genética , Epitopos/genética , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Sequência de Aminoácidos , Animais , Brasil , Proteínas do Capsídeo/química , Proteínas do Capsídeo/imunologia , Infecções por Circoviridae/virologia , Circovirus/classificação , Circovirus/imunologia , Circovirus/isolamento & purificação , Epitopos/química , Epitopos/imunologia , Dados de Sequência Molecular , Filogenia , Polimorfismo de Nucleotídeo Único , SuínosRESUMO
Associations between Torque teno sus viruses (TTSuVs) and the occurrence of postweaning multisystemic wasting syndrome (PMWS) have been reported with controversial results. Currently, no studies have been performed comparing simultaneously viral loads of TTSuVs and PCV2. To examine the role for TTSuVs in PMWS-affected animals, a SYBR Green-based quantitative PCR (qPCR) was designed to detect and quantify TTSuV1, TTSuV2 and PCV2 genomes in swine sera. TTSuV1 genome loads were significantly higher in healthy adults than in young and SPF animals (p<0.05) suggesting that the prevalence of TTSuV1 infection increases with age and bears no association with PMWS. Regarding TTSuV2, no significant variation was detected in viral loads within any of the groups. As expected, PCV2 genome loads were higher in PMWS-affected swine than in healthy or SPF animals (p<0.001). These findings provide clear evidence to indicate that neither TTSuV1 nor TTSuV2 viral loads have any correlation with the occurrence of PMWS.
Assuntos
Circovirus/genética , Genoma Viral/genética , Síndrome Definhante Multissistêmico de Suínos Desmamados/epidemiologia , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Soro/virologia , Torque teno virus/genética , Carga Viral/veterinária , Animais , Benzotiazóis , Brasil , Diaminas , Compostos Orgânicos , Quinolinas , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Testes Sorológicos/veterinária , Suínos , Carga Viral/genéticaRESUMO
Porcine circovirus 2 (PCV2) is a common virus in pig population and is associated with the postweaning multisystemic wasting disease (PMWS). In this study, it was developed and evaluated the single-tube nested PCR (STNPCR) method for the detection of PCV2 DNA. PCV2 reference controls and swine tissue samples were used, and primers were selected for targeting specific regions of the viral genome. In comparison of the methods, STNPCR was 10 times more sensitive than conventional PCR and showed the same sensitivity to nested PCR (NPCR), but with reduction in the risk of cross-contamination. In clinical application, 55 tissue samples were analysed by conventional PCR and resulted in 67% (37/55) of positive reactions, while the NPCR and STNPCR were able to identify the presence of viral DNA in 100% (55/55) of the samples. The high sensitivity combined with the elimination of cross-contamination makes the STNPCR method suitable for the epidemiological studies of PCV2 and can aid in the diagnosis of PMWS.
Assuntos
Circovirus/isolamento & purificação , Reação em Cadeia da Polimerase/veterinária , Síndrome Definhante Multissistêmico de Suínos Desmamados/diagnóstico , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Animais , Sequência de Bases , Circovirus/genética , Biologia Computacional , Primers do DNA/genética , DNA Viral/genética , Feminino , Genoma Viral/genética , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/métodos , Sensibilidade e Especificidade , Análise de Sequência de DNA/veterinária , SuínosRESUMO
The swine production is characterized by high productivity due to improvements especially in environmental conditions, genetics and animal nutrition and is constantly evolving to meet the demands of the consumer market. In this context, a confl ict of interest occurs when combining high production rates in short time with the welfare animal. However some changes directly impact on production rates, as the weaning phase which is considered the most traumatic, with direct refl ection on the performance and welfare of animals. Weaning has a direct impact on the development of piglets and several factors corroborate that this phase is considered the most traumatic in the lives of animals. Early weaning can increase stress, raise the diarrhea index, reduce growth and increase mortality in swine. It is necessary to be more careful on weaning due to the inherent mellow process and all behavioral physiological, endocrine and productive issues involved.
A produção suína se caracteriza pela alta produtividade decorrente de melhorias principalmente em condições de ambiente, genética e nutrição animal, estando em constante evolução para atender as exigências do mercado consumidor. Neste contexto, um conflito de interesse acontece ao associar altos índices produtivos em curto espaço de tempo com o bem-estar dos animais. No entanto algumas mudanças impactam diretamente nos índices produtivos, como a fase de desmame que é considerada a mais traumática, com reflexo direto no desempenho e bem-estar dos animais. O desmame tem impacto direto no desenvolvimento dos leitões e vários fatores corroboram para que esta fase seja considerada a mais traumática na vida dos animais. O desmame precoce pode aumentar o estresse, elevar o índice de diarreia, reduzir o crescimento e aumentar a taxa de mortalidade na suinocultura. É preciso ser mais criterioso no desmame em virtude da delicadeza inerente ao processo e a todas as questões comportamentais, fisiológicas, endócrinas e produtivas envolvidas.
Assuntos
Animais , Animais Lactentes/fisiologia , Animais Recém-Nascidos/fisiologia , Desmame , Suínos/crescimento & desenvolvimento , Bem-Estar do Animal , Comportamento Animal , Síndrome Definhante Multissistêmico de Suínos DesmamadosRESUMO
The swine production is characterized by high productivity due to improvements especially in environmental conditions, genetics and animal nutrition and is constantly evolving to meet the demands of the consumer market. In this context, a confl ict of interest occurs when combining high production rates in short time with the welfare animal. However some changes directly impact on production rates, as the weaning phase which is considered the most traumatic, with direct refl ection on the performance and welfare of animals. Weaning has a direct impact on the development of piglets and several factors corroborate that this phase is considered the most traumatic in the lives of animals. Early weaning can increase stress, raise the diarrhea index, reduce growth and increase mortality in swine. It is necessary to be more careful on weaning due to the inherent mellow process and all behavioral physiological, endocrine and productive issues involved.(AU)
A produção suína se caracteriza pela alta produtividade decorrente de melhorias principalmente em condições de ambiente, genética e nutrição animal, estando em constante evolução para atender as exigências do mercado consumidor. Neste contexto, um conflito de interesse acontece ao associar altos índices produtivos em curto espaço de tempo com o bem-estar dos animais. No entanto algumas mudanças impactam diretamente nos índices produtivos, como a fase de desmame que é considerada a mais traumática, com reflexo direto no desempenho e bem-estar dos animais. O desmame tem impacto direto no desenvolvimento dos leitões e vários fatores corroboram para que esta fase seja considerada a mais traumática na vida dos animais. O desmame precoce pode aumentar o estresse, elevar o índice de diarreia, reduzir o crescimento e aumentar a taxa de mortalidade na suinocultura. É preciso ser mais criterioso no desmame em virtude da delicadeza inerente ao processo e a todas as questões comportamentais, fisiológicas, endócrinas e produtivas envolvidas.(AU)
Assuntos
Animais , Animais Recém-Nascidos/fisiologia , Animais Lactentes/fisiologia , Suínos/crescimento & desenvolvimento , Desmame , Bem-Estar do Animal , Comportamento Animal , Síndrome Definhante Multissistêmico de Suínos DesmamadosRESUMO
Porcine circovirus type 2 (PCV2) is the essential etiological infectious agent of postweaning multisystemic wasting syndrome (PMWS), which is considered one of the most economically important swine diseases worldwide. In this study, a comparison between methodologies based on classical phylogenetic trees and networks to infer the origin of PCV2 in Cuba was performed. In addition, the mechanisms supporting the genetic variability of Cuban PCV2 populations were investigated. A retrospective study, using pig sera collected in Cuba from 1993 to 2004, to evaluate the presence of PCV2 genome and PCV2-specific antibodies was also conducted and revealed a lack of evidence of PCV2 infection in Cuban swine from years 1993 to 2004. A total of 24 complete Cuban PCV2 sequences collected between 2005 and 2009 from different regions of the country were analyzed. Three classical methods of phylogenetic analysis, namely Neighbour-Joining, Maximum Parsimony and Bayesian Inference, as well as haplotype network construction, were used. Whereas the classical phylogenetic trees suggested different origins for the Cuban PCV2 strains, the haplotype network revealed a direct connection between all the Cuban sequences in agreement with the obtained epidemiological and viral sequence data. Moreover, the importation of pigs carried out in 2005 from the Quebec-Ontario region, Canada, seems to be the most likely origin of PCV2 in Cuba. Likewise, the genetic variability of Cuban PCV2 sequences was supported by geographic segregation and positive selection pressure with estimated rates of nucleotide substitution on the order of 3.12×10(-3) and 6.57×10(-3) substitutions/site/year, which are closer to those reported for RNA viruses.
Assuntos
Infecções por Circoviridae/veterinária , Circovirus/genética , Filogenia , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Animais , Anticorpos Antivirais/sangue , Teorema de Bayes , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/virologia , Circovirus/classificação , Cuba/epidemiologia , Haplótipos , Modelos Genéticos , Ontário , Síndrome Definhante Multissistêmico de Suínos Desmamados/epidemiologia , Análise de Componente Principal , Quebeque , Estudos Retrospectivos , Análise de Sequência de DNA , Suínos/virologiaRESUMO
Porcine circovirus-2 (PCV-2) is the main agent related to post-weaning multisystemic wasting syndrome (PMWS) and it is also associated with other syndromes affecting pigs. Not all pigs infected with PCV-2 will develop PMWS and the incidence of PMWS is higher when coinfecting viral and bacterial pathogens are present. In this study, PCV-2 viral loads were evaluated in the tissues of animals with and without PMWS in order to investigate the relationship between viral load and microscopical lesions. Lymph nodes had the highest average viral load, but there was no significant difference between lesion severity and the viral load in these structures. There was no significant difference between the average viral load in inguinal lymph nodes of animals with and without PMWS. However, samples from pigs with PMWS had more severe lesions compared with samples from non-PMWS animals. These findings suggest that other infectious and non-infectious cofactors may be important in the pathogenesis of PMWS.
Assuntos
Circovirus/fisiologia , Síndrome Definhante Multissistêmico de Suínos Desmamados/patologia , Animais , Circovirus/isolamento & purificação , DNA Viral/análise , Interações Hospedeiro-Patógeno , Linfonodos/patologia , Linfonodos/virologia , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Suínos , Carga ViralRESUMO
Porcine circovirus-2 (PCV-2) is considered the major etiological agent of post-weaning multisystemic wasting syndrome (PMWS) in pigs. The clinical manifestations of the disease are correlated with moderate to high amounts of PCV-2 DNA in biological samples of affected pigs. A threshold of 10(7) DNA copies/ml is suggested as the trigger factor for symptoms. A comparative study was conducted to determine which quantitative method would be more suitable to estimate the PCV-2 DNA load. Two polymerase chain reaction (PCR) assays were developed: a competitive PCR (cPCR) and a SYBR Green-based real-time PCR. The assays were compared for their capacity to detect PCV-2 in DNA samples extracted from liver, lung, spleen, mesenteric lymph nodes, and kidney of PMWS-affected (n = 23) or non-PMWS-affected pigs (n = 9). Both assays could successfully quantify PCV-2 DNA in all tissue samples and were able to detect significant differences between the numbers of PCV-2 DNA copies found in tissues of PMWS-affected and non-PMWS-affected pigs (≥ 10(2.5)). The highest mean viral loads were detected by the SYBR Green real-time PCR, up to 10(7.0 ± 1.5) copies/100 ng of total DNA sample, while the cPCR detected up to 10(4.8 ± 1.5). A mean difference of 10(1.8) was found between the amounts of PCV-2 DNA detected, using the SYBR Green real-time PCR and the cPCR, suggesting that the viral load threshold for PMWS should be determined for each particular assay.
Assuntos
Circovirus/classificação , Circovirus/genética , DNA Viral/isolamento & purificação , Corantes Fluorescentes/farmacologia , Reação em Cadeia da Polimerase/veterinária , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Animais , Reação em Cadeia da Polimerase/métodos , Síndrome Definhante Multissistêmico de Suínos Desmamados/diagnóstico , Sensibilidade e Especificidade , Suínos , Carga ViralRESUMO
Postweaning multisystemic wasting syndrome (PMWS) is considered a multifactorial emerging disease of which Porcine circovirus-2 (PCV-2) is the necessary infectious cause. However, retrospective studies have shown that PMWS is not a new disease and that PCV-2 has been circulating in pig farms for years. Most of these studies were performed in Europe and Asia; only a few were performed in North or South America. A PCV-2 retrospective serological survey was carried out with 659 serum samples collected from pigs in Mexico between 1972 and 2000. Serological analyses were performed with an immunoperoxidase monolayer assay (IPMA). The overall prevalence of PCV-2 antibodies was 59% (387/659); the prevalence was 27% (24/90) for the period from 1972-1979; 44% (74/169) from 1980-1989, and 72% (289/400) from 1990-2000. Antibodies to PCV-2 were detected in at least 1 pig from all tested years since 1973. This study shows evidence of enzootic PCV-2 infection in Mexico for many years before the first description of PMWS in the country (in 2001), further supporting results obtained in other parts of the world. To date, this study provides the earliest evidence of PCV-2 infection in the North and South American continents.
Assuntos
Infecções por Circoviridae/veterinária , Síndrome Definhante Multissistêmico de Suínos Desmamados/epidemiologia , Doenças dos Suínos/epidemiologia , Animais , Infecções por Circoviridae/epidemiologia , DNA de Cadeia Simples/genética , DNA Viral/genética , Inquéritos Epidemiológicos , México/epidemiologia , Estudos Retrospectivos , Estudos Soroepidemiológicos , Testes Sorológicos , Suínos , Doenças dos Suínos/sangue , Doenças dos Suínos/virologiaRESUMO
Porcine circovirus 2 (PCV2) is the major causative agent of postweaning multisystemic wasting syndrome (PMWS) and is associated with different syndromes affecting pigs. The PCV2 genome has three main open reading frames (ORFs) among which the ORF2 encodes the capsid protein. In this study, the ORF2 nucleotide sequences of 30 Brazilian isolates were analyzed. The sequences were compared to other GenBank sequences using phylogenic and phylogeographic approaches. Our results show high sequence variability in Brazil, since, in this work, the Brazilian isolates were classified into subgroup 1AB, 2D and 2, which reveals that the virus was introduced in Brazil more than once. On the other hand, most of Brazilian isolates seem to be derived from only one introduction. According to the data from the Pig Breeders' Association, the multiple introductions of the virus probably occurred through the import of animals with the asymptomatic form of the virus or through the import of contaminated semen. The results point to the necessity of implementing programs aimed at selecting sows in order to avoid the import of animals infected by Group 1 PCV2.
Assuntos
Circovirus/classificação , Circovirus/genética , Variação Genética , Filogenia , Animais , Brasil , Clonagem Molecular , DNA Viral/genética , Genoma Viral , Geografia , Haplótipos , Fases de Leitura Aberta , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Análise de Sequência de DNA , Suínos/virologiaRESUMO
Neste trabalho, foi estudada a ocorrência e a bacteriologia das otites purulentas em suínos apresentando três condições clínico-patológicas distintas: síndrome multissistêmica do definhamento dos suínos (SMDS), crescimento retardado (porém sem apresentação de sinais clínicos da SMDS) e crescimento normal. No total, foram examinados 385 animais com idade de 60-130 dias, sendo a confirmação do diagnóstico da SMDS obtida pelos sinais clínicos e achados patológicos e pela detecção de antígenos virais por imunoistoquímica. De 242 animais com a SMDS, 57 (23,5 por cento) apresentaram lesões purulentas no ouvido médio. Entre os 119 animais de baixo desenvolvimento, apenas 1 (0,7 por cento) apresentou a lesão. Não foram detectadas lesões macroscópicas no ouvido médio dos 24 animais com crescimento normal. Os agentes isolados com maior freqüência foram Arcanobacterium pyogenes (43 por cento), Streptococcus α-hemolíticos (37,2 por cento) e Pasteurella multocida (27,9 por cento) dos 86 ouvidos submetidos à bacteriologia. A alta ocorrência de lesões purulentas no ouvido médio de animais com a SMDS sugere que a infecção pelo PCV2 pode tornar o suíno mais suscetível às otites bacterianas. A ocorrência reduzida dessas lesões em suínos de baixo desenvolvimento, sem a manifestação clínica da SMDS, sugere que a otite média não representa uma causa importante de mau desempenho em leitões nas fases de crescimento e terminação. O envolvimento de A. pyogenes, Streptococcus α-hemolíticos e P. multocida na maioria das lesões apontam a importância desses organismos como agentes causais de otite média em suínos.(AU)
The occurrence and bacteriology of purulent otitis in groups of pigs affected by three different clinical conditions are described: postweaning multisystemic wasting syndrome (PMWS), depressed growth (attrition) and normal growth (control). A total of 385 animals, 60-130 days of age, were examined. Diagnosis of PMWS was confirmed by the presence of clinical signs and pathological findings compatible with the disease, and through detection of viral antigens in tissues by immunohistochemistry. From 242 pigs with PMWS, 57 (23.5 percent) showed purulent lesions in the middle ear. Among 119 pigs with attrition, only 1 (0.7 percent) presented the lesion. In 24 control pigs, middle ear lesions were not detected. The most frequently isolated agents from the lesions were Arcanobacterium pyogenes (43 percent), á-hemolytic Streptococci (37.2 percent) and Pasteurella multocida (27.9 percent) out of 86 materials. The frequent occurrence of purulent lesions in the middle ear of PMWS affected pigs suggests that PCV2 infection may increase the susceptibility to bacterial otitis. The low occurrence of this disease in piglets with attrition suggests that otitis does not represent a significant cause for depressed growth in pigs from growing and finishing age. The isolation of A. pyogenes, á-hemolytic Streptococci and P. multocida from most of the lesions emphasizes the importance of these organisms as causal agents of otitis media in swine.(AU)
Assuntos
Animais , Recém-Nascido , Otite Média Supurativa/complicações , Otite Média Supurativa/etiologia , Otite Média Supurativa/veterinária , Síndrome Definhante Multissistêmico de Suínos Desmamados/complicações , Técnicas Bacteriológicas/métodos , Técnicas Bacteriológicas/veterinária , Transtornos do Crescimento/microbiologia , Transtornos do Crescimento/veterinária , Suínos/crescimento & desenvolvimento , Suínos/microbiologiaRESUMO
A técnica de imunoperoxidase em monocamada de células (IPMC) para demonstração de anticorpos contra o circovírus suíno tipo 2 (CVS2) foi empregada para a investigação sorológica em oito granjas de suínos destinadas à produção comercial. Das 240 amostras de soros testadas, 229 (95,4%) foram reagentes com títulos que variaram de 20 até 10.240. Títulos de anticorpos foram detectados nas faixas etárias de duas a três semanas até animais acima de 24 semanas e encontrados em granjas com e sem a síndrome multissistêmica do definhamento (SMD). A média dos títulos de anticorpos revelou diferenças estatísticas (P<0,05) nas faixas etárias de 11 a 13 e 14 a 22 semanas nos animais oriundos de granjas com e sem a SMD. Os resultados refletem a importância de conhecer o perfil sorológico do rebanho e assegurar a implantação de um efetivo cronograma de vacinação contra o CVS2.(AU)
The immunoperoxidase in monolayer cells (IPMC) technique for the demonstration of antibodies against type 2 porcine circovirus (PCV2) was used for the serological investigation in eight industrial swine farms. Out of the 240 tested sera, 229 (95,4%) were reactive with titers which varied from 20 up to 10.240. Titers of antibodies were detected in pigs from two to three weeks of age up to above 24 weeks of age, and were observed in farms with and without clinical signs indicative of the post-weaning multisystemic wasting syndrome (PMWS). Analysing the mean titers, statistical differences (P<0.05) were evidentiated in two age intervals, of 11 to 13 and 14 to 22 weeks of age. The results indicate the importance of determining the serological profiles of commercial swine herds, in order to enable the implantation of effective hygiene and vaccination protocols for PCV2 prevention.(AU)
Assuntos
Animais , Sorologia , Circovirus , Síndrome Definhante Multissistêmico de Suínos Desmamados , Técnicas Imunoenzimáticas/veterinária , SuínosRESUMO
A técnica de imunoperoxidase em monocamada de células (IPMC) para demonstração de anticorpos contra o circovírus suíno tipo 2 (CVS2) foi empregada para a investigação sorológica em oito granjas de suínos destinadas à produção comercial. Das 240 amostras de soros testadas, 229 (95,4%) foram reagentes com títulos que variaram de 20 até 10.240. Títulos de anticorpos foram detectados nas faixas etárias de duas a três semanas até animais acima de 24 semanas e encontrados em granjas com e sem a síndrome multissistêmica do definhamento (SMD). A média dos títulos de anticorpos revelou diferenças estatísticas (P<0,05) nas faixas etárias de 11 a 13 e 14 a 22 semanas nos animais oriundos de granjas com e sem a SMD. Os resultados refletem a importância de conhecer o perfil sorológico do rebanho e assegurar a implantação de um efetivo cronograma de vacinação contra o CVS2.
The immunoperoxidase in monolayer cells (IPMC) technique for the demonstration of antibodies against type 2 porcine circovirus (PCV2) was used for the serological investigation in eight industrial swine farms. Out of the 240 tested sera, 229 (95,4%) were reactive with titers which varied from 20 up to 10.240. Titers of antibodies were detected in pigs from two to three weeks of age up to above 24 weeks of age, and were observed in farms with and without clinical signs indicative of the post-weaning multisystemic wasting syndrome (PMWS). Analysing the mean titers, statistical differences (P<0.05) were evidentiated in two age intervals, of 11 to 13 and 14 to 22 weeks of age. The results indicate the importance of determining the serological profiles of commercial swine herds, in order to enable the implantation of effective hygiene and vaccination protocols for PCV2 prevention.