Avian reovirus infection: an overview / Reovirose aviária: um panorama

Poultry production is an activity of great importance in Brazilian economy, both due to the domestic consumption and the large amount of chicken meat exportation. Poultry activity modernization allowed the creation of animals in high density facilities, however, it facilitates the rapid dissemination of pathogens, which reduces the productivity rates. This review aims to highlight the avian reovirus, an important agent of arthritis in birds that has a worldwide distribution. The affected birds present a reduction in weight gain due to movement difficulties. In addition to arthritis, the virus may be related to a variety of pathological conditions, such as enteric and respiratory disorders, Hepatitis and myocarditis. The main prevention and control measure is the flock vaccination. Nevertheless, due to the avian reovirus great genetic variability, the vaccine may not be effective against circulating strains. This article aims to overview the virus biology, its variability and classification, and the infection pathology and diagnosis.

A avicultura é um setor de grande importância na economia brasileira tanto pelo aumento do consumo interno quanto pelo crescimento na exportação de carne de frango. A modernização da atividade avícola permitiu a criação adensada de animais, facilitando, no entanto, a rápida disseminação de patógenos que reduzem os índices de produtividade dos plantéis. Nesta revisão, é destacado o reovírus aviário, importante agente de artrite em aves que apresenta distribuição mundial. As aves acometidas apresentam redução no ganho de peso devido à dificuldade de locomoção. Além da artrite, o vírus pode estar relacionado a uma variedade de condições patológicas, como distúrbios entéricos e respiratórios, hepatite e miocardite. A principal forma de prevenção e controle é a vacinação do plantel. No entanto, devido à grande variabilidade genética do reovírus aviário, a vacina utilizada pode não ser eficiente contra estirpes que circulam no campo. O artigo traz uma visão geral sobre a biologia do vírus, sua variabilidade e propostas de classificação dos isolados, patologia da doença e diagnóstico da infecção.

Avian reovirus infection: an overview / Reovirose aviária: um panorama

Poultry production is an activity of great importance in Brazilian economy, both due to the domestic consumption and the large amount of chicken meat exportation. Poultry activity modernization allowed the creation of animals in high density facilities, however, it facilitates the rapid dissemination of pathogens, which reduces the productivity rates. This review aims to highlight the avian reovirus, an important agent of arthritis in birds that has a worldwide distribution. The affected birds present a reduction in weight gain due to movement difficulties. In addition to arthritis, the virus may be related to a variety of pathological conditions, such as enteric and respiratory disorders, Hepatitis and myocarditis. The main prevention and control measure is the flock vaccination. Nevertheless, due to the avian reovirus great genetic variability, the vaccine may not be effective against circulating strains. This article aims to overview the virus biology, its variability and classification, and the infection pathology and diagnosis.(AU)

A avicultura é um setor de grande importância na economia brasileira tanto pelo aumento do consumo interno quanto pelo crescimento na exportação de carne de frango. A modernização da atividade avícola permitiu a criação adensada de animais, facilitando, no entanto, a rápida disseminação de patógenos que reduzem os índices de produtividade dos plantéis. Nesta revisão, é destacado o reovírus aviário, importante agente de artrite em aves que apresenta distribuição mundial. As aves acometidas apresentam redução no ganho de peso devido à dificuldade de locomoção. Além da artrite, o vírus pode estar relacionado a uma variedade de condições patológicas, como distúrbios entéricos e respiratórios, hepatite e miocardite. A principal forma de prevenção e controle é a vacinação do plantel. No entanto, devido à grande variabilidade genética do reovírus aviário, a vacina utilizada pode não ser eficiente contra estirpes que circulam no campo. O artigo traz uma visão geral sobre a biologia do vírus, sua variabilidade e propostas de classificação dos isolados, patologia da doença e diagnóstico da infecção.(AU)

Investigation of enteric viruses in the feces of neotropical migratory birds captured on the coast of the State of Pará, Brazil

Migratory birds can become long-distance vectors for a wide range of microorganisms and can cause human disease, being the Brazilian coast a gateway for northern migratory birds. These animals are considered natural reservoirs of different viruses that cause important diseases, being relevant research of viral pathogens in migratory birds to epidemiology surveillance. The objective of the study was to investigate the presence of avian rotavirus (AvRV), avian reovirus (ARV) and picobirnavirus (PBV) in Neotropical migratory birds captured on the coast of Brazil. A total of 23 individual fecal samples of the migratory birds species Calidris pusilla (20 birds), Numenius phaeopus (1 bird) and Charadrius semipalmatus (2 birds) were collected. Fecal suspensions were prepared from the collected samples for subsequent extraction of double-stranded RNA (dsRNA), which was subjected to polyacrylamide gel electrophoresis (PAGE) and reverse transcription polymerase chain reaction (RT-PCR). The electrophoretic profiles were not detected by PAGE, and the amplification for the studied viruses PBV, ARV and AvRV (specie D, gene VP6 and NSP4) were negative. Positivity for AvRVD, VP7 gene was of 4.35% (1/23) for the migratory bird Calidris pusilla. After sequencing and building the tree of phylogenetic relationships avian Rotavirus Group D identified in this study was phylogenetically related and grouped into one branch, together to previously reported AvRVD from Brazil in chicken flocks with 99.8% nucleotide and 100% amino acid similarities.(AU)

Investigation of enteric viruses in the feces of neotropical migratory birds captured on the coast of the State of Pará, Brazil

Migratory birds can become long-distance vectors for a wide range of microorganisms and can cause human disease, being the Brazilian coast a gateway for northern migratory birds. These animals are considered natural reservoirs of different viruses that cause important diseases, being relevant research of viral pathogens in migratory birds to epidemiology surveillance. The objective of the study was to investigate the presence of avian rotavirus (AvRV), avian reovirus (ARV) and picobirnavirus (PBV) in Neotropical migratory birds captured on the coast of Brazil. A total of 23 individual fecal samples of the migratory birds species Calidris pusilla (20 birds), Numenius phaeopus (1 bird) and Charadrius semipalmatus (2 birds) were collected. Fecal suspensions were prepared from the collected samples for subsequent extraction of double-stranded RNA (dsRNA), which was subjected to polyacrylamide gel electrophoresis (PAGE) and reverse transcription polymerase chain reaction (RT-PCR). The electrophoretic profiles were not detected by PAGE, and the amplification for the studied viruses PBV, ARV and AvRV (specie D, gene VP6 and NSP4) were negative. Positivity for AvRVD, VP7 gene was of 4.35% (1/23) for the migratory bird Calidris pusilla. After sequencing and building the tree of phylogenetic relationships avian Rotavirus Group D identified in this study was phylogenetically related and grouped into one branch, together to previously reported AvRVD from Brazil in chicken flocks with 99.8% nucleotide and 100% amino acid similarities.

Distribution of IFITM3 in yellow-feathered broilers and inhibition of Avian Reovirus multiplication by IFITM3

This study was carried to express the interferon-induced transmembrane protein 3 (IFITM3) in vitro and examine its function in inhibition of avian reovirus (ARV) replication. The recombinant prokaryotic vector expressing yellow-feathered broiler IFITM3 was successfully constructed, and the recombinant protein was expressed in competent Escherichia coli BL21 cells. New Zealand white rabbits were immunized with the purified recombinant protein to prepare a polyclonal antibody, with a titer of 1:128,000. Immunohistochemistry, reverse transcription-PCR, and real-time fluorescence quantitative PCR showed that IFITM3 was distributed in the yellow-feathered broiler immune organs, and the expression of IFITM3 in bursa of Fabricius was more than in spleen and thymus. It was found that in the thymus, spleen and bursa of Fabricius the mRNA expression levels of IFN and IFITM3 were significantly induced after ARV infection. And it was also certified in the chicken embryo fibroblasts (CEFs) which infected with ARV. Then the IFN was added into the cell culture medium before CEFs were infected with ARV. The results indicated that the mRNA of IFITM3 expression was significantly increased and ARV multiplication was significantly inhibited. And when the expression of IFITM3 was knocked down by siRNA-IFITM3, the expression of IFITM3 was significantly reduced, but the ARV multiplication was significantly increased, which indicated that IFITM3 protein could inhibit the ARV replication.(AU)

Distribution of IFITM3 in yellow-feathered broilers and inhibition of Avian Reovirus multiplication by IFITM3

This study was carried to express the interferon-induced transmembrane protein 3 (IFITM3) in vitro and examine its function in inhibition of avian reovirus (ARV) replication. The recombinant prokaryotic vector expressing yellow-feathered broiler IFITM3 was successfully constructed, and the recombinant protein was expressed in competent Escherichia coli BL21 cells. New Zealand white rabbits were immunized with the purified recombinant protein to prepare a polyclonal antibody, with a titer of 1:128,000. Immunohistochemistry, reverse transcription-PCR, and real-time fluorescence quantitative PCR showed that IFITM3 was distributed in the yellow-feathered broiler immune organs, and the expression of IFITM3 in bursa of Fabricius was more than in spleen and thymus. It was found that in the thymus, spleen and bursa of Fabricius the mRNA expression levels of IFN and IFITM3 were significantly induced after ARV infection. And it was also certified in the chicken embryo fibroblasts (CEFs) which infected with ARV. Then the IFN was added into the cell culture medium before CEFs were infected with ARV. The results indicated that the mRNA of IFITM3 expression was significantly increased and ARV multiplication was significantly inhibited. And when the expression of IFITM3 was knocked down by siRNA-IFITM3, the expression of IFITM3 was significantly reduced, but the ARV multiplication was significantly increased, which indicated that IFITM3 protein could inhibit the ARV replication.

The occurrence of Orthoreovirus, Rotavirus and chicken anemia virus in chickens of the poultry industry in Minas Gerais, Brazil / Ocorrência de Orthoreovirus, Rotavirus e vírus da anemia das galinhas em frangos de corte da indústria avícola de Minas Gerais

Fifty-four fecal samples taken from broiler chickens from 1 to 45 days of age, and of pullets from 10 to 13 weeks of age, original from eight different poultry regions in the state of Minas Gerais, Brazil, were collected from March 2008 to January 2010 for avian Orthoreovirus (ARV) and avian Rotavirus (AvRV) analyses. For the assay of ARV, RNA was immediately extracted (Trizolâ) and transcribed into cDNA for assaying in a nested-PCR with ARV-specific primers. For AvRV, polyacrylamide gel electrophoresis (PAGE) was performed with RNA extracts obtained by phenol-chloroform extraction. CAV was additionally investigated through a nested-PCR of thymus and spleen. Results found 5.55% positive for ARV and 9.25% for AvRV. Also, CAV and ARV genomes were detected in co-infection, in a highly prostrated and claudicating chicken flock. No ARV or AvRV infections were detected in pullets. Material of a clinically affected flock was inoculated into SPF embryos, resulting in embryonic hemorrhage, whitish foci in the chorio-allantoic membrane and death. Sequencing of ARV amplicons and isolate cDNA grouped local strains with the ARV S1133 strain, historically used in live vaccines, suggesting the continued circulation of this vaccine virus strain in intensive poultry regions. Detection rates for ARV and AvRV, as well as the presence of CAV, were additionally indicative of failing biosecurity strategies for the intensive poultry regions examined.(AU)

Avaliou-se a ocorrência de Orthoreovirus (ARV) e Rotavirus (AvRV) aviários na avicultura industrial de Minas Gerais. Foram colhidas cinquenta e quatro amostras de fezes de frangos de corte entre um e 45 dias e de frangas de postura de 10 a 13 semanas de idade. Para análise de ARV, o RNA foi imediatamente extraído (Trizol), transcrito em cDNA e avaliado em uma PCR com oligonucleotídeos iniciadores específicos para ARV. Para a investigação de AvRV, os extratos de RNA foram obtidos por fenol-clorofórmio e submetidos à eletroforese em gel de poliacrilamida. Todas as amostras foram também avaliadas para o DNA do vírus da anemia das galinhas (CAV) em uma nested-PCR específica. Em frangos de corte, a positividade encontrada para ARV foi de 5,55% e para AvRV de 9,25%. CAV foi detectado em coinfecção em um plantel com refugagem, claudicação e prostração. Nenhuma amostra de poedeiras foi positiva para ARV ou AvRV. Material de plantel com sinais clínicos foi purificado e inoculado em ovos SPF embrionados, sendo obtidas lesões hemorrágicas e focos brancos na membrana cório-alantóide. O sequenciamento dos produtos de PCR e de embrião agrupou os isolados de ARV com a estirpe S1133, historicamente usada como vacina viva. Os resultados sugerem a continuada circulação da infecção por estirpes assemelhadas a ARV S1133 nas regiões de avicultura industrial. Os índices de detecção de ARV, AvRV e CAV indicam que a intensificação nas regiões produtoras tem resultado em falhas de biosseguridade.(AU)

Studies with reovirus isolated from guinea fowls (Numida meleagridis) / Estudos com reovirus isolado de galinha-dangola (Numida meleagridis)

This paper describes some properties of a reovirus isolated from the pancreas and intestines of guinea fowls suffering from a transmissible enteritis. Coronavirus was also recovered from kidneys of the same birds. The guinea fowl reovirus is pathogenic for guinea fowl, duck and chicken embryos, but it does not reproduce by itself the field findings when inoculated in day-old guinea poults, nor was it found to be pathogenic for chicks and ducklings on experimental infection..

Este trabalho descreve algumas propriedades de um reovírus que foi isolado de pâncreas e intestino de galinhasdangolaque padeciam de uma enterite transmissível. Coronavírus foi isolado do rim das mesmas aves. O reovírusde galinhas-dangola é patogênico para embriões de galinha-dangola, de pata e de galinha mas não reproduziu osachados de campo, quando inoculado em angolinhas, e nem foi patogênico para pintos e patinhos inoculados experimentalmente.

Enteric virus with segmented double-stranded RNA genome in broiler chicken: Rotavirus, Reovirus and Picobirnavirus / Virus entéricos RNA fita dupla, segmentado, em aves: Rotavírus, Reovírus e Picobirnavírus

Enteric infections account for considerable economic losses to the poultry industry through weight loss, low food conversion, direct and indirect expenses with treatments and increased death rates. Poultry intestinal pathologies, either with local or general manifestations, can be caused by bacteria, protozoa or virus, acting alone or in association. Regarding viral etiology, several genera have been isolated from poultry with enteric disease. However, two genera from the Reoviridae family, the rotavirus and the reovirus are found more frequently in broiler chicken and/or laying hen feces. These viruses have been associated with clinical signs of enteritis in most epidemiological research. This revision aims to present some topics on the etiological agents (rotavirus, reovirus and picobirnavirus), the clinical disease and the diagnostic and control methods and prophylaxis of the infection.  

As infecções entéricas são responsáveis por consideráveis prejuízos econômicos à indústria avícola representados por perda de peso, baixa conversão alimentar, custos diretos e indiretos com tratamentos e por aumento na taxa de mortalidade. As patologias intestinais em aves, tanto com manifestação local quanto geral, podem ser determinadas por bactérias, protozoários e vírus, atuando de forma isolada ou em associação. Com relação a etiologia virai, vários gêneros têm sido isolados a partir de aves com enteropatias. Porém, dois gêneros na família Reoviridae, o rotavírus e o reovírus são encontrados com maior freqüência em fezes de frangos de corte e/ou galinhas poedeiras. Na maioria dos inquéritos epidemiológicos esses vírus estão associados a sinais clínicos de enterite. Esta revisão tem por objetivo apresentar alguns tópicos relativos aos agentes etiológicos (Rotavírus, Reovírus e Picobirnavírus), à doença clínica e aos métodos de diagnóstico, controle e profilaxia da infecção.  

Segmented double-stranded genomic RNA viruses in fecal samples from broiler chicken

Segmented double-stranded RNA (dsRNA) viruses were identified by polyacrylamide gel electrophoresis (PAGE) technique in fecal samples from broiler chicken. A total of 378 fecal samples from 1-7 weeks old chickens were analyzed. dsRNA with migration profile characteristic of avian rotavirus (AvRV), reovirus (ARV) or picobirnavirus (PBV) was identified in 32 (8.5%), 7 (1.8%) and 13 (3.4%) samples, respectively. AvRV and ARV occurred more frequently in chickens up to 1 month old and were related with enteritis signs. Considering only fecal samples of chickens with diarrhea, the AvRV was detected in 37.8% (14/37) and the ARV in 13.5% (5/37) of analyzed samples. AvRV was identified in only 1.5% (4/274) and ARV was not detected in normal feces collected from assymptomatic chickens (controls). PBV dsRNA was detected in broiler chickens from two to seven weeks old, more frequently in feces with pasty consistency. The AvRV showed great electrophoretic profile variability in the dsRNA segments and nine different electropherotypes were identified. Variation in genome pattern was not observed in either ARV or PBV.

A técnica de eletroforese em gel de poliacrilamida foi utilizada com o objetivo de identificar vírus com genoma contituído por RNA de fita dupla (dsRNA) segmentado, em material fecal de frangos de corte. Foram analisadas 378 amostras de fezes de aves, com idade entre a primeira e sétima semanas de vida, provenientes de granjas avícolas localizadas no Estado do Paraná, Brasil. dsRNA com perfil de migração característico de rotavírus (AvRV), reovírus (ARV) ou picobirnavírus (PBV), foi identificado em 32 (8,5%), 7 (1,8%) e 13 (3,4%) amostras, respectivamente. AvRV e ARV ocorreram com maior freqüência em aves com até um mês de idade e estiveram diretamente relacionados a fezes diarréicas e pastosas, provenientes de aves com sinais clínicos de enterite. Considerando-se apenas as amostras de fezes colhidas em aves com diarréia, o AvRV foi detectado em 37,8% (14/37) e o ARV em 13,5% (5/37) da amostragem analisada. Em fezes com aspectos normais (controle) obtidas de aves clinicamente sadias, o AvRV foi identificado em apenas 1,5% (4/274) e o ARV não foi detectado. O ácido nucléico do PBV foi detectado com maior freqüência em fezes pastosas colhidas de aves com duas a sete semanas de vida. O AvRV apresentou grande variabilidade eletroforética dos segmentos de dsRNA, tendo sido identificados nove eletroferotipos distintos. Não foram observadas variações no perfil genômico nas amostras de ARV e também de PBV.

Enteric virus with segmented double-stranded RNA genome in broiler chicken: Rotavirus, Reovirus and Picobirnavirus / Virus entéricos RNA fita dupla, segmentado, em aves: Rotavírus, Reovírus e Picobirnavírus

Enteric infections account for considerable economic losses to the poultry industry through weight loss, low food conversion, direct and indirect expenses with treatments and increased death rates. Poultry intestinal pathologies, either with local or general manifestations, can be caused by bacteria, protozoa or virus, acting alone or in association. Regarding viral etiology, several genera have been isolated from poultry with enteric disease. However, two genera from the Reoviridae family, the rotavirus and the reovirus are found more frequently in broiler chicken and/or laying hen feces. These viruses have been associated with clinical signs of enteritis in most epidemiological research. This revision aims to present some topics on the etiological agents (rotavirus, reovirus and picobirnavirus), the clinical disease and the diagnostic and control methods and prophylaxis of the infection.  

As infecções entéricas são responsáveis por consideráveis prejuízos econômicos à indústria avícola representados por perda de peso, baixa conversão alimentar, custos diretos e indiretos com tratamentos e por aumento na taxa de mortalidade. As patologias intestinais em aves, tanto com manifestação local quanto geral, podem ser determinadas por bactérias, protozoários e vírus, atuando de forma isolada ou em associação. Com relação a etiologia virai, vários gêneros têm sido isolados a partir de aves com enteropatias. Porém, dois gêneros na família Reoviridae, o rotavírus e o reovírus são encontrados com maior freqûência em fezes de frangos de corte e/ou galinhas poedeiras. Na maioria dos inquéritos epidemiológicos esses vírus estão associados a sinais clínicos de enterite. Esta revisão tem por objetivo apresentar alguns tópicos relativos aos agentes etiológicos (Rotavírus, Reovírus e Picobirnavírus), à doença clínica e aos métodos de diagnóstico, controle e profilaxia da infecção.