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O vírus da doença de Marek (MDV) é um agente infeccioso que atinge, principalmente, galinhas domésticas (Gallus gallus domesticus), tanto da avicultura industrial quanto de subsistência, causando uma doença inflamatória linfo-proliferativa conhecida como doença de Marek (DM). A doença acarreta em grandes perdas produtivas e econômicas à avicultura tecnificada, com impacto também à avicultura de subsistência. A ocorrência de MD foi reduzida dramaticamente com o uso da vacinação obrigatória dos pintinhos no incubatório desde os anos 1970. A emergência de estirpes de alta e muito alta virulência do vírus de MD (MDV), entretanto, foi relatada em vários países, envolvidas em surtos em plantéis vacinados. No entanto, apesar do Brasil ser o maior exportador mundial de carne de frango, não se conhece o perfil genético molecular de MDV. Descreve-se a caracterização molecular de estirpes de MDV baseada no sequenciamento de parte do gene que codifica a proteína Meq de MDV, em galinhas da avicultura de subsistência e industrial de Belo Horizonte e região metropolitana. Aves com quadro clínico sugestivo de DM foram admitidas no Laboratório de Doenças das Aves e examinadas. De um total de 112 aves positivas para MDV, quinze (13,4%) isolados com potencial patogênico foram detectados, dois sendo caracterizados como MDV de alta virulência (vvMDV), e os demais treze isolados caracterizaram-se como MDV virulentos (vMDV) clássicos. A presença de estirpes de vvMDV pode representar aumento do risco de falha da proteção vacinal nos plantéis industriais. Entretanto, na grande maioria das aves (86,6%) não foi detectado MDV patogênico. De um total de cento e doze galinhas positivas para MDV, setenta e cinco aves apresentaram um quadro de infecção simultânea entre MDV e um ou mais agentes infecciosos. O cenário de infecções simultâneas ou coinfecções entre MDV e outros agentes endêmicos sugere ser representativo da condição comum na epidemiologia das infecções em aves. A caracterização molecular de MDV e a co-infecção por alguns importantes agentes infecciosos é discutida. Marek disease virus (MDV) is an infectious agent that affects primarily domestic chickens (Gallus gallus domesticus), both of industrial poultry farming as of subsistence, causing a lymphocytic inflammatory disease-known as proliferative Marek disease (MD). The disease causes in productive and economic losses to poultry, but also impact the poultry. The occurrence of MD was reduced dramatically with the use of mandatory vaccination of hatchery chicks since the years 1970. The emergence of strains of high and very high virulence of MD virus (MDV), however, was reported in several countries, involved in outbreaks in vaccinated flocks. However, in spite of Brazil being the world's largest exporter of chicken meat, no known molecular genetic profile of MDV. Describes the molecular characterization of MDV strains based on sequencing of the gene encoding the protein Meq of MDV, in chickens of subsistence and industrial poultry farming of Belo Horizonte and metropolitan region. Birds with clinical picture suggestive of DM were admitted in the laboratory of poultry Diseases and examined. A total of 112 birds positive for MDV, fifteen (13.4%) isolates with pathogenic potential were detected, two being characterized as high virulence MDV (vvMDV), and the remaining thirteen isolates were characterised as MDV virulent (vMDV) classics. The presence of vvMDV strains may represent increased risk of failure of vaccine protection in industrial stocks. However, in the vast majority of birds (86.6%) was not detected MDV pathogen. A total of 112 chickens positive for MDV, 75 birds presented a painting of simultaneous infection between MDV and one or more infectious agents. The scenario of concurrent infections or coinfecções between MDV and other endemic agents suggests be representative of common condition on epidemiology of infections in birds. Molecular characterization of MDV and co-infection by some important infectious agents is discussed.

INTRODUCTION: The precise identification of the genetic variants of the dengue virus is important to understand its dispersion and virulence patterns and to identify the strains responsible for epidemic outbreaks. This study investigated the genetic variants of the capsid-premembrane junction region fragment in the dengue virus serotypes 1 and 2 (DENV1-2). METHODS: Samples from 11 municipalities in the State of Paraná, Brazil, were provided by the Central Laboratory of Paraná. They were isolated from the cell culture line C6/36 (Aedes albopictus) and were positive for indirect immunofluorescence. Ribonucleic acid (RNA) extracted from these samples was submitted to the reverse transcription polymerase chain reaction (RT-PCR) and nested PCR. RESULTS: RT-PCR revealed that 4 of the samples were co-infected with both serotypes. The isolated DENV-1 sequences were 95-100% similar to the sequences of other serotype 1 strains deposited in GenBank. Similarly, the isolated DENV-2 sequences were 98-100% similar to other serotype 2 sequences in GenBank. According to our neighbor-joining tree, all strains obtained in this study belonged to genotype V of DENV-1. The DENV-2 strains, by contrast, belonged to the American/Asian genotypes. CONCLUSIONS: The monitoring of circulating strains is an important tool to detect the migration of virus subtypes involved in dengue epidemics.

INTRODUCTION: The precise identification of the genetic variants of the dengue virus is important to understand its dispersion and virulence patterns and to identify the strains responsible for epidemic outbreaks. This study investigated the genetic variants of the capsid-premembrane junction region fragment in the dengue virus serotypes 1 and 2 (DENV1-2). METHODS: Samples from 11 municipalities in the State of Paraná, Brazil, were provided by the Central Laboratory of Paraná. They were isolated from the cell culture line C6/36 (Aedes albopictus) and were positive for indirect immunofluorescence. Ribonucleic acid (RNA) extracted from these samples was submitted to the reverse transcription polymerase chain reaction (RT-PCR) and nested PCR. RESULTS: RT-PCR revealed that 4 of the samples were co-infected with both serotypes. The isolated DENV-1 sequences were 95-100% similar to the sequences of other serotype 1 strains deposited in GenBank. Similarly, the isolated DENV-2 sequences were 98-100% similar to other serotype 2 sequences in GenBank. According to our neighbor-joining tree, all strains obtained in this study belonged to genotype V of DENV-1. The DENV-2 strains, by contrast, belonged to the American/Asian genotypes. CONCLUSIONS: The monitoring of circulating strains is an important tool to detect the migration of virus subtypes involved in dengue epidemics. INTRODUÇÃO:A identificação precisa da variante genética do vírus da dengue é importante para compreender a dispersão, virulência e identificação das cepas responsáveis pelas epidemias. O objetivo da pesquisa foi investigar a variação genética do fragmento da junção do gene capsídeo/pré-membrana dos sorotipos 1 e 2. MÉTODOS: Amostras de onze municípios do Estado Paraná, Brasil, foram cedidas pelo Laboratório Central do Paraná e consistiam em isolados de cultura de células da linhagem C6/36 (Aedes albopictus), positivos para técnica de imunofluorescência indireta. O Ribonucleic acid (RNA) dessas amostras foi extraído, seguido da transcrição reversa, reação em cadeia da polimerase (PCR) e nested PCR. RESULTADOS: Co-infecção por DENV-1 e 2 (virus da dengue 1 e 2) foi observada em quatro pacientes, através da técnica Reverse transcriptase-polymerase chain reaction (RT-PCR). Para o DENV-1 a porcentagem de similaridade variou de 95 a 100% comparando com cepas do Genbank. Para o DENV-2 a porcentagem de similaridade variou de 98 a 100%. De acordo com o cladograma gerado, todas as cepas deste estudo se agruparam no genótipo V para DENV-1. Para o DENV-2 foi encontrada a cepa referente ao genótipo asiático/americano. CONCLUSÕES: O monitoramento das cepas circulantes torna-se uma ferramenta importante na detecção da migração dos subtipos do vírus da dengue envolvidos em epidemias.