Agrupamento genético de isolados do vírus da bronquite infecciosa das aves no Brasil com base na análise do gene S1 por RT-PCR-RFLP

Doze isolados de campo do Brasil e uma estirpe de referência vacinal do vírus da bronquite infecciosa das aves (VBI) foram propagadas em ovos embrionados SPF. O gene S1 dessas amostras foi analisado por RT-PCR seguido de RFLP, empregando-se as enzimas de restrição HaeIII, XcmI e BstyI. Observou-se a existência de cinco genótipos diferentes: M (Massachusetts), A , B, C e D. Cinco dos doze isolados de campo do VBI foram classificados no genótipo Massachusetts e os sete vírus restantes foram classificados em quatro genotipos diferentes; A (2), B (2), C (2) ou D (1). Os resultados desta genotipagem concordam com os dados obtidos na análise imunológica previamente realizada para a maior parte destes vírus, destacando a ocorrência de uma variabilidade marcante entre os isolados do VBI que estão circulando nas granjas avícolas comerciais do BrasilTwelve Brazilian isolates and one reference vaccine strain of avian infectious bronchitis virus (IBV) were propagated in embryonating chicken eggs. The entire S1 glycoprotein gene of these viruses was analysed by reverse-transcriptase-polymerase chain reaction and restriction fragment length polymorphism (RT-PCR-RFLP), using the restriction enzymes HaeIII, XcmI and BstyI. The RFLP patterns led to the classification of these isolates into five distinct genotypes: A, B, C, D and Massachusetts. Five of twelve isolates were grouped in Massachusetts genotype and the remaining seven viruses were classified into four distinct genotypes: A (2), B (2), C (2) or D (1). Such genotyping classification agreed with previous immunological analysis for most of these viruses, highlighting the occurrence of a relevant variability among the IBV strains that are circulating in Brazilian commercial poultry flock

Pesquisa de anticorpos anti antígeno VIA (“Virus-infection associated” ) do virus da febre aftosa em búfalos (Bubalus bubalis, Linnaeus, 1758), ovinos e caprinos de alguns municípios do Estado de São Paulo, Brasil

The results of experiments to investigate antibody to virus-infection-associated (VIA) antigen in 157 sera samples from Indian buffalos (Bubalus bubalis), 370 sera from sheep and 180 sera from goats from some cities of São Paulo State, Brazil, are reported. Antibody against virus-infection-associated (VIA) antigen was found in 52 per cent of Indian buffalos, in 5,4 per cent of sheep and in 11 per cent of goats. These studies were done with sera from animals with well-documented pre-and postexposure histories of foot-and-mouth disease and vaccination.Foi realizado um estudo sorológico em 157 amostras de soros de búfalos indianos (Bubalus bubalis), em 370 soros de ovinos e em 180 soros de caprinos de algumas propriedades do Estado de São Paulo, Brasil. Os resultados encontrados revelam que 52% dos búfalos, 5,4% dos ovinos e 11% dos caprinos continham anticorpos anti antígeno VIA do vírus da febre aftosa. Esse estudo foi realizado em animais cujo histórico de vacinação e de exposição ao vírus da febre aftosa era conhecido

Evaluation of an indirect ELISA method for the detection of chicken antibodies against infectious bronchitis virus

An indirect ELISA method was developed and applied to detect antibodies against infectious bronchitis virus (IBV). Three hundred serum samples collected from vaccinated and non-vaccinated chickens under field conditions were tested. The ELISA results were compared with antibody titers determined by a serum neutralization assay (SN). Good coefficients of correlation (r2 = 0.750) and of agreement (80%) were recorded and the ELISA reproducibility was high. The cutoff point between those techniques corresponded to ELISA level 2. It is concluded that our indirect ELISA method can advantageously replace the conventional SN test, allowing a good follow-up of IBV post-vaccination antibodies due to its convenience and applicability compared to the other assay.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Analise filogenética do gene da hemaglutinina do vírus da cinomose em canídeos domésticos e silvestres naturalmente infectados

Canine distemper is one of the most important infecto-contagious diseases that affects dogs. It is a disease caused by the Canine Distemper Virus (CDV), a Paramyxovirus, of the genus Morbilivirus, worldwide, without seasonality, without predilection for sex or race, has a higher incidence in young animals, and can affect all ages. Although a single CDV serotype has been recognized, outbreaks in recent years in the United States and studies of phylogeny based primarily on the H gene, also conducted in other countries, have pointed to a genetic distance between the CDV samples used as vaccine strains and the circulating strains in the domestic and wild canine population. Based on this context, the objective of this study was to perform the molecular and phylogenetic analysis of the H gene from strains isolated from CDV in naturally infected domestic and wild canines. For phylogenetic analysis, complete sequences of the H gene of CDV variants isolated from Brazil and the United States were selected from domestic and wild canids, then analyzed by the PAUP v.4.0 program using the Maximum Parsimony method with Branch-and- Bound. The results obtained suggest that the group of CDV isolates in Brazil are distinct from the North American isolates and genotypically close to the vaccine isolates. In addition, the viral phylogeny of CDV isolates in wild animals indicates domestic dogs as a source of infection for these wild carnivores.A cinomose canina é uma das enfermidades infectocontagiosas mais importantes que acomete os cães. É uma doença causada pelo vírus da Cinomose (CDV), um Paramyxovirus, do gênero Morbilivirus, de ocorrência mundial, sem sazonalidade, sem predileção de sexo ou raça, apresenta maior incidência em animais jovens, podendo acometer todas as idades. Ainda que seja reconhecido um único sorotipo do CDV, surtos ocorridos nos últimos anos nos Estados Unidos e estudos de filogenia com base principalmente no gene H realizados também em outros países têm apontado para um distanciamento genético entre as amostras de CDV utilizadas como estirpes vacinais e as estirpes circulantes na população canina doméstica e silvestre. Com base neste contexto, o objetivo deste estudo foi realizar a análise molecular e filogenética do gene H de estirpes isoladas do CDV em caninos domésticos e silvestres naturalmente infectados. Para análise filogenética foram selecionadas sequências completas do gene H de variantes do CDV isoladas no Brasil e Estados Unidos de canídeos domésticos e silvestres, em seguida foram analisadas pelo programa PAUP v.4.0 utilizando o método de Máxima Parcimônia com modelo de busca Branch-and-Bound. Os resultados obtidos sugerem que o grupo de isolados do CDV no brasil são distintos dos isolados norte-americanos e próximos genotipicamente dos isolados vacinais. Além disso, a filogenia viral dos isolados do CDV em animais silvestres indica os cães domésticos como fonte de infecção para estes carnívoros selvagens

Vírus da bronquite infecciosa aviária: Perfis de imunogenicidade e novos patotipos no brasil – revisão de literatura

Infectious bronchitis of chickens (BIG) is an infectious disease caused by avian coronavirus (IBV) that is widely disseminated among commercial poultry farms in most parts of the world. IBV has a high genetic variability, which is reflected by the appearance of marked changes in the composition, structure and antigenic and biological properties of its proteins. Therefore, the objective of this work is to carry out a bibliographical review on the new genotypes, antigenic types and IBV pathotype that have been isolated in the last decades in Brazil, mainly addressing their immunogenicity profiles. With the appearance of antigenic and biological variants among IBV strains in the last years, different genotypes, serotypes and pathophyses of this virus occurred, which resulted in an increase in vaccine failures against this disease and the need to develop new vaccine preparations which provide both antibody and T cell mediated responses, especially in the mucosal compartment, and which result in a more effective protection status against Brazilian VBI variants.A bronquite infecciosa das galinhas (BIG) é uma doença infecciosa causada pelo coronavírus aviário (vírus da bronquite infecciosa – VBI) que está amplamente disseminada entre as criações avícolas comerciais na maior parte do mundo. O VBI apresenta alta capacidade de variabilidade genética, o que se traduz pelo aparecimento de alterações marcantes na composição, estrutura e propriedades antigênicas de suas proteínas. Diante disso, este trabalho tem por objetivo realizar uma revisão bibliográfica sobre os novos patotipos desses vírus que surgiram nas últimas décadas abordando principalmente seus perfis de imunogenicidade. Com o aparecimento de variantes antigênicas e biológicas entre as estirpes do VBI nos últimos anos, ocorreu o surgimento de diferentes genótipos, sorotipos e patotipos deste vírus o que proporcionou um aumento nas falhas vacinais contra esta doença

Early immune responses and development of pathogenesis of avian infectious bronchitis viruses with different virulence profiles

<div><p>Avian infectious bronchitis virus (IBV) primarily replicates in epithelial cells of the upper respiratory tract of chickens, inducing both morphological and immune modulatory changes. However, the association between the local immune responses induced by IBV and the mechanisms of pathogenesis has not yet been completely elucidated. This study compared the expression profile of genes related to immune responses in tracheal samples after challenge with two Brazilian field isolates (A and B) of IBV from the same genotype, associating these responses with viral replication and with pathological changes in trachea and kidney. We detected a suppressive effect on the early activation of TLR7 pathway, followed by lower expression levels of inflammatory related genes induced by challenge with the IBV B isolate when compared to the challenge with to the IBV A isolate. Cell-mediated immune (CMI) related genes presented also lower levels of expression in tracheal samples from birds challenged with B isolate at 1dpi. Increased viral load and a higher percentage of birds with relevant lesions were observed in both tracheal and renal samples from chickens exposed to challenge with IBV B isolate. This differential pattern of early immune responses developed after challenge with IBV B isolate, related to the downregulation of TLR7, leading to insufficient pro-inflammatory response and lower CMI responses, seem to have an association with a most severe renal lesion and an enhanced capability of replication of this isolate in chicken.</p></div

Relative expression of cell-mediated immune response related genes in tracheal samples from chickens experimentally infected with IBV or mock infected.

<p>Relative expression of cell-mediated immune response related genes measured by RT-qPCR: CD3 (A), CD4 (B), CD8β (C), IFNγ (D) and Granzyme homolog A (E), in tracheal samples collected 1 day-post infection (dpi), 5dpi and 8dpi from chickens experimentally challenged at 28 days of age with Brazilian field isolates A or B of infectious bronchitis virus, or mock infected (NC). Medians followed by different letters differ significantly (p≤0.05).</p