RESUMO
The aim of this retrospective study was to use RT-PCR and nucleotide sequencing analysis to determine the G (VP7 gene) and P (VP4 gene) genotypes of 155 Brazilian bovine rotavirus A (RVA) wild-type strains detected in diarrheic calves from all Brazilian geographical regions from 2006 to 2015. The RVA strains evaluated belonged to the G6, G10, P[5], and P[11] genotypes. The G6P[5] genotype was prevalent (65.5%; P < 0.05) in beef, and the G10P[11] (38.4%) and G6P[11] (30.8%) genotypes were more prevalent in dairy cattle herds. The Midwest was the region with the highest number of genotyped RVA strains, where the genotypes G6, P[5], and P[11] were identified. Genotype combination G6-IV/P[5]-IX, prevalent in beef herds, and G6-III/P[11]-III or G10-IV/P[11]-III, prevalent in dairy herds, were detected. In addition, for the first time in Brazil, we detected the P[5] and P[11] genotype RVA strains that belong to lineage II and VII, respectively.
Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/virologia , Diarreia/veterinária , Infecções por Rotavirus/veterinária , Rotavirus/genética , Animais , Animais Recém-Nascidos , Brasil/epidemiologia , Bovinos/virologia , Diarreia/epidemiologia , Diarreia/virologia , Fezes/virologia , Feminino , Perfil Genético , Variação Genética , Genótipo , Filogenia , Reação em Cadeia da Polimerase em Tempo Real , Estudos Retrospectivos , Rotavirus/isolamento & purificação , Infecções por Rotavirus/epidemiologiaRESUMO
Aichivirus B has been reported worldwide in calves and adult cattle with and without diarrhea. The aim of this study was to describe the molecular characteristics of the RdRP and VP1 genes of aichivirus B strains identified as the most frequent etiologic agent in a neonatal diarrhea outbreak in a high-production Brazilian dairy cattle herd. Preliminary laboratory analysis ruled out important enteropathogens (Cryptosporidium spp; Eimeria spp., E. coli F5, and bovine coronavirus). Fecal samples from diarrheic (n = 24) and asymptomatic (n = 5) calves up to 30 days old were collected for virological analysis. RT-PCR assays were performed for the detection of aichivirus B RdRP and VP1 genes and for rotavirus A VP7 and VP4 genes in fecal samples. Asymptomatic calves (control group) were negative for both viruses. Aichivirus B and rotavirus A G10P[11] genotypes were found in 54.2% (13/24) and 25% (6/24) of the diarrheic fecal samples, respectively. Aichivirus B was only identified (83.3%, 10/12) in calves up to two weeks old. Phylogenetic analysis based on the RdRP gene grouped the Brazilian strains in a new branch within the aichivirus B group. Comparative analysis of the nucleotide sequence of the VP1 gene of Brazilian and Chinese aichivirus B strains allowed the strains identified in this study to be classified in the putative lineage 1. This is the first description of a high rate of aichivirus B detection in a diarrhea outbreak in dairy calves, and the first phylogenetic study of the VP1 gene of aichivirus B wild-type strains performed in South America.
Assuntos
Doenças dos Bovinos/virologia , Diarreia/veterinária , Surtos de Doenças , Kobuvirus/classificação , Kobuvirus/isolamento & purificação , Filogenia , Infecções por Picornaviridae/veterinária , Animais , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Diarreia/epidemiologia , Diarreia/virologia , Kobuvirus/genética , Infecções por Picornaviridae/epidemiologia , Infecções por Picornaviridae/virologia , RNA Polimerase Dependente de RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência , Proteínas Estruturais Virais/genéticaRESUMO
Porcine group C rotavirus (RVC) is recognised as an enteric pathogen in piglets worldwide. The VP6 gene of RVC is divided into seven I-genotypes. Genotypes I2 and I3 are found in human and bovine strains, respectively; the porcine strains are divided into the other five genotypes (I1, I4-I7). In this study, molecular analysis of nearly the full length of the VP6 gene was performed in 11 Brazilian wild-type porcine RVC strains identified in diarrhoeic faecal samples, which were collected from eight pig farms located in five Brazilian states from piglets of 1-4 weeks of age. The nucleotide sequences of the VP6 gene showed 82.9-100 % identity between the Brazilian strains, 84.9-93.1 % with the prototype Cowden strain, and 82.4-92.2 % with other porcine RVC strains. In the 11 diarrhoeic faecal samples analysed in this study, three distinct porcine RVC genotypes (I1, I5, and I6) were identified and none were predominant. The results presented in this study revealed a high nucleotide diversity of the VP6 gene in porcine RVC field strains circulating in Brazil, which highlights the importance of further epidemiological and molecular surveys worldwide.
Assuntos
Antígenos Virais/genética , Proteínas do Capsídeo/genética , Variação Genética , Infecções por Rotavirus/veterinária , Rotavirus/classificação , Rotavirus/isolamento & purificação , Animais , Brasil , Análise por Conglomerados , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Rotavirus/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Suínos , Doenças dos Suínos/virologiaRESUMO
The aim of this study was to perform the molecular characterization of the eleven genes of a G6P[5] bovine group A rotavirus (RVA) strain detected in a diarrhea outbreak from a vaccinated beef cattle herd. The outbreak affected 80 % of calves between 15-30 days old. RVA was identified by RT-PCR in 12 (70.6 %) out of 17 diarrheic fecal samples evaluated. The rotavirus wild-type strain had the genotype constellation G6(IV)-P[5](IX)-I2c-R2-C2-M2-A3-N2-T6-E2e-H3a. This study confirms the importance of homotypic immunity against the bovine RVA P[5] genotype in neonatal diarrhea in cattle herds that are regularly vaccinated against rotaviruses.
Assuntos
Doenças dos Bovinos/virologia , Diarreia/veterinária , Surtos de Doenças/veterinária , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/veterinária , Rotavirus/classificação , Animais , Antígenos Virais/genética , Proteínas do Capsídeo/genética , Bovinos , Diarreia/prevenção & controle , Diarreia/virologia , Surtos de Doenças/prevenção & controle , Fezes/virologia , Genoma Viral , Filogenia , Rotavirus/genética , Infecções por Rotavirus/virologia , VacinaçãoRESUMO
Group A rotavirus (RV-A) with short electropherotype was identified by ss-PAGE in a neonatal diarrhea outbreak at a Brazilian pig farm where the sows were regularly vaccinated with a commercial vaccine containing OSU (G5P[7]) and Gottfried (G4P[6]) porcine RV-A (PoRV-A) strains. The ss-PAGE positive stool samples (n=20) were characterized as P[6] genotype by multiplex-nested-RT-PCR assay. The nucleotide analysis of the VP4 gene (VP8*) state that the viruses clustered in P[6] lineages that are also shared by RV-A strains identified in human hosts. Nucleotide analysis of the VP7 gene identified different lineages in G4 including a new lineage tentatively designated IX. The immunological pressure induced by commercial vaccine with a rotavirus containing a G4P[6] genotype of porcine origin (Gottfried strain) might have allowed the selection of PoRV-A strains with characteristics found in RV-A strains isolated of human hosts, such as P[6]-Ie and If, and promoted the selection or emergence of RV-A strains with a new lineage of the G4 genotype. The characterization of PoRV-A strains with unusual genotypes described in this study highlight the importance of surveys on the relationship between human and animal rotavirus strains.