RESUMO
We investigated deaths in a group of feedlot steers in Argentina. The main findings in 3 steers autopsied were pulmonary congestion and edema, necrotizing myocarditis, pericarditis, suppurative leptomeningitis, and bronchopneumonia. Histophilus somni was detected by bacterial culture and immunohistochemistry in the hearts of the 3 animals. Partial sequences of the 16S rRNA gene of a H. somni isolate had 99% similarity with other H. somni sequences in GenBank. Most reports of H. somni septicemia in cattle originate from North America and western Europe. There is scant information about cardiac histophilosis in South America. A survey of diagnostic laboratory personnel in 7 South American countries documented various forms of bovine histophilosis in Argentina, Brazil, Uruguay, and Venezuela.
Assuntos
Doenças dos Bovinos/diagnóstico , Meningite/veterinária , Miocardite/veterinária , Infecções por Pasteurellaceae/veterinária , Pasteurellaceae/isolamento & purificação , Animais , Argentina , Brasil , Bovinos , Doenças dos Bovinos/microbiologia , Masculino , Meningite/diagnóstico , Meningite/microbiologia , Miocardite/diagnóstico , Miocardite/microbiologia , Pasteurellaceae/classificação , Infecções por Pasteurellaceae/diagnóstico , Infecções por Pasteurellaceae/microbiologia , RNA Bacteriano/análise , RNA Ribossômico 16S/análise , Uruguai , VenezuelaRESUMO
The objectives of this study were to determine the serovar of a collection of Actinobacillus pleuropneumoniae strains within the 3-6-8-15 cross-reacting group and to analyze their phenotypic and genetic properties. Based on the serological tests, forty-seven field strains of Actinobacillus pleuropneumoniae isolated from lungs with pleuropneumonia lesions in Japan and Argentina were found to be serovars belonging to the 3-6-8-15 cross-reacting group. By using a capsule loci-based PCR, twenty-nine (96.7%) and one (3.3%) from Japan were identified as serovars 15 and 8, respectively, whereas seventeen (100%) from Argentina were identified as serovar 8. The findings suggested that serovars 8 and 15 were prevalent within the 3-6-8-15 cross-reacting group, in Argentina and Japan, respectively. Phenotypic analyses revealed that the protein patterns observed on SDS-PAGE and the lipopolysaccharide antigen detected by immunoblotting of the reference and field strains of serovars 8 and 15 were similar to each other. Genetic (16S rDNA, apxIIA, apxIIIA, cps, cpx genes, apx and omlA patterns) analyses revealed that the apxIIA and apxIIIA genes of the field strains of serovars 8 and 15 were similar to those of the reference strains of serovars 3, 4, 6, 8 and 15. The results obtained in the present study may be useful for the development of more effective vaccines against disease caused by A. pleuropneumoniae by including the homologous antigens to the most prevalent serovars in specific geographical areas.
Assuntos
Infecções por Actinobacillus , Actinobacillus pleuropneumoniae , Doenças dos Suínos , Infecções por Actinobacillus/genética , Infecções por Actinobacillus/veterinária , Actinobacillus pleuropneumoniae/genética , Animais , Argentina , Japão , Suínos , Doenças dos Suínos/genéticaRESUMO
A total of 120 purebred Hereford cattle were selected from a herd on a ranch in Argentina that had a severe outbreak of infectious bovine keratoconjunctivitis (IBK, pinkeye) caused by Moraxella bovis. The animals were separated into six treatment groups: a nonmedicated control group, a group that received oxytetracycline at 300 mg injected intrapalpebrally, and four groups that received tilmicosin (Micotil, Elanco Animal Health, Indianapolis, IN; one group injected intrapalpebrally at 300 mg and three groups injected subcutaneously at 2.5, 5, and 10 mg/kg body weight, respectively). Animals were individually observed for resolution of lesions associated with IBK (ocular discharge, blepharospasin, and corneal lesions) every 7 days for 3 weeks. Corneal improvement was significantly better (P< or = .05) for all doses and for either route of injection for tilmicosin compared with no treatment or treatment with oxytetracycline. Tilmicosin given subcutaneously demonstrated a significant (P < or = .05) dose response for overall improvement (one or more score improved, none worsened). Tilmicosin given subcutaneously at 10 mg/kg was significantly more effective than tilmicosin at 2.5 mg/kg, oxytetracycline, and no treatment. Results for tilmicosin at 5 mg/kg were numerically better than no treatment, and tilmicosin at 10 mg/kg was numerically better than the drug given by intrapalpebral injection. Tilmicosin given by subcutaneous injection at 5 or 10 mg/kg was effective against IBK under the conditions of this study.