ABSTRACT
Abstract The Equine Strangles, caused by Streptococcus equi subs. equi, is a contagious disease, causing high rates of morbidity been responsible for important economic losses. The M protein synthesized by S. equi plays an important role in the pathogenesis and is a promising candidate for a vaccine antigen. The innate immune system is responsible for the first immune response against microorganisms, this response is mediated by receptors that detect PAMPs and their activation trigger crucial modulation of the adaptative immune response. This work describes the immune response of S. equi subs. equi. recombinant SeM protein, using Escherichia coli BL21 (DE3) as an expression and delivery vaccine system. To characterize and to determine the vaccine efficacy, mice were vaccinated as followed: 1. Recombinant E. coli expressing rSeM protein; 2. The same recombinant E. coli, inactivated adsorbed in Alumen; 3. Purified rSeM protein adsorbed in Alumen; 4. Inactivated S. equi whole cells adsorbed in Alumen; 5. Control group. All vaccinated mice developed protective response against S. equi infection, however the groups that received the E. coli expressing rSeM presented significant higher IgG level than other vaccinated groups. The recombinant E. coli delivery vaccine system also induced a highest IgG response than inactivated S. equi or purified rSeM vaccines in horses. This study evidence that the recombinant E. coli, live or inactivated, enhanced the humoral response, reaching significant higher antibodies levels than those obtained in the vaccination with the bacterin or purified antigen, showing the feasibility of producing low-cost vaccines against strangles.
ABSTRACT
Foram avaliados fatores de risco associados à ocorrência de doenças respiratórias em 349 potros Puro Sangue Inglês (PSI) monitorados do nascimento ao sexto mês de vida na região de Bagé, Rio Grande do Sul (RS), Brasil. A partir da avaliação clínica e laboratorial pôde-se registrar a frequência de 9,5 por cento (33) casos respiratórios, com mortalidade de 0,57 por cento (2). A ocorrência de casos foi mais elevada nos meses de verão, e potros com idade entre quatro e seis meses foram mais suscetíveis (P<0,001). O desenvolvimento de doenças foi influenciado (P<0,001) pelo sistema de criação e pelas práticas de manejo, os quais aumentaram o potencial de contaminação do ambiente. Na avaliação microbiológica, a maior frequência de isolados foi de Streptococcus equi (57 por cento), seguido do Rhodococcus equi (17 por cento), letal em 50 por cento dos casos. Nenhum caso clínico foi associado ao vírus da influenza equina (EIV) e ao herpesvírus equino (EHV-1-4). Os resultados sugerem que fatores ligados ao manejo, na criação de equinos PSI, parecem contribuir decisivamente para a manifestação da doença respiratória e alertam para a morbidade causada pela adenite equina e a letalidade atribuída à rodococose.
Risk factors associated the occurrence of respiratory diseases they were evaluated between 349 Thoroughbred foals, monitored of the birth to the sixth month of life in the region of Bagé-RS-Brazil. From the laboratory and clinical evaluation, the frequency of 9.5 percent (33) of respiratory cases with mortality of 0.57 percent (2) was recorded. The occurrence of cases was higher in months of summer and foals with age between four and six months were more susceptible (P<0.001). The development of the diseases was influenced (P<0.001) by the breeding system of and management practices that increased the environmental contamination potential. In the evaluation microbiological, , the highest frequency of isolated was of Streptococcus equi (57 percent), followed by the Rhodococcus equi (17 percent), lethal in 50 percent of the cases. No clinic case was associated to the equine influenza virus (EIV) and to the equine herpesvirus (EHV-1-4). The results suggest that connected factors to the management in the breeding of thoroughbred equine are going to contribute decisively for the manifestation of the respiratory disease and alert for the morbidity caused by the equine adenitis and the lethality related to rodococosis.