Isolamento de leptospiras em bovinos abatidos em frigoríficos de Pelotas/RS

• Ano de defesa: 2012
• Autor(a) principal: Seixas Neto, Amilton Clair Pinto
• Orientador(a): Silva, Éverton Fagonde da
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Pelotas
• Programa de Pós-Graduação: Programa de Pós-Graduação em Veterinária
• Departamento: Veterinária
• País: BR
• Palavras-chave em Português: Leptospirose; Abatedouros; Diagnóstico; Risco ocupacional; VNTR
• Palavras-chave em Inglês: Leptospirosis; Slaughterhouse; Diagnosis; Occupational risk; VNTR
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA
• Link de acesso: http://repositorio.ufpel.edu.br/handle/ri/2483

Leptospirosis is caused by a variety of leptospiral serovars which are distributed worldwide. Bovine leptospirosis has economic importance to countries involved on dairy and beef raising, due the losses in milk yield of affected cows and in weight among beef cattle. In addition, inapparent infection in herds presents a serious problem in the recognition and spread of infection. Bovine leptospirosis is not only a financial hazard in endemic herds, but also an occupational risk factor for veterinarians, rural workers, and slaughterhouse employees. Furthermore, available vaccines for bovine leptospirosis are killed whole-cell preparations that protect against the serovars present, making imported vaccines unsatisfactory for the control of the disease in Brazilian herds. In this light, the present study´s objective was to obtain new isolates of leptospires from cattle slaughtered in abattoirs of the city of Pelotas, Brazil. Bovine kidneys were obtained from 250 animals at three abattoirs of the city of Pelotas. Each kidney was transported to the laboratory in individual tubes and processed for isolation within two hours after slaughter. Cultures were incubated at 30°C and examined weekly for ten weeks by darkfield microscopy to detect the presence of leptospires. In order to determine if the isolates would produce infection in laboratory animals, groups of two 28-day-old hamsters were inoculated intraperitoneally with 108 leptospires of each isolate. To definitely characterize the new isolates, bacterial culture and DNA were sent to Fundação Oswaldo Cruz for serogrouping and DNA sequencing. A total of three (1.2%) strains were isolated from the kidney tissue of adult male bovines from the Capão do Leão (n=1) and Pedro Osório (n=2) municipalities. The new strains were named BOV3, BOV14, and BOV15. The virulence test using young hamsters showed that the two strains (BOV3 and BOV15) were capable of reproducing the main clinical and pathological findings of experimental leptospirosis in hamsters. None of the animals demonstrated clinical signs of infection when infected with BOV14. This study reports the isolation of three strains of Leptospira from cattle and their preliminary virulence characterization. These results are demonstrating the risk of leptospirosis in farms and slaughterhouses in Southern Brazil, transmission to other livestock species, and exposure to humans. Additional tests are being employed for the classification of new isolates.