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Advisor(s)
Abstract(s)
Mycoplasma bovis é um agente patogénico envolvido no complexo respiratório
bovino, em mastites, queratoconjuntivites, otites, artrites e infertilidade em bovinos.
Tem distribuição mundial, e na Europa é responsável por 25% a 33% das
pneumonias em bovinos. No presente estudo foram seleccionadas para recolha de
amostras sanguíneas 3 Organizações de Produtores Pecuários (OPP) de áreas
geográficas de Portugal Continental com características de exploração distintas:
OPP de Vila do Conde (Norte), OPP de Acripinhal (Centro) e OPP do Campo Branco
(Sul). A unidade epidemiológica considerada foi a exploração de bovinos,
pretendendo-se determinar, por ELISA, a prevalência de explorações com animais
seropositivos para M. bovis nas OPP, bem como a prevalência intra-exploração
destes animais. Foram amostradas 61 explorações em Vila do Conde, 59
explorações no Campo Branco e 3 explorações em Acripinhal, num total de 123
explorações e de 1519 animais. Os resultados, expressos semi-quantitativamente,
demonstraram a presença de anticorpos contra M. bovis em 98% das explorações
testadas (n=121). Na prevalência intra-exploração foi encontrada uma mediana de
animais positivos por exploração de 50% na OPP de Vila do Conde, 85% na OPP de
Acripinhal e de 73% na OPP do Campo Branco. Os resultados revelam uma elevada
exposição dos bovinos em estudo a M. bovis. Adicionalmente, como forma de
complementar a investigação realizada nas OPP, foram efectuados 2 estudos de
caso: um numa exploração de engorda e outro numa exploração leiteira. Na
exploração de engorda foi encontrada elevada prevalência de anticorpos anti-M.
bovis (98%), não tendo sido verificadas diferenças significativas na seroconversão
ao fim de 30 dias. Na exploração de leite foi encontrada uma elevada prevalência de
anticorpos anti-M. bovis (98%), compatível com o isolamento do agente por métodos
microbiológicos e moleculares bem como com a sintomatologia clínica evidenciada
pelos animais, tendo sido observada uma relação entre o grau de positividade do
teste comercial de ELISA e o isolamento do agente. O elevado contacto com
Mycoplasma bovis nas explorações portuguesas, revelado pela elevada prevalência
de anticorpos encontrada nos estudos realizados poderá ter consequências
negativas tanto a nível de saúde e bem-estar animal, como de rendimento
económico das explorações nacionais.
ABSTRACT - Mycoplasma bovis prevalence in 3 Portuguese OPPs: sero-epidemiologic study - Mycoplasma bovis is a pathogen frequently involved in the bovine respiratory complex, mastitis, keratoconjunctivites, arthritis and infertility. It has a worldwide distribution and, in Europe, is responsible for one third to one quarter of bovine pneumonia cases. The present study was conducted in 3 Farmers’ Associations (Organização de Produtores Pecuários, OPP): Vila do Conde (North), Acripinhal (Center) and Campo Branco (South). The epidemiologic unit considered was the farm, aiming at determining, through an ELISA test, the prevalence of herds with seropositives animals, as well the seropositive animals’ prevalence within each herd. A total of 123 farms, comprising 1519 animals, were sampled: 61 farms in Vila do Conde, 3 in Acripinhal and 59 in Campo Branco. The results, expressed semiquantitatively, showed anti-Mycoplasma bovis antibodies present in 98% of the tested herds (n=121). Concerning the prevalence within each herd, a median of 50% positive animals was found in the OPP of Vila do Conde, 85% in the OPP of Acripinhal and 73% in the OPP of Campo Branco. Additionally, two case-studies were performed to complement the main study in the 3 OPPs: one in a feedlot and another in a dairy farm. In the feedlot, a high prevalence of seropositive animals was found as well (98%) and no significant differences were found in the seroconverstion after 30 days. In the dairy farm, a high prevalence of seropositive animals was found (98%), which is compatible with the results obtained by microbiology and PCR techniques, as well as with the clinical history from the farm. In the same case study, an association between the degree of antibodies and the identification of the bacteria was found. These results reveal a high exposure of the animals comprised in these studies to Mycoplasma bovis, which will most likely carry negative consequences to animal health and welfare, as well as to the economic performance of the farms.
ABSTRACT - Mycoplasma bovis prevalence in 3 Portuguese OPPs: sero-epidemiologic study - Mycoplasma bovis is a pathogen frequently involved in the bovine respiratory complex, mastitis, keratoconjunctivites, arthritis and infertility. It has a worldwide distribution and, in Europe, is responsible for one third to one quarter of bovine pneumonia cases. The present study was conducted in 3 Farmers’ Associations (Organização de Produtores Pecuários, OPP): Vila do Conde (North), Acripinhal (Center) and Campo Branco (South). The epidemiologic unit considered was the farm, aiming at determining, through an ELISA test, the prevalence of herds with seropositives animals, as well the seropositive animals’ prevalence within each herd. A total of 123 farms, comprising 1519 animals, were sampled: 61 farms in Vila do Conde, 3 in Acripinhal and 59 in Campo Branco. The results, expressed semiquantitatively, showed anti-Mycoplasma bovis antibodies present in 98% of the tested herds (n=121). Concerning the prevalence within each herd, a median of 50% positive animals was found in the OPP of Vila do Conde, 85% in the OPP of Acripinhal and 73% in the OPP of Campo Branco. Additionally, two case-studies were performed to complement the main study in the 3 OPPs: one in a feedlot and another in a dairy farm. In the feedlot, a high prevalence of seropositive animals was found as well (98%) and no significant differences were found in the seroconverstion after 30 days. In the dairy farm, a high prevalence of seropositive animals was found (98%), which is compatible with the results obtained by microbiology and PCR techniques, as well as with the clinical history from the farm. In the same case study, an association between the degree of antibodies and the identification of the bacteria was found. These results reveal a high exposure of the animals comprised in these studies to Mycoplasma bovis, which will most likely carry negative consequences to animal health and welfare, as well as to the economic performance of the farms.
Description
Dissertação de Mestrado Integrado em Medicina Veterinária
Keywords
Mycoplasma bovis Serologia Prevalência Epidemiologia Portugal Mycoplasma bovis Serology Prevalence Epidemiology
Pedagogical Context
Citation
Raposo, J.M.C.R. (2009). Prevalência de Mycoplasma bovis em 3 OPP Portuguesas: estudo sero-epidemiológico
Publisher
Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária