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Contagious bovine pleuropneumonia

Thiaucourt F.. 2012. In : Manual of diagnostic tests and vaccines for terrestrial animals : (mammals, birds and bees). Paris : OIE, p. 704-716.

Contagious bo vine pleuropneumonia (CBPP) is a disease of cattle caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC; SC = small colonies). lt is manifested by anorexia, fever and respiratory signs such as dyspnoea, polypnoea, cough and nasal discharges in bovines. Diagnosis depends on the isolation of the aetiological agent. The main problems for control or eradication are the frequent occurrence of subacute or subclinical infections and the persistence of chronic carriers after the clinical phase. Identification of the agent: Samples to be taken from live animals are nasal swabs and/or broncho-alveolar washings or pleural fluid obtained by puncture. Samples to be taken at necropsy are lung lesions, lymph nodes, pleural fluid and synovial fluid from those animals with arthritis. Direct examination of the exudate or smears is possible, but requires great skill. For cultivation of the pathogen, the tissues are ground in medium containing antibiotics and inoculated into media that contain inhibitors to prevent the growth of contaminating bacteria. The growth of MmmSC takes several days. In broth, growth is visible within 2-4 days as a homogeneous cloudiness with whirls when shaken; on agar, small colonies develop, 1 mm in diameter, with the classical 'fried-egg' appearance. The biochemical characteristics of MmmSC are the following: sensitivity to digitonin, reduction of tetrazolium salts, fermentation of glucose, absence of arginine hydrolysis, and the absence of or very slight phosphatase and proteolytic activities. Special media have been described that are recommended for these tests. Diagnosis is confirmed by immunological tests, such as the growth inhibition and immunofluorescence tests (both use hyperimmune sera). The polymerase chain reaction is now used as a rapid, specific, sensitive and easy to use test. Serological tests: For diagnosis, the modified Campbell & Turner complement fixation test remains a prescribed test for international trade. However, it has significant limitations regarding sensitivity and specificity. The competitive enzyme-linked immunosorbent assay was designated as an OIE prescribed test for international trade by the OIE International Committee in May 2004. An immunoblotting test has undergone evaluation and is highly specific and sensitive. Requirements for vaccines: A ttenuated strains now recommended for vaccine production: the T1/44 and T1sr. The minimal recommended titre is 107 mycoplasmas per vaccinal dose, but higher titres of at least 1 oB are recommended. (Résumé d'auteur)

Mots-clés : Épidémiologie; technique immunologique; identification; vaccin; test biologique; immunologie; diagnostic; mycoplasma mycoides; péripneumonie contagieuse bovine; production de vaccin

Thématique : Maladies des animaux

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