Abstract

The effect of long-acting oxytetracycline treatment in the development of sequestra in contagious bovine pleuropneumonia (CBPP)-infected animals was determined. Thirty five clinically healthy zebu cattle, negative for CBPP antibodies (as tested by a competitive ELISA), were infected with Mycoplasma mycoides subsp. mycoidessmall colony variant - field isolate. All the animals were monitored for clinical signs of illness and regularly sampled for serological and bacteriological analysis. Nine animals were treated with long-acting tetracycline upon the first evidence of clinical signs of illness. The 26 remaining animals were left untreated and served as control animals. Post-mortem examinations were performed to assess the presence or absence of CBPP gross lesions. The experimentation lasted for 10 months during which, 13 animals (all untreated) died with acute lung lesions. When the 22 surviving animals (13 untreated and 9 treated) were slaughtered at the end of experimentation, chronic lesions were observed in all of them. Among the 13 untreated animals, 10 had visible lung sequestra and 3 had cicatrical lesions indicative of resolved lung lesions. Conversely, among the 9 treated animals, only 1 had a small lung sequestrum and the remaining 8 had pulmonary adhesions. The results presented demonstrate that, under the experimental conditions used, treatment with oxytetracycline did not result in significant sequestra formation in CBPP-infected animals. Full field validation is required in order to confirm these findings.

Key words: Contagious bovine pleuropneumonia, antibiotherapy, oxytetracycline, lung sequestra, experimental transmission, Mali.