Pathogenicity of Mycoplasma capricolum Subspecies capripneumoniae for Cattle Immunosuppressed by
AbstractMycoplasma capricolum subsp capripneumoniae (Mccp) produced no overt disease in Red Bororo calves inoculated intratracheally with 10ml of 1x109 CFU/ml of the organism. However when Red Bororo calves were immunosuppressed with Trypanosoma congolense (Tc) and subsequently challenged intratracheally with Mccp, typical lesions of CBPP were produced. The mean PCV value (mPCV), of each of the four Tc-infected RB calves (20.7±2.4%, 23.5±2.5%, 23.3±3.9% and 22.3±2.4%) was significantly (P<0.05) lower than that of the control (32.1±1.7%) and (31.6±1.7%) recorded for calf inoculated with only Mccp. The mean rectal temperature (mRT), of each of the four calves (40.6±0.8oC, 41.0±0.5oC, 37.9±0.5oC and 38.1±0.2oC) with Tc and Mccp or Tc infections was significantly (P<0.05) higher than that of the control (38.2±0.5oC) and (38.5±0.9oC) recorded in calf inoculated with only Mccp. Necropsy examinations revealed oedema, congestion, consolidation and marbling of the lungs. Histopathological changes observed, were thickening of the interlobular septae by fibrin with lymphocytic infiltrations. The spleen and lymph nodes showed lymphoid depletion, haemosiderosis and erythrophagocytosis. It is suggested that calves in trypanosome endemic areas should be treated regularly with trypanocides to prevent calves from coming down with pneumonia caused by caprine strains of Mycoplasma like M. capricolum subspecies capripneumoniae.
Key Words: Calves, Trypanosoma congolense, immunosuppression, Mycoplasma capricolum subsp capripneumoniae, intratracheal inoculation, Nigeria.
Trop. Vet. Vol.22: (1) 33-40 (2004)