The clinical course of infection following endobronchial inoculation of three strains of Mycoplasma mycoides
subspecies mycoides small colony (MmmSC), the causative agent of Contagious Bovine Pleuropneumonia (CBPP), was
compared in 15 mixed-breed Bos taurus steers. Two of these strains have not previously been investigated under
experimental conditions. The cattle were inoculated endobronchially with MmmSC strain Gladysdale, Ondangwa or
Shawawa and monitored for 42 days. Four of five Gladysdale-inoculated cattle developed acute clinical CBPP. Four of
five Ondangwa and 3/5 Shawawa-inoculated cattle developed subacute to chronic CBPP without overt clinical signs but
had characteristic pathological lesions. MmmSC was isolated from cattle both during the course of infection and at
necropsy. Clinical signs and necropsy lesions were consistent within groups. Ondangwa and Shawawa strains of MmmSC
may be useful for study of subacute and chronic CBPP, which is more common in natural infection than peracute CBPP.
Use of recent strains will enhance study of CBPP host response, pathogen detection and vaccine development.