Pathogenicity of Mycoplasma mycoides subsp. capri in calves previously infected with Trypanosoma congolense

Pathogenicity of Mycoplasma mycoides subsp. capri (Mmc) for calves with and without Trypanosoma congolense (Tc) infection was undertaken. Four calves were inoculated with Tc and two of them were challenged with Mmc, while one calf was inoculated with Mmc only; another calf was inoculated with sterile broth as control. No overt disease was found in the Mmc-infected calf. The two calves with dual Tc/Mmc infections died 53.0 ± 1.4 days post-inoculation, showing marbling and consolidation of the lungs. Histopathologically there was widening of interstitial spaces by fibrin and inflammatory cells. The spleen and lymph nodes showed lymphoid depletion, haemosiderosis and erythrophagocytosis. However, the two Tc-infected calves recovered following trypanocidal treatment. The mean PCV value (mPCV), of each of the four Tc-infected calves (22.5 ± 2.9%, 23.0 ± 2.6%, 25.0 ± 2.1%, 25.4 ± 2.5%, respectively) was significantly (P<0.05) lower than that of the control (30.1 ± 1.0%) and Mmc-infected calf (30.2 ± 1.0%), respectively. Similarly, the mean rectal temperature (mRT) of each of the two calves (41.6 ± 0.8 °C, 40.5 ± 0.8 °C) with dual Tc/Mmc infections was significantly (P<0.05) higher than that of Tc-infected calves (38.1 ± 0.5 °C and 38.0 ± 0.3oC), control calf (37.8 ± 0.3 °C) and Mmc-infected calf (37.7 ± 0.3 °C), respectively. These findings confirm the pervasiveness of Mycoplasma mycoides cluster It is suggested that calves in trypanosome endemic areas should be given regular prophylactic trypanocides treatment to rid them of trypanosomes which can cause immunosuppression, thereby predisposing calves to caprine strains of Mycoplasma.