Previous clinical study indicated Babesia infections can be refractory to drug treatment, and recrudescence or relapse of infection may occur after current treatment and can persist even for more than two years.
In an immunodeficient mouse model, Lawres et al. have proved that current treatment with azithromycin up to 50 mg/kg, clindamycin up to 50 mg/kg, or quinine up to 100 mg/kg had no significant effect on B. microti, only atovaquone showed potent activity against B. microti during treatment period, but recrudescence [relapse] appeared in a few days after treatment.
Atovaquone also showed potent activity against B. bovis.
However, in a human erythrocyte culture system, Abraham et al. have reported that B. duncani revealed unusually high tolerance to the current recommended therapies.
These results are consistent with our findings with B. duncani, which demonstrated that atovaquone had incredible inhibitory effect at relatively low concentration (0.25 M), but relapse was observed in subculture test.
