Testing of antiinfective susceptibility of A. phagocytophilum showed doxycycline, rifampin, and levofloxacin to be most effective. For puppies under one year of age, chloramphenicol can be used to avoid yellowing of teeth.

The treatment of choice for granulocytic anaplasmosis in dogs is doxycycline (5 mg/kg PO q 12h for 2-3 weeks). Most dogs show clinical improvement within 24 – 48 hrs of antibiotic treatment.

Following the therapeutic elimination of the organism, dogs do not develop protective immunity and can be reinfected when exposed again to a pathogen infected tick. Reinfection has not been reported in dogs so far, in human medicine one case has been documented. Horses have been shown to resist infection after recovery from initial infection with A. phagocytophilum.

A. platys infections have been successfully treated by the application of tetracyclines (e.g. doxycycline 5-10 mg/kg PO q 12 hrs for 10 days and enrofloxacin 5 mg/kg PO q 12 hrs for 14-21 days).