This study examined the effect of
minocycline alone and in combination with
immunotherapy against
pythiosis. Twenty rabbits, aged three months old and subcutaneously inoculated with Pythium insidiosum zoospores were divided into four groups (n = 5): treated with
minocycline (10 mg/kg/day twice daily), treated with
immunotherapy (34 mg subcutaneously every 14 days), treated with
minocycline plus
immunotherapy, and untreated (control group). The treatments were started 30 days after inoculation and continued for 70 days. The subcutaneous nodular injury areas in infected groups were measured every seven days after the beginning of treatment. Only the rabbits that developed lesions were selected for this study. When compared with the control group over 70 days, the
minocycline and
minocycline plus
immunotherapy groups of rabbits with
pythiosis showed significantly reduced
injuries. The histopathology showed the presence of
inflammation, macrophages and eosinophils. Grocott's staining revealed irregular hyphae-like structures that were ramified and occasionally septate. Our results suggest that
minocycline has fungistatic activity and that the combination of
minocycline and
immunotherapy is more effective than the individual
therapies tested.