CANINE CUTANEOUS NEOSPOROSIS - CLINICAL IMPROVEMENT WITH CLINDAMYCIN

Progranulomatous dermatitis caused by the protozoan parasite Neospora caninum was diagnosed in a 12-year-old Golden Retriever dog. Multiple draining nodules were located in the skin of the head and thorax. Numerous tachyzoites of N. caninum were found in histologic sections of the biopsy tissue from the cutaneous nodules and the diagnosis was confirmed by immunohistochemical staining and by electron microscopic examination. The dog had a 1:3200 serum antibody titer to N. caninum in the indirect fluorescent antibody test. The cutaneous lesions resolved after a 45-day treatment with clindamycin hydrochloride. The dog eventually died because of lymphosarcoma and also had a latent infection with Toxoplasma gondii. Neospora caninum could not be demonstrated by bioassays in cell culture or mice inoculated with canine tissue obtained at necropsy. Only degenerating N. caninum tachyzoites were seen in skin tissue taken at necropsy. These observations indicate that neosporosis should be considered in the differential diagnosis of pyogranulomatous dermatitis in dogs and that clindamycin may be an effective drug for treating cutaneous neosporosis.