252 Brief Communications J Vet Diagn Invest 13:252–255 (2001) Cutaneous neosporosis in two adult dogs on chronic immunosuppressive therapy

Abstract. Antemortem diagnosis of generalized ulcerative and pyogranulomatous dermatitis with numerous intralesional tachyzoites was made from skin biopsy specimens from 2 adult dogs on chronic immunosuppres-sive therapy. A 9-year-old Italian Greyhound was on long-term corticosteroid therapy for the treatment of a lupus-like systemic autoimmune disorder, and a 7-year-old Labrador Retriever had received several months of chemotherapy for lymphosarcoma. The tachyzoites were identified as Neospora caninum by immunoperoxidase immunohistochemistry. Both dogs were treated with clindamycin. Lesions in the Greyhound resolved; however, the Labrador Retriever was euthanized because of evidence of neuromuscular disease, despite improvement of the skin lesions. These 2 cases indicate that cutaneous neosporosis can occur in adult dogs on chronic immu-nosuppressive therapy. The disease may result from reactivation of a congenital infection and/or a recently acquired primary infection. Neospora caninum is a recently characterized, cyst-form-ing protozoan parasite7 that causes natural disease in multi-ple species, including dogs, cattle, sheep, goats, horses, and deer.12 Although its life cycle has not been completely elu-cidated, N. caninum is reportedly transmitted through trans