Submitted to: Veterinary Clinical Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2004
Publication Date: 12/15/2005
Citation: Little, L., Shokek, A., Dubey, J.P., Deheer, H.L. 2005. Subcutaneous skin nodules in a cat. Veterinary Clinical Pathology. 4(2):156-160. Interpretive Summary: Infection by the single-celled parasite, Toxoplasma gondii, causes mental retardation and loss of vision in children and abortion in livestock. Cats are the main reservoir hosts for this parasite. Scientists at the Beltsville Agrlcultural Research Center and the University of Pennsylvania report dermatitis due to toxoplasmosis in an adult cat. The results will be of interest to parasitologists, veterinarians and biologists.
Technical Abstract: An 8-year-old, male domestic short-haired cat was referred to the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania with a three day history of lethargy, inappetance, hyperemic skin nodules, coughing and vomiting. Laboratory results included a non-regenerative anemia, lymphopenia, thrombocytopenia, hypoalbuminemia, hyponatremia, increased ALT, and increased AST. Cytology of the skin nodules revealed many spindle to crescent shaped protozoal organisms, with morphology consistent with Toxoplasma gondii or Neospora caninum. Gross necropsy findings, histopathology, immunohistochemistry, and transmission electron microscopy confirmed a diagnosis of a systemic protozoal infection; however, it exhibited characteristics of N. caninum and T. gondii. A diagnosis of a T. gondii-like infection was based on the internal structures and positive reaction to rabbit polyclonal antibodies to T. gondii. Reports of toxoplasmic dermatitis are rare in the cat and dog and this is the first reported diagnosis of T. gondii-like protozoa on skin aspirates.