A three-month-old intact female DSH presented to the Cornell University Hospital for Animals Emergency Service on 9/29/03 with a presumptive diagnosis of panleukopenia. Significant physical examination and diagnostic findings included pale mucous membranes, dehydration, crusted ocular and nasal discharge, lingual ulcers, pytalism, flea dirt, microcytic, normochromic, nonregenerative anemia, leukopenia, neutropenia, low normal lymphocyte count, thrombocytopenia, hypokalemia, hypoproteinemia, hypoalbuminemia, FeLV negative, canine ELISA parvovirus test positive, Isospora rivolta positive fecal analysis, and calicivirus isolation negative. Her littermate, who also presented to CUHA for presumptive panleukopenia, was positive for Mycoplasma hemofelis on a blood smear. Arty represented a complicated panleukopenia case with multiple concurrent disease processes. Typical and atypical presentations of panleukopenia are discussed. Additionally, recent work in the evolutionary patterns of canine and feline parvovirus has identified a new isolate of canine parvovirus (CPV-2c). Subsequent studies suggest a future switch in the commonly seen parvoviruses present in domestic dogs and cats.