A juvenile female cougar presented for three day history of inappetence, vomiting, diarrhea and progressive lethargy with no vaccination history. Abdominal radiographs were inconclusive in ruling out a small intestinal obstruction, so she was transferred to a referral institution for an abdominal ultrasound and further diagnostic workup. Abdominal ultrasound showed diffuse gastroenteritis and visceral lymphadenopathy, and the animal was weakly Parvovirus SNAP test positive. She was discharged under medical management while further diagnostic measures were taken. Initial bloodwork indicated generalized severe leukopenia and a mild thrombocytopenia and anemia. Bacterial cultures and viral diagnostics indicated a Canine Parvovirus (CPV-2) or Feline Panleukopenia Virus (FPV) infection complicated by secondary C/ostridium perfringens overgrowth. Further genotyping of the virus indicated that a Canine Parvovirus 2/2a infection was responsible for the cougar's disease.