Toxoplasma gondii-associated cholecystitis in a cat receiving immunosuppressive treatment

A 9-year-old female neutered domestic shorthair cat diagnosed with immune-mediated thrombocytopenia that was treated with prednisolone and cyclosporine, was presented for anorexia, vomiting, increased liver enzymes, and hyperbilirubinemia. Abdominal ultrasound revealed a markedly thickened gallbladder and common bile duct wall. Bile cytology detected severe neutrophilic inflammation and protozoal zoites. Suspected Toxoplasma gondii infection was confirmed by real-time PCR of bile. The cat was treated with clindamycin and ursodeoxycholic acid for 6 weeks, recovered and remained stable for 2 years despite ongoing immunosuppressive treatment. Thereafter, the cat was presented with suspicion of intestinal lymphoma, and recurrence of toxoplasmosis was diagnosed. Following treatment with clindamycin and prednisolone over 4 weeks the cat was euthanized. This is the first report of Toxoplasma gondii zoites detected in bile fluid from a cat with cholecystitis. Pathogenesis of toxoplasmosis in cats is still not fully understood. Although immunosuppression can represent a relevant predisposing factor, other factors, such as virulence of the parasite and genetic polymorphism of the host, can also play an important role. Toxoplasmosis should be included as a differential diagnosis in cats developing clinical signs of an inflammatory disease while receiving immunosuppressive treatment.