First clinical case report of Cytauxzoon sp. infection in a domestic cat in France

Background Feline cytauxzoonosis is an emerging infection caused by tick-transmitted apicomplexan parasites of the genus Cytauxzoon. The association of clinical disease with Cytauxzoon infection appears to be limited to C. felis infections in the Americas. Sporadic infections of wild and domestic felids with Cytauxzoon sp. were recently described in European countries but clinical reports of the infection are rare and incomplete. This case report brings new interesting information on cytauxzoonosis expression in Europe. Case presentation A 9-years-old castrated European shorthair cat living in rural area of north-eastern France (Saint Sauveur, Bourgogne-Franche-Comté region), without any travel history was presented for consultation due to hyperthermia, anorexia, depression and prolonged fever that didn’t respond to antibiotic therapy. The cat had outdoor access with a history of vagrancy and was adequately vaccinated (core vaccines and FeLV vaccine). During biological investigations, intraerythrocytic inclusions were observed on blood smear and were further investigated by PCR analysis and sequencing. Molecular analyses confirmed Cytauxzoon sp. infection. The cat was treated with a subcutaneous injection of imidocarb dipropionate (3.5 mg/kg). One week after treatment, the cat improved clinically, although parasitic inclusions within erythrocytes persisted, and only a mild lymphocytosis was found. Two weeks after treatment, the cat appeared in excellent health, appetite was normal and parasitemia was negative. However, one month after treatment the cat relapsed with hyperthermia, anorexia, and depression. Blood smears and PCR were once again positive. Subsequently, the cat received an additional dose of imidocarb dipropionate (3.5 mg/kg SC) and recovered rapidly without other clinical signs. Two weeks after the second imidocarb injection, the cat was hit by a car and died. Conclusion This case provides the first clinical description of infection by Cytauxzoon sp. in a domestic cat in France. These findings support the fact that cytauxzoonosis should be considered in the differential diagnosis of acute febrile illness which does not respond to antibiotic in cats with outdoor access especially in areas where populations of wild felids are present.