Fatal infection caused by Cytauxzoon felis in a captive-reared jaguar (Panthera onca)

Fatal infections with Cytauxzoon felis are common in domestic cats, and jaguars (Panthera onca) are believed carriers of this protozoan. Fatal C. felis infections have never been described in jaguars before. Thus, this study describes such an infection in a 5-month-old captive-reared jaguar that presented hyporexia and died at 26 days after the first clinical signs. During necropsy, samples were taken from several tissues, some were fixed in 10% formalin and process for histopathological diagnosis, and some samples were used for DNA extraction, amplification via PCR and sequencing of the potential pathogens. Grossly, marked splenomegaly and icterus were observed. Histologically, numerous structures that are morphologically compatible with Cytauxzoon spp. schizonts obliterated multiple blood vessels in the brain, leptomeninges, spinal cord, lungs, heart, skeletal muscle, adrenal gland, kidneys, spleen, small intestine and pancreas. C. felis was identified by PCR in many organs. Thus, C. felis infection in jaguars can be fatal, and the clinicopathological findings are similar to those of cytauxzoonosis in other wild and domestic felid species.

LOPH: a novel chemotherapeutic protocol for feline high-grade multicentric or mediastinal lymphoma, developed in an area endemic for feline leukemia virus

OBJECTIVES

The aim of this study was to establish the safety and efficacy of a novel multidrug lomustine-based chemotherapeutic protocol for cats with high-grade multicentric or mediastinal lymphoma, in an area endemic for feline leukemia virus (FeLV).

METHODS

This prospective study included owned cats, diagnosed (cytologically) with multicentric or mediastinal lymphoma and treated with the LOPH (lomustine, vincristine [Oncovin; Antibióticos do Brasil], prednisolone and hydroxydaunorubicin [doxorubicin]) protocol. A complete blood count was performed before every chemotherapy session and any significant abnormalities recorded as possible related toxicities. Median survival time (MST) and disease-free interval were estimated by Kaplan-Meier curves.

RESULTS

Twenty-one cats were included in this study. Nineteen (90.5%) tested positive for FeLV and were therefore considered to have persistent viremia. Complete response was reported in 81% (n = 17/21), while three had partial remission and one had no response. Seven cats finished the induction protocol within 20-31 weeks (23.1 ± 4.5; median 20) and all seven received a maintenance protocol. The MST (lymphoma-related survival) for the 21 cats was 214 days. The MST was 214 days for cats with mediastinal lymphoma (n = 13), but it was not reached for multicentric lymphoma (n = 8; P = 0.9). The MST of cats with persistent FeLV antigenemia was 171 days. Grade I anorexia and vomiting occurred in 19% of the cats (n = 4/21). Hematologic toxicity was found in 100% of the cats at some point during their treatment, but it was mostly grade I or II. Neutropenia, thrombocytopenia and anemia occurred in 16/21, 21/21 and 15/21 cats, respectively.

CONCLUSIONS AND RELEVANCE

The LOPH protocol was well tolerated by cats with lymphoma and persistent FeLV viremia, and resulted in a better MST than similar studies with other protocols. Novel studies and controlled trials are necessary in order to evaluate the efficacy of different protocols according to the lymphoma subtype, anatomic form and FeLV status.