Molecular diagnosis of severe co-infection with Babesia canis and Hepatozoon canis in a red fox (Vulpes vulpes) from Tehran, Iran: a rare case report

Background Red foxes ( Vulpes vulpes ) are important reservoirs of tick-borne pathogens, but severe co-infection with Babesia canis and Hepatozoon canis has rarely been documented. This report describes a molecularly confirmed fatal co-infection in a red fox from Tehran, Iran. Case presentation A juvenile female red fox was presented with anorexia, lethargy, pyrexia (41°C), pale mucous membranes, and progressive weakness. Hematological examination and Giemsa-stained blood smear analysis were performed. Genomic DNA was extracted from whole blood, and conventional PCR targeting the 18 S rRNA gene was used for detection of Babesia and Hepatozoon , followed by Sanger sequencing and phylogenetic analysis. Results Hematological findings revealed severe anemia, thrombocytopenia, and leukocytosis. Blood smears demonstrated intraerythrocytic pear-shaped merozoites consistent with Babesia spp. and intracytoplasmic gamonts of Hepatozoon spp. PCR and sequencing confirmed infection with B. canis (GenBank: PZ359598.1) and H. canis (GenBank: PZ359594.1). Despite treatment, the animal died approximately 72 h after admission. Discussion To the best of our knowledge, this is the first molecularly confirmed fatal co-infection with B. canis and H. canis reported in a red fox from Iran. Conclusion These findings highlight the value of molecular diagnostics for wildlife pathogens and the potential role of red foxes as reservoirs of canine vector-borne diseases.