RESUMEN
A species of Hepatozoon closely related to Hepatozoon felis found in the skeletal and cardiac muscle of a wild Pampas gray fox (Lycalopex gymnocercus) is described. The fox was euthanized after showing severe incoordination. On necropsy and histopathology there was bilateral, diffuse, severe, sub-acute, necrotizing bronchointerstitial pneumonia, with intracytoplasmic and intranuclear eosinophilic inclusion bodies. Canine distemper virus was detected by immunohistochemistry in the bronchiolar epithelium, syncytial cells, alveolar macrophages and pneumocytes. The skeletal muscle and myocardium contained multiple round to oval protozoan cysts ranging from 64 µm × 75 µm to 98 µm × 122 µm, with a central eosinophilic meront-like core surrounded by concentric rings of mucinous material resembling Hepatozoon americanum cysts but smaller in size. Macrophages within rare pyogranulomas and monocytes/macrophages in adjacent sinusoidal blood vessels in the skeletal muscle contained intracytoplasmic round protozoa consistent with merozoites or developing gamonts of Hepatozoon. Hepatozoon sp. infection was confirmed by PCR of skeletal muscle and the sequenced 18S rRNA PCR product was found to be 99% identical to H. felis by BLAST analysis and deposited in GenBank as accession number HQ020489. It clustered together in the phylogenetic analysis with published H. felis sequences and separately from H. canis, H. americanum and other Hepatozoon species. However, the close relatedness of the fox Hepatozoon to H. felis does not rule out infection with a different and possibly unknown Hepatozoon species.
Asunto(s)
Apicomplexa/clasificación , Virus del Moquillo Canino , Moquillo/virología , Zorros , Infecciones Protozoarias en Animales/parasitología , Animales , Apicomplexa/genética , Argentina/epidemiología , ADN Protozoario/genética , Moquillo/complicaciones , Moquillo/epidemiología , Femenino , Datos de Secuencia Molecular , Músculo Esquelético/parasitología , Músculo Esquelético/patología , Filogenia , Infecciones Protozoarias en Animales/complicaciones , Infecciones Protozoarias en Animales/epidemiologíaRESUMEN
Canine hepatozoonosis is a tick-borne disease caused by protozoans of the genus Hepatozoon. Several tick species have been implicated as potential vectors. Therefore, extensive studies are needed to determine the 'natural' endemic cycle of this parasite. This paper presents the first report of the presence of Hepatozoon canis oocysts in Rhipicephalus (Boophilus) microplus collected from an infected dog.