Natural Infection of Wild Canids (Cerdocyon thous and Lycalopex gymnocercus) with the Intraendothelial Piroplasm Rangelia vitalii in Southern Brazil

Rangelia vitalii is a piroplasm that infects canines, causing lesions typical of a hemolytic disorder. Two wild canids, a crab-eating fox (Cerdocyon thous) and a Pampas fox (Lycalopex gymnocercus), were presented for necropsy in Setor de Patologia Veterinaria at the Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. On gross examination, both animals had pale mucosae and moderate tick infestation (Amblyomma aureolatum). There was severe splenomegaly, and the liver had a diffusely orange-reddish lobular pattern. The mesenteric lymph nodes were brownish and slightly enlarged. Structures compatible with R. vitalii were observed in the cytoplasm of endothelial cells in the liver, stomach, heart, kidney, lungs, lymph nodes, and bladder. The agent was characterized by PCR and genetic sequencing of liver samples and ticks. We show that parasitism with R. vitalii follows an epidemiologic cycle in which wild canids act as reservoirs.