Molecular detection of Rangelia vitalii in domestic dogs from Uruguay.

The piroplasm Rangelia vitalii is the etiological agent of canine rangeliosis, a severe disease affecting domestic dogs in South America. Two domestic dogs from two different Departments (Salto and Treinta y Tres) of Uruguay presented with clinical signs such as apathy, anorexia, pale mucous membranes, jaundice, and hemorrhagic manifestations, suggestive of a canine vector-borne disease. Molecular analysis, based on PCR and DNA sequencing of portions of the 18S rRNA gene, revealed that both dogs were infected by R. vitalii. Two consensus sequences, one from Salto and one from Treinta y Tres, differed from each other by only 1 nucleotide (99.8% similarity) and were 99.8-100% identical to corresponding sequences of R. vitalii from Brazil and Argentina available in GenBank. Through phylogenetic analysis inferred by the 18S rRNA gene, the two Uruguayan sequences of R. vitalii were aligned with the corresponding sequences from 7 other R. vitalii sequences available in GenBank (5 from Brazil and, 2 from Argentina) under high bootstrap support. The two dogs of the present study were negative for Ehrlichia canis according to the E. canis-specific real-time PCR assay. Our findings not only confirm the occurrence of R. vitalii in Uruguay but also provide the southernmost record of this re-emerging agent. The only previous report of R. vitalii in Uruguay dated from 1976, a period when molecular analyses were not available. We provide the first molecular detection of R. vitalii in Uruguay. Currently, canine rangeliosis is confirmed to occur in Brazil, Argentina, and Uruguay.