Ehrlichia canis (Rickettsiales: Anaplasmataceae) in Rhipicephalus sanguineus sensu lato ticks of the temperate lineage (Acari Ixodidae), Buenos Aires Province, Argentina

Abstract

The aim of the present study was to report the presence of Ehrlichia canis in Rhipicephalus sanguineus sensu lato (s. l.) ticks of the temperate lineage (LTe) collected on a dog with canine monocytic ehrlichiosis from José C. Paz (northwest area of the Buenos Aires Metropolitan Area - BAMA-). Thirty-two ticks were collected (30 larvae and 2 nymphs). A group of 10 larvae and one nymph were positive to Ehrlichia in the initial PCR targeting a fragment of the Anaplasmataceae family 16S rRNA gene. These positive samples were also amplified by PCR for a fragment of the dsb gene of the genus Ehrlichia, and then sequenced, resulting in a 100% identity with E. canis. Specimens of R. sanguineus s.l. positive for E. canis were determined as belonging to the temperate lineage of R. sanguineus s. l. through the analysis of sequences from the tick mitochondrial 16S rRNA gene. Experimental studies and epidemiological background have related E. canis infection with R. sanguineus s. l. ticks of the tropical lineage, but the results of this study put in evidence the needed of new epidemiological studies on the vectorial competence of the different lineages of R. sanguineus s.l. to transmit E. canis.