Molecular detection of tick-borne pathogens in Rhipicephalus sanguineus group ticks

The Rhipicephalus sanguineus group includes some of the most widespread dog ticks, whose identification currently represents a difficult task due to the morphological similarities of these ixodid species. Recently, following the morphological and molecular characterization of tick specimens collected from dogs in all continents, Rhipicephalus sanguineus sensu lato (s.l.), Rhipicephalus turanicus and three different operational taxonomic units (namely Rhipicephalus sp. I-III) have been identified. Therefore, a comprehensive molecular study has been herein carried out to detect selected canine vector-borne pathogens (i.e., Anaplasma platys, Cercopithifilaria spp., Ehrlichia canis and Hepatozoon canis) in ticks belonging to the R. sanguineus group. A total of 204 tick specimens from dogs were examined and identified as R. sanguineus s.l. (n=81), R. turanicus (n=17), Rhipicephalus sp. I (n=66), Rhipicephalus sp. II (n=37), and Rhipicephalus sp. III (n=3). PCR assays were performed to detect mitochondrial and ribosomal target genes of Cercopithifilaria spp., A. platys, E. canis and H. canis. Out of 204 specimens examined, 2.5%, 7.4% and 21.6% scored positive to A. platys, H. canis and Cercopithifilaria spp., respectively. In addition, co-infections with two pathogens (i.e., Cercopithifilaria bainae and A. platys or H. canis) were detected in four tick specimens. This study suggests a relationship between ticks belonging to the R. sanguineus group and the geographical distribution of A. platys, H. canis and Cercopithifilaria spp. However, the role of each representative tick species within the R. sanguineus group in the transmission of these canine pathogens needs to be further investigated.