Molecular heterogeneity of Rhipicephalus sanguineus sensu lato and screening for Ehrlichia canis in mainland Portugal

The present study aimed to expand knowledge regarding the molecular characterization of R. sanguineus s.l. in Portugal and to screen for ticks naturally infected with E. canis. A total of 113 R. sanguineus s.l. were collected questing or attached to domestic and wild animals from the 18 administrative regions of mainland Portugal. All the ticks were analyzed for the 16S rRNA and the partial sequences obtained showed high genetic similarities with specimens belonging to the temperate lineage. These sequences revealed eight haplotypes (H1‒H8), with a genetic distance ranging from 0.3% to 1.4%. A convenience sample representing approximately 75% of all the R. sanguineus s.l. ticks collected was tested for the presence of E. canis by qPCR for the dsb gene. No ticks were found to be infected with this pathogen. Accordingly, further studies are required to determine the role of the R. sanguineus s.l. temperate lineage in E. canis maintenance and transmission, as well as to elucidate if a different R. sanguineus s.l. lineage or other tick species act as E. canis vectors for dogs in Portugal.