Title : Multi-marker analysis reveals an extensive genetic diversity in Rhipicephalus sanguineus (temperate lineage) and the first identification of Rhipicephalus rutilus in Tunisia
Abstract:
Accurate identification of Rhipicephalus species circulating in Tunisia is essential for improving disease surveillance and implementing effective control strategies, as these ticks are key vectors of numerous pathogens affecting both animals and humans. This study aimed to evaluate the utility of three mitochondrial markers (16S rRNA, 12S rRNA, and COI) for the molecular identification, genetic diversity assessment, and phylogenetic classification of tick specimens belonging to the Rhipicephalus sanguineus sensu lato complex in Tunisia.
A total of 28 tick specimens were collected from cattle and sheep across five Tunisian governorates representing diverse bioclimatic zones. Morphological identification, supported by molecular tools, enabled the detection of two species: Rhipicephalus sanguineus and Rhipicephalus rutilus. BLAST analysis, along with genetic diversity and phylogenetic assessments, confirmed for the first time the presence of Rh. rutilus (n = 9) in Tunisia, exhibiting moderate genetic diversity. Meanwhile, Rh. sanguineus specimens (n = 19) showed substantial genetic variability and were distributed across two distinct clusters of the temperate lineage.
Among the tested markers, COI demonstrated the highest discriminatory power, revealing clear evolutionary divergence and notable intra-species diversity within both Rh. sanguineus and Rh. rutilus. These findings provide novel insights into the genetic structure and distribution of Rhipicephalus ticks in Tunisia, underscoring the critical role of molecular tools in vector identification. The results have significant implications for vector-borne disease management and highlight the necessity for continued research into the evolutionary dynamics of tick populations and their impact on pathogen transmission.
