Molecular identification of Borrelia spirochetes in questing Ixodes ricinus from northwestern Spain

• Main Authors: Pablo Díaz, Jose Luis Arnal, Susana Remesar, Ana Pérez-Creo, José Manuel Venzal, María Esther Vázquez-López, Alberto Prieto, Gonzalo Fernández, Ceferino Manuel López, Rosario Panadero, Alfredo Benito, Pablo Díez-Baños, Patrocinio Morrondo
• Format: Article
• Language: English
• Published: BMC 2017-12-01
• Series: Parasites & Vectors
• Subjects: Borrelia burgdorferi (s.l.); Borrelia miyamotoi; Ixodes ricinus; NW Spain
• Online Access: http://link.springer.com/article/10.1186/s13071-017-2574-x

Abstract Background Ixodes ricinus, the predominant tick species in Europe, can transmit the causative agents of important human diseases such as Lyme borreliosis (LB), caused by Borrelia spirochetes. In northern Spain, LB is considered endemic; recently, a significant increase of the annual incidence of LB was reported in the northwestern (NW) region. Methods In order to provide information on the prevalence of Borrelia spp., pooled and individually free-living I. ricinus from NW Spain were molecularly analyzed. Positive samples were characterized at the fla and Glpq genes and the rrfA-rrlB intergenic spacer region to identify Borrelia species/genospecies. Results Borrelia burgdorferi (sensu lato) (s.l.) individual prevalence and MIR were significantly higher in adult females (32.3 and 16%) than in nymphs (18.8 and 6.2%) and adult males (15.6 and 8.4%). Five Borrelia genospecies belonging to the B. burgdorferi (s.l.) group were identified: B. garinii was predominant, followed by B. valaisiana, B. lusitaniae, B. afzelii and B. burgdorferi (sensu stricto) (s.s.). One species belonging to the tick-borne relapsing fever group (B. miyamotoi) was also found, showing low individual prevalence (1%), positive pool (0.7%) and MIR (0.1%) values. To our knowledge, this is the first citation of B. miyamotoi in free-living ticks from Spain. Conclusions The significant prevalences of B. burgdorferi (s.l.) genospecies detected in questing ticks from NW Spain are similar to those detected in northern and central European countries and higher to those previously found in Spain. These results together with the high incidence of LB in humans and the high seroprevalence of B. burgdorferi (s.l.) in roe deer shown in other studies reveal that the northwest area is one of the most risky regions for acquiring LB in Spain.