Characterization of Borrelia lusitaniae Isolates Collected in Tunisia and Morocco

Abstract

Borrelia lusitaniae is a species within the complex Borrelia burgdorferi sensu lato and is infrequently isolated in Europe. In contrast, this species is by far the most predominant in North Africa and in Portugal. In this study, we analyzed the genetic diversity, at several loci, of a large population of isolates from free-living Ixodes ricinus ticks collected in Tunisia and Morocco. We found a moderate diversity of the whole genome by using pulsed-field gel electrophoresis as well as in the ospA gene sequences, compared to a high level of strain homogeneity in the small noncoding ribosomal spacer. In contrast, a high diversity of this locus has been previously reported for Portuguese isolates. We hypothesize that B. lusitaniae strains isolated in North Africa constitute a clone of Portuguese origin.Within the complex Borrelia burgdorferi sensu lato, three species, B. burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii, are known to cause a broad spectrum of human manifestations that are described as Lyme borreliosis. The genetic diversity of pathogenic species has been largely investigated both at the species level and at the strain level within each species (41). Otherwise, although its pathogenicity for humans is only suspected (31, 33), Borrelia valaisiana represents a widely distributed species in ticks throughout Europe and Asia and therefore has been extensively studied (12,22,32,38,40).In contrast to these species, little data are available concerning Borrelia lusitaniae. Only sporadic isolates have been characterized from ticks collected in the Czech Republic, Moldavia, Ukraine, and Belarus (20), in Slovakia (11), in Spain (3), in Poland (25), in France (30), in Switzerland (15-17), or in Turkey (13), and these isolates did not show any significant diversity. However, a study conducted in Portugal revealed a large diversity among B. lusitaniae strains isolated from a local tick population (6). Moreover, it is noteworthy that, among the three first Portuguese isolates identified as B. lusitaniae, two different types were demonstrated (20,26). Hence, these studies suggested a higher diversity among B. lusitaniae around the Mediterranean basin. However, all these studies only focused on the small ribosomal rrf-rrl spacer and, therefore, the global diversity of this species remained unknown.Recently, we reported that B. lusitaniae was, by far, the most prevalent species, ranging from 96.6 to 100% of the B. burgdorferi sensu lato species identified in Tunisia and Morocco (35,44,46). The report of some Lyme borreliosis cases in North Africa (1, 27) and the recent isolation in Portugal of B.lusitaniae from the skin of a human patient with chronic lesions (5) prompted us to characterize this species as a potential human pathogen. Therefore, we investigated the molecular characterization and the genetic diversity of B. lusitaniae isolated from free-living Ixodes ricinus ticks in Tunisia and Morocco. For these purposes we studied two single loci (ospC and ospA) and the noncoding intergenic spacer (r...

Infections and Coinfections of Questing Ixodes ricinus Ticks by Emerging Zoonotic Pathogens in Western Switzerland

“…B. lusitaniae-infected ticks are very common around the southern limit of the distribution of I. ricinus ticks (16,64) but are quite uncommon in other regions. In Switzerland, B. lusitaniae has been detected in free-living ticks in some localities of Canton Ticino (32), in ticks feeding on birds (43), and in Western Switzerland (33); our findings report its occurrence in two additional localities.…”

Borrelia lusitaniae OspA Gene Heterogeneity in Mediterranean Basin Area

“…The first human isolate of B. lusitaniae was identified in a 46-year-old woman from the Lisbon area in Portugal (Collares-Pereira et al 2004). Such genospecies are the most prevalent in the Mediterranean area (Collares-Pereira et al 2004;Sarih et al 2003;Younsi et al 2005) and recent studies indicate lizards as the reservoir hosts (Amore et al 2007;Majlathova et al 2006;Richter and Matuschka 2006;Tomassone et al 2005;Younsi et al 2005).…”

Prevalence of Borrelia burgdorferi Sensu Lato and Anaplasmataceae Members in Ixodes ricinus Ticks in Alsace, a Focus of Lyme Borreliosis Endemicity in France

“…Adult and nymph ticks were transported still alive to the laboratory, where they were analyzed for infection by B. burgdorferi sensu lato. We proceeded using either culture or PCR on DNA directly extracted from ticks as described previously (31,38), after having checked the concordance between the two methods. Identification at the species level was assessed by PCR-restriction fragment length polymorphism of the intergenic spacer as described previously (31,38).…”

“…We proceeded using either culture or PCR on DNA directly extracted from ticks as described previously (31, 38), after having checked the concordance between the two methods. Identification at the species level was assessed by PCR-restriction fragment length polymorphism of the intergenic spacer as described previously (31,38). For the detection of members of Anaplasmataceae, we used primers Ehr521 and Ehr747 (27) to amplify 247 bp of the rrs gene.…”