ABSTRACT
The distribution of Borrelia burgdorferi sensu lato genospecies in questing Ixodes ricinus ticks from ecologically distinct habitats in Latvia was analyzed. A significant variation in the frequency of the genospecies across sites was observed, pointing to the importance of the host community in the ecology of Lyme borreliosis.
Subject(s)
Borrelia burgdorferi Group/genetics , Borrelia burgdorferi Group/isolation & purification , Lipoproteins , Alleles , Animals , Antigens, Surface/genetics , Bacterial Outer Membrane Proteins/genetics , Bacterial Vaccines , Borrelia burgdorferi Group/classification , Environment , Genes, Bacterial , Genetic Variation , Ixodes/microbiology , Latvia , SerotypingABSTRACT
The roles of selection and migration of B. burgdorferi s. l. were studied. Questing adult Ixodes ricinus ticks were collected across Europe and analysed for infection with B. burgdorferi s. l. Analysis of the genospecies in individual ticks showed that B. garinii and B. valaisiana segregate from B. afzelii. Segregation of bird- and rodent-associated Borrelia genotypes can be explained by the operation of complement-mediated selection in the midgut of the feeding tick. Phylogenetic analyses of B. burgdorferi s. l. indicate high rates of migration for bird-associated genotypes. Altogether, it is emerging that the ecology of Lyme borreliosis is largely host-driven and that selection and migration are major forces shaping the population structures of B. burgdorferi s. l.
Subject(s)
Arachnid Vectors/microbiology , Borrelia burgdorferi Group/classification , Ixodes/microbiology , Lyme Disease/microbiology , Animals , Birds , Borrelia burgdorferi Group/genetics , Borrelia burgdorferi Group/isolation & purification , Disease Transmission, Infectious , Ecosystem , Europe , Genotype , Host-Parasite Interactions , Humans , Lyme Disease/transmission , Phylogeny , RodentiaABSTRACT
Borrelia burgdorferi sensu lato (s.l.), the tick-borne agent of Lyme borreliosis, is a bacterial species complex comprising 11 genospecies. Here, we discuss whether the delineation of genospecies is ecologically relevant. We provide evidence that B. burgdorferi s.l. is structured ecologically into distinct clusters that are host specific. An immunological model for niche adaptation is proposed that suggests the operation of complement-mediated selection in the midgut of the feeding tick. We conclude that vertebrate hosts rather than tick species are the key to Lyme borreliosis spirochaete diversity.
