Evolution of antigenic diversity in the tick‐transmitted bacterium <i>Borrelia afzelii</i>: a role for host specialization?

Råberg, Lars; Hagström, Åsa K.; Andersson, Martin; Bartkova, Simona; Scherman, Kristin; Strandh, Maria; Tschirren, Barbara

doi:10.1111/jeb.13075

Cited by 29 publications

(34 citation statements)

References 40 publications

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“…Our work on a wild population of I. ricinus in Neuchâtel, Switzerland found that approximately 80% of nymphs infected with B. afzelii carried more than one strain [42,44]. In the present study, the rodents were infected with a maximum of two strains whereas in the field, rodents are often infected with more than two strains [10,29,54]. These differences in strain richness in the rodent host explain why the percentage of co-infected nymphs in our experiment (43.7%) was lower than what we have observed in nature.…”

Section: Discussionmentioning

confidence: 44%

Competition between strains ofBorrelia afzeliiinside the rodent host and the tick vector

et al. 2018

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Multiple-strain pathogens often establish mixed infections inside the host that result in competition between strains. In vector-borne pathogens, the competitive ability of strains must be measured in both the vertebrate host and the arthropod vector to understand the outcome of competition. Such studies could reveal the existence of trade-offs in competitive ability between different host types. We used the tick-borne bacterium Borrelia afzelii to test for competition between strains in the rodent host and the tick vector, and to test for a trade-off in competitive ability between these two host types. Mice were infected via tick bite with either one or two strains, and these mice were subsequently used to create ticks with single or mixed infections. Competition in the rodent host reduced strain-specific host-to-tick transmission and competition in the tick vector reduced the abundance of both strains. The strain that was competitively superior in host-to-tick transmission was competitively inferior with respect to bacterial abundance in the tick. This study suggests that in multiple-strain vector-borne pathogens there are trade-offs in competitive ability between the vertebrate host and the arthropod vector. Such trade-offs could play an important role in the coexistence of pathogen strains. rspb.royalsocietypublishing.org Proc. R. Soc. B 285: 20181804

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Section: Discussionmentioning

confidence: 44%

Competition between strains ofBorrelia afzeliiinside the rodent host and the tick vector

et al. 2018

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“…The uniform distribution of B. garinii STs among ticks collected from various bird species, and other sources (e.g., questing ticks), does not suggest specialization of certain B. garinii STs to certain hosts, contrary to the hypothesis of multiple niche polymorphism associated with OspC variation (Brisson, Drecktrah, Eggers, & Samuels, ) found for B. burgdorferi sensu stricto (Brisson & Dykhuizen, ; Vuong et al, ), but not for B. afzelii (Raberg et al, ). Our results are consistent with birds being the main reservoir hosts of B. garinii : they maintain its natural transmission cycle and are the source of infection for questing vector ticks.…”

Section: Discussionmentioning

confidence: 76%

Host dispersal shapes the population structure of a tick‐borne bacterial pathogen

Norte

Margos²,

Becker

et al. 2020

Molecular Ecology

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Birds are hosts for several zoonotic pathogens. Because of their high mobility, especially of longdistance migrants, birds can disperse these pathogens, affecting their distribution and phylogeography. We focused on Borrelia burgdorferi sensu lato, which includes the causative agents of Lyme borreliosis, as an example for tick‐borne pathogens, to address the role of birds as propagation hosts of zoonotic agents at a large geographical scale. We collected ticks from passerine birds in 11 European countries. B. burgdorferi s.l. prevalence in Ixodes spp. was 37% and increased with latitude. The fieldfare Turdus pilaris and the blackbird T. merula carried ticks with the highest Borrelia prevalence (92 and 58%, respectively), whereas robin Erithacus rubecula ticks were the least infected (3.8%). Borrelia garinii was the most prevalent genospecies (61%), followed by B. valaisiana (24%), B. afzelii (9%), B. turdi (5%) and B. lusitaniae (0.5%). A novel Borrelia genospecies “Candidatus Borrelia aligera” was also detected. Multilocus sequence typing (MLST) analysis of B. garinii isolates together with the global collection of B. garinii genotypes obtained from the Borrelia MLST public database revealed that: (a) there was little overlap among genotypes from different continents, (b) there was no geographical structuring within Europe, and (c) there was no evident association pattern detectable among B. garinii genotypes from ticks feeding on birds, questing ticks or human isolates. These findings strengthen the hypothesis that the population structure and evolutionary biology of tick‐borne pathogens are shaped by their host associations and the movement patterns of these hosts.

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“…Thus, there may be ‘general’ drivers of tick-borne diseases that operate directly through the shared tick vector, as well as ‘specific’ drivers that are associated with the dynamics and distributions of the various reservoir hosts of the pathogen. In Europe, the most common pathogen that causes Lyme disease is Borrelia afzelii , which has a small mammal reservoir 24 – 27 ; less common are B. garinii (in birds) and B. burgdorferi sensu stricto (a generalist). A. phagocytophilum has a wide range of reservoir hosts in Europe including wild ruminants, rodents, insectivores, birds, carnivores, and domestic animals 28 .…”

Section: Introductionmentioning

confidence: 99%

Emergence of tick-borne diseases at northern latitudes in Europe: a comparative approach

Mysterud

Jore

Østerås³

et al. 2017

Sci Rep

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The factors that drive the emergence of vector-borne diseases are difficult to identify due to the complexity of the pathogen-vector-host triad. We used a novel comparative approach to analyse four long-term datasets (1995–2015) on the incidence of tick-borne diseases in humans and livestock (Lyme disease, anaplasmosis and babesiosis) over a geographic area that covered the whole of Norway. This approach allowed us to separate general (shared vector) and specific (pathogen reservoir host) limiting factors of tick-borne diseases, as well as the role of exposure (shared and non-shared pathogens in different hosts). We found broadly similar patterns of emergence across the four tick-borne diseases. Following initial increases during the first decade of the time series, the numbers of cases peaked at slightly different years and then stabilized or declined in the most recent years. Contrasting spatial patterns of disease incidence were consistent with exposure to ticks being an important factor influencing disease incidence in livestock. Uncertainty regarding the reservoir host(s) of the pathogens causing anaplasmosis and babesiosis prevented a firm conclusion regarding the role of the reservoir host-pathogen distribution. Our study shows that the emergence of tick-borne diseases at northern latitudes is linked to the shared tick vector and that variation in host-pathogen distribution and exposure causes considerable variation in emergence.

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Evolution of antigenic diversity in the tick‐transmitted bacterium Borrelia afzelii: a role for host specialization?

Cited by 29 publications

References 40 publications

Competition between strains ofBorrelia afzeliiinside the rodent host and the tick vector

Competition between strains ofBorrelia afzeliiinside the rodent host and the tick vector

Host dispersal shapes the population structure of a tick‐borne bacterial pathogen

Emergence of tick-borne diseases at northern latitudes in Europe: a comparative approach

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