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

Abstract

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.

Local Population Structure and Seasonal Variability of Borrelia garinii Genotypes in Ixodes ricinus Ticks, Slovakia

“…In comparison, for countries with most thorough MLST data (Latvia, Germany, Russia, UK), 21 to 35 STs of B. garinii were detected at the country scale over multiple years [50]. Additionally, in a recent study on bird-feeding ticks conducted over multiple years at a European scale, authors were able to resolve 20 B. garinii STs (nine of which were new) for 11 countries [33]. Therefore, we believe that our study is sufficiently representative of a local richness of B. garinii genotypes using MLST.…”

“…With respect to B. garinii, the concept of ecological niches can be rather complex for local avian communities involving migratory or transient bird species, because the niches fluctuate dynamically in space and time. Moreover, the majority of the European bird studies have focused on tick infestations at the time of autumn and spring migration, e.g., [31][32][33], whereas the role of songbirds in the transmission dynamics of borreliae at the breeding or wintering sites, as well as the role of resident birds, remain poorly investigated [34].…”

Shared geographic histories and dispersal contribute to congruent phylogenies between amphipods and their microsporidian parasites at regional and global scales

“…shown in ticks on their penguin hosts and tick-borne bacterial pathogens in birds (Moon et al, 2019;Norte et al, 2020). This scenario can explain especially the global distribution of talitroid hosts and their associated Dictyocoela parasites.…”

“…Therefore, the degree of host-parasite associations and dispersal capabilities of hosts and parasites can influence cophylogenetic patterns. Although some studies have underscored the role of host dispersal ability (Moon, Chown, & Fraser, 2019;Norte et al, 2020), parasite dispersal ability (Engelbrecht, Matthee, Du Toit, & Matthee, 2016;Sweet & Johnson, 2018), and geographic barriers (Larose & Schwander, 2016;Weckstein, 2004) in parasite diversification, studies linking life history traits of hosts and parasites and their respective biogeographical patterns to the outcome of their co-evolutionary association are still scarce (Nieberding et al, 2010).…”

Detection of Borrelia burgdorferi Sensu Lato and Relapsing Fever Borrelia in Feeding Ixodes Ticks and Rodents in Sarawak, Malaysia: New Geographical Records of Borrelia yangtzensis and Borrelia miyamotoi

“…By targeting multi loci, eight housekeeping genes were developed for the Bbsl complex [ 47 ] and have been subsequently used in other studies to characterize the complexity of the Bbsl genospecies [ 33 , 35 ]. In recent years, this method has also proven to be useful in comparing the intraspecific diversity, elucidating population genetic structure, and other ecological aspects that may contribute to the transmission dynamics of the Bbsl genospecies [ 48 , 49 ]. Further, MLSA has been used to confirm B. yangtzensis from the isolates of ticks and rodents from China and Japan [ 33 ].…”