The Genetic Diversity of "Rickettsiella" Symbionts in "Ixodes ricinus" Throughout Europe

• Aitor Garcia-Vozmediano ^[1] ; Laura Tomassone ^[1] ; Manoj Fonville ^[2] ; Luigi Bertolotti ^[1] ; Dieter Heylen ^{[6] [4] [9]} ; Nannet D. Fabri ^{[3] [5]} ; Jolyon M. Medlock ^[7] ; Ard M. Nijhof ^[8] ; Kayleigh M. Hansford ^[7] ; Hein Sprong ^[2] ; Aleksandra I. Krawczyk ^{[2] [10]}
  1. [1] University of Turin

     University of Turin

     Torino, Italia

     
  2. [2] National Institute for Public Health and the Environment

     National Institute for Public Health and the Environment

     Países Bajos

     
  3. [3] Swedish University of Agricultural Sciences

     Swedish University of Agricultural Sciences

     Uppsala domkyrkoförs., Suecia

     
  4. [4] University of Antwerp

     University of Antwerp

     Arrondissement Antwerpen, Bélgica

     
  5. [5] Utrecht University

     Utrecht University

     Países Bajos

     
  6. [6] Eco-Epidemiology Group, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
  7. [7] Infections Medical Entomology & Zoonoses Ecology, Public Health England, Porton Down, UK
  8. [8] Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
  9. [9] Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium
  10. [10] Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands

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• Localización: Microbial ecology, ISSN-e 1432-184X, ISSN 0095-3628, Vol. 84, Nº. 2, 2022, págs. 613-626
• Idioma: inglés
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  • Rickettsiella species are bacterial symbionts that are present in a great variety of arthropod species, including ixodid ticks. However, little is known about their genetic diversity and distribution in Ixodes ricinus, as well as their relationship with other tick-associated bacteria. In this study, we investigated the occurrence and the genetic diversity of Rickettsiella spp. in I. ricinus throughout Europe and evaluated any preferential and antagonistic associations with Candidatus Midichloria mitochondrii and the pathogens Borrelia burgdorferi sensu lato and Borrelia miyamotoi. Rickettsiella spp. were detected in most I. ricinus populations investigated, encompassing a wide array of climate types and environments. The infection prevalence significantly differed between geographic locations and was significantly higher in adults than in immature life stages. Phylogenetic investigations and protein characterization disclosed four Rickettsiella clades (I–IV). Close phylogenetic relations were observed between Rickettsiella strains of I. ricinus and other arthropod species. Isolation patterns were detected for Clades II and IV, which were restricted to specific geographic areas. Lastly, although coinfections occurred, we did not detect significant associations between Rickettsiella spp. and the other tick-associated bacteria investigated. Our results suggest that Rickettsiella spp. are a genetically and biologically diverse facultative symbiont of I. ricinus and that their distribution among tick populations could be influenced by environmental components.