The Genetic Diversity of Rickettsiella Symbionts in Ixodes ricinus Throughout Europe

AbstractRickettsiella 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.

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Spatial and temporal patterns of the emerging tick-borne pathogen Borrelia miyamotoi in blacklegged ticks (Ixodes scapularis) in New York

Parasites & Vectors ◽

10.1186/s13071-020-04569-2 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

F. Keesing ◽

D. J. McHenry ◽

M. H. Hersh ◽

R. S. Ostfeld

Keyword(s):

New York ◽

Ixodes Scapularis ◽

Quantitative Polymerase Chain Reaction ◽

Human Infection ◽

Ixodid Ticks ◽

Transovarial Transmission ◽

Infection Prevalence ◽

Borrelia Miyamotoi ◽

Spatial And Temporal Patterns ◽

Reservoir Hosts

AbstractBorrelia miyamotoi, a bacterium that causes relapsing fever, is found in ixodid ticks throughout the northern hemisphere. The first cases of human infection with B. miyamotoi were identified in 2011. In the eastern USA, blacklegged ticks (Ixodes scapularis) become infected by feeding on an infected vertebrate host, or through transovarial transmission. We surveyed B. miyamotoi prevalence in ticks within forested habitats in Dutchess County, New York, and identified possible reservoir hosts. To assess spatial variation in infection, we collected questing nymphal ticks at > 150 sites. To assess temporal variation in infection, we collected questing nymphs for 8 years at a single study site. We collected questing larval ticks from nine plots to estimate the amount of transovarial transmission. To evaluate potential reservoir hosts, we captured 14 species of mammal and bird hosts naturally infested with larval blacklegged ticks and held these hosts in the laboratory until ticks fed to repletion and molted to nymphs. We determined infection for all ticks using quantitative polymerase chain reaction. The overall infection prevalence of questing nymphal ticks across all sites was ~ 1%, but prevalence at individual sites was as high as 9.1%. We detected no significant increase in infection through time. Only 0.4% of questing larval ticks were infected. Ticks having fed as larvae from short-tailed shrews, red squirrels, and opossums tended to have higher infection prevalence than did ticks having fed on other hosts. Further studies of the role of hosts in transmission are warranted. The locally high prevalence of B. miyamotoi in the New York/New England landscape suggests the importance of vigilance by health practitioners and the public.

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GENETIC DIVERSITY IN BAMBARA GROUNDNUT (Vigna subterranean) AS REVEALED BY MOLECULAR WEIGHTS OF THE SEEDS’ PROTEINS

Bangladesh Journal of Plant Breeding and Genetics ◽

10.3329/bjpbg.v30i2.35528 ◽

2018 ◽

Vol 30 (2) ◽

pp. 19-28

Author(s):

A. J. Oludare ◽

J. I. Kioko ◽

A. A. Akeem ◽

A. T. Olumide ◽

K. R. Justina ◽

...

Keyword(s):

Genetic Diversity ◽

Seed Proteins ◽

Electrophoretic Analysis ◽

Protein Characterization ◽

Bambara Groundnut ◽

Vigna Subterranea ◽

Phylogenetic Relatedness ◽

Molecular Weights ◽

National Centre ◽

Standard Marker

Nine accessions of Bambara groundnut (Vigna subterranea (L.) Verdc.,syn. Voandzeia subterranea (L.) Thouars ex DC.) obtained from National Centre for Genetic Resources and Biotechnology (NACGRAB), Ibadan, Oyo state, were assessed for their genetic and phylogenetic relatedness through electrophoretic analysis of the seed proteins. 0.2g of the seeds were weighed and macerated with mortar and pestle in 0.2M phosphate buffer containing 0.133M of acid (NaH2PO4) and 0.067 of base (Na2HPO4) at pH 6.5. Protein characterization with standard marker revealed that the seeds of the nine accessions contained proteins (B.S.A, Oval Albumin, Pepsinogen, Trypsinogen and Lysozyme) with molecular weights ranging from 66kda and above, 45 – 65 kDa, 44 – 33 kda, 32-24 kDa and 23-14 kDa, respectively. The student T-test revealed that accessions B, C, E, F, H and I have molecular weights not significantly different from one another (P<0.05) while samples A, D and G showed significantly different values (P>0.05). All the accessions had at least two proteins and two major bands in common. The study revealed intra-specific similarities and genetic diversity in protein contents among the nine accessions of Bambara groundnut (Vigna subterraranea (L.) Verdc.syn

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Ecological Factors Characterizing the Prevalence of Bacterial Tick-Borne Pathogens in Ixodes ricinus Ticks in Pastures and Woodlands

Applied and Environmental Microbiology ◽

10.1128/aem.00610-10 ◽

2010 ◽

Vol 76 (13) ◽

pp. 4413-4420 ◽

Cited By ~ 75

Author(s):

Lénaïg Halos ◽

Séverine Bord ◽

Violaine Cotté ◽

Patrick Gasqui ◽

David Abrial ◽

...

Keyword(s):

Forest Fragmentation ◽

Ixodes Ricinus ◽

Spotted Fever ◽

Ecological Factors ◽

Adult Tick ◽

Reservoir Host ◽

Host Community ◽

Infection Prevalence ◽

Spotted Fever Group ◽

Reservoir Hosts

ABSTRACT Ecological changes are recognized as an important driver behind the emergence of infectious diseases. The prevalence of infection in ticks depends upon ecological factors that are rarely taken into account simultaneously. Our objective was to investigate the influences of forest fragmentation, vegetation, adult tick hosts, and habitat on the infection prevalence of three tick-borne bacteria, Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, and Rickettsia sp. of the spotted fever group, in questing Ixodes ricinus ticks, taking into account tick characteristics. Samples of questing nymphs and adults were taken from 61 pastures and neighboring woodlands in central France. The ticks were tested by PCR of pools of nymphs and individual adults. The individual infection prevalence was modeled using multivariate regression. The highest infection prevalences were found in adult females collected in woodland sites for B. burgdorferi sensu lato and A. phagocytophilum (16.1% and 10.7%, respectively) and in pasture sites for Rickettsia sp. (8.7%). The infection prevalence in nymphs was lower than 6%. B. burgdorferi sensu lato was more prevalent in woodlands than in pastures. Forest fragmentation favored B. burgdorferi sensu lato and A. phagocytophilum prevalence in woodlands, and in pastures, the B. burgdorferi sensu lato prevalence was favored by shrubby vegetation. Both results are probably because large amounts of edges or shrubs increase the abundance of small vertebrates as reservoir hosts. The Rickettsia sp. prevalence was maximal on pasture with medium forest fragmentation. Female ticks were more infected by B. burgdorferi sensu lato than males and nymphs in woodland sites, which suggests an interaction between the ticks and the bacteria. This study confirms the complexity of the tick-borne pathogen ecology. The findings support the importance of small vertebrates as reservoir hosts and make a case for further studies in Europe on the link between the composition of the reservoir host community and the infection prevalence in ticks.

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Genetic diversity, infection prevalence, and possible transmission routes of Bartonella spp. in vampire bats

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0006786 ◽

2018 ◽

Vol 12 (9) ◽

pp. e0006786 ◽

Cited By ~ 16

Author(s):

Daniel J. Becker ◽

Laura M. Bergner ◽

Alexandra B. Bentz ◽

Richard J. Orton ◽

Sonia Altizer ◽

...

Keyword(s):

Genetic Diversity ◽

Infection Prevalence ◽

Vampire Bats

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Diversifying forest communities may change Lyme disease risk: extra dimension to the dilution effect in Europe

Parasitology ◽

10.1017/s0031182016000688 ◽

2016 ◽

Vol 143 (10) ◽

pp. 1310-1319 ◽

Cited By ~ 15

Author(s):

SANNE C. RUYTS ◽

EVY AMPOORTER ◽

ELENA C. COIPAN ◽

LANDER BAETEN ◽

DIETER HEYLEN ◽

...

Keyword(s):

North America ◽

Lyme Disease ◽

Borrelia Burgdorferi ◽

Disease Risk ◽

Severe Disease ◽

Dilution Effect ◽

Ixodid Ticks ◽

Infection Prevalence ◽

Host Diversity ◽

Pine Stands

SUMMARYLyme disease is caused by bacteria of theBorrelia burgdorferigenospecies complex and transmitted by Ixodid ticks. In North America only one pathogenic genospecies occurs, in Europe there are several. According to the dilution effect hypothesis (DEH), formulated in North America, nymphal infection prevalence (NIP) decreases with increasing host diversity since host species differ in transmission potential. We analysedBorreliainfection in nymphs from 94 forest stands in Belgium, which are part of a diversification gradient with a supposedly related increasing host diversity: from pine stands without to oak stands with a shrub layer. We expected changing tree species and forest structure to increase host diversity and decrease NIP. In contrast with the DEH, NIP did not differ between different forest types. Genospecies diversity however, and presumably also host diversity, was higher in oak than in pine stands. Infected nymphs tended to harbourBorrelia afzeliiinfection more often in pine stands whileBorrelia gariniiandBorrelia burgdorferiss. infection appeared to be more prevalent in oak stands. This has important health consequences, since the latter two cause more severe disease manifestations. We show that the DEH must be nuanced for Europe and should consider the response of multiple pathogenic genospecies.

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Causation without correlation: parasite-mediated frequency-dependent selection and infection prevalence

10.1101/2021.11.13.468422 ◽

2021 ◽

Author(s):

Curtis M Lively ◽

Julie Xu ◽

Frida Ben-Ami

Keyword(s):

Genetic Diversity ◽

Natural Populations ◽

Infection Prevalence ◽

Strong Positive Correlation ◽

Frequency Dependent ◽

Frequency Dependent Selection ◽

Host Diversity ◽

Host Genetic ◽

Host Parasite

Parasite-mediated selection is thought to maintain host genetic diversity for resistance. We might thus expect to find a strong positive correlation between host genetic diversity and infection prevalence across natural populations. Here we used computer simulations to examine host-parasite coevolution in 20 simi-isolated clonal populations across a broad range of values for both parasite virulence and parasite fecundity. We found that the correlation between host genetic diversity and infection prevalence can be significantly positive for intermediate values of parasite virulence and fecundity. But the correlation can also be weak and statistically non-significant, even when parasite-mediated frequency-dependent selection is the sole force maintaining host diversity. Hence correlational analyses of field populations, while useful, might underestimate the role of parasites in maintaining host diversity.

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Questing Ixodes ricinus ticks (Acari, Ixodidae) as a vector of Borrelia burgdorferi sensu lato and Borrelia miyamotoi in an urban area of north-eastern Poland

Experimental and Applied Acarology ◽

10.1007/s10493-019-00379-z ◽

2019 ◽

Vol 78 (1) ◽

pp. 113-126 ◽

Cited By ~ 3

Author(s):

Katarzyna Kubiak ◽

Janina Dziekońska-Rynko ◽

Hanna Szymańska ◽

Dariusz Kubiak ◽

Małgorzata Dmitryjuk ◽

...

Keyword(s):

Borrelia Burgdorferi ◽

Urban Area ◽

Ixodes Ricinus ◽

Borrelia Burgdorferi Sensu Lato ◽

Borrelia Miyamotoi ◽

North Eastern ◽

Ixodes Ricinus Ticks

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Detection of Asian-Type Borrelia miyamotoi from Ixodes ricinus Inhabiting Tver Province (Russia): A Sympatric Region for I. ricinus and Ixodes persulcatus

Vector-Borne and Zoonotic Diseases ◽

10.1089/vbz.2020.2653 ◽

2020 ◽

Vol 20 (12) ◽

pp. 921-923

Author(s):

Toshiyuki Masuzawa ◽

Keiko Sakakibara ◽

Kazushi Suzuki ◽

Hiroki Sato ◽

Shima Yasuda

Keyword(s):

Ixodes Ricinus ◽

Ixodes Persulcatus ◽

Borrelia Miyamotoi

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Relative Importance of Ixodes ricinus and Ixodes trianguliceps as Vectors for Anaplasma phagocytophilum and Babesia microti in Field Vole (Microtus agrestis) Populations

Applied and Environmental Microbiology ◽

10.1128/aem.00625-08 ◽

2008 ◽

Vol 74 (23) ◽

pp. 7118-7125 ◽

Cited By ~ 81

Author(s):

K. J. Bown ◽

X. Lambin ◽

G. R. Telford ◽

N. H. Ogden ◽

S. Telfer ◽

...

Keyword(s):

United Kingdom ◽

Ixodes Ricinus ◽

Anaplasma Phagocytophilum ◽

Babesia Microti ◽

Infection Prevalence ◽

Microtus Agrestis ◽

Relative Importance ◽

The United Kingdom ◽

Ixodes Trianguliceps ◽

Larval Burden

ABSTRACT The importance of Ixodes ricinus in the transmission of tick-borne pathogens is well recognized in the United Kingdom and across Europe. However, the role of coexisting Ixodes species, such as the widely distributed species Ixodes trianguliceps, as alternative vectors for these pathogens has received little attention. This study aimed to assess the relative importance of I. ricinus and I. trianguliceps in the transmission of Anaplasma phagocytophilum and Babesia microti among United Kingdom field voles (Microtus agrestis), which serve as reservoir hosts for both pathogens. While all instars of I. trianguliceps feed exclusively on small mammals, I. ricinus adults feed primarily on larger hosts such as deer. The abundance of both tick species and pathogen infection prevalence in field voles were monitored at sites surrounded with fencing that excluded deer and at sites where deer were free to roam. As expected, fencing significantly reduced the larval burden of I. ricinus on field voles and the abundance of questing nymphs, but the larval burden of I. trianguliceps was not significantly affected. The prevalence of A. phagocytophilum and B. microti infections was not significantly affected by the presence of fencing, suggesting that I. trianguliceps is their principal vector. The prevalence of nymphal and adult ticks on field voles was also unaffected, indicating that relatively few non-larval I. ricinus ticks feed upon field voles. This study provides compelling evidence for the importance of I. trianguliceps in maintaining these enzootic tick-borne infections, while highlighting the potential for such infections to escape into alternative hosts via I. ricinus.

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