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Nowak TA, Burke RL, Diuk-Wasser MA, Lin YP. Lizards and the enzootic cycle of Borrelia burgdorferi sensu lato. Mol Microbiol 2024; 121:1262-1272. [PMID: 38830767 DOI: 10.1111/mmi.15271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 04/06/2024] [Accepted: 04/16/2024] [Indexed: 06/05/2024]
Abstract
Emerging and re-emerging pathogens often stem from zoonotic origins, cycling between humans and animals, and are frequently vectored and maintained by hematophagous arthropod vectors. The efficiency by which these disease agents are successfully transmitted between vertebrate hosts is influenced by many factors, including the host on which a vector feeds. The Lyme disease bacterium Borrelia burgdorferi sensu lato has adapted to survive in complex host environments, vectored by Ixodes ticks, and maintained in multiple vertebrate hosts. The versatility of Lyme borreliae in disparate host milieus is a compelling platform to investigate mechanisms dictating pathogen transmission through complex networks of vertebrates and ticks. Squamata, one of the most diverse clade of extant reptiles, is comprised primarily of lizards, many of which are readily fed upon by Ixodes ticks. Yet, lizards are one of the least studied taxa at risk of contributing to the transmission and life cycle maintenance of Lyme borreliae. In this review, we summarize the current evidence, spanning from field surveillance to laboratory infection studies, supporting their contributions to Lyme borreliae circulation. We also summarize the current understanding of divergent lizard immune responses that may explain the underlying molecular mechanisms to confer Lyme spirochete survival in vertebrate hosts. This review offers a critical perspective on potential enzootic cycles existing between lizard-tick-Borrelia interactions and highlights the importance of an eco-immunology lens for zoonotic pathogen transmission studies.
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Affiliation(s)
- Tristan A Nowak
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, State University of New York at Albany, Albany, New York, USA
| | - Russell L Burke
- Department of Biology, Hofstra University, Hempstead, New York, USA
| | - Maria A Diuk-Wasser
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, USA
| | - Yi-Pin Lin
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, State University of New York at Albany, Albany, New York, USA
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts, USA
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2
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Wülbern J, Windorfer L, Sato K, Nakao M, Hepner S, Margos G, Fingerle V, Kawabata H, Becker NS, Kraiczy P, Rollins RE. Unprecedented genetic variability of PFam54 paralogs among Eurasian Lyme borreliosis-causing spirochetes. Ecol Evol 2024; 14:e11397. [PMID: 38779535 PMCID: PMC11109050 DOI: 10.1002/ece3.11397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 04/17/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024] Open
Abstract
Lyme borreliosis (LB) is the most common vector-borne disease in the Northern Hemisphere caused by spirochetes belonging to the Borrelia burgdorferi sensu lato (Bbsl) complex. Borrelia spirochetes circulate in obligatory transmission cycles between tick vectors and different vertebrate hosts. To successfully complete this complex transmission cycle, Bbsl encodes for an arsenal of proteins including the PFam54 protein family with known, or proposed, influences to reservoir host and/or vector adaptation. Even so, only fragmentary information is available regarding the naturally occurring level of variation in the PFam54 gene array especially in relation to Eurasian-distributed species. Utilizing whole genome data from isolates (n = 141) originated from three major LB-causing Borrelia species across Eurasia (B. afzelii, B. bavariensis, and B. garinii), we aimed to characterize the diversity of the PFam54 gene array in these isolates to facilitate understanding the evolution of PFam54 paralogs on an intra- and interspecies level. We found an extraordinarily high level of variation in the PFam54 gene array with 39 PFam54 paralogs belonging to 23 orthologous groups including five novel paralogs. Even so, the gene array appears to have remained fairly stable over the evolutionary history of the studied Borrelia species. Interestingly, genes outside Clade IV, which contains genes encoding for proteins associated with Borrelia pathogenesis, more frequently displayed signatures of diversifying selection between clades that differ in hypothesized vector or host species. This could suggest that non-Clade IV paralogs play a more important role in host and/or vector adaptation than previously expected, which would require future lab-based studies to validate.
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Affiliation(s)
- Janna Wülbern
- Evolutionary Ecology and Genetics, Faculty of BiologyChristian‐Albrechts‐Universität Zu KielKielGermany
| | - Laura Windorfer
- Terrestrial Ecology Research Group, Department of Life Science Systems, School of Life SciencesTechnical University of MunichFreisingGermany
- Disrupt.Design Lab, Faculty of Architecture and Town Planning, Segoe BuildingTechnion – Israel Institute of TechnologyTechnion CityIsrael
| | - Kozue Sato
- Department of Bacteriology INational Institute for Infectious DiseaseTokyoJapan
| | - Minoru Nakao
- Department of ParasitologyAsahikawa Medical UniversityAsahikawaJapan
| | - Sabrina Hepner
- German National Reference Center for Borrelia, Bavarian Health and Food Safety AuthorityOberschleissheimGermany
| | - Gabriele Margos
- German National Reference Center for Borrelia, Bavarian Health and Food Safety AuthorityOberschleissheimGermany
| | - Volker Fingerle
- German National Reference Center for Borrelia, Bavarian Health and Food Safety AuthorityOberschleissheimGermany
| | - Hiroki Kawabata
- Department of Bacteriology INational Institute for Infectious DiseaseTokyoJapan
| | - Noémie S. Becker
- Division of Evolutionary Biology, Faculty of BiologyLMU MunichPlanegg‐MartinsriedGermany
| | - Peter Kraiczy
- Institute of Medical Microbiology and Infection Control, University Hospital of FrankfurtGoethe University FrankfurtFrankfurtGermany
| | - Robert E. Rollins
- Institute of Avian Research “Vogelwarte Helgoland”WilhelmshavenGermany
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Margos G, Hofmann M, Casjens S, Dupraz M, Heinzinger S, Hartberger C, Hepner S, Schmeusser M, Sing A, Fingerle V, McCoy KD. Genome diversity of Borrelia garinii in marine transmission cycles does not match host associations but reflects the strains evolutionary history. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2023; 115:105502. [PMID: 37716446 DOI: 10.1016/j.meegid.2023.105502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 08/15/2023] [Accepted: 09/13/2023] [Indexed: 09/18/2023]
Abstract
Borrelia burgdorferi sensu lato is a species complex of spirochetal bacteria that occupy different ecological niches which is reflected in their reservoir host- and vector-associations. Borrelia genomes possess numerous linear and circular plasmids. Proteins encoded by plasmid genes play a major role in host- and vector-interaction and are important for Borrelia niche adaptation. However, the plasmid composition and therewith the gene repertoire may vary even in strains of a single species. Borrelia garinii, one of the six human pathogenic species, is common in Europe (vector Ixodes ricinus), Asia (vector Ixodes persulcatus) and in marine birds (vector Ixodes uriae). For the latter, only a single culture isolate (Far04) and its genome were previously available. The genome was rather small containing only one circular and six linear plasmids with a notable absence of cp32 plasmids. To further investigate B. garinii from marine transmission cycles and to explore i) whether the small number of plasmids found in isolate Far04 is a common feature in B. garinii from marine birds and presents an adaptation to this particular niche and ii) whether there may be a correlation between genome type and host species, we initiated in vitro cultures from live I. uriae collected in 2017 and 2018 from marine avian hosts and their nests. Hosts included common guillemots, Atlantic Puffin, razorbill, and kittiwake. We obtained 17 novel isolates of which 10 were sequenced using Illumina technology, one also with Pacific Bioscience technology. The 10 genomes segregated into five different genome types defined by plasmid types (based on PFam32 loci). We show that the genomes of seabird associated B. garinii contain fewer plasmids (6-9) than B. garinii from terrestrial avian species (generally ≥10), potentially suggesting niche adaptation. However, genome type did not match an association with the diverse avian seabird hosts investigated but matched the clonal complex they originated from, perhaps reflecting the isolates evolutionary history. Questions that should be addressed in future studies are (i) how is plasmid diversity related to host- and/or vector adaptation; (ii) do the different seabird species differ in reservoir host competence, and (iii) can the genome types found in seabirds use terrestrial birds as reservoir hosts.
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Affiliation(s)
- Gabriele Margos
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Markus Hofmann
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Sherwood Casjens
- Pathology Department, School of Medicine, University of Utah, 15 North Medical Drive East Ste. #1100, Salt Lake City, UT 84112, USA.
| | - Marlene Dupraz
- MIVEGEC, University of Montpellier - CNRS - IRD, Centre IRD, Domaine La Valette - 900, rue Jean François BRETON, 34090 Montpellier, France
| | - Susanne Heinzinger
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Christine Hartberger
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Sabrina Hepner
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Mercy Schmeusser
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Andreas Sing
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Volker Fingerle
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Karen D McCoy
- MIVEGEC, University of Montpellier - CNRS - IRD, Centre IRD, Domaine La Valette - 900, rue Jean François BRETON, 34090 Montpellier, France.
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Roy S, Booth CE, Powell-Pierce AD, Schulz AM, Skare JT, Garcia BL. Conformational dynamics of complement protease C1r inhibitor proteins from Lyme disease- and relapsing fever-causing spirochetes. J Biol Chem 2023; 299:104972. [PMID: 37380082 PMCID: PMC10413161 DOI: 10.1016/j.jbc.2023.104972] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/16/2023] [Accepted: 06/19/2023] [Indexed: 06/30/2023] Open
Abstract
Borrelial pathogens are vector-borne etiological agents known to cause Lyme disease, relapsing fever, and Borrelia miyamotoi disease. These spirochetes each encode several surface-localized lipoproteins that bind components of the human complement system to evade host immunity. One borrelial lipoprotein, BBK32, protects the Lyme disease spirochete from complement-mediated attack via an alpha helical C-terminal domain that interacts directly with the initiating protease of the classical complement pathway, C1r. In addition, the B. miyamotoi BBK32 orthologs FbpA and FbpB also inhibit C1r, albeit via distinct recognition mechanisms. The C1r-inhibitory activities of a third ortholog termed FbpC, which is found exclusively in relapsing fever-causing spirochetes, remains unknown. Here, we report the crystal structure of the C-terminal domain of Borrelia hermsii FbpC to a limiting resolution of 1.5 Å. We used surface plasmon resonance and assays of complement function to demonstrate that FbpC retains potent BBK32-like anticomplement activities. Based on the structure of FbpC, we hypothesized that conformational dynamics of the complement inhibitory domains of borrelial C1r inhibitors may differ. To test this, we utilized the crystal structures of the C-terminal domains of BBK32, FbpA, FbpB, and FbpC to carry out molecular dynamics simulations, which revealed borrelial C1r inhibitors adopt energetically favored open and closed states defined by two functionally critical regions. Taken together, these results advance our understanding of how protein dynamics contribute to the function of bacterial immune evasion proteins and reveal a surprising plasticity in the structures of borrelial C1r inhibitors.
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Affiliation(s)
- Sourav Roy
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Charles E Booth
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Alexandra D Powell-Pierce
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, Texas, USA
| | - Anna M Schulz
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Jon T Skare
- Department of Microbial Pathogenesis and Immunology, School of Medicine, Texas A&M University, Bryan, Texas, USA.
| | - Brandon L Garcia
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.
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Marcinkiewicz AL, Brangulis K, Dupuis AP, Hart TM, Zamba‐Campero M, Nowak TA, Stout JL, Akopjana I, Kazaks A, Bogans J, Ciota AT, Kraiczy P, Kolokotronis SO, Lin YP. Structural evolution of an immune evasion determinant shapes pathogen host tropism. Proc Natl Acad Sci U S A 2023; 120:e2301549120. [PMID: 37364114 PMCID: PMC10319004 DOI: 10.1073/pnas.2301549120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
Modern infectious disease outbreaks often involve changes in host tropism, the preferential adaptation of pathogens to specific hosts. The Lyme disease-causing bacterium Borrelia burgdorferi (Bb) is an ideal model to investigate the molecular mechanisms of host tropism, because different variants of these tick-transmitted bacteria are distinctly maintained in rodents or bird reservoir hosts. To survive in hosts and escape complement-mediated immune clearance, Bb produces the outer surface protein CspZ that binds the complement inhibitor factor H (FH) to facilitate bacterial dissemination in vertebrates. Despite high sequence conservation, CspZ variants differ in human FH-binding ability. Together with the FH polymorphisms between vertebrate hosts, these findings suggest that minor sequence variation in this bacterial outer surface protein may confer dramatic differences in host-specific, FH-binding-mediated infectivity. We tested this hypothesis by determining the crystal structure of the CspZ-human FH complex, and identifying minor variation localized in the FH-binding interface yielding bird and rodent FH-specific binding activity that impacts infectivity. Swapping the divergent region in the FH-binding interface between rodent- and bird-associated CspZ variants alters the ability to promote rodent- and bird-specific early-onset dissemination. We further linked these loops and respective host-specific, complement-dependent phenotypes with distinct CspZ phylogenetic lineages, elucidating evolutionary mechanisms driving host tropism emergence. Our multidisciplinary work provides a novel molecular basis for how a single, short protein motif could greatly modulate pathogen host tropism.
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Affiliation(s)
- Ashley L. Marcinkiewicz
- New York State Department of Health, Division of Infectious Diseases, Wadsworth Center, Albany, NY12208
| | - Kalvis Brangulis
- Latvian Biomedical Research and Study Centre, RigaLV-1067, Latvia
- Department of Human Physiology and Biochemistry, Riga Stradins University, RigaLV-1007, Latvia
| | - Alan P. Dupuis
- New York State Department of Health, Division of Infectious Diseases, Wadsworth Center, Albany, NY12208
| | - Thomas M. Hart
- New York State Department of Health, Division of Infectious Diseases, Wadsworth Center, Albany, NY12208
- Department of Biological Sciences, State University of New York Albany, Albany, NY12222
| | - Maxime Zamba‐Campero
- New York State Department of Health, Division of Infectious Diseases, Wadsworth Center, Albany, NY12208
| | - Tristan A. Nowak
- New York State Department of Health, Division of Infectious Diseases, Wadsworth Center, Albany, NY12208
- Department of Biomedical Sciences, State University of New York Albany, Albany, NY12222
| | - Jessica L. Stout
- New York State Department of Health, Division of Infectious Diseases, Wadsworth Center, Albany, NY12208
| | - Inara Akopjana
- Latvian Biomedical Research and Study Centre, RigaLV-1067, Latvia
| | - Andris Kazaks
- Latvian Biomedical Research and Study Centre, RigaLV-1067, Latvia
| | - Janis Bogans
- Latvian Biomedical Research and Study Centre, RigaLV-1067, Latvia
| | - Alexander T. Ciota
- New York State Department of Health, Division of Infectious Diseases, Wadsworth Center, Albany, NY12208
- Department of Biomedical Sciences, State University of New York Albany, Albany, NY12222
| | - Peter Kraiczy
- Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt, Goethe University Frankfurt, Frankfurt60596, Germany
| | - Sergios-Orestis Kolokotronis
- Department of Epidemiology and Biostatistics, School of Public Health, Brooklyn, NY 11203-2098
- Institute for Genomics in Health, Brooklyn, NY11203-2098
- Division of Infectious Diseases, Department of Medicine, College of Medicine, Brooklyn, NY11203-2098
- Department of Cell Biology, College of Medicine, State University of New York Downstate Health Sciences University, Brooklyn, NY11203-2098
| | - Yi-Pin Lin
- New York State Department of Health, Division of Infectious Diseases, Wadsworth Center, Albany, NY12208
- Department of Biomedical Sciences, State University of New York Albany, Albany, NY12222
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Roy S, Booth CE, Powell-Pierce AD, Schulz AM, Skare JT, Garcia BL. "Conformational dynamics of C1r inhibitor proteins from Lyme disease and relapsing fever spirochetes". BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.01.530473. [PMID: 36909632 PMCID: PMC10002728 DOI: 10.1101/2023.03.01.530473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Borrelial pathogens are vector-borne etiological agents of Lyme disease, relapsing fever, and Borrelia miyamotoi disease. These spirochetes each encode several surface-localized lipoproteins that bind to components of the human complement system. BBK32 is an example of a borrelial lipoprotein that protects the Lyme disease spirochete from complement-mediated attack. The complement inhibitory activity of BBK32 arises from an alpha helical C-terminal domain that interacts directly with the initiating protease of the classical pathway, C1r. Borrelia miyamotoi spirochetes encode BBK32 orthologs termed FbpA and FbpB, and these proteins also inhibit C1r, albeit via distinct recognition mechanisms. The C1r-inhibitory activities of a third ortholog termed FbpC, which is found exclusively in relapsing fever spirochetes, remains unknown. Here we report the crystal structure of the C-terminal domain of B. hermsii FbpC to a limiting resolution of 1.5 Å. Surface plasmon resonance studies and assays of complement function demonstrate that FbpC retains potent BBK32-like anti-complement activities. Based on the structure of FbpC, we hypothesized that conformational dynamics of the complement inhibitory domains of borrelial C1r inhibitors may differ. To test this, we utilized the crystal structures of the C-terminal domains of BBK32, FbpA, FbpB, and FbpC to carry out 1 µs molecular dynamics simulations, which revealed borrelial C1r inhibitors adopt energetically favored open and closed states defined by two functionally critical regions. This study advances our understanding of how protein dynamics contribute to the function of bacterial immune evasion proteins and reveals a surprising plasticity in the structures of borrelial C1r inhibitors.
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Affiliation(s)
- Sourav Roy
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Charles E. Booth
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Alexandra D. Powell-Pierce
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, TX, United States of America
| | - Anna M. Schulz
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Jon T. Skare
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, TX, United States of America
- Correspondence to Jon T. Skare and () and Brandon L. Garcia ()
| | - Brandon L. Garcia
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
- Correspondence to Jon T. Skare and () and Brandon L. Garcia ()
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Outer surface protein E (OspE) mediates Borrelia burgdorferi sensu stricto strain-specific complement evasion in the eastern fence lizard, Sceloporus undulatus. Ticks Tick Borne Dis 2023; 14:102081. [PMID: 36403322 DOI: 10.1016/j.ttbdis.2022.102081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 10/31/2022] [Accepted: 11/01/2022] [Indexed: 11/11/2022]
Abstract
In North America, Lyme disease is primarily caused by the spirochetal bacterium Borrelia burgdorferi sensu stricto (Bb), which is transmitted between multiple vertebrate hosts and ixodid ticks, and is a model commonly used to study host-pathogen interactions. While Bb is consistently observed in its mammalian and avian reservoirs, the bacterium is rarely isolated from North American reptiles. Two closely related lizard species, the eastern fence lizard (Sceloporus undulatus) and the western fence lizard (Sceloporus occidentalis), are examples of reptiles parasitized by Ixodes ticks. Vertebrates are known to generate complement as an innate defense mechanism, which can be activated before Bb disseminate to distal tissues. Complement from western fence lizards has proven lethal against one Bb strain, implying the role of complement in making those lizards unable to serve as hosts to Bb. However, Bb DNA is occasionally identified in distal tissues of field-collected eastern fence lizards, suggesting some Bb strains may overcome complement-mediated clearance in these lizards. These findings raise questions regarding the role of complement and its impact on Bb interactions with North American lizards. In this study, we found Bb seropositivity in a small population of wild-caught eastern fence lizards and observed Bb strain-specific survivability in lizard sera. We also found that a Bb outer surface protein, OspE, from Bb strains viable in sera, promotes lizard serum survivability and binds to a complement inhibitor, factor H, from eastern fence lizards. Our data thus identify bacterial and host determinants of eastern fence lizard complement evasion, providing insights into the role of complement influencing Bb interactions with North American lizards.
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Shaughnessy J, Chabeda A, Lewis LA, Ram S. Alternative pathway amplification and infections. Immunol Rev 2023; 313:162-180. [PMID: 36336911 DOI: 10.1111/imr.13160] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The alternative pathway (AP) is the phylogenetically oldest arm of the complement system and may have evolved to mark pathogens for elimination by phagocytes. Studies using purified AP proteins or AP-specific serum showed that C3b amplification on bacteria commenced following a lag phase of about 5 min and was highly dependent on the concentration of complement. Most pathogens have evolved several elegant mechanisms to evade complement, including expressing proteases that degrade AP proteins and secreting proteins that block function of C3 convertases. In an example of convergent evolution, many microbes recruit the AP inhibitor factor H (FH) using molecular mechanisms that mimic FH interactions with host cells. In most instances, the AP serves to amplify C3b deposited on microbes by the classical pathway (CP). The role of properdin on microbes appears to be restricted to stabilization of C3 convertases; scant evidence exists for its role as an initiator of the AP on pathogens in the context of serum. Therapeutic complement inhibition carries with it an increased risk of infection. Antibody (Ab)-dependent AP activation may be critical for complement activation by vaccine-elicited Ab when the CP is blocked, and its molecular mechanism is discussed.
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Affiliation(s)
- Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Aleyo Chabeda
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Lisa A Lewis
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
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9
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Garrigues RJ, Thomas S, Leong JM, Garcia BL. Outer surface lipoproteins from the Lyme disease spirochete exploit the molecular switch mechanism of the complement protease C1s. J Biol Chem 2022; 298:102557. [PMID: 36183830 PMCID: PMC9637899 DOI: 10.1016/j.jbc.2022.102557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 10/14/2022] Open
Abstract
Proteolytic cascades comprise several important physiological systems, including a primary arm of innate immunity called the complement cascade. To safeguard against complement-mediated attack, the etiologic agent of Lyme disease, Borreliella burgdorferi, produces numerous outer surface-localized lipoproteins that contribute to successful complement evasion. Recently, we discovered a pair of B. burgdorferi surface lipoproteins of the OspEF-related protein family-termed ElpB and ElpQ-that inhibit antibody-mediated complement activation. In this study, we investigate the molecular mechanism of ElpB and ElpQ complement inhibition using an array of biochemical and biophysical approaches. In vitro assays of complement activation show that an independently folded homologous C-terminal domain of each Elp protein maintains full complement inhibitory activity and selectively inhibits the classical pathway. Using binding assays and complement component C1s enzyme assays, we show that binding of Elp proteins to activated C1s blocks complement component C4 cleavage by competing with C1s-C4 binding without occluding the active site. C1s-mediated C4 cleavage is dependent on activation-induced binding sites, termed exosites. To test whether these exosites are involved in Elp-C1s binding, we performed site-directed mutagenesis, which showed that ElpB and ElpQ binding require C1s residues in the anion-binding exosite located on the serine protease domain of C1s. Based on these results, we propose a model whereby ElpB and ElpQ exploit activation-induced conformational changes that are normally important for C1s-mediated C4 cleavage. Our study expands the known complement evasion mechanisms of microbial pathogens and reveals a novel molecular mechanism for selective C1s inhibition by Lyme disease spirochetes.
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10
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Combs M, Marcinkiewicz AL, Dupuis AP, Davis AD, Lederman P, Nowak TA, Stout JL, Strle K, Fingerle V, Margos G, Ciota AT, Diuk-Wasser MA, Kolokotronis SO, Lin YP. Phylogenomic Diversity Elucidates Mechanistic Insights into Lyme Borreliae-Host Association. mSystems 2022; 7:e0048822. [PMID: 35938719 PMCID: PMC9426539 DOI: 10.1128/msystems.00488-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/19/2022] [Indexed: 12/24/2022] Open
Abstract
Host association-the selective adaptation of pathogens to specific host species-evolves through constant interactions between host and pathogens, leaving a lot yet to be discovered on immunological mechanisms and genomic determinants. The causative agents of Lyme disease (LD) are spirochete bacteria composed of multiple species of the Borrelia burgdorferi sensu lato complex, including B. burgdorferi (Bb), the main LD pathogen in North America-a useful model for the study of mechanisms underlying host-pathogen association. Host adaptation requires pathogens' ability to evade host immune responses, such as complement, the first-line innate immune defense mechanism. We tested the hypothesis that different host-adapted phenotypes among Bb strains are linked to polymorphic loci that confer complement evasion traits in a host-specific manner. We first examined the survivability of 20 Bb strains in sera in vitro and/or bloodstream and tissues in vivo from rodent and avian LD models. Three groups of complement-dependent host-association phenotypes emerged. We analyzed complement-evasion genes, identified a priori among all strains and sequenced and compared genomes for individual strains representing each phenotype. The evolutionary history of ospC loci is correlated with host-specific complement-evasion phenotypes, while comparative genomics suggests that several gene families and loci are potentially involved in host association. This multidisciplinary work provides novel insights into the functional evolution of host-adapted phenotypes, building a foundation for further investigation of the immunological and genomic determinants of host association. IMPORTANCE Host association is the phenotype that is commonly found in many pathogens that preferential survive in particular hosts. The Lyme disease (LD)-causing agent, B. burgdorferi (Bb), is an ideal model to study host association, as Bb is mainly maintained in nature through rodent and avian hosts. A widespread yet untested concept posits that host association in Bb strains is linked to Bb functional genetic variation conferring evasion to complement, an innate defense mechanism in vertebrate sera. Here, we tested this concept by grouping 20 Bb strains into three complement-dependent host-association phenotypes based on their survivability in sera and/or bloodstream and distal tissues in rodent and avian LD models. Phylogenomic analysis of these strains further correlated several gene families and loci, including ospC, with host-specific complement-evasion phenotypes. Such multifaceted studies thus pave the road to further identify the determinants of host association, providing mechanistic insights into host-pathogen interaction.
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Affiliation(s)
- Matthew Combs
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, USA
- Department of Epidemiology and Biostatistics, School of Public Health, SUNY Downstate Health Sciences University, Brooklyn, New York, USA
- Institute for Genomics in Health, SUNY Downstate Health Sciences University, Brooklyn, New York, USA
| | - Ashley L. Marcinkiewicz
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Alan P. Dupuis
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - April D. Davis
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Patricia Lederman
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Tristan A. Nowak
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, SUNY Albany, Albany, New York, USA
| | - Jessica L. Stout
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Klemen Strle
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, SUNY Albany, Albany, New York, USA
| | - Volker Fingerle
- German National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Oberschleissheim, Germany
| | - Gabriele Margos
- German National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Oberschleissheim, Germany
| | - Alexander T. Ciota
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, SUNY Albany, Albany, New York, USA
| | - Maria A. Diuk-Wasser
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, USA
| | - Sergios-Orestis Kolokotronis
- Department of Epidemiology and Biostatistics, School of Public Health, SUNY Downstate Health Sciences University, Brooklyn, New York, USA
- Institute for Genomics in Health, SUNY Downstate Health Sciences University, Brooklyn, New York, USA
- Division of Infectious Diseases, Department of Medicine, College of Medicine, SUNY Downstate Health Sciences University, Brooklyn, New York, USA
- Department of Cell Biology, College of Medicine, SUNY Downstate Health Sciences University, Brooklyn, New York, USA
| | - Yi-Pin Lin
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, SUNY Albany, Albany, New York, USA
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Stevenson B, Krusenstjerna AC, Castro-Padovani TN, Savage CR, Jutras BL, Saylor TC. The Consistent Tick-Vertebrate Infectious Cycle of the Lyme Disease Spirochete Enables Borrelia burgdorferi To Control Protein Expression by Monitoring Its Physiological Status. J Bacteriol 2022; 204:e0060621. [PMID: 35380872 PMCID: PMC9112904 DOI: 10.1128/jb.00606-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The Lyme disease spirochete, Borrelia burgdorferi, persists in nature by alternatingly cycling between ticks and vertebrates. During each stage of the infectious cycle, B. burgdorferi produces surface proteins that are necessary for interactions with the tick or vertebrate tissues it encounters while also repressing the synthesis of unnecessary proteins. Among these are the Erp surface proteins, which are produced during vertebrate infection for interactions with host plasmin, laminin, glycosaminoglycans, and components of the complement system. Erp proteins are not expressed during tick colonization but are induced when the tick begins to ingest blood from a vertebrate host, a time when the bacteria undergo rapid growth and division. Using the erp genes as a model of borrelial gene regulation, our research group has identified three novel DNA-binding proteins that interact with DNA to control erp transcription. At least two of those regulators are, in turn, affected by DnaA, the master regulator of chromosome replication. Our data indicate that B. burgdorferi has evolved to detect the change from slow to rapid replication during tick feeding as a signal to begin expression of Erp and other vertebrate-specific proteins. The majority of other known regulatory factors of B. burgdorferi also respond to metabolic cues. These observations lead to a model in which the Lyme spirochete recognizes unique environmental conditions encountered during the infectious cycle to "know" where they are and adapt accordingly.
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Affiliation(s)
- Brian Stevenson
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
- Department of Entomology, University of Kentucky, Lexington, Kentucky, USA
| | - Andrew C. Krusenstjerna
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Tatiana N. Castro-Padovani
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Christina R. Savage
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Brandon L. Jutras
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, USA
| | - Timothy C. Saylor
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
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Predictive Model of Lyme Disease Epidemic Process Using Machine Learning Approach. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12094282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Lyme disease is the most prevalent tick-borne disease in Eastern Europe. This study focuses on the development of a machine learning model based on a neural network for predicting the dynamics of the Lyme disease epidemic process. A retrospective analysis of the Lyme disease cases reported in the Kharkiv region, East Ukraine, between 2010 and 2017 was performed. To develop the neural network model of the Lyme disease epidemic process, a multilayered neural network was used, and the backpropagation algorithm or the generalized delta rule was used for its learning. The adequacy of the constructed forecast was tested on real statistical data on the incidence of Lyme disease. The learning of the model took 22.14 s, and the mean absolute percentage error is 3.79%. A software package for prediction of the Lyme disease incidence on the basis of machine learning has been developed. Results of the simulation have shown an unstable epidemiological situation of Lyme disease, which requires preventive measures at both the population level and individual protection. Forecasting is of particular importance in the conditions of hostilities that are currently taking place in Ukraine, including endemic territories.
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Lipoproteome screening of the Lyme disease agent identifies inhibitors of antibody-mediated complement killing. Proc Natl Acad Sci U S A 2022; 119:e2117770119. [PMID: 35312359 PMCID: PMC9060444 DOI: 10.1073/pnas.2117770119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Spirochetal pathogens encode an abundance of lipoproteins that can provide a critical interface with the host environment. Borrelia burgdorferi, the model species for spirochetal biology, must survive an enzootic life cycle defined by fluctuations between vector (tick) and vertebrate host. While B. burgdorferi expresses over 80 surface lipoproteins—many of which likely contribute to host survival—the B. burgdorferi lipoproteome is poorly characterized. Here, we generated a platform to rapidly identify targets of B. burgdorferi surface lipoproteins and identified two paralogs that confer resistance to antibody-initiated complement killing that may promote survival in immunocompetent hosts. This work expands our understanding of complement evasion mechanisms and points toward a discovery approach for identifying host–pathogen interactions central to spirochete pathogenesis. Spirochetal pathogens, such as the causative agent of Lyme disease, Borrelia burgdorferi sensu lato, encode an abundance of lipoproteins; however, due in part to their evolutionary distance from more well-studied bacteria, such as Proteobacteria and Firmicutes, few spirochetal lipoproteins have assigned functions. Indeed, B. burgdorferi devotes almost 8% of its genome to lipoprotein genes and interacts with its environment primarily through the production of at least 80 surface-exposed lipoproteins throughout its tick vector–vertebrate host lifecycle. Several B. burgdorferi lipoproteins have been shown to serve roles in cellular adherence or immune evasion, but the functions for most B. burgdorferi surface lipoproteins remain unknown. In this study, we developed a B. burgdorferi lipoproteome screening platform utilizing intact spirochetes that enables the identification of previously unrecognized host interactions. As spirochetal survival in the bloodstream is essential for dissemination, we targeted our screen to C1, the first component of the classical (antibody-initiated) complement pathway. We identified two high-affinity C1 interactions by the paralogous lipoproteins, ElpB and ElpQ (also termed ErpB and ErpQ, respectively). Using biochemical, microbiological, and biophysical approaches, we demonstrate that ElpB and ElpQ bind the activated forms of the C1 proteases, C1r and C1s, and represent a distinct mechanistic class of C1 inhibitors that protect the spirochete from antibody-mediated complement killing. In addition to identifying a mode of complement inhibition, our study establishes a lipoproteome screening methodology as a discovery platform for identifying direct host–pathogen interactions that are central to the pathogenesis of spirochetes, such as the Lyme disease agent.
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14
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Utilizing Two Borrelia bavariensis Isolates Naturally Lacking the PFam54 Gene Array To Elucidate the Roles of PFam54-Encoded Proteins. Appl Environ Microbiol 2022; 88:e0155521. [PMID: 34986011 DOI: 10.1128/aem.01555-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lyme borreliosis is the most common vector-borne disease in the Northern Hemisphere, caused by spirochetes belonging to the Borrelia burgdorferi sensu lato species complex, which are transmitted by ixodid ticks. B. burgdorferi sensu lato species produce a family of proteins on the linear plasmid 54 (PFam54), some of which confer the functions of cell adhesion and inactivation of complement, the first line of host defense. However, the impact of PFam54 in promoting B. burgdorferi sensu lato pathogenesis remains unclear because of the hurdles to simultaneously knock out all PFam54 proteins in a spirochete. Here, we describe two Borrelia bavariensis strains, PBN and PNi, isolated from patients naturally lacking PFam54 but maintaining the rest of the genome with greater than 95% identity to the reference B. bavariensis strain, PBi. We found that PBN and PNi less efficiently survive in human serum than PBi. Such defects were restored by introducing two B. bavariensis PFam54 recombinant proteins, BGA66 and BGA71, confirming the role of these proteins in providing complement evasion of B. bavariensis. Further, we found that all three strains remain detectable in various murine tissues 21 days post-subcutaneous infection, supporting the nonessential role of B. bavariensis PFam54 in promoting spirochete persistence. This study identified and utilized isolates deficient in PFam54 to associate the defects with the absence of these proteins, building the foundation to further study the role of each PFam54 protein in contributing to B. burgdorferi sensu lato pathogenesis. IMPORTANCE To establish infections, Lyme borreliae utilize various means to overcome the host's immune system. Proteins encoded by the PFam54 gene array play a role in spirochete survival in vitro and in vivo. Moreover, this gene array has been described in all currently available Lyme borreliae genomes. By investigating the first two Borrelia bavariensis isolates naturally lacking the entire PFam54 gene array, we showed that both patient isolates display an increased susceptibility to human serum, which can be rescued in the presence of two PFam54 recombinant proteins. However, both isolates remain infectious to mice after intradermal inoculation, suggesting the nonessential role of PFam54 during the long-term, but may differ slightly in the colonization of specific tissues. Furthermore, these isolates show high genomic similarity to type strain PBi (>95%) and could be used in future studies investigating the role of each PFam54 protein in Lyme borreliosis pathogenesis.
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15
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Lin YP, Tufts DM, Combs M, Dupuis AP, Marcinkiewicz AL, Hirsbrunner AD, Diaz AJ, Stout JL, Blom AM, Strle K, Davis AD, Kramer LD, Kolokotronis SO, Diuk-Wasser MA. Cellular and immunological mechanisms influence host-adapted phenotypes in a vector-borne microparasite. Proc Biol Sci 2022; 289:20212087. [PMID: 35193398 PMCID: PMC8864362 DOI: 10.1098/rspb.2021.2087] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Predicting pathogen emergence and spillover risk requires understanding the determinants of a pathogens' host range and the traits involved in host competence. While host competence is often considered a fixed species-specific trait, it may be variable if pathogens diversify across hosts. Balancing selection can lead to maintenance of pathogen polymorphisms (multiple-niche-polymorphism; MNP). The causative agent of Lyme disease, Borrelia burgdorferi (Bb), provides a model to study the evolution of host adaptation, as some Bb strains defined by their outer surface protein C (ospC) genotype, are widespread in white-footed mice and others are associated with non-rodent vertebrates (e.g. birds). To identify the mechanisms underlying potential strain × host adaptation, we infected American robins and white-footed mice, with three Bb strains of different ospC genotypes. Bb burdens varied by strain in a host-dependent fashion, and strain persistence in hosts largely corresponded to Bb survival at early infection stages and with transmission to larvae (i.e. fitness). Early survival phenotypes are associated with cell adhesion, complement evasion and/or inflammatory and antibody-mediated removal of Bb, suggesting directional selective pressure for host adaptation and the potential role of MNP in maintaining OspC diversity. Our findings will guide future investigations to inform eco-evolutionary models of host adaptation for microparasites.
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Affiliation(s)
- Yi-Pin Lin
- Division of Infectious Diseases, Wadsworth Center, NYSDOH, Albany, NY, USA,Department of Biomedical Sciences, SUNY Albany, Albany, NY, USA
| | - Danielle M. Tufts
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA,Infectious Diseases and Microbiology Department, University of Pittsburgh, Pittsburgh, PA, USA
| | - Matthew Combs
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA
| | - Alan P. Dupuis
- Division of Infectious Diseases, Wadsworth Center, NYSDOH, Albany, NY, USA
| | | | | | - Alexander J. Diaz
- Division of Infectious Diseases, Wadsworth Center, NYSDOH, Albany, NY, USA
| | - Jessica L. Stout
- Division of Infectious Diseases, Wadsworth Center, NYSDOH, Albany, NY, USA
| | - Anna M. Blom
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmo, Sweden
| | - Klemen Strle
- Division of Infectious Diseases, Wadsworth Center, NYSDOH, Albany, NY, USA,Department of Biomedical Sciences, SUNY Albany, Albany, NY, USA
| | - April D. Davis
- Division of Infectious Diseases, Wadsworth Center, NYSDOH, Albany, NY, USA
| | - Laura D. Kramer
- Division of Infectious Diseases, Wadsworth Center, NYSDOH, Albany, NY, USA,Department of Biomedical Sciences, SUNY Albany, Albany, NY, USA
| | - Sergios-Orestis Kolokotronis
- Department of Epidemiology and Biostatistics, School of Public Health, College of Medicine, SUNY Downstate Health Sciences University, Brooklyn, NY, USA,Institute for Genomic Health, College of Medicine, SUNY Downstate Health Sciences University, Brooklyn, NY, USA,Division of Infectious Diseases, Department of Medicine, College of Medicine, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Maria A. Diuk-Wasser
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA
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16
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The evolving story of Borrelia burgdorferi sensu lato transmission in Europe. Parasitol Res 2022; 121:781-803. [PMID: 35122516 PMCID: PMC8816687 DOI: 10.1007/s00436-022-07445-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 01/19/2022] [Indexed: 12/13/2022]
Abstract
Beside mosquitoes, ticks are well-known vectors of different human pathogens. In the Northern Hemisphere, Lyme borreliosis (Eurasia, LB) or Lyme disease (North America, LD) is the most commonly occurring vector-borne infectious disease caused by bacteria of the genus Borrelia which are transmitted by hard ticks of the genus Ixodes. The reported incidence of LB in Europe is about 22.6 cases per 100,000 inhabitants annually with a broad range depending on the geographical area analyzed. However, the epidemiological data are largely incomplete, because LB is not notifiable in all European countries. Furthermore, not only differ reporting procedures between countries, there is also variation in case definitions and diagnostic procedures. Lyme borreliosis is caused by several species of the Borrelia (B.) burgdorferi sensu lato (s.l.) complex which are maintained in complex networks including ixodid ticks and different reservoir hosts. Vector and host influence each other and are affected by multiple factors including climate that have a major impact on their habitats and ecology. To classify factors that influence the risk of transmission of B. burgdorferi s.l. to their different vertebrate hosts as well as to humans, we briefly summarize the current knowledge about the pathogens including their astonishing ability to overcome various host immune responses, regarding the main vector in Europe Ixodes ricinus, and the disease caused by borreliae. The research shows, that a higher standardization of case definition, diagnostic procedures, and standardized, long-term surveillance systems across Europe is necessary to improve clinical and epidemiological data.
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