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Eisen L, Eisen RJ. Changes in the geographic distribution of the blacklegged tick, Ixodes scapularis, in the United States. Ticks Tick Borne Dis 2023; 14:102233. [PMID: 37494882 PMCID: PMC10862374 DOI: 10.1016/j.ttbdis.2023.102233] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/29/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023]
Abstract
Ixodes scapularis (the blacklegged tick) was considered a species of no medical concern until the mid-1970s. By that time, the tick's geographic distribution was thought to be mainly in the southeastern United States (US), with additional localized populations along the Eastern Seaboard north to southern Massachusetts and in the Upper Midwest. Since 1975, I. scapularis has been implicated as a vector of seven human pathogens and is now widely distributed across the eastern US up to the border with Canada. Geographic expansion of tick-borne diseases associated with I. scapularis (e.g., Lyme disease, anaplasmosis, and babesiosis) is attributed to an expanding range of the tick. However, due to changes in tick surveillance efforts over time, it is difficult to differentiate between range expansion and increased recognition of already established tick populations. We provide a history of the documented occurrence of I. scapularis in the US from its description in 1821 to present, emphasizing studies that provide evidence of expansion of the geographic distribution of the tick. Deforestation and decimation of the white-tailed deer (Odocoileus virginianus), the primary reproductive host for I. scapularis adults, during the 1800s presumably led to the tick disappearing from large areas of the eastern US where it previously had been established. Subsequent reforestation and deer population recovery, together with recent climate warming, contributed to I. scapularis proliferating in and spreading from refugia where it had persisted into the early 1900s. From documented tick collection records, it appears I. scapularis was present in numerous locations in the southern part of the eastern US in the early 1900s, whereas in the north it likely was limited to a small number of refugia sites during that time period. There is clear evidence for established populations of I. scapularis in coastal New York and Massachusetts by 1950, and in northwestern Wisconsin by the late 1960s. While recognizing that surveillance for I. scapularis increased dramatically from the 1980s onward, we describe multiple instances of clearly documented expansion of the tick's geographic distribution in the Northeast, Upper Midwest, and Ohio Valley regions from the 1980s to present. Spread and local population increase of I. scapularis, together with documentation of Borrelia burgdorferi sensu stricto in host-seeking ticks, was universally followed by increases in Lyme disease cases in these areas. Southward expansion of northern populations of I. scapularis, for which the host questing behavior of the nymphal stage leads to substantially higher risk of human bites compared with southern populations, into Virginia and North Carolina also was followed by rising numbers of Lyme disease cases. Ongoing surveillance of ticks and tick-borne pathogens is essential to provide the data needed for studies that seek to evaluate the relative roles of land cover, tick hosts, and climate in explaining and predicting geographic expansion of ticks and tick-borne diseases.
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Affiliation(s)
- Lars Eisen
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521, United States.
| | - Rebecca J Eisen
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521, United States
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2
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Rollins RE, Margos G, Brachmann A, Krebs S, Mouchet A, Dingemanse NJ, Laatamna A, Reghaissia N, Fingerle V, Metzler D, Becker NS, Chitimia-Dobler L. German Ixodes inopinatus samples may not actually represent this tick species. Int J Parasitol 2023; 53:751-761. [PMID: 37516335 DOI: 10.1016/j.ijpara.2023.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 07/31/2023]
Abstract
Ticks are important vectors of human and animal pathogens, but many questions remain unanswered regarding their taxonomy. Molecular sequencing methods have allowed research to start understanding the evolutionary history of even closely related tick species. Ixodes inopinatus is considered a sister species and highly similar to Ixodes ricinus, an important vector of many tick-borne pathogens in Europe, but identification between these species remains ambiguous with disagreement on the geographic extent of I. inopinatus. In 2018-2019, 1583 ticks were collected from breeding great tits (Parus major) in southern Germany, of which 45 were later morphologically identified as I. inopinatus. We aimed to confirm morphological identification using molecular tools. Utilizing two genetic markers (16S rRNA, TROSPA) and whole genome sequencing of specific ticks (n = 8), we were able to determine that German samples, morphologically identified as I. inopinatus, genetically represent I. ricinus regardless of previous morphological identification, and most likely are not I. ricinus/I. inopinatus hybrids. Further, our results showed that the entire mitochondrial genome, let alone singular mitochondrial genes (i.e., 16S), is unable to distinguish between I. ricinus and I. inopinatus. Our results suggest that I. inopinatus is geographically isolated as a species (northern Africa and potentially southern Spain and Portugal) and brings into question whether I. inopinatus exists in central Europe. Our results highlight the probable existence of I. inopinatus and the power of utilizing genomic data in answering questions regarding tick taxonomy.
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Affiliation(s)
- Robert E Rollins
- Institute of Avian Research "Vogelwarte Helgoland", Wilhelmshaven, Germany.
| | - Gabriele Margos
- National Reference Center for Borrelia, Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Oberschleißheim, Germany
| | - Andreas Brachmann
- Genetics, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Stefan Krebs
- Gene Center, Laboratory for Functional Genome Analysis, LMU Munich, Munich, Germany
| | - Alexia Mouchet
- Behavioural Ecology Group, LMU Munich/Department of Biology, Planegg-Martinsried, Germany; IDEEV UMR Evolution, Génomes, Comportement, Ecologie, IRD, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Niels J Dingemanse
- Behavioural Ecology Group, LMU Munich/Department of Biology, Planegg-Martinsried, Germany
| | - AbdElkarim Laatamna
- Faculty of Nature and Life Sciences, University of Djelfa, Moudjbara Road, BP 3117, Djelfa, Algeria
| | - Nassiba Reghaissia
- Laboratory of Sciences and Living Techniques, Institute of Agronomic and Veterinary Sciences, University of Souk Ahras, Annaba Road 41000, Souk Ahras, Algeria
| | - Volker Fingerle
- National Reference Center for Borrelia, Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Oberschleißheim, Germany
| | - Dirk Metzler
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Germany
| | - Noémie S Becker
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Germany
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3
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Frederick JC, Thompson AT, Sharma P, Dharmarajan G, Ronai I, Pesapane R, Smith RC, Sundstrom KD, Tsao JI, Tuten HC, Yabsley MJ, Glenn TC. Phylogeography of the blacklegged tick (Ixodes scapularis) throughout the USA identifies candidate loci for differences in vectorial capacity. Mol Ecol 2023; 32:3133-3149. [PMID: 36912202 DOI: 10.1111/mec.16921] [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: 08/22/2022] [Revised: 02/25/2023] [Accepted: 03/08/2023] [Indexed: 03/14/2023]
Abstract
The blacklegged tick (Ixodes scapularis (Journal of the Academy of Natural Sciences of Philadelphia, 1821, 2, 59)) is a vector of Borrelia burgdorferi sensu stricto (s.s.) (International Journal of Systematic Bacteriology, 1984, 34, 496), the causative bacterial agent of Lyme disease, part of a slow-moving epidemic of Lyme borreliosis spreading across the northern hemisphere. Well-known geographical differences in the vectorial capacity of these ticks are associated with genetic variation. Despite the need for detailed genetic information in this disease system, previous phylogeographical studies of these ticks have been restricted to relatively few populations or few genetic loci. Here we present the most comprehensive phylogeographical study of genome-wide markers in I. scapularis, conducted by using 3RAD (triple-enzyme restriction-site associated sequencing) and surveying 353 ticks from 33 counties throughout the species' range. We found limited genetic variation among populations from the Northeast and Upper Midwest, where Lyme disease is most common, and higher genetic variation among populations from the South. We identify five spatially associated genetic clusters of I. scapularis. In regions where Lyme disease is increasing in frequency, the I. scapularis populations genetically group with ticks from historically highly Lyme-endemic regions. Finally, we identify 10 variable DNA sites that contribute the most to population differentiation. These variable sites cluster on one of the chromosome-scale scaffolds for I. scapularis and are within identified genes. Our findings illuminate the need for additional research to identify loci causing variation in the vectorial capacity of I. scapularis and where additional tick sampling would be most valuable to further understand disease trends caused by pathogens transmitted by I. scapularis.
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Affiliation(s)
- Julia C Frederick
- Department of Environmental Health Science, University of Georgia, Athens, Georgia, 30602, USA
| | - Alec T Thompson
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, Georgia, 30602, USA
- Center for the Ecology of Infectious Diseases, Odom School of Ecology, University of Georgia, Athens, Georgia, 30602, USA
| | - Prisha Sharma
- Department of Environmental Health Science, University of Georgia, Athens, Georgia, 30602, USA
| | - Guha Dharmarajan
- Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, 29808, USA
- Division of Sciences, School of Interwoven Arts and Sciences, Krea University, Sri City, Andhra Pradesh, India
| | - Isobel Ronai
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, 02138, USA
| | - Risa Pesapane
- Department of Veterinary Preventive Medicine, The Ohio State University, Columbus, Ohio, 43210, USA
- School of Environment and Natural Resources, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Ryan C Smith
- Department of Plant Pathology, Entomology, and Microbiology, Iowa State University, Ames, Iowa, 50011, USA
| | - Kellee D Sundstrom
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, 74078, USA
| | - Jean I Tsao
- Department of Wildlife and Fisheries, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Holly C Tuten
- Illinois Natural History Survey, University of Illinois Urbana-Champaign, Champaign, Illinois, 61820, USA
| | - Michael J Yabsley
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, Georgia, 30602, USA
- Center for the Ecology of Infectious Diseases, Odom School of Ecology, University of Georgia, Athens, Georgia, 30602, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, 30602, USA
| | - Travis C Glenn
- Department of Environmental Health Science, University of Georgia, Athens, Georgia, 30602, USA
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, 30602, USA
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4
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Morris CN, Gaff HD, Berghaus RD, Wilson CM, Gleim ER. Tick Species Composition, Collection Rates, and Phenology Provide Insights into Tick-Borne Disease Ecology in Virginia. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1993-2005. [PMID: 35996864 PMCID: PMC9667727 DOI: 10.1093/jme/tjac121] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Indexed: 06/12/2023]
Abstract
To better understand tick ecology in Virginia and the increasing Lyme disease incidence in western Virginia, a comparative phenological study was conducted in which monthly collections were performed at twelve sampling locations in southwestern Virginia (high Lyme disease incidence) and 18 equivalent sampling locations in southeastern Virginia (low Lyme disease incidence) for one year. In western Virginia, we also explored the effect of elevation on collection rates of Ixodes scapularis Say (Acari: Ixodidae) and Amblyomma americanum (L.) (Acari: Ixodidae). In total, 35,438 ticks were collected (33,106 A. americanum; 2,052 I. scapularis; 134 Ixodes affinis Neumann [Acari: Ixodidae]; 84 Dermacentor variabilis [Say] [Acari: Ixodidae]; 49 Dermacentor albipictus [Packard] [Acari: Ixodidae]; 10 Haemaphysalis leporispalustris [Packard] [Acari: Ixodidae]; 2 Ixodes brunneus Koch [Acari: Ixodidae]; 1 Haemaphysalis longicornis Neumann [Acari: Ixodidae]). Within southwestern Virginia, Ixodes scapularis collection rates were not influenced by elevation, unlike A. americanum which were collected more frequently at lower elevations (e.g., below 500 m). Notably, I. scapularis larvae and nymphs were commonly collected in southwestern Virginia (indicating that they were questing on or above the leaf litter) but not in southeastern Virginia. Questing on or above the leaf litter is primarily associated with northern populations of I. scapularis. These findings may support the hypothesis that I. scapularis from the northeastern United States are migrating into western Virginia and contributing to the higher incidence of Lyme disease in this region. This comparative phenological study underscores the value of these types of studies and the need for additional research to further understand the rapidly changing tick-borne disease dynamics in Virginia.
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Affiliation(s)
- Ciera N Morris
- Department of Biology, Hollins University, Roanoke, VA 24020, USA
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23508, USA
- University of KwaZulu-Natal, School of Mathematics, Statistics, and Computer Sciences, Durban, South Africa
| | - Roy D Berghaus
- Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - C Morgan Wilson
- Department of Biology, Hollins University, Roanoke, VA 24020, USA
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5
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Differentiation of Laboratory-Obtained Ixodes ricinus × Ixodes persulcatus Hybrid Ticks: Selection of Suitable Genes. Microorganisms 2022; 10:microorganisms10071306. [PMID: 35889025 PMCID: PMC9323786 DOI: 10.3390/microorganisms10071306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 11/17/2022] Open
Abstract
Ixodes ricinus and Ixodes persulcatus ticks are the main vectors of tick-borne encephalitis virus and some bacterial pathogens. The regions where these tick species live overlap, forming large sympatric areas. It has previously been shown that these tick species have no morphological barrier, and interspecies crossing is possible with the appearance of sterile hybrids. It has also been shown that hybrid larvae and nymphs can be differentiated using discriminant functions based on a set of morphological features. However, such an approach is laborious and rather ineffective with adult ticks, making a molecular approach necessary. In the current work, we tested the ability of different systems to differentiate laboratory-obtained hybrid ticks. Our data suggest that commonly used primer sets that target rRNA are unsuitable for hybrid tick determination, likely due to the rRNA region being linked with the X chromosome in I. ricinus and I. persulcatus ticks. We tested several primer sets targeting different non rRNA genes to assess their ability to determine hybrids. The best primer set, Toll_R, targeting the putative Toll gene, showed little to no bias when used for DNA amplification from hybrid ticks. Thus, Toll gene can be further used for hybrid detection.
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6
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Mohamed WMA, Moustafa MAM, Thu MJ, Kakisaka K, Chatanga E, Ogata S, Hayashi N, Taya Y, Ohari Y, Naguib D, Qiu Y, Matsuno K, Bawm S, Htun LL, Barker SC, Katakura K, Ito K, Nonaka N, Nakao R. Comparative mitogenomics elucidates the population genetic structure of
Amblyomma testudinarium
in Japan and a closely related
Amblyomma
species in Myanmar. Evol Appl 2022; 15:1062-1078. [PMID: 35899249 PMCID: PMC9309438 DOI: 10.1111/eva.13426] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/27/2022] [Accepted: 05/29/2022] [Indexed: 12/05/2022] Open
Abstract
Ticks are the second most important vector capable of transmitting diseases affecting the health of both humans and animals. Amblyomma testudinarium Koch 1844 (Acari: Ixodidae), is a hard tick species having a wide geographic distribution in Asia. In this study, we analyzed the composition of A. testudinarium whole mitogenomes from various geographical regions in Japan and investigated the population structure, demographic patterns, and phylogeographic relationship with other ixodid species. In addition, we characterized a potentially novel tick species closely related to A. testudinarium from Myanmar. Phylogeographic inference and evolutionary dynamics based on the 15 mitochondrial coding genes supported that A. testudinarium population in Japan is resolved into a star‐like haplogroup and suggested a distinct population structure of A. testudinarium from Amami island in Kyushu region. Correlation analysis using Mantel test statistics showed that no significant correlation was observed between the genetic and geographic distances calculated between the A. testudinarium population from different localities in Japan. Finally, demographic analyses, including mismatch analysis and Tajima’s D test, suggested a possibility of recent population expansion occurred within Japanese haplogroup after a bottleneck event. Although A. testudinarium has been considered widespread and common in East and Southeast Asia, the current study suggested that potentially several cryptic Amblyomma spp. closely related to A. testudinarium are present in Asia.
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Affiliation(s)
- Wessam Mohamed Ahmed Mohamed
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
- Division of Bioinformatics, International Institute for Zoonosis Control Hokkaido University Sapporo Hokkaido Japan
| | - Mohamed Abdallah Mohamed Moustafa
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
- Department of Animal Medicine, Faculty of Veterinary Medicine South Valley University Qena Egypt
| | - May June Thu
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
- Department of Food and Drug Administration, Ministry of Health, Zabu Thiri, Nay Pyi Taw 15011 Myanmar
| | - Keita Kakisaka
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
| | - Elisha Chatanga
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
- Department of Veterinary Pathobiology, Faculty of Veterinary Medicine Lilongwe University of Agriculture and Natural Resources Lilongwe Malawi
| | - Shohei Ogata
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
| | - Naoki Hayashi
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
| | - Yurie Taya
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
| | - Yuma Ohari
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
| | - Doaa Naguib
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
- Department of Hygiene and Zoonoses, Faculty of Veterinary Medicine Mansoura University Mansoura Egypt
| | - Yongjin Qiu
- Division of International Research Promotion, International Institute for Zoonosis Control Hokkaido University Sapporo Hokkaido Japan
| | - Keita Matsuno
- Division of Risk Analysis and Management, International Institute for Zoonosis Control Hokkaido University Sapporo Hokkaido Japan
- International Collaboration Unit, International Institute for Zoonosis Control Hokkaido University Sapporo Hokkaido Japan
- One Health Research Center Hokkaido University Sapporo Hokkaido Japan
| | - Saw Bawm
- Department of International Relations and Information Technology University of Veterinary Science Yezin, Nay Pyi Taw Myanmar
- Department of Pharmacology and Parasitology University of Veterinary Science Yezin, Nay Pyi Taw Myanmar
| | - Lat Lat Htun
- Department of Pharmacology and Parasitology University of Veterinary Science Yezin, Nay Pyi Taw Myanmar
| | - Stephen C. Barker
- Department of Parasitology, School of Chemistry and Molecular Biosciences The University of Queensland Brisbane QLD Australia
| | - Ken Katakura
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
| | - Kimihito Ito
- Division of Bioinformatics, International Institute for Zoonosis Control Hokkaido University Sapporo Hokkaido Japan
| | - Nariaki Nonaka
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
| | - Ryo Nakao
- Laboratory of Parasitology, Department of Disease Control, Faculty of Veterinary Medicine Hokkaido University Sapporo Hokkaido Japan
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7
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Whitlow AM, Cumbie AN, Eastwood G. Pathogen prevalence in Amblyomma americanum and Ixodes scapularis ticks from central Appalachian Virginia, U.S.A. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2022; 47:51-60. [PMID: 35366679 DOI: 10.52707/1081-1710-47.1.51] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
Ticks are known vectors of several viral, bacterial, and protozoal pathogens that cause disease in both humans and animals. While pathogen prevalence has been studied extensively in other portions of the United States, pathogen surveillance studies within tick populations in the central Appalachian region of Virginia is almost nonexistent. Two prominent species in this region are Ixodes scapularis (the blacklegged tick) and Amblyomma americanum (the lone star tick). In this study, we collected ticks biweekly from three habitat types (forest, urban, and pasture) across eight counties in southwest Virginia from June, 2019-November, 2020. Ixodes scapularis and A. americanum captures were screened for evidence of associated tick-borne pathogens. In this region, Borrelia burgdorferi sensu stricto (15.3% in nymphs and 37.6% in adults), Anaplasma phagocytophilum (1.9% in nymphs and 12.2% in adults), and Borrelia miyamotoi (2.97% in nymphs and 2.33% in adults) were detected in I. scapularis ticks. Aside from two previously reported Powassan-positive I. scapularis ticks from Floyd County, VA, no additional Powassan-positive ticks are reported here. No evidence of Ehrlichia chaffeensis, Heartland virus (HRTV), or Bourbon virus (BRBV) was detected in collected A. americanum. Detection and confirmation of multiple emerging tick-borne pathogens in this region raises an increased concern for public health risk, calling for heightened awareness of tick-borne pathogen transmission and increased tick surveillance in understudied areas.
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Affiliation(s)
- Amanda M Whitlow
- Department of Entomology, College of Agriculture & Life Sciences, Virginia Polytechnic Institute & State University, Blacksburg,VA 24061, U.S.A
| | - Alexandra N Cumbie
- Department of Entomology, College of Agriculture & Life Sciences, Virginia Polytechnic Institute & State University, Blacksburg,VA 24061, U.S.A
- Center for Zoonotic & Arthropod-borne Pathogens, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, U.S.A
| | - Gillian Eastwood
- Department of Entomology, College of Agriculture & Life Sciences, Virginia Polytechnic Institute & State University, Blacksburg,VA 24061, U.S.A.,
- Center for Zoonotic & Arthropod-borne Pathogens, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, U.S.A
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8
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Semicentennial of Human Babesiosis, Nantucket Island. Pathogens 2021; 10:pathogens10091159. [PMID: 34578191 PMCID: PMC8469295 DOI: 10.3390/pathogens10091159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/23/2021] [Accepted: 08/28/2021] [Indexed: 11/17/2022] Open
Abstract
Fifty years ago, the index case of human babesiosis due to Babesia microti was diagnosed in a summer resident of Nantucket Island. Human babesiosis, once called “Nantucket fever” due to its seeming restriction to Nantucket and the terminal moraine islands of southern New England, has emerged across the northeastern United States to commonly infect people wherever Lyme disease is endemic. We review the history of babesiosis on Nantucket, analyze its epidemiology and ecology there, provide summaries of the first case histories, and comment on its future public health burden.
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9
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Narasimhan S, Swei A, Abouneameh S, Pal U, Pedra JHF, Fikrig E. Grappling with the tick microbiome. Trends Parasitol 2021; 37:722-733. [PMID: 33962878 PMCID: PMC8282638 DOI: 10.1016/j.pt.2021.04.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 04/04/2021] [Accepted: 04/10/2021] [Indexed: 02/07/2023]
Abstract
Ixodes scapularis and Ixodes pacificus are the predominant vectors of multiple human pathogens, including Borrelia burgdorferi, one of the causative agents of Lyme disease in North America. Differences in the habitats and host preferences of these closely related tick species present an opportunity to examine key aspects of the tick microbiome. While advances in sequencing technologies have accelerated a descriptive understanding of the tick microbiome, molecular and mechanistic insights into the tick microbiome are only beginning to emerge. Progress is stymied by technical difficulties in manipulating the microbiome and by biological variables related to the life cycle of Ixodid ticks. This review highlights these challenges and examines avenues to understand the significance of the tick microbiome in tick biology.
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Affiliation(s)
- Sukanya Narasimhan
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06420, USA.
| | - Andrea Swei
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - Selma Abouneameh
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06420, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland School of Medicine, College Park, MD 20472, USA
| | - Joao H F Pedra
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 20472, USA
| | - Erol Fikrig
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06420, USA
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10
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Lantos PM, Tsao J, Janko M, Arab A, von Fricken ME, Auwaerter PG, Nigrovic LE, Fowler V, Ruffin F, Gaines D, Broyhill J, Swenson J. Environmental Correlates of Lyme Disease Emergence in Southwest Virginia, 2005-2014. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1680-1685. [PMID: 33825903 PMCID: PMC8285012 DOI: 10.1093/jme/tjab038] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Indexed: 06/12/2023]
Abstract
Lyme disease is the most common tick-borne disease in North America. Though human infection is mostly transmitted in a limited geography, the range has expanded in recent years. One notable area of recent expansion is in the mountainous region of southwestern Virginia. The ecological factors that facilitate or constrain the range of human Lyme disease in this region remain uncertain. To evaluate this further, we obtained ecological data, including remotely sensed data on forest structure and vegetation, weather data, and elevation. These data were aggregated within the census block groups of a 9,153 km2 area around the cities of Blacksburg and Roanoke, VA, an area with heterogeneous Lyme disease transmission. In this geographic area, 755 individuals were reported to have Lyme disease in the 10 yr from 2006 to 2015, and these cases were aggregated by block group. A zero-inflated negative binomial model was used to evaluate which environmental variables influenced the abundance of Lyme disease cases. Higher elevation and higher vegetation density had the greatest effect size on the abundance of Lyme disease. Measures of forest edge, forest integrity, temperature, and humidity were not associated with Lyme disease cases. Future southward expansion of Lyme disease into the southeastern states may be most likely in ecologically similar mountainous areas.
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Affiliation(s)
- Paul M Lantos
- Departments of Medicine, Pediatrics, Community and Family Medicine, and Global Health, Duke University, Durham, NC
| | - Jean Tsao
- Department of Fisheries and Wildlife, Michigan State University, Lansing, MI
| | - Mark Janko
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA
| | - Ali Arab
- Department of Mathematics and Statistics, Georgetown University, Washington, DC
| | | | - Paul G Auwaerter
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Lise E Nigrovic
- Department of Emergency Medicine, Boston Children’s Hospital, Boston, MA
| | - Vance Fowler
- Department of Medicine, Duke University, Durham, NC
| | | | - David Gaines
- Office of Epidemiology, Virginia Department of Health, Richmond, VA
| | - James Broyhill
- Office of Epidemiology, Virginia Department of Health, Richmond, VA
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11
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Abstract
With one exception (epidemic relapsing fever), borreliae are obligately maintained in nature by ticks. Although some Borrelia spp. may be vertically transmitted to subsequent generations of ticks, most require amplification by a vertebrate host because inheritance is not stable. Enzootic cycles of borreliae have been found globally; those receiving the most attention from researchers are those whose vectors have some degree of anthropophily and, thus, cause zoonoses such as Lyme disease or relapsing fever. To some extent, our views on the synecology of the borreliae has been dominated by an applied focus, viz., analyses that seek to understand the elements of human risk for borreliosis. But, the elements of borrelial perpetuation do not necessarily bear upon risk, nor do our concepts of risk provide the best structure for analyzing perpetuation. We identify the major global themes for the perpetuation of borreliae, and summarize local variations on those themes, focusing on key literature to outline the factors that serve as the basis for the distribution and abundance of borreliae.
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Affiliation(s)
- Sam R. Telford
- Dept of Infectious Disease and Global Health, Tufts University, Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA 01536, USA
| | - Heidi K. Goethert
- Dept of Infectious Disease and Global Health, Tufts University, Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA 01536, USA
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12
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Sakamoto JM, Silva Diaz GE, Wagner EA. Bacterial Communities of Ixodes scapularis from Central Pennsylvania, USA. INSECTS 2020; 11:insects11100718. [PMID: 33092135 PMCID: PMC7593946 DOI: 10.3390/insects11100718] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 01/21/2023]
Abstract
Native microbiota represent a potential resource for biocontrol of arthropod vectors. Ixodes scapularis is mostly inhabited by the endosymbiotic Rickettsia buchneri, but the composition of bacterial communities varies with life stage, fed status, and/or geographic location. We compared bacterial community diversity among I. scapularis populations sampled within a small geographic range in Central Pennsylvania. We collected and extracted DNA from ticks and sequenced amplicons of the eubacterial 16S rRNA gene from individuals and pooled samples. We then used taxon-specific PCR and/or qPCR to confirm the abundance or infection frequency of select pathogenic and symbiotic bacteria. Bacterial communities were more diverse in pools of males than females and the most abundant taxon was Rickettsia buchneri followed by Coxiellaceae (confirmed by sequencing as an unknown Rickettsiella species). High Rickettsiella titers in pools were likely due to a few heavily infected males. We determined that the infection frequency of Borrelia burgdorferi ranged from 20 to 75%. Titers of Anaplasma phagocytophilum were significantly different between sexes. Amplicon-based bacterial 16S sequencing is a powerful tool for establishing the baseline community diversity and focusing hypotheses for targeted experiments, but care should be taken not to overinterpret data based on too few individuals. We identified intracellular bacterial candidates that may be useful as targets for manipulation.
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Affiliation(s)
- Joyce Megumi Sakamoto
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA;
- Correspondence:
| | | | - Elizabeth Anne Wagner
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA;
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13
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Ghosh P, Saleh MN, Sundstrom KD, Ientile M, Little SE. Ixodes spp. from Dogs and Cats in the United States: Diversity, Seasonality, and Prevalence of Borrelia burgdorferi and Anaplasma phagocytophilum. Vector Borne Zoonotic Dis 2020; 21:11-19. [PMID: 32986535 DOI: 10.1089/vbz.2020.2637] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ixodes spp. are commonly found on dogs and cats throughout the world. In the eastern United States, 16S rDNA sequence of Ixodes scapularis, the predominant species, reveals two clades-American and Southern. To confirm the species and clades of Ixodes spp. ticks submitted from pets, we examined ticks morphologically and evaluated 16S rDNA sequence from 500 ticks submitted from 253 dogs, 99 cats, 1 rabbit, and 1 ferret from 41 states. To estimate pathogen prevalence, flaB of Borrelia burgdorferi (Bb) sensu stricto and 16S rDNA of Anaplasma phagocytophilum (Ap) were amplified and sequenced. Most Ixodes spp. from the Northeast (n = 115/115; 100%) and the Midwest (n = 77/80; 96.3%) were I. scapularis, American clade. Borrelia spp. were identified in 34 of 192 (17.8%) and Ap in 5 of 192 (2.6%) I. scapularis. Two Ixodes cookei and one Ixodes texanus were identified from Ohio, Illinois, and Michigan. In contrast, 156 of 261 (59.8%) Ixodes spp. from the Southeast were I. scapularis, American clade; 86 of 261 (33.0%) were I. scapularis, Southern clade; 9 of 261 (3.4%) were Ixodes affinis; and 10 of 261 (3.8%) were I. cookei. Southern clade was significantly more common in Florida and less common in the upper South (p < 0.0001). One I. scapularis (1/242; 0.4%) from the Southeast (Kentucky) tested positive for Bb and 6 of 242 (2.5%) were positive for Ap. In the West, most (34/44; 77.3%) Ixodes spp. were Ixodes pacificus, with Ixodes angustus (n = 6) submitted from dogs in Alaska, Washington, and Oregon and Ixodes haerlei (n = 4) preliminarily identified from a dog in Montana. Pathogens were not detected in any ticks from the West. Although I. scapularis, American clade, predominated in the Northeast and Midwest, additional Ixodes spp. were found on dogs and cats in other regions and pathogens were less commonly detected. The role of less common Ixodes spp. as disease vectors, if any, warrants continued investigation.
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Affiliation(s)
- Parna Ghosh
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Meriam N Saleh
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Kellee D Sundstrom
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Michelle Ientile
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Susan E Little
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
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14
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A comparative evaluation of northern and southern Ixodes scapularis questing height and hiding behaviour in the USA. Parasitology 2020; 147:1569-1576. [PMID: 32772958 DOI: 10.1017/s003118202000147x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ticks display a distinct type of host-seeking behaviour called questing. It has been proposed that the questing behaviour of Ixodes scapularis explains the geographic variation in Lyme disease (LD) risk in the eastern USA because the northern population has been shown to quest more often than the southern population. The height at which questing occurs is variable and this study aimed to characterize questing height for I. scapularis. Ticks were collected from a northern and southern state (i.e. Maryland and Texas) and bioassays were conducted. We report that nymphs from Texas quested at lower heights compared to nymphs from Maryland. In addition, only Texas nymphs exhibited a behaviour we call 'hiding behaviour'. These results may reflect the different composition of hosts between these two areas as the south has a higher abundance of lizards. In contrast, there was no significant difference in questing height between Maryland adults and Texas adults which was to be expected since adults are feeding on white-tailed deer in both locations. If all southern I. scapularis nymphs are questing at lower heights, this might make them less likely to come into contact with humans and this may be contributing to the geographical difference in LD prevalence.
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15
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Lado P, Smith ML, Carstens BC, Klompen H. Population genetic structure and demographic history of the lone star tick, Amblyomma americanum (Ixodida: Ixodidae): New evidence supporting old records. Mol Ecol 2020; 29:2810-2823. [PMID: 32574413 DOI: 10.1111/mec.15524] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 01/25/2023]
Abstract
Range expansions are a potential outcome of changes in habitat suitability, which commonly result as a consequence of climate change. Hypotheses on such changes in the geographic distribution of a certain species can be evaluated using population genetic structure and demography. In this study we explore the population genetic structure, genetic variability, demographic history of, and habitat suitability for Amblyomma americanum, a North American tick species that is a known vector of several pathogenic microorganisms. We used a double digestion restriction site-associated DNA sequencing technique (dd-RAD seq) and discovered 8,181 independent single nucleotide polymorphisms (SNPs) in 189 ticks from across the geographic range of the species. Genetic diversity was low, particularly when considering the broad geographic range of this species. The edge populations were less diverse than populations belonging to the historic range, possibly indicative of a range expansion, but this hypothesis was not statistically supported by a test based on genetic data. Nonetheless, moderate levels of population structure and substructure were detected between geographic regions. For New England, demographic and species distribution models support a scenario where A. americanum was present in more northern locations in the past, underwent a bottleneck, and subsequently recovered. These results are consistent with a hypothesis that this species is re-establishing in this area, rather than one focused on range expansion from the south. This hypothesis is consistent with old records describing the presence of A. americanum in the northeastern US in the early colonial period.
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Affiliation(s)
- Paula Lado
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA
| | - Megan L Smith
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA
| | - Bryan C Carstens
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA
| | - Hans Klompen
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA
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16
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Mitochondrial Gene Heterogeneity and Population Genetics of Haemaphysalis longicornis (Acari: Ixodidae) in China. Acta Parasitol 2019; 64:360-366. [PMID: 31077030 DOI: 10.2478/s11686-019-00053-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 03/28/2019] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Haemaphysalis longicornis is an important ectoparasite of domestic and wild animals that can transmit many pathogens including viruses, fungi, bacteria and protozoa. MATERIALS AND METHODS In this study, we examined genetic variation and population genetics in three mitochondrial (mt) genes [cox1 (cytochrome c subunit 1), rrnL (large subunit ribosomal RNA) and nad5 (NADH dehydrogenase 5)] among four H. longicornis populations from China. RESULTS The sizes of the partial sequences of cox1, rrnL and nad5 were 776 bp, 409 bp, 510 bp, respectively. Among the obtained sequences, we identified 22 haplotypes for cox1, 2 haplotypes for rrnL and 17 haplotypes for nad5. Low gene flow and significant genetic differentiation (66.2%) were detected among H. longicornis populations. There was no rapid expansion event in the demographic history of four H. longicornis populations in China. In addition, phylogenetic analyses confirmed that all the Haemaphysalis isolates were H. longicornis which were segregated into two major clades. CONCLUSION The mt DNA genes provide a potential novel genetic marker for molecular epidemiology of H. longicornis and assist in the control of tick and tick-borne diseases in humans and animals.
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17
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Pak D, Jacobs SB, Sakamoto JM. A 117-year retrospective analysis of Pennsylvania tick community dynamics. Parasit Vectors 2019; 12:189. [PMID: 31036065 PMCID: PMC6489237 DOI: 10.1186/s13071-019-3451-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/20/2019] [Indexed: 11/29/2022] Open
Abstract
Background Tick-borne diseases have been increasing at the local, national, and global levels. Researchers studying ticks and tick-borne diseases need a thorough knowledge of the pathogens, vectors, and epidemiology of disease spread. Both active and passive surveillance approaches are typically used to estimate tick population size and risk of tick encounter. Our data consists of a composite of active and long-term passive surveillance, which has provided insight into spatial variability and temporal dynamics of ectoparasite communities and identified rarer tick species. We present a retrospective analysis on compiled data of ticks from Pennsylvania over the last 117 years. Methods We compiled data from ticks collected during tick surveillance research, and from citizen-based submissions. The majority of the specimens were submitted by citizens. However, a subset of the data was collected through active methods (flagging or dragging, or removal of ticks from wildlife). We analyzed all data from 1900–2017 for tick community composition, host associations, and spatio-temporal dynamics. Results In total there were 4491 submission lots consisting of 7132 tick specimens. Twenty-four different species were identified, with the large proportion of submissions represented by five tick species. We observed a shift in tick community composition in which the dominant species of tick (Ixodes cookei) was overtaken in abundance by Dermacentor variabilis in the early 1990s and then replaced in abundance by I. scapularis. We analyzed host data and identified overlaps in host range amongst tick species. Conclusions We highlight the importance of long-term passive tick surveillance in investigating the ecology of both common and rare tick species. Information on the geographical distribution, host-association, and seasonality of the tick community can help researchers and health-officials to identify high-risk areas. Electronic supplementary material The online version of this article (10.1186/s13071-019-3451-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Damie Pak
- Department of Biology, Pennsylvania State University, W-234A, Millennium Science Complex, University Park, PA, 16802, USA
| | - Steven B Jacobs
- Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA, 16802, USA
| | - Joyce M Sakamoto
- Department of Entomology, Pennsylvania State University, W-104 Millennium Science Complex, University Park, PA, 16802, USA.
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18
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Lado P, Nava S, Mendoza-Uribe L, Caceres AG, Delgado-de la Mora J, Licona-Enriquez JD, Delgado-de la Mora D, Labruna MB, Durden LA, Allerdice MEJ, Paddock CD, Szabó MPJ, Venzal JM, Guglielmone AA, Beati L. The Amblyomma maculatum Koch, 1844 (Acari: Ixodidae) group of ticks: phenotypic plasticity or incipient speciation? Parasit Vectors 2018; 11:610. [PMID: 30497533 PMCID: PMC6267817 DOI: 10.1186/s13071-018-3186-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/06/2018] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The goal of this study was to reassess the taxonomic status of A. maculatum, A. triste and A. tigrinum by phylogenetic analysis of five molecular markers [four mitochondrial: 12S rDNA, 16S rDNA, the control region (DL) and cytochrome c oxidase 1 (cox1), and one nuclear: ribosomal intergenic transcribed spacer 2 (ITS2)]. In addition, the phenotypic diversity of adult ticks identified as A. maculatum and A. triste from geographically distinct populations was thoroughly re-examined. RESULTS Microscopic examination identified four putative morphotypes distinguishable by disjunct geographical ranges, but very scant fixed characters. Analysis of the separated mitochondrial datasets mostly resulted in conflicting tree topologies. Nuclear gene sequences were almost identical throughout the geographical ranges of the two species, suggesting a very recent, almost explosive radiation of the terminal operational taxonomic units. Analysis of concatenated molecular datasets was more informative and indicated that, although genetically very close to the A. maculatum - A. triste lineage, A. tigrinum was a monophyletic separate entity. Within the A. maculatum - A. triste cluster, three main clades were supported. The two morphotypes, corresponding to the western North American and eastern North American populations, consistently grouped in a single monophyletic clade with many shared mitochondrial sequences among ticks of the two areas. Ticks from the two remaining morphotypes, south-eastern South America and Peruvian, corresponded to two distinct clades. CONCLUSIONS Given the paucity of morphological characters, the minimal genetic distance separating morphotypes, and more importantly the fact that two morphotypes are genetically indistinguishable, our data suggest that A. maculatum and A. triste should be synonymized and that morphological differences merely reflect very recent local adaptation to distinct environments in taxa that might be undergoing the first steps of speciation but have yet to complete lineage sorting. Nonetheless, future investigations using more sensitive nuclear markers and/or crossbreeding experiments might reveal the occurrence of very rapid speciation events in this group of taxa. Tentative node dating revealed that the A. tigrinum and A. maculatum - A. triste clades split about 2 Mya, while the A. maculatum - A.triste cluster radiated no earlier than 700,000 years ago.
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Affiliation(s)
- Paula Lado
- U. S. National Tick Collection, Institute for Coastal Plain Science, Georgia Southern University, Statesboro, GA 30460 USA
- Present address: Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43212 USA
| | - Santiago Nava
- Instituto Nacional de Tecnologia Agropecuaria, Estación Experimental Agropecuaria Rafaela, Santa Fe, Argentina
| | | | - Abraham G. Caceres
- Departamento Académico de Microbiologia Médica, Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Peru
- Laboratorio de Entomología, Instituto Nacional de Salud, Lima, Peru
| | | | | | - David Delgado-de la Mora
- Department of Agronomic and Veterinary Sciences, Technologic Institute of Sonora, Ciudad Obregón, Sonora Mexico
| | - Marcelo B. Labruna
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Lance A. Durden
- Department of Biology, Georgia Southern University, Statesboro, GA 30460 USA
| | - Michelle E. J. Allerdice
- Rickettsial Zoonoses Branch, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA USA
| | - Christopher D. Paddock
- Rickettsial Zoonoses Branch, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA USA
| | - Matias P. J. Szabó
- Laboratório de Ixodologia, Faculdade de Medicina Veterinária, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais Brazil
| | - José M. Venzal
- Departamento de Parasitología Veterinaria, Facultad de Veterinaria, Universidad de la República, Regional Norte - Salto, Rivera 1350, 50000 Salto, CP Uruguay
| | - Alberto A. Guglielmone
- Instituto Nacional de Tecnologia Agropecuaria, Estación Experimental Agropecuaria Rafaela, Santa Fe, Argentina
| | - Lorenza Beati
- U. S. National Tick Collection, Institute for Coastal Plain Science, Georgia Southern University, Statesboro, GA 30460 USA
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19
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Dubie TR, Turner J, Noden BH. Questing Behavior and Analysis of Tick-Borne Bacteria in Ixodes scapularis (Acari: Ixodidae) in Oklahoma. JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:1569-1574. [PMID: 30085216 DOI: 10.1093/jme/tjy133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Indexed: 06/08/2023]
Abstract
The blacklegged tick, Ixodes scapularis Say (Acari: Ixodidae), is an economically important tick that affects veterinary and public health, but it can be difficult to collect in Oklahoma. The primary goal of this research was to examine the diel activity of each species to help improve collection methods for future field research and test field-collected I. scapularis for endemic and nonendemic tick-borne bacterial genera in the southern Great Plains region. Questing behavior was observed using caged bioassays over 24-h periods throughout fall and spring, and field collections were conducted throughout the afternoon and evening in different locations across Oklahoma. Blacklegged ticks were found to be more active during late afternoon and evening hours, and more ticks were recovered in pastures in the evening. None of the pools of adult I. scapularis tested positive for Borrelia burgdorferi (Spirochaetales: Spirochaetaceae) or Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae) DNA. Of the 46 pools of I. scapularis tested, 27 (58.7%) were positive for Rickettsia sp. with ticks collected from the same location infected with the same species of rickettsial endosymbionts. Results suggest that sampling times later in the day may benefit off-host recovery of I. scapularis in Oklahoma ecosystems.
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Affiliation(s)
- Trisha R Dubie
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK
| | - Justin Turner
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK
| | - Bruce H Noden
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK
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20
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Soghigian J, Ridge GE, Stafford KC, Molaei G. The First Evidence of Nanism in Ixodes (Ixodes) scapularis (Acari: Ixodidae), Found Parasitizing a Human Host. JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:1224-1228. [PMID: 28591843 DOI: 10.1093/jme/tjx111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Indexed: 06/07/2023]
Abstract
Ixodes scapularis Say 1821, the primary vector of several human pathogens in the northeastern and upper Midwestern United States, has considerable genetic and morphological variation throughout its range. Recently, developmental or teratological abnormalities have been observed in this species for the first time, further complicating morphological identification. Here, we report the first evidence of nanism (dwarfism) in I. scapularis, found parasitizing a human host. We used molecular methods and scanning electron microscopy to identify the specimen. Morphological identification confirmed that the specimen is substantially smaller, approximately half the size, than a typical I. scapularis female. Here we discuss the recent reports of teratological abnormalities in I. scapularis, particularly from the Hudson River valley region of the northeastern United States, and highlight the need for additional studies of teratology in this important species and its potential implications in disease transmission.
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Affiliation(s)
- John Soghigian
- Department of Environmental Sciences and Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06511
| | - Gale E Ridge
- Department of Entomology, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06511
| | - Kirby C Stafford
- Department of Entomology and Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06511
| | - Goudarz Molaei
- Department of Environmental Sciences and Center for Vector Biology & Zoonotic Diseases, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06511
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, 60 College St., P.O. Box 208034, New Haven, CT 06520-8034
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21
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Levine JF, Apperson CS, Levin M, Kelly TR, Kakumanu ML, Ponnusamy L, Sutton H, Salger SA, Caldwell JM, Szempruch AJ. Stable Transmission of Borrelia burgdorferi Sensu Stricto on the Outer Banks of North Carolina. Zoonoses Public Health 2016; 64:337-354. [PMID: 27966833 DOI: 10.1111/zph.12302] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Indexed: 02/01/2023]
Abstract
The spirochaete (Borrelia burgdorferi) associated with Lyme disease was detected in questing ticks and rodents during a period of 18 years, 1991-2009, at five locations on the Outer Banks of North Carolina. The black-legged tick (Ixodes scapularis) was collected at varied intervals between 1991 and 2009 and examined for B. burgdorferi. The white-footed mouse (Peromyscus leucopus), house mouse (Mus musculus) marsh rice rat (Oryzomys palustris), marsh rabbit (Sylvilagus palustris), eastern cottontail (Sylvilagus floridanus) and six-lined racerunner (Cnemidophorus sexlineatus) were live-trapped, and their tissues cultured to isolate spirochaetes. Borrelia burgdorferi isolates were obtained from questing adult I. scapularis and engorged I. scapularis removed from P. leucopus, O. palustris and S. floridanus. The prevalence of B. burgdorferi infection was variable at different times and sites ranging from 7 to 14% of examined questing I. scapularis. Mitochondrial (16S) rRNA gene phylogenetic analysis from 65 adult I. scapularis identified 12 haplotypes in two major clades. Nine haplotypes were associated with northern/Midwestern I. scapularis populations and three with southern I. scapularis populations. Sixteen isolates obtained from tick hosts in 2005 were confirmed to be B. burgdorferi by amplifying and sequencing of 16S rRNA and 5S-23S intergenic spacer fragments. The sequences had 98-99% identity to B. burgdorferi sensu stricto strains B31, JD1 and M11p. Taken together, these studies indicate that B. burgdorferi sensu stricto is endemic in questing I. scapularis and mammalian tick hosts on the Outer Banks of North Carolina.
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Affiliation(s)
- J F Levine
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - C S Apperson
- Department of Entomology, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC, USA
| | - M Levin
- National Center for Emerging and Zoonotic Infectious Diseases, The Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - T R Kelly
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - M L Kakumanu
- Department of Entomology, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC, USA
| | - L Ponnusamy
- Department of Entomology, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC, USA
| | - H Sutton
- Department of Entomology, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC, USA
| | - S A Salger
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - J M Caldwell
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - A J Szempruch
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
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22
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Sirianni NM, Yuan H, Rice JE, Kaufman RS, Deng J, Fulton C, Wangh LJ. Closed-Tube Barcoding. Genome 2016; 59:1049-1061. [PMID: 27809602 DOI: 10.1139/gen-2016-0026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Here, we present a new approach for increasing the rate and lowering the cost of identifying, cataloging, and monitoring global biodiversity. These advances, which we call Closed-Tube Barcoding, are one application of a suite of proven PCR-based technologies invented in our laboratory. Closed-Tube Barcoding builds on and aims to enhance the profoundly important efforts of the International Barcode of Life initiative. Closed-Tube Barcoding promises to be particularly useful when large numbers of small or rare specimens need to be screened and characterized at an affordable price. This approach is also well suited for automation and for use in portable devices.
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Affiliation(s)
- Nicky M Sirianni
- Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA.,Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA
| | - Huijun Yuan
- Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA.,Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA
| | - John E Rice
- Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA.,Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA
| | - Ronit S Kaufman
- Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA.,Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA
| | - John Deng
- Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA.,Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA
| | - Chandler Fulton
- Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA.,Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA
| | - Lawrence J Wangh
- Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA.,Brandeis University, Department of Biology, Waltham, MA 02453-9110, USA
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23
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Sakamoto JM, Ng TFF, Suzuki Y, Tsujimoto H, Deng X, Delwart E, Rasgon JL. Bunyaviruses are common in male and female Ixodes scapularis ticks in central Pennsylvania. PeerJ 2016; 4:e2324. [PMID: 27602290 PMCID: PMC4991847 DOI: 10.7717/peerj.2324] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 07/13/2016] [Indexed: 12/02/2022] Open
Abstract
The blacklegged tick Ixodes scapularis is widely distributed in the United States and transmits multiple pathogens to humans, wildlife and domestic animals. Recently, several novel viruses in the family Bunyaviridae (South Bay virus (SBV) and Blacklegged tick phlebovirus (BTPV)) were identified infecting female I. scapularis ticks collected in New York State. We used metagenomic sequencing to investigate the distribution of viruses infecting male and female I. scapularis ticks collected in Centre County, Pennsylvania. We identified both SBV and BTPV in both male and female ticks from all collection locations. The role of male I. scapularis in pathogen epidemiology has been overlooked because they rarely bite and are not considered important pathogen vectors. However, males may act as reservoirs for pathogens that can then be transmitted to females during mating. Our data highlight the importance of examining all potential avenues of pathogen maintenance and transmission throughout the vector-pathogen life cycle in order to understand the epidemiology of tick-borne pathogens.
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Affiliation(s)
- Joyce M Sakamoto
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, United States.,Department of Entomology, Pennsylvania State University, University Park, PA, United States
| | - Terry Fei Fan Ng
- Molecular Virology, Blood Systems Research Institute, San Francisco, California, United States.,Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States
| | - Yasutsugu Suzuki
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, United States.,Department of Virology, Institute Pasteur, Paris, France.,The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, United States
| | - Hitoshi Tsujimoto
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, United States.,Department of Entomology, Pennsylvania State University, University Park, PA, United States.,The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, United States.,Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - Xutao Deng
- Department of Laboratory Medicine, Blood Systems Research Institute, San Francisco, CA, USA.,University of California, San Francisco, CA, USA
| | - Eric Delwart
- Department of Laboratory Medicine, Blood Systems Research Institute, San Francisco, CA, USA.,University of California, San Francisco, CA, USA
| | - Jason L Rasgon
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, United States.,Department of Entomology, Pennsylvania State University, University Park, PA, United States.,The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, United States
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24
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Esteve-Gassent MD, Castro-Arellano I, Feria-Arroyo TP, Patino R, Li AY, Medina RF, Pérez de León AA, Rodríguez-Vivas RI. TRANSLATING ECOLOGY, PHYSIOLOGY, BIOCHEMISTRY, AND POPULATION GENETICS RESEARCH TO MEET THE CHALLENGE OF TICK AND TICK-BORNE DISEASES IN NORTH AMERICA. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2016; 92:38-64. [PMID: 27062414 PMCID: PMC4844827 DOI: 10.1002/arch.21327] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 02/20/2016] [Indexed: 06/05/2023]
Abstract
Emerging and re-emerging tick-borne diseases threaten public health and the wellbeing of domestic animals and wildlife globally. The adoption of an evolutionary ecology framework aimed to diminish the impact of tick-borne diseases needs to be part of strategies to protect human and animal populations. We present a review of current knowledge on the adaptation of ticks to their environment, and the impact that global change could have on their geographic distribution in North America. Environmental pressures will affect tick population genetics by selecting genotypes able to withstand new and changing environments and by altering the connectivity and isolation of several tick populations. Research in these areas is particularly lacking in the southern United States and most of Mexico with knowledge gaps on the ecology of these diseases, including a void in the identity of reservoir hosts for several tick-borne pathogens. Additionally, the way in which anthropogenic changes to landscapes may influence tick-borne disease ecology remains to be fully understood. Enhanced knowledge in these areas is needed in order to implement effective and sustainable integrated tick management strategies. We propose to refocus ecology studies with emphasis on metacommunity-based approaches to enable a holistic perspective addressing whole pathogen and host assemblages. Network analyses could be used to develop mechanistic models involving multihost-pathogen communities. An increase in our understanding of the ecology of tick-borne diseases across their geographic distribution will aid in the design of effective area-wide tick control strategies aimed to diminish the burden of pathogens transmitted by ticks.
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Affiliation(s)
- Maria D. Esteve-Gassent
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical sciences, Texas A&M University, College Station, TX-77843, USA
| | - Ivan Castro-Arellano
- Department of Biology, College of Science and Engineering, Texas State University, San Marcos, TX-78666, USA
| | - Teresa P. Feria-Arroyo
- Department of Biology, The University of Texas Rio Grande Valley, Edinburg, TX-78539, USA
| | - Ramiro Patino
- Department of Biology, The University of Texas Rio Grande Valley, Edinburg, TX-78539, USA
| | - Andrew Y. Li
- USDA-ARS Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, Maryland 20705, USA
| | - Raul F. Medina
- Department of Entomology, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX-77843, USA
| | - Adalberto A. Pérez de León
- USDA-ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory, and Veterinary Pest Genomics Center, Kerrville, TX-78028, USA
| | - Roger Iván Rodríguez-Vivas
- Campus de Ciencias Biológicas y Agropecuarias. Facultad de Medicina Veterinaria y Zootecnia. Km 15.5 carretera Mérida-Xmatkuil. Yucatán, México
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25
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Eisen RJ, Eisen L, Beard CB. County-Scale Distribution of Ixodes scapularis and Ixodes pacificus (Acari: Ixodidae) in the Continental United States. JOURNAL OF MEDICAL ENTOMOLOGY 2016; 53:349-86. [PMID: 26783367 PMCID: PMC4844559 DOI: 10.1093/jme/tjv237] [Citation(s) in RCA: 289] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The blacklegged tick, Ixodes scapularis Say, is the primary vector to humans in the eastern United States of the Lyme disease spirochete Borrelia burgdorferi, as well as causative agents of anaplasmosis and babesiosis. Its close relative in the far western United States, the western blacklegged tick Ixodes pacificus Cooley and Kohls, is the primary vector to humans in that region of the Lyme disease and anaplasmosis agents. Since 1991, when standardized surveillance and reporting began, Lyme disease case counts have increased steadily in number and in geographical distribution in the eastern United States. Similar trends have been observed for anaplasmosis and babesiosis. To better understand the changing landscape of risk of human exposure to disease agents transmitted by I. scapularis and I. pacificus, and to document changes in their recorded distribution over the past two decades, we updated the distribution of these species from a map published in 1998. The presence of I. scapularis has now been documented from 1,420 (45.7%) of the 3,110 continental United States counties, as compared with 111 (3.6%) counties for I. pacificus. Combined, these vectors of B. burgdorferi and other disease agents now have been identified in a total of 1,531 (49.2%) counties spread across 43 states. This marks a 44.7% increase in the number of counties that have recorded the presence of these ticks since the previous map was presented in 1998, when 1,058 counties in 41 states reported the ticks to be present. Notably, the number of counties in which I. scapularis is considered established (six or more individuals or one or more life stages identified in a single year) has more than doubled since the previous national distribution map was published nearly two decades ago. The majority of county status changes occurred in the North-Central and Northeastern states, whereas the distribution in the South remained fairly stable. Two previously distinct foci for I. scapularis in the Northeast and North-Central states appear to be merging in the Ohio River Valley to form a single contiguous focus. Here we document a shifting landscape of risk for human exposure to medically important ticks and point to areas of re-emergence where enhanced vector surveillance and control may be warranted.
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Affiliation(s)
- Rebecca J. Eisen
- Division of Vector-Borne Diseases, NCEZID/CDC, 3156 Rampart Rd., Fort Collins, CO 80522
| | - Lars Eisen
- Division of Vector-Borne Diseases, NCEZID/CDC, 3156 Rampart Rd., Fort Collins, CO 80522
| | - Charles B. Beard
- Division of Vector-Borne Diseases, NCEZID/CDC, 3156 Rampart Rd., Fort Collins, CO 80522
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26
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Abstract
Lyme disease is the most common vector-borne illness in North America and Europe. The etiologic agent, Borrelia burgdorferi sensu lato, is transmitted to humans by certain species of Ixodes ticks, which are found widely in temperate regions of the Northern hemisphere. Clinical features are diverse, but death is rare. The risk of human infection is determined by the geographic distribution of vector tick species, ecologic factors that influence tick infection rates, and human behaviors that promote tick bite. Rates of infection are highest among children 5 to 15 years old and adults older than 50 years.
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Affiliation(s)
- Paul S Mead
- Epidemiology and Surveillance Activity, Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention (CDC), 3156 Rampart Road, Fort Collins, CO 80521, USA.
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27
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Nuclear Markers Reveal Predominantly North to South Gene Flow in Ixodes scapularis, the Tick Vector of the Lyme Disease Spirochete. PLoS One 2015; 10:e0139630. [PMID: 26536360 PMCID: PMC4633295 DOI: 10.1371/journal.pone.0139630] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/14/2015] [Indexed: 12/04/2022] Open
Abstract
Ixodes scapularis, the tick vector of the Lyme disease spirochete, is distributed over most of the eastern United States, but >80% of all Lyme disease cases occur in the northeast. The role that genetic differences between northern and southern tick populations play in explaining this disparate distribution of Lyme disease cases is unclear. The present study was conducted with 1,155 SNP markers in eight nuclear genes; the 16S mitochondrial gene was examined for comparison with earlier studies. We examined 350 I. scapularis from 7 states covering a representative area of the species. A demographic analysis using Bayesian Extended Skyline Analysis suggested that I. scapularis populations in Mississippi and Georgia began expanding 500,000 years ago, those in Florida and North Carolina 200,000 years ago and those from Maryland and New Jersey only during the past 50,000 years with an accompanying bottleneck. Wisconsin populations only began expanding in the last 20,000 years. Analysis of current migration patterns suggests large amounts of gene flow in northern collections and equally high rates of gene flow among southern collections. In contrast there is restricted and unidirectional gene flow between northern and southern collections, mostly occurring from northern into southern populations. Northern populations are characterized by nymphs that quest above the leaf litter, are easy to collect by flagging, frequently feed on mammals such as rodents and shrews, commonly attach to people, and about 25% of which are infected with B. burgdorferi. If there is a genetic basis for these behaviors, then the patterns detected in this study are of concern because they suggest that northern I. scapularis populations with a greater ability to vector B. burgdorferi to humans are expanding south.
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28
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Bergamo LW, Fresia P, Azeredo-Espin AML. Incongruent nuclear and mitochondrial genetic structure of new world screwworm fly populations due to positive selection of mutations associated with dimethyl- and diethyl-organophosphates resistance. PLoS One 2015; 10:e0128441. [PMID: 26030866 PMCID: PMC4451984 DOI: 10.1371/journal.pone.0128441] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/27/2015] [Indexed: 11/30/2022] Open
Abstract
Livestock production is an important economic activity in Brazil, which has been suffering significant losses due to the impact of parasites. The New World screwworm (NWS) fly, Cochliomyia hominivorax, is an ectoparasite and one of the most important myiasis-causing flies endemic to the Americas. The geographic distribution of NWS has been reduced after the implementation of the Sterile Insect Technique (SIT), being eradicated in North America and part of Central America. In South America, C. hominivorax is controlled by chemical insecticides, although indiscriminate use can cause selection of resistant individuals. Previous studies have associated the Gly137Asp and Trp251Leu mutations in the active site of carboxylesterase E3 to resistance of diethyl and dimethyl-organophosphates insecticides, respectively. Here, we have sequenced a fragment of the carboxylesterase E3 gene (ChαE7), comprising part of intron iII, exon eIII, intron iIII and part of exon eIV, and three mitochondrial gene sequences (CR, COI and COII), of NWS flies from 21 locations in South America. These markers were used for population structure analyses and the ChαE7 gene was also investigated to gain insight into the selective pressures that have shaped its evolution. Analysis of molecular variance (AMOVA) and pairwise FST analysis indicated an increased genetic structure between locations in the ChαE7 compared to the concatenated mitochondrial genes. Discriminant analysis of principal components (DAPC) and spatial analysis of molecular variance (SAMOVA) indicated different degrees of genetic structure for all markers, in agreement with the AMOVA results, but with low correlation to geographic data. The NWS fly is considered a panmitic species based on mitochondrial data, while it is structured into three groups considering the ChαE7 gene. A negative association between the two mutations related to organophosphate resistance and Fay & Wu’s H significant negative values for the exons, suggest that these mutations evolved under positive selection.
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Affiliation(s)
- Luana Walravens Bergamo
- Center for Molecular Biology and Genetic Engineering (CBMEG), Campinas State University (UNICAMP), Campinas, SP, Brazil
- Department of Genetics, Evolution and Bioagents (DGEB), Institute of Biology (IB), Campinas State University (UNICAMP), Campinas, SP, Brazil
- * E-mail:
| | - Pablo Fresia
- Center for Molecular Biology and Genetic Engineering (CBMEG), Campinas State University (UNICAMP), Campinas, SP, Brazil
| | - Ana Maria L. Azeredo-Espin
- Center for Molecular Biology and Genetic Engineering (CBMEG), Campinas State University (UNICAMP), Campinas, SP, Brazil
- Department of Genetics, Evolution and Bioagents (DGEB), Institute of Biology (IB), Campinas State University (UNICAMP), Campinas, SP, Brazil
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29
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Krakowetz CN, Sproat A, Lindsay LR, Chilton NB. Sequence variability in the mitochondrial 12S rRNA and tRNA Val genes of Ixodes scapularis (Acari: Ixodidae) individuals shown previously to be genetically invariant. Mol Cell Probes 2015; 29:177-81. [PMID: 25863143 DOI: 10.1016/j.mcp.2015.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 03/31/2015] [Accepted: 03/31/2015] [Indexed: 10/23/2022]
Abstract
The DNA sequences of the mitochondrial (mt) 12S rRNA and tRNA(Val) genes were characterized for 82 blacklegged ticks (Ixodes scapularis) that were genetically identical for Domains IV and V of the mt 16S rRNA gene. Thirty-one haplotypes, differed in sequence by 1-9 bp, were detected among the 82 ticks. Most nucleotide alterations in DNA sequence did not affect the stability of the secondary structures of the RNAs. The magnitude of the DNA sequence variation in the mt 12S rRNA and tRNA(Val) genes among blacklegged ticks suggests that this region of the mitochondrial genome has potential as a genetic marker for examining the population genetics and phylogeography of I. scapularis.
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Affiliation(s)
- Chantel N Krakowetz
- Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
| | - Allison Sproat
- Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
| | - L Robbin Lindsay
- Public Health Agency of Canada, National Microbiology Laboratory, Winnipeg, MB R3E 3R2, Canada
| | - Neil B Chilton
- Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada.
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30
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Goethert HK, Telford SR. Not "out of Nantucket": Babesia microti in southern New England comprises at least two major populations. Parasit Vectors 2014; 7:546. [PMID: 25492628 PMCID: PMC4272771 DOI: 10.1186/s13071-014-0546-y] [Citation(s) in RCA: 15] [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] [Received: 10/17/2014] [Accepted: 11/18/2014] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Deer tick-transmitted human babesiosis due to Babesia microti appears to be expanding its distribution and prevalence in the northeastern United States. One hypothesis for this emergence is the introduction of parasites into new sites from areas of long-standing transmission, such as Nantucket Island, Massachusetts. METHODS We developed a typing system based on variable number tandem repeat loci that distinguished individual B. microti genotypes. We thereby analyzed the population structure of parasites from 11 sites, representing long-standing and newly emerging transmission in southern New England (northeastern United States), and compared their haplotypes and allele frequencies to determine the most probable number of B. microti populations represented by our enzootic collections. We expected to find evidence for a point source introduction across southern New England, with all parasites clearly derived from Nantucket, the site with the most intense longstanding transmission. RESULTS B. microti in southern New England comprises at least two major populations, arguing against a single source. The Nantucket group comprises Martha's Vineyard, Nantucket and nearby Cape Cod. The Connecticut/Rhode Island (CT/RI) group consists of all the samples from those states along with samples from emerging sites in Massachusetts. CONCLUSIONS The expansion of B. microti in the southern New England mainland is not due to parasites from the nearby terminal moraine islands (Nantucket group), but rather from the CT/RI group. The development of new B. microti foci is likely due to a mix of local intensification of transmission within relict foci across southern New England as well as long distance introduction events.
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Affiliation(s)
- Heidi K Goethert
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, 200 Westboro Rd, 01536, North Grafton, MA, USA.
| | - Sam R Telford
- Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, 200 Westboro Rd, 01536, North Grafton, MA, USA.
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