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Krakowetz CN, Lindsay LR, Chilton NB. Genetic variation in the mitochondrial 16S ribosomal RNA gene of Ixodes scapularis (Acari: Ixodidae). Parasit Vectors 2014; 7:530. [PMID: 25430547 PMCID: PMC4258262 DOI: 10.1186/s13071-014-0530-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 11/07/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ixodes scapularis is a vector of several human pathogens in the United States, and there is geographical variation in the relative number of persons infected with these pathogens. Geographically isolated populations of I. scapularis have established or are in the process of establishing in southern Canada. Knowledge of the genetic variation within and among these populations may provide insight into their geographical origins in the United States and the potential risk of exposure of Canadians to the different pathogens carried by I. scapularis. METHODS Part of the mitochondrial (mt) 16S ribosomal (r) RNA gene was amplified by PCR from 582 ticks collected from southern Canada, and Minnesota and Rhode Island in the United States. Sequence variation was examined in relation to the predicted secondary structure of the gene. Genetic diversity among populations was also determined. RESULTS DNA sequence analyses revealed 52 haplotypes. Most mutational alterations in DNA sequence occurred at unpaired sites or represented partial compensatory base pair changes that maintained the stability of the secondary structure. Significant genetic variation was detected within and among populations in different geographical regions. A greater proportion of the haplotypes of I. scapularis from the Canadian Prairie Provinces were found in the Midwest of the United States than in other regions, whereas more of the haplotypes of I. scapularis from the Canadian Central and Atlantic Provinces occurred in the Northeast of the United States. Nonetheless, 58% of I. scapularis were of a haplotype that occurs in the Midwest and Northeast of the United States; thus, their geographical origins could not be determined. CONCLUSIONS There is considerable genetic variation in the mt 16S rRNA gene of I. scapularis. There is some evidence to support the hypothesis that some lineages of I. scapularis in the Atlantic and Central Provinces of Canada may be derived from colonizing individuals originating in the Northeast of the United States, whereas those in the Prairie Provinces may be derived from individuals originating in the Midwest of the United States. However, additional genetic markers are needed to test hypotheses concerning the geographical origins of I. scapularis in Canada.
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Affiliation(s)
- Chantel N Krakowetz
- 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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152
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Esteve-Gassent MD, Pérez de León AA, Romero-Salas D, Feria-Arroyo TP, Patino R, Castro-Arellano I, Gordillo-Pérez G, Auclair A, Goolsby J, Rodriguez-Vivas RI, Estrada-Franco JG. Pathogenic Landscape of Transboundary Zoonotic Diseases in the Mexico-US Border Along the Rio Grande. Front Public Health 2014; 2:177. [PMID: 25453027 PMCID: PMC4233934 DOI: 10.3389/fpubh.2014.00177] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 09/19/2014] [Indexed: 01/11/2023] Open
Abstract
Transboundary zoonotic diseases, several of which are vector borne, can maintain a dynamic focus and have pathogens circulating in geographic regions encircling multiple geopolitical boundaries. Global change is intensifying transboundary problems, including the spatial variation of the risk and incidence of zoonotic diseases. The complexity of these challenges can be greater in areas where rivers delineate international boundaries and encompass transitions between ecozones. The Rio Grande serves as a natural border between the US State of Texas and the Mexican States of Chihuahua, Coahuila, Nuevo León, and Tamaulipas. Not only do millions of people live in this transboundary region, but also a substantial amount of goods and people pass through it everyday. Moreover, it occurs over a region that functions as a corridor for animal migrations, and thus links the Neotropic and Nearctic biogeographic zones, with the latter being a known foci of zoonotic diseases. However, the pathogenic landscape of important zoonotic diseases in the south Texas-Mexico transboundary region remains to be fully understood. An international perspective on the interplay between disease systems, ecosystem processes, land use, and human behaviors is applied here to analyze landscape and spatial features of Venezuelan equine encephalitis, Hantavirus disease, Lyme Borreliosis, Leptospirosis, Bartonellosis, Chagas disease, human Babesiosis, and Leishmaniasis. Surveillance systems following the One Health approach with a regional perspective will help identifying opportunities to mitigate the health burden of those diseases on human and animal populations. It is proposed that the Mexico-US border along the Rio Grande region be viewed as a continuum landscape where zoonotic pathogens circulate regardless of national borders.
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Affiliation(s)
- Maria Dolores Esteve-Gassent
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | | | - Dora Romero-Salas
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Veracruzana, Veracruz, México
| | | | - Ramiro Patino
- Department of Biology, University of Texas-Pan American, Edinburg, TX, USA
| | - Ivan Castro-Arellano
- Department of Biology, College of Science and Engineering, Texas State University, San Marcos, TX, USA
| | - Guadalupe Gordillo-Pérez
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional SXXI, IMSS, Distrito Federal, México
| | - Allan Auclair
- Environmental Risk Analysis Systems, Policy and Program Development, Animal and Plant Health Inspection Service, United States Department of Agriculture, Riverdale, MD, USA
| | - John Goolsby
- Cattle Fever Tick Research Laboratory, United States Department of Agriculture, Agricultural Research Service, Edinburg, TX, USA
| | - Roger Ivan Rodriguez-Vivas
- Facultad de Medicina Veterinaria y Zootecnia, Cuerpo Académico de Salud Animal, Universidad Autónoma de Yucatán, Mérida, México
| | - Jose Guillermo Estrada-Franco
- Facultad de Medicina Veterinaria Zootecnia, Centro de Investigaciones y Estudios Avanzados en Salud Animal, Universidad Autónoma del Estado de México, Toluca, México
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153
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Mays SE, Hendricks BM, Paulsen DJ, Houston AE, Trout Fryxell RT. Prevalence of five tick-borne bacterial genera in adult Ixodes scapularis removed from white-tailed deer in western Tennessee. Parasit Vectors 2014; 7:473. [PMID: 25331818 PMCID: PMC4207311 DOI: 10.1186/s13071-014-0473-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 10/02/2014] [Indexed: 11/10/2022] Open
Abstract
Background In the northeastern and midwestern regions of the United States Ixodes scapularis Say transmits the causal agents of anaplasmosis (Anaplasma phagocytophilum), babesiosis (Babesia microti), and borreliosis (Borrelia burgdorferi and B. miyamotoi). In the southeastern United States, none of those pathogens are considered endemic and two other tick-borne diseases (TBDs) (ehrlicihosis and rickettiosis) are more common. Our objective was to determine baseline presence and absence data for three non-endemic bacterial agents (Anaplasma, Borrelia and Babesia) and two commonly reported bacterial agents (Ehrlichia, and Rickettsia) in southern I. scapularis (n = 47) collected from 15 hunter-harvested white-tailed deer (Odocoileus virginianus) in western Tennessee. Findings Of the 47 ticks, 27 tested PCR positive for non-pathogenic Rickettsia species, two for Ehrlichia ewingii, one for Ehrlichia sp. “Panola Mountain”, and one for Anaplasma phagocytophilum variant 1 strain. None of these ticks were positive for Babesia or Borrelia (including B. burgdorferi). Conclusions Finding human pathogens in host-fed I. scapularis merits additional studies surveying pathogen prevalence in questing ticks. Collection of questing I. scapularis in their peak activity months should be undertaken to determine the overall encounter rates and relative risk of pathogenic Ehrlichia in southern I. scapularis. Ehrlichia sequences were homologous to previous human isolates, but neither Babesia nor B. burgdorferi were identified in these ticks. With the identification of pathogenic bacteria in this relatively small collection of I. scapularis from western Tennessee, the study of the absence of Lyme disease in the south should be refocused to evaluate the role of pathogenic Ehrlichia in southern I. scapularis.
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Affiliation(s)
- Sarah E Mays
- Department of Entomology and Plant Pathology, University of Tennessee, 370 Plant Biotechnology Building 2505 E J Chapman Drive, Knoxville, TN, USA.
| | - Brian M Hendricks
- Department of Entomology and Plant Pathology, University of Tennessee, 370 Plant Biotechnology Building 2505 E J Chapman Drive, Knoxville, TN, USA.
| | - David J Paulsen
- Department of Entomology and Plant Pathology, University of Tennessee, 370 Plant Biotechnology Building 2505 E J Chapman Drive, Knoxville, TN, USA.
| | - Allan E Houston
- Department of Forestry, Fisheries, and Wildlife, University of Tennessee, Tennessee and Ames Plantation, Grand Junction, Knoxville, Tennessee, USA.
| | - Rebecca T Trout Fryxell
- Department of Entomology and Plant Pathology, University of Tennessee, 370 Plant Biotechnology Building 2505 E J Chapman Drive, Knoxville, TN, USA.
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154
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Norris SJ, Barbour AG, Fish D, Diuk-Wasser MA. Analysis of the intergenic sequences provided by Feria-Arroyo et al. does not support the claim of high Borrelia burgdorferi tick infection rates in Texas and northeastern Mexico. Parasit Vectors 2014; 7:467. [PMID: 25428816 PMCID: PMC4203928 DOI: 10.1186/s13071-014-0467-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 09/29/2014] [Indexed: 11/10/2022] Open
Affiliation(s)
- Steven J Norris
- Departments of Pathology & Laboratory Medicine and Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston 77225-0708, TX, USA.
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Padgett K, Bonilla D, Kjemtrup A, Vilcins IM, Yoshimizu MH, Hui L, Sola M, Quintana M, Kramer V. Large scale spatial risk and comparative prevalence of Borrelia miyamotoi and Borrelia burgdorferi sensu lato in Ixodes pacificus. PLoS One 2014; 9:e110853. [PMID: 25333277 PMCID: PMC4205013 DOI: 10.1371/journal.pone.0110853] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 09/23/2014] [Indexed: 11/20/2022] Open
Abstract
Borrelia miyamotoi is a newly described emerging pathogen transmitted to people by Ixodes species ticks and found in temperate regions of North America, Europe, and Asia. There is limited understanding of large scale entomological risk patterns of B. miyamotoi and of Borreila burgdorferi sensu stricto (ss), the agent of Lyme disease, in western North America. In this study, B. miyamotoi, a relapsing fever spirochete, was detected in adult (n=70) and nymphal (n=36) Ixodes pacificus ticks collected from 24 of 48 California counties that were surveyed over a 13 year period. Statewide prevalence of B. burgdorferi sensu lato (sl), which includes B. burgdorferi ss, and B. miyamotoi were similar in adult I. pacificus (0.6% and 0.8%, respectively). In contrast, the prevalence of B. burgdorferi sl was almost 2.5 times higher than B. miyamotoi in nymphal I. pacificus (3.2% versus 1.4%). These results suggest similar risk of exposure to B. burgdorferi sl and B. miyamotoi from adult I. pacificus tick bites in California, but a higher risk of contracting B. burgdorferi sl than B. miyamotoi from nymphal tick bites. While regional risk of exposure to these two spirochetes varies, the highest risk for both species is found in north and central coastal California and the Sierra Nevada foothill region, and the lowest risk is in southern California; nevertheless, tick-bite avoidance measures should be implemented in all regions of California. This is the first study to comprehensively evaluate entomologic risk for B. miyamotoi and B. burgdorferi for both adult and nymphal I. pacificus, an important human biting tick in western North America.
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Affiliation(s)
- Kerry Padgett
- California Department of Public Health, Vector-Borne Disease Section, Richmond, California, United States of America
| | - Denise Bonilla
- California Department of Public Health, Vector-Borne Disease Section, Richmond, California, United States of America
| | - Anne Kjemtrup
- California Department of Public Health, Vector-Borne Disease Section, Richmond, California, United States of America
| | - Inger-Marie Vilcins
- California Department of Public Health, Vector-Borne Disease Section, Richmond, California, United States of America
| | - Melissa Hardstone Yoshimizu
- California Department of Public Health, Vector-Borne Disease Section, Richmond, California, United States of America
| | - Lucia Hui
- California Department of Public Health, Vector-Borne Disease Section, Richmond, California, United States of America
| | - Milagros Sola
- Public Health Command Region-West, Joint Base Lewis-McChord, Washington, United States of America
| | - Miguel Quintana
- Public Health Command Region-West, Joint Base Lewis-McChord, Washington, United States of America
| | - Vicki Kramer
- California Department of Public Health, Vector-Borne Disease Section, Richmond, California, United States of America
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156
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The Western progression of lyme disease: infectious and Nonclonal Borrelia burgdorferi Sensu Lato populations in Grand Forks County, North Dakota. Appl Environ Microbiol 2014; 81:48-58. [PMID: 25304515 DOI: 10.1128/aem.02422-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Scant attention has been paid to Lyme disease, Borrelia burgdorferi, Ixodes scapularis, or reservoirs in eastern North Dakota despite the fact that it borders high-risk counties in Minnesota. Recent reports of B. burgdorferi and I. scapularis in North Dakota, however, prompted a more detailed examination. Spirochetes cultured from the hearts of five rodents trapped in Grand Forks County, ND, were identified as B. burgdorferi sensu lato through sequence analyses of the 16S rRNA gene, the 16S rRNA gene-ileT intergenic spacer region, flaB, ospA, ospC, and p66. OspC typing revealed the presence of groups A, B, E, F, L, and I. Two rodents were concurrently carrying multiple OspC types. Multilocus sequence typing suggested the eastern North Dakota strains are most closely related to those found in neighboring regions of the upper Midwest and Canada. BALB/c mice were infected with B. burgdorferi isolate M3 (OspC group B) by needle inoculation or tick bite. Tibiotarsal joints and ear pinnae were culture positive, and B. burgdorferi M3 was detected by quantitative PCR (qPCR) in the tibiotarsal joints, hearts, and ear pinnae of infected mice. Uninfected larval I. scapularis ticks were able to acquire B. burgdorferi M3 from infected mice; M3 was maintained in I. scapularis during the molt from larva to nymph; and further, M3 was transmitted from infected I. scapularis nymphs to naive mice, as evidenced by cultures and qPCR analyses. These results demonstrate that isolate M3 is capable of disseminated infection by both artificial and natural routes of infection. This study confirms the presence of unique (nonclonal) and infectious B. burgdorferi populations in eastern North Dakota.
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157
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Larsen AE, MacDonald AJ, Plantinga AJ. Lyme disease risk influences human settlement in the wildland-urban interface: evidence from a longitudinal analysis of counties in the northeastern United States. Am J Trop Med Hyg 2014; 91:747-55. [PMID: 25048372 PMCID: PMC4183398 DOI: 10.4269/ajtmh.14-0181] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 06/13/2014] [Indexed: 11/07/2022] Open
Abstract
The expansion of human settlement into wildland areas, including forests in the eastern United States, has resulted in fragmented forest habitat that has been shown to drive higher entomological risk for Lyme disease. We investigated an alternative pathway between fragmentation and Lyme disease, namely whether increased risk of Lyme disease results in a reduced propensity to settle in high-risk areas at the interface of developed and undeveloped lands. We used longitudinal data analyses at the county level to determine whether Lyme disease incidence (LDI) influences the proportion of the population residing in the wildland-urban interface in 12 high LDI states in the eastern United States. We found robust evidence that a higher LDI reduces the proportion of a county's population residing in the wildland-urban interface in high-LDI states. This study provides some of the first evidence of human behavioral responses to Lyme disease risk via settlement decisions.
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Affiliation(s)
- Ashley E Larsen
- Department of Ecology, Evolution, and Marine Biology, and Bren School of Environmental Science and Management, University of California, Santa Barbara, California
| | - Andrew J MacDonald
- Department of Ecology, Evolution, and Marine Biology, and Bren School of Environmental Science and Management, University of California, Santa Barbara, California
| | - Andrew J Plantinga
- Department of Ecology, Evolution, and Marine Biology, and Bren School of Environmental Science and Management, University of California, Santa Barbara, California
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158
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Gomes-Solecki M. Blocking pathogen transmission at the source: reservoir targeted OspA-based vaccines against Borrelia burgdorferi. Front Cell Infect Microbiol 2014; 4:136. [PMID: 25309883 PMCID: PMC4176399 DOI: 10.3389/fcimb.2014.00136] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 09/08/2014] [Indexed: 12/26/2022] Open
Abstract
Control strategies are especially challenging for microbial diseases caused by pathogens that persist in wildlife reservoirs and use arthropod vectors to cycle amongst those species. One of the most relevant illnesses that pose a direct human health risk is Lyme disease; in the US, the Centers for Disease Control and Prevention recently revised the probable number of cases by 10-fold, to 300,000 cases per year. Caused by Borrelia burgdorferi, Lyme disease can affect the nervous system, joints and heart. No human vaccine is approved by the Food and Drug Administration. In addition to novel human vaccines, new strategies for prevention of Lyme disease consist of pest management interventions, vector-targeted vaccines and reservoir-targeted vaccines. However, even human vaccines can not prevent Lyme disease expansion into other geographical areas. The other strategies aim at reducing tick density and at disrupting the transmission of B. burgdorferi by targeting one or more key elements that maintain the enzootic cycle: the reservoir host and/or the tick vector. Here, I provide a brief overview of the application of an OspA-based wildlife reservoir targeted vaccine aimed at reducing transmission of B. burgdorferi and present it as a strategy for reducing Lyme disease risk to humans.
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Affiliation(s)
- Maria Gomes-Solecki
- *Correspondence: Maria Gomes-Solecki, Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, 858 Madison Ave, Suite 301A, Memphis, TN 38163, USA e-mail:
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159
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Russart NM, Dougherty MW, Vaughan JA. Survey of ticks (Acari: Ixodidae) and tick-borne pathogens in North Dakota. JOURNAL OF MEDICAL ENTOMOLOGY 2014; 51:1087-1090. [PMID: 25276942 DOI: 10.1603/me14053] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ticks were sampled at nine locations throughout North Dakota during early summer of 2010, using flagging techniques and small mammals trapping. In total, 1,762 ticks were collected from eight of the nine locations. The dominant species were Dermacentor variabilis (Say) (82%), found throughout the state, and Ixodes scapularis Say (17%), found in northeastern counties. A few nymphal and adult I. scapularis tested positive for Borrelia burgdorferi (3%) and Anaplasma phagocytophilum (8%). This is the first report of I. scapularis and associated pathogens occurring in North Dakota and provides evidence for continued westward expansion of this important vector tick species in the United States.
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160
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Ginsberg HS, Rulison EL, Azevedo A, Pang GC, Kuczaj IM, Tsao JI, LeBrun RA. Comparison of survival patterns of northern and southern genotypes of the North American tick Ixodes scapularis (Acari: Ixodidae) under northern and southern conditions. Parasit Vectors 2014; 7:394. [PMID: 25160464 PMCID: PMC4153913 DOI: 10.1186/1756-3305-7-394] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 08/19/2014] [Indexed: 12/30/2022] Open
Abstract
Background Several investigators have reported genetic differences between northern and southern populations of Ixodes scapularis in North America, as well as differences in patterns of disease transmission. Ecological and behavioral correlates of these genetic differences, which might have implications for disease transmission, have not been reported. We compared survival of northern with that of southern genotypes under both northern and southern environmental conditions in laboratory trials. Methods Subadult I. scapularis from laboratory colonies that originated from adults collected from deer from several sites in the northeastern, north central, and southern U.S. were exposed to controlled conditions in environmental chambers. Northern and southern genotypes were exposed to light:dark and temperature conditions of northern and southern sites with controlled relative humidities, and mortality through time was recorded. Results Ticks from different geographical locations differed in survival patterns, with larvae from Wisconsin surviving longer than larvae from Massachusetts, South Carolina or Georgia, when held under the same conditions. In another experiment, larvae from Florida survived longer than larvae from Michigan. Therefore, survival patterns of regional genotypes did not follow a simple north–south gradient. The most consistent result was that larvae from all locations generally survived longer under northern conditions than under southern conditions. Conclusions Our results suggest that conditions in southern North America are less hospitable than in the north to populations of I. scapularis. Southern conditions might have resulted in ecological or behavioral adaptations that contribute to the relative rarity of I. scapularis borne diseases, such as Lyme borreliosis, in the southern compared to the northern United States.
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Affiliation(s)
- Howard S Ginsberg
- USGS Patuxent Wildlife Research Center, RI Field Station, Woodward Hall - PSE, University of Rhode Island, Kingston, RI 02881, USA.
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161
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Hamer SA, Hickling GJ, Walker ED, Tsao JI. Increased diversity of zoonotic pathogens and Borrelia burgdorferi strains in established versus incipient Ixodes scapularis populations across the Midwestern United States. INFECTION GENETICS AND EVOLUTION 2014; 27:531-42. [PMID: 24953506 DOI: 10.1016/j.meegid.2014.06.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 06/02/2014] [Accepted: 06/06/2014] [Indexed: 10/25/2022]
Abstract
The center of origin theory predicts that genetic diversity will be greatest near a specie's geographic origin because of the length of time for evolution. By corollary, diversity will decrease with distance from the origin; furthermore, invasion and colonization are frequently associated with founder effects that reduce genetic variation in incipient populations. The blacklegged tick, Ixodes scapularis, harbors a suite of zoonotic pathogens, and the geographic range of the tick is expanding in the upper Midwestern United States. Therefore, we posited that diversity of I. scapularis-borne pathogens across its Midwestern range should correlate with the rate of the range expansion of this tick as well as subsequent disease emergence. Analysis of 1565 adult I. scapularis ticks from 13 sites across five Midwestern states revealed that tick infection prevalence with multiple microbial agents (Borrelia burgdorferi, Borrelia miyamotoi, Babesia odocoilei, Babesia microti, and Anaplasma phagocytophilum), coinfections, and molecular genetic diversity of B. burgdorferi all were positively correlated with the duration of establishment of tick populations, and therefore generally support the center of origin - pathogen diversity hypothesis. The observed differences across the gradient of establishment, however, were not strong and were nuanced by the high frequency of coinfections in tick populations at both established and recently-invaded tick populations. These results suggest that the invasion of ticks and their associated pathogens likely involve multiple means of pathogen introduction, rather than the conventionally presented scenario whereby infected, invading ticks are solely responsible for introducing pathogens to naïve host populations.
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Affiliation(s)
- Sarah A Hamer
- Texas A&M University, 4458 TAMU, College Station, TX 77843, USA.
| | - Graham J Hickling
- University of Tennessee, 274 Ellington Plant Science Building, Knoxville, TN 37996, USA.
| | - Edward D Walker
- Michigan State University, 13 Natural Resources Building, East Lansing, MI 48823, USA.
| | - Jean I Tsao
- Michigan State University, 13 Natural Resources Building, East Lansing, MI 48823, USA.
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162
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Wang P, Glowacki MN, Hoet AE, Needham GR, Smith KA, Gary RE, Li X. Emergence of Ixodes scapularis and Borrelia burgdorferi, the Lyme disease vector and agent, in Ohio. Front Cell Infect Microbiol 2014; 4:70. [PMID: 24926441 PMCID: PMC4044495 DOI: 10.3389/fcimb.2014.00070] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/14/2014] [Indexed: 11/13/2022] Open
Abstract
Lyme disease, the most common vector-borne disease in the United States, is caused by a tick-borne infection with Borrelia burgdorferi. Currently, Ohio is considered by the Centers for Disease Control and Prevention (CDC) to be non-endemic for Lyme disease. The low incidence of Lyme disease in this state was largely attributed to the absence of the transmitting vector, Ixodes scapularis, commonly known as the blacklegged tick. However, a tick surveillance program established by Ohio Department of Health indicated that the number of I. scapularis in Ohio had increased sharply in recent years, from 0 - 5 ticks per year during 1983-2008 to 15 in 2009, 40 in 2010, and 184 in 2011. During the fall deer hunting season, examination of deer heads submitted to Ohio Department of Agriculture found 29 I. scapularis from 7 counties in 2010 and 1,830 from 25 counties in 2011. As of 2012, the tick had been found in 57 of the 88 counties of Ohio. In addition, all three active stages (larva, nymph, and adult) of I. scapularis were found in Tiverton Township of Coshocton County, demonstrating the presence of established tick populations at this central Ohio location. Of 530 nymphal or adult I. scapularis analyzed by quantitative polymerase chain reaction (qPCR), 32 (6.1%) tested positive for the B. burgdorferi flaB gene, ranging from 36 to 390,000 copies per tick. Antibodies to B. burgdorferi antigens were detected in 2 of 10 (20%) field-captured Peromyscus leucopus from Tiverton Township, and in 41 of 355 (11.5%) dogs residing in Ohio. Collectively, these data suggest that the enzootic life cycle of B. burgdorferi has become established in Ohio, which poses risk of Lyme disease to people and animals in the area.
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Affiliation(s)
- Peng Wang
- Department of Veterinary Biosciences, The Ohio State University , Columbus, OH, USA
| | - Meaghan N Glowacki
- Department of Veterinary Biosciences, The Ohio State University , Columbus, OH, USA ; Department of Veterinary Preventive Medicine, The Ohio State University , Columbus, OH, USA
| | - Armando E Hoet
- Department of Veterinary Preventive Medicine, The Ohio State University , Columbus, OH, USA ; Division of Epidemiology, The Ohio State University , Columbus, OH, USA
| | - Glen R Needham
- Department of Entomology, The Ohio State University , Columbus, OH, USA
| | | | | | - Xin Li
- Department of Veterinary Biosciences, The Ohio State University , Columbus, OH, USA
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163
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Kelly RR, Gaines D, Gilliam WF, Brinkerhoff RJ. Population genetic structure of the Lyme disease vector Ixodes scapularis at an apparent spatial expansion front. INFECTION GENETICS AND EVOLUTION 2014; 27:543-50. [PMID: 24882702 DOI: 10.1016/j.meegid.2014.05.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 05/18/2014] [Accepted: 05/21/2014] [Indexed: 10/25/2022]
Abstract
Modeling and empirical evidence suggests that Lyme disease is undergoing geographic expansion from principal foci in the midwestern and northeastern United States. Virginia is at the southern edge of the current expansion zone and has seen dramatic rise in human Lyme disease cases since 2007, potentially owing to a recent increase in vector abundance. Ixodes scapularis is known throughout the eastern US but behavioral or physiological variation between northern and southern lineages might lead northern-variant ticks to more frequently parasitize humans. We hypothesized that recent spatial and numerical increase in Lyme disease cases is associated with demographic and/or spatial expansion of I. scapularis and that signals of these phenomena would be detectable and discernable in population genetic signals. In summer and fall 2011, we collected nymphal I. scapularis by drag sampling and adult I. scapularis from deer carcasses at hunting check stations at nine sites arranged along an east-west transect through central Virginia. We analyzed 16S mtDNA sequences data from up to 24 I. scapularis individuals collected from each site and detected a total of 24 haplotypes containing 29 segregating sites. We found no evidence for population genetic structure among these sites but we did find strong signals of both demographic and spatial expansion throughout our study system. We found two haplotypes (one individual each) representing a lineage of ticks that is only found in the southeastern United States, with the remaining individuals representing a less genetically diverse clade that is typical of the northern United States, but that has also been detected in the American South. Taken together, these results lead us to conclude that I. scapularis populations in Virginia are expanding and that this expansion may account for recent observed increases in Lyme disease.
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Affiliation(s)
- Rebecca R Kelly
- Department of Biology, University of Richmond, 28 Westhampton Way, Richmond, VA 23173, United States
| | - David Gaines
- Division of Environmental Epidemiology, Virginia Department of Health, Richmond, VA 23219, United States
| | - Will F Gilliam
- Department of Biology, University of Richmond, 28 Westhampton Way, Richmond, VA 23173, United States
| | - R Jory Brinkerhoff
- Department of Biology, University of Richmond, 28 Westhampton Way, Richmond, VA 23173, United States; School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa.
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164
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Herman-Giddens ME. Erythema Migrans-Like Lesions in the South Require Treatment Given the Current State of Knowledge. Vector Borne Zoonotic Dis 2014; 14:461-3. [DOI: 10.1089/vbz.2013.1545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Marcia E. Herman-Giddens
- University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina
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165
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Ogden NH, Radojevic M, Wu X, Duvvuri VR, Leighton PA, Wu J. Estimated effects of projected climate change on the basic reproductive number of the Lyme disease vector Ixodes scapularis. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:631-8. [PMID: 24627295 PMCID: PMC4050516 DOI: 10.1289/ehp.1307799] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 03/10/2014] [Indexed: 05/03/2023]
Abstract
BACKGROUND The extent to which climate change may affect human health by increasing risk from vector-borne diseases has been under considerable debate. OBJECTIVES We quantified potential effects of future climate change on the basic reproduction number (R0) of the tick vector of Lyme disease, Ixodes scapularis, and explored their importance for Lyme disease risk, and for vector-borne diseases in general. METHODS We applied observed temperature data for North America and projected temperatures using regional climate models to drive an I. scapularis population model to hindcast recent, and project future, effects of climate warming on R0. Modeled R0 increases were compared with R0 ranges for pathogens and parasites associated with variations in key ecological and epidemiological factors (obtained by literature review) to assess their epidemiological importance. RESULTS R0 for I. scapularis in North America increased during the years 1971-2010 in spatio-temporal patterns consistent with observations. Increased temperatures due to projected climate change increased R0 by factors (2-5 times in Canada and 1.5-2 times in the United States), comparable to observed ranges of R0 for pathogens and parasites due to variations in strains, geographic locations, epidemics, host and vector densities, and control efforts. CONCLUSIONS Climate warming may have co-driven the emergence of Lyme disease in northeastern North America, and in the future may drive substantial disease spread into new geographic regions and increase tick-borne disease risk where climate is currently suitable. Our findings highlight the potential for climate change to have profound effects on vectors and vector-borne diseases, and the need to refocus efforts to understand these effects.
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Affiliation(s)
- Nicholas H Ogden
- Zoonoses Division, Centre for Food-borne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, Saint-Hyacinthe, Quebec, Canada
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166
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Little SE, Beall MJ, Bowman DD, Chandrashekar R, Stamaris J. Canine infection with Dirofilaria immitis, Borrelia burgdorferi, Anaplasma spp., and Ehrlichia spp. in the United States, 2010-2012. Parasit Vectors 2014; 7:257. [PMID: 24886589 PMCID: PMC4057565 DOI: 10.1186/1756-3305-7-257] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/24/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The geographic distribution of canine infection with vector-borne disease agents in the United States appears to be expanding. METHODS To provide an updated assessment of geographic trends in canine infection with Dirofilaria immitis, Borrelia burgdorferi, Ehrlichia spp., and Anaplasma spp., we evaluated results from an average of 3,588,477 dogs tested annually by veterinarians throughout the United States from 2010 - 2012. RESULTS As in an earlier summary report, the percent positive test results varied by agent and region, with antigen of D. immitis and antibody to Ehrlichia spp. most commonly identified in the Southeast (2.9% and 3.2%, respectively) and antibody to both B. burgdorferi and Anaplasma spp. most commonly identified in the Northeast (13.3% and 7.1%, respectively) and upper Midwest (4.4% and 3.9%, respectively). Percent positive test results for D. immitis antigen were lower in every region considered, including in the Southeast, than previously reported. Percent positive test results for antibodies to B. burgdorferi and Ehrlichia spp. were higher nationally than previously reported, and, for antibodies to Anaplasma spp., were higher in the Northeast but lower in the Midwest and West, than in the initial report. Annual reports of human cases of Lyme disease, ehrlichiosis, and anaplasmosis were associated with percent positive canine test results by state for each respective tick-borne disease agent (R2=0.701, 0.457, and 0.314, respectively). Within endemic areas, percent positive test results for all three tick-borne agents demonstrated evidence of geographic expansion. CONCLUSIONS Continued national monitoring of canine test results for vector-borne zoonotic agents is an important tool for accurately mapping the geographic distribution of these agents, and greatly aids our understanding of the veterinary and public health threats they pose.
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Affiliation(s)
- Susan E Little
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Room 250 McElroy Hall, Stillwater, OK 74078, USA
| | | | - Dwight D Bowman
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
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167
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Lee X, Coyle DR, Johnson DKH, Murphy MW, McGeehin MA, Murphy RJ, Raffa KF, Paskewitz SM. Prevalence of Borrelia burgdorferi and Anaplasma phagocytophilum in Ixodes scapularis (Acari: Ixodidae) nymphs collected in managed red pine forests in Wisconsin. JOURNAL OF MEDICAL ENTOMOLOGY 2014; 51:694-701. [PMID: 24897864 DOI: 10.1603/me13140] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Changes in the structure of managed red pine forests in Wisconsin caused by interacting root- and stem-colonizing insects are associated with increased abundance of the blacklegged tick, Ixodes scapularis Say, in comparison with nonimpacted stands. However, the frequency and variability of the occurrence of tick-borne pathogens in this coniferous forest type across Wisconsin is unknown. Red pine forests were surveyed from 2009 to 2013 to determine the prevalence of Borrelia burgdorferi and Anaplasma phagocytophilum in questing I. scapularis nymphs. Polymerase chain reaction analysis revealed geographical differences in the nymphal infection prevalence (NIP) of these pathogens in red pine forests. In the Kettle Moraine State Forest (KMSF) in southeastern Wisconsin, NIP of B. burgdorferi across all years was 35% (range of 14.5-53.0%). At the Black River State Forest (BRSF) in western Wisconsin, NIP of B. burgdorferi across all years was 26% (range of 10.9-35.5%). Differences in NIP of B. burgdorferi between KMSF and BRSF were statistically significant for 2010 and 2011 and for all years combined (P < 0.05). NIP ofA. phagocytophilum (human agent) averaged 9% (range of 4.6-15.8%) at KMSF and 3% (range of 0-6.4%) at BRSF, and was significantly different between the sites for all years combined (P < 0.05). Differences in coinfection of B. burgdorferi and A. phagocytophilum were not statistically significant between KMSF and BRSF, with an average of 3.4% (range of 1.7-10.5%) and 2.5% (range of 0-5.5%), respectively. In 2013, the density of infected nymphs in KMSF and BRSF was 14 and 30 per 1000m2, respectively, among the highest ever recorded for the state. Differences in the density of nymphs and NIP among sites were neither correlated with environmental factors nor time since tick colonization. These results document significant unexplained variation in tick-borne pathogens between coniferous forests in Wisconsin that warrants further study.
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168
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States SL, Brinkerhoff RJ, Carpi G, Steeves TK, Folsom-O'Keefe C, DeVeaux M, Diuk-Wasser MA. Lyme disease risk not amplified in a species-poor vertebrate community: similar Borrelia burgdorferi tick infection prevalence and OspC genotype frequencies. INFECTION GENETICS AND EVOLUTION 2014; 27:566-75. [PMID: 24787999 DOI: 10.1016/j.meegid.2014.04.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/29/2014] [Accepted: 04/18/2014] [Indexed: 10/25/2022]
Abstract
The effect of biodiversity declines on human health is currently debated, but empirical assessments are lacking. Lyme disease provides a model system to assess relationships between biodiversity and human disease because the etiologic agent, Borrelia burgdorferi, is transmitted in the United States by the generalist black-legged tick (Ixodes scapularis) among a wide range of mammalian and avian hosts. The 'dilution effect' hypothesis predicts that species-poor host communities dominated by white-footed mice (Peromyscus leucopus) will pose the greatest human risk because P. leucopus infects the largest numbers of ticks, resulting in higher human exposure to infected I. scapularis ticks. P. leucopus-dominated communities are also expected to maintain a higher frequency of those B. burgdorferi outer surface protein C (ospC) genotypes that this host species more efficiently transmits ('multiple niche polymorphism' hypothesis). Because some of these genotypes are human invasive, an additive increase in human disease risk is expected in species-poor settings. We assessed these theoretical predictions by comparing I. scapularis nymphal infection prevalence, density of infected nymphs and B. burgdorferi genotype diversity at sites on Block Island, RI, where P. leucopus dominates the mammalian host community, to species-diverse sites in northeastern Connecticut. We found no support for the dilution effect hypothesis; B. burgdorferi nymphal infection prevalence was similar between island and mainland and the density of B. burgdorferi infected nymphs was higher on the mainland, contrary to what is predicted by the dilution effect hypothesis. Evidence for the multiple niche polymorphism hypothesis was mixed: there was lower ospC genotype diversity at island than mainland sites, but no overrepresentation of genotypes with higher fitness in P. leucopus or that are more invasive in humans. We conclude that other mechanisms explain similar nymphal infection prevalence in both communities and that high ospC genotype diversity can be maintained in both species-poor and species-rich communities.
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Affiliation(s)
- S L States
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA
| | - R J Brinkerhoff
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA; University of Richmond, Department of Biology, 28 Westhampton Way, Richmond, VA 23173, USA; University of KwaZulu-Natal, School of Life Sciences, Pietermaritzburg, South Africa
| | - G Carpi
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA
| | - T K Steeves
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA
| | - C Folsom-O'Keefe
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA; Audubon Connecticut, 185 East Flat Hill Rd., Southbury, CT 06488, USA
| | - M DeVeaux
- Yale School of Public Health, Department of Biostatistics, 60 College Street, New Haven, CT 06520, USA
| | - M A Diuk-Wasser
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA.
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169
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Feria-Arroyo TP, Castro-Arellano I, Gordillo-Perez G, Cavazos AL, Vargas-Sandoval M, Grover A, Torres J, Medina RF, de León AAP, Esteve-Gassent MD. Implications of climate change on the distribution of the tick vector Ixodes scapularis and risk for Lyme disease in the Texas-Mexico transboundary region. Parasit Vectors 2014; 7:199. [PMID: 24766735 PMCID: PMC4022269 DOI: 10.1186/1756-3305-7-199] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 04/18/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Disease risk maps are important tools that help ascertain the likelihood of exposure to specific infectious agents. Understanding how climate change may affect the suitability of habitats for ticks will improve the accuracy of risk maps of tick-borne pathogen transmission in humans and domestic animal populations. Lyme disease (LD) is the most prevalent arthropod borne disease in the US and Europe. The bacterium Borrelia burgdorferi causes LD and it is transmitted to humans and other mammalian hosts through the bite of infected Ixodes ticks. LD risk maps in the transboundary region between the U.S. and Mexico are lacking. Moreover, none of the published studies that evaluated the effect of climate change in the spatial and temporal distribution of I. scapularis have focused on this region. METHODS The area of study included Texas and a portion of northeast Mexico. This area is referred herein as the Texas-Mexico transboundary region. Tick samples were obtained from various vertebrate hosts in the region under study. Ticks identified as I. scapularis were processed to obtain DNA and to determine if they were infected with B. burgdorferi using PCR. A maximum entropy approach (MAXENT) was used to forecast the present and future (2050) distribution of B. burgdorferi-infected I. scapularis in the Texas-Mexico transboundary region by correlating geographic data with climatic variables. RESULTS Of the 1235 tick samples collected, 109 were identified as I. scapularis. Infection with B. burgdorferi was detected in 45% of the I. scapularis ticks collected. The model presented here indicates a wide distribution for I. scapularis, with higher probability of occurrence along the Gulf of Mexico coast. Results of the modeling approach applied predict that habitat suitable for the distribution of I. scapularis in the Texas-Mexico transboundary region will remain relatively stable until 2050. CONCLUSIONS The Texas-Mexico transboundary region appears to be part of a continuum in the pathogenic landscape of LD. Forecasting based on climate trends provides a tool to adapt strategies in the near future to mitigate the impact of LD related to its distribution and risk for transmission to human populations in the Mexico-US transboundary region.
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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.
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170
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Evolutionary genomics of Borrelia burgdorferi sensu lato: findings, hypotheses, and the rise of hybrids. INFECTION GENETICS AND EVOLUTION 2014; 27:576-93. [PMID: 24704760 DOI: 10.1016/j.meegid.2014.03.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/23/2014] [Accepted: 03/24/2014] [Indexed: 01/14/2023]
Abstract
Borrelia burgdorferi sensu lato (B. burgdorferi s.l.), the group of bacterial species represented by Lyme disease pathogens, has one of the most complex and variable genomic architectures among prokaryotes. Showing frequent recombination within and limited gene flow among geographic populations, the B. burgdorferi s.l. genomes provide an excellent window into the processes of bacterial evolution at both within- and between-population levels. Comparative analyses of B. burgdorferi s.l. genomes revealed a highly dynamic plasmid composition but a conservative gene repertoire. Gene duplication and loss as well as sequence variations at loci encoding surface-localized lipoproteins (e.g., the PF54 genes) are strongly associated with adaptive differences between species. There are a great many conserved intergenic spacer sequences that are candidates for cis-regulatory elements and non-coding RNAs. Recombination among coexisting strains occurs at a rate approximately three times the mutation rate. The coexistence of a large number of genomic groups within local B. burgdorferi s.l. populations may be driven by immune-mediated diversifying selection targeting major antigen loci as well as by adaptation to multiple host species. Questions remain regarding the ecological causes (e.g., climate change, host movements, or new adaptations) of the ongoing range expansion of B. burgdorferi s.l. and on the genomic variations associated with its ecological and clinical variability. Anticipating an explosive growth of the number of B. burgdorferi s.l. genomes sampled from both within and among species, we propose genome-based methods to test adaptive mechanisms and to identify molecular bases of phenotypic variations. Genome sequencing is also necessary for monitoring a likely increase of genetic admixture of previously isolated species and populations in North America and elsewhere.
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171
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Han GS, Stromdahl EY, Wong D, Weltman AC. Exposure to Borrelia burgdorferi and other tick-borne pathogens in Gettysburg National Military Park, South-Central Pennsylvania, 2009. Vector Borne Zoonotic Dis 2014; 14:227-33. [PMID: 24689815 DOI: 10.1089/vbz.2013.1363] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Since 1998, Lyme disease cases have increased in south-central Pennsylvania, which includes Gettysburg National Military Park (NMP). Limited information is available about tick populations or pathogens in this area, and no data regarding frequency of tick bites or prevention measures among Gettysburg NMP employees are available. To address these gaps, ticks were collected, classified, and replaced (to minimize disruptions to tick populations) at two sites within Gettysburg NMP during April-September, 2009, among eight nonremoval samplings. On two additional occasions during May and June, 2009, ticks were collected and removed from the two original sites plus 10 additional sites and tested for tick-borne pathogens by using PCR. A self-administered anonymous survey of Gettysburg NMP employees was conducted to determine knowledge, attitudes, and practices regarding tick-borne diseases. Peak Ixodes scapularis nymph populations were observed during May-July. Of 115 I. scapularis ticks tested, 21% were infected with Borrelia burgdorferi, including 18% of 74 nymphs and 27% of 41 adults; no other pathogen was identified. The entomologic risk index was calculated at 1.3 infected nymphs/hour. An adult and nymph Amblyomma americanum were also found, representing the first confirmed field collection of this tick in Pennsylvania, but no pathogens were detected. The survey revealed that most park employees believed Lyme disease was a problem at Gettysburg NMP and that they frequently found ticks on their skin and clothing. However, use of personal preventive measures was inconsistent, and 6% of respondents reported contracting Lyme disease while employed at Gettysburg NMP. These findings indicate a need to improve surveillance for tick bites among employees and enhance prevention programs for park staff and visitors.
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Affiliation(s)
- George S Han
- 1 Epidemic Intelligence Service, Centers for Disease Control and Prevention , Atlanta, Georgia
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172
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Ogden NH, Koffi JK, Pelcat Y, Lindsay LR. Environmental risk from Lyme disease in central and eastern Canada: a summary of recent surveillance information. CANADA COMMUNICABLE DISEASE REPORT = RELEVE DES MALADIES TRANSMISSIBLES AU CANADA 2014; 40:74-82. [PMID: 29769885 PMCID: PMC5864485 DOI: 10.14745/ccdr.v40i05a01] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
BACKGROUND Lyme disease is the most commonly reported vector-borne disease in the temperate world. It is emerging in central and eastern Canada due to spread of the tick vector Ixodes scapularis into and within Canada to form new areas of environmental risk known as Lyme disease-endemic areas. Identifying the geographic location of Lyme disease-endemic areas is important to identify the population at risk, target interventions, and inform the clinical diagnosis of Lyme disease patients. OBJECTIVE To provide an up-to-date picture of current and emerging areas of Lyme disease risk in eastern and central Canada by summarizing recent information on Lyme disease-endemic areas, and surveillance for I. scapularis ticks. METHODS Data on locations where I. scapularis have been found in field surveillance studies by a range of federal and provincial organizations were collated and mapped to obtain a fuller picture of the occurrence of I. scapularis in Canada. The geographic locations of ticks submitted in passive tick surveillance were mapped for comparison. RESULTS The number of confirmed Lyme disease-endemic areas in southern Manitoba, southern and eastern Ontario, southern Quebec, southern New Brunswick and in some locations in Nova Scotia increased from 10 in 2009 to 22 confirmed endemic areas in 2012. The collated field surveillance data indicated that I. scapularis tick populations and Lyme disease risk are more geographically widespread than known Lyme disease-endemic areas and that the pattern of emergence of tick populations varies among provinces. There was a tenfold increase in the numbers of I. scapularis reported for passive surveillance from 2 059 submissions from 1990 to 2003 to 25 738 submissions from 2004 to 2012. CONCLUSIONS The increasing numbers of Lyme disease-endemic areas, the much wider distribution of tick populations identified by field surveillance, as well as the marked increase in numbers of ticks identified through passive surveillance suggest that the geographic scope of environmental risk of acquiring Lyme disease is expanding in central and eastern Canada, although here it still remains mostly limited to the southern parts of five provinces.
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Affiliation(s)
- NH Ogden
- Centre for Food-borne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, Saint-Hyacinthe, Quebec
- Corresponding author:
| | - JK Koffi
- Centre for Food-borne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, Saint-Hyacinthe, Quebec
| | - Y Pelcat
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba
| | - LR Lindsay
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba
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173
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Abstract
Background Lyme disease is emerging in eastern and central Canada due to the spread of the tick vector Ixodes scapularis. Currently, the test to establish Lyme disease-endemic areas requires multiple site visits and multiple sampling methods, and is consequently complex, time-consuming, and resource-expensive. Objective To assess the capacity of drag sampling alone as a screening technique to identify areas of Lyme disease risk. Method We conducted a retrospective analysis of field surveillance data obtained at 100 site visits in 2007 and 2008 in southern Quebec. Outcome Drag sampling used alone had 50% sensitivity but 86% specificity to identify early-established I. scapularis populations. Ticks were found throughout the period May to October. Conclusion One site visit of drag sampling of three person-hours between May and October may be sufficient to identify a Lyme disease risk location. This information can be used by public health professionals to develop public health responses and by medical practitioners to assist in the clinical diagnosis of Lyme disease.
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174
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Pultorak EL, Breitschwerdt EB. Survey of veterinarians' perceptions of borreliosis in North Carolina. J Am Vet Med Assoc 2014; 244:592-6. [PMID: 24548235 DOI: 10.2460/javma.244.5.592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE--To evaluate the practices and perceptions of veterinarians in North Carolina regarding borreliosis in dogs in various geographic regions of the state. DESIGN--Cross-sectional survey. SAMPLE--Data from 208 completed surveys. PROCEDURES--Surveys were distributed to veterinary clinics throughout North Carolina. Descriptive statistics were used to summarize perceptions pertaining to borreliosis among dogs in North Carolina. RESULts--A significantly higher proportion of responding veterinarians believed that borreliosis was endemic in the coastal (67.2%) and Piedmont (60.9%) areas of North Carolina, compared with more western regions (37.5%). The 3 variables found to be significantly different between the northern and southern regions of the state were the estimated number of borreliosis cases diagnosed by each responding veterinary clinic during the past year, the perception of borreliosis endemicity, and the perceptions related to the likelihood of a dog acquiring borreliosis in the state. CONCLUSIONS AND CLINICAL RELEVANCE--Veterinarians' perception of the risk of borreliosis in North Carolina was consistent with recent scientific reports pertaining to geographic expansion of borreliosis in the state. As knowledge of the epidemiological features of borreliosis in North Carolina continues to evolve, veterinarians should promote routine screening of dogs for Borrelia burgdorferi exposure as a simple, inexpensive form of surveillance that can be used to better educate their clients on the threat of transmission of borreliosis in this transitional geographic region.
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Affiliation(s)
- Elizabeth L Pultorak
- Intracellular Pathogens Research Laboratory, Center for Comparative Medicine and Translational Research, and the Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607
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175
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Richer LM, Brisson D, Melo R, Ostfeld RS, Zeidner N, Gomes-Solecki M. Reservoir targeted vaccine against Borrelia burgdorferi: a new strategy to prevent Lyme disease transmission. J Infect Dis 2014; 209:1972-80. [PMID: 24523510 DOI: 10.1093/infdis/jiu005] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A high prevalence of infection with Borrelia burgdorferi in ixodid ticks is correlated with a high incidence of Lyme disease. The transmission of B. burgdorferi to humans can be disrupted by targeting 2 key elements in its enzootic cycle: the reservoir host and the tick vector. In a prospective 5-year field trial, we show that oral vaccination of wild white-footed mice resulted in outer surface protein A-specific seropositivity that led to reductions of 23% and 76% in the nymphal infection prevalence in a cumulative, time-dependent manner (2 and 5 years, respectively), whereas the proportion of infected ticks recovered from control plots varied randomly over time. Significant decreases in tick infection prevalence were observed within 3 years of vaccine deployment. Implementation of such a long-term public health measure could substantially reduce the risk of human exposure to Lyme disease.
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Affiliation(s)
| | | | - Rita Melo
- University of Tennessee Health Sciences Center
| | | | - Nordin Zeidner
- Division of High Consequence Pathogens and Pathology, One Health Office, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Dhaka, Bangladesh
| | - Maria Gomes-Solecki
- University of Tennessee Health Sciences Center Biopeptides, Memphis, Tennessee
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176
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Hojgaard A, Lukacik G, Piesman J. Detection of Borrelia burgdorferi, Anaplasma phagocytophilum and Babesia microti, with two different multiplex PCR assays. Ticks Tick Borne Dis 2014; 5:349-51. [PMID: 24507434 DOI: 10.1016/j.ttbdis.2013.12.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 12/20/2013] [Accepted: 12/31/2013] [Indexed: 10/25/2022]
Abstract
We have developed 2 real-time multiplex PCR assays for detection of Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti. The efficiency and sensitivity of each multiplex PCR assay was evaluated using field-collected Ixodes scapularis ticks that were positive for each of the pathogens, cloned plasmids harboring each of the PCR targets, and laboratory I. scapularis infected with B. burgdorferi B31. There was no difference in efficiency or sensitivity when comparing the multiplex PCR with the individual PCR reactions. If the 2 multiplex PCR assays are used in the same analysis, field-collected ticks that only harbor B. miyamotoi can also be identified. The multiplex assays are fast and cost-effective methods for screening and detecting pathogens in ticks, when compared to single-target PCR.
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Affiliation(s)
- Andrias Hojgaard
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA.
| | - Gary Lukacik
- New York State Department of Health, Bureau of Communicable Disease Control, Albany, NY, USA
| | - Joseph Piesman
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA
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177
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Finch C, Al-Damluji MS, Krause PJ, Niccolai L, Steeves T, O'Keefe CF, Diuk-Wasser MA. Integrated assessment of behavioral and environmental risk factors for Lyme disease infection on Block Island, Rhode Island. PLoS One 2014; 9:e84758. [PMID: 24416278 PMCID: PMC3885597 DOI: 10.1371/journal.pone.0084758] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 11/19/2013] [Indexed: 11/23/2022] Open
Abstract
Peridomestic exposure to Borrelia burgdorferi-infected Ixodes scapularis nymphs is considered the dominant means of infection with black-legged tick-borne pathogens in the eastern United States. Population level studies have detected a positive association between the density of infected nymphs and Lyme disease incidence. At a finer spatial scale within endemic communities, studies have focused on individual level risk behaviors, without accounting for differences in peridomestic nymphal density. This study simultaneously assessed the influence of peridomestic tick exposure risk and human behavior risk factors for Lyme disease infection on Block Island, Rhode Island. Tick exposure risk on Block Island properties was estimated using remotely sensed landscape metrics that strongly correlated with tick density at the individual property level. Behavioral risk factors and Lyme disease serology were assessed using a longitudinal serosurvey study. Significant factors associated with Lyme disease positive serology included one or more self-reported previous Lyme disease episodes, wearing protective clothing during outdoor activities, the average number of hours spent daily in tick habitat, the subject’s age and the density of shrub edges on the subject’s property. The best fit multivariate model included previous Lyme diagnoses and age. The strength of this association with previous Lyme disease suggests that the same sector of the population tends to be repeatedly infected. The second best multivariate model included a combination of environmental and behavioral factors, namely hours spent in vegetation, subject’s age, shrub edge density (increase risk) and wearing protective clothing (decrease risk). Our findings highlight the importance of concurrent evaluation of both environmental and behavioral factors to design interventions to reduce the risk of tick-borne infections.
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Affiliation(s)
- Casey Finch
- Department of Epidemiology of Microbial Diseases at Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Mohammed Salim Al-Damluji
- Department of Epidemiology of Microbial Diseases at Yale School of Public Health, New Haven, Connecticut, United States of America ; Department of Internal Medicine at Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Peter J Krause
- Department of Epidemiology of Microbial Diseases at Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Linda Niccolai
- Department of Epidemiology of Microbial Diseases at Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Tanner Steeves
- Department of Epidemiology of Microbial Diseases at Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Corrine Folsom O'Keefe
- Department of Epidemiology of Microbial Diseases at Yale School of Public Health, New Haven, Connecticut, United States of America ; Audubon Connecticut, Southbury, Connecticut, United States of America
| | - Maria A Diuk-Wasser
- Department of Epidemiology of Microbial Diseases at Yale School of Public Health, New Haven, Connecticut, United States of America
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178
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Goltz L, Varela-Stokes A, Goddard J. Survey of adult Ixodes scapularis Say for disease agents in Mississippi. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2013; 38:401-403. [PMID: 24581371 DOI: 10.1111/j.1948-7134.2013.12056.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- Lauren Goltz
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, U.S.A
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179
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Social-ecological factors determine spatial variation in human incidence of tick-borne ehrlichiosis. Epidemiol Infect 2013; 142:1911-24. [DOI: 10.1017/s0950268813002951] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
SUMMARYThe spatial distribution of human cases of tick-borne diseases is probably determined by a combination of biological and socioeconomic factors. A zoonotic tick-borne pathogen, Ehrlichia chaffeensis, is increasing in human incidence in the USA. In this study, the spatial patterns of probable and confirmed E. chaffeensis-associated cases of ehrlichiosis from 2000 to 2011 were investigated at the zip-code level in Missouri. We applied spatial statistics, including global and local regression models, to investigate the biological and socioeconomic factors associated with human incidence. Our analysis confirms that the distribution of ehrlichiosis in Missouri is non-random, with numerous clusters of high incidence. Furthermore, we identified significant, but spatially variable, associations between incidence and both biological and socioeconomic factors, including a positive association with reservoir host density and a negative association with human population density. Improved understanding of local variation in these spatial factors may facilitate targeted interventions by public health authorities.
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180
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Efficacy of an experimental azithromycin cream for prophylaxis of tick-transmitted lyme disease spirochete infection in a murine model. Antimicrob Agents Chemother 2013; 58:348-51. [PMID: 24165183 DOI: 10.1128/aac.01932-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
As an alternative to oral prophylaxis for the prevention of tick transmission of Borrelia burgdorferi, we tested antibiotic cream prophylactic formulations in a murine model of spirochete infection. A 4% preparation of doxycycline cream afforded no protection, but a single application of 4% azithromycin cream was 100% protective when applied directly to the tick bite site at the time of tick removal. Indeed, the azithromycin cream was 100% effective when applied at up to 3 days after tick removal and protected 74% of mice exposed to tick bite when applied at up to 2 weeks after tick removal. Azithromycin cream was also protective when applied at a site distal to the tick bite site, suggesting that it was having a systemic effect in addition to a local transdermal effect. Mice that were protected from tick-transmitted infection did not seroconvert and did not infect larval ticks on xenodiagnosis. Azithromycin cream formulations appear to hold promise for Lyme disease prophylaxis.
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181
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Lantos PM, Brinkerhoff RJ, Wormser GP, Clemen R. Empiric antibiotic treatment of erythema migrans-like skin lesions as a function of geography: a clinical and cost effectiveness modeling study. Vector Borne Zoonotic Dis 2013; 13:877-83. [PMID: 24107201 DOI: 10.1089/vbz.2013.1365] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The skin lesion of early Lyme disease, erythema migrans (EM), is so characteristic that routine practice is to treat all such patients with antibiotics. Because other skin lesions may resemble EM, it is not known whether presumptive treatment of EM is appropriate in regions where Lyme disease is rare. We constructed a decision model to compare the cost and clinical effectiveness of three strategies for the management of EM: Treat All, Observe, and Serology as a function of the probability that an EM-like lesion is Lyme disease. Treat All was found to be the preferred strategy in regions that are endemic for Lyme disease. Where Lyme disease is rare, Observe is the preferred strategy, as presumptive treatment would be expected to produce excessive harm and increased costs. Where Lyme disease is rare, clinicians and public health officials should consider observing patients with EM-like lesions who lack travel to Lyme disease-endemic areas.
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Affiliation(s)
- Paul M Lantos
- 1 Department of Medicine, Duke University School of Medicine , Durham, North Carolina
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182
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Mariet AS, Retel O, Avocat H, Serre A, Schapman L, Schmitt M, Charron M, Monnet E. Estimated Incidence of Erythema Migrans in Five Regions of France and Ecological Correlations with Environmental Characteristics. Vector Borne Zoonotic Dis 2013; 13:666-73. [DOI: 10.1089/vbz.2012.1199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Anne-Sophie Mariet
- Institut de veille sanitaire, Département de Coordination des Alertes et Région, CIRE Bourgogne/Franche-Comté, Dijon, France
- Université de Franche-Comté, Laboratoire EA 4266, Agents Pathogènes et Inflammation, Besançon, France
| | - Olivier Retel
- Institut de veille sanitaire, Département de Coordination des Alertes et Région, CIRE Bourgogne/Franche-Comté, Dijon, France
| | - Hélène Avocat
- UFR Lettres Sciences Humaines et Sociales, UMR ThéMA, Besançon, France
| | - Anne Serre
- Institut de veille sanitaire, Département de Coordination des Alertes et Région, CIRE Bourgogne/Franche-Comté, Dijon, France
| | - Lucie Schapman
- Institut de veille sanitaire, Département de Coordination des Alertes et Région, CIRE Bourgogne/Franche-Comté, Dijon, France
- Institut de Veille Sanitaire, Département de Coordination des Alertes et Région, CIRE Limousin/Poitou-Charentes, Poitiers, France
| | - Marielle Schmitt
- Institut de Veille Sanitaire, Département de Coordination des Alertes et Région, CIRE Rhône-Alpes, Lyon, France
- Institut de Veille Sanitaire, Département de Coordination des Alertes et Région, CIRE Lorraine-Alsace, Nancy, France
| | - Martine Charron
- Institut de Veille Sanitaire, Département de Coordination des Alertes et Région, CIRE Aquitaine, Bordeaux, France
| | - Elisabeth Monnet
- Université de Franche-Comté, Laboratoire EA 4266, Agents Pathogènes et Inflammation, Besançon, France
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183
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Lee X, Hardy K, Johnson DH, Paskewitz SM. Hunter-killed deer surveillance to assess changes in the prevalence and distribution of Ixodes scapularis (Acari: Ixodidae) in Wisconsin. JOURNAL OF MEDICAL ENTOMOLOGY 2013; 50:632-639. [PMID: 23802460 DOI: 10.1603/me12234] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
As a result of the increasing incidence of Lyme disease and other tick-borne pathogens in Wisconsin, we assessed the distribution of adult blacklegged ticks through collections from hunter-killed deer in 2008 and 2009 and compared results with prior surveys beginning in 1981. Volunteers staffed 21 Wisconsin Department of Natural Resources registration stations in 21 counties in the eastern half of Wisconsin in 2008 and 10 stations in seven counties in northwestern Wisconsin in 2009. In total, 786 and 300 white-tailed deer (Odocoileus virginianus) were examined in 2008 and 2009, respectively. All but three stations in 2008 were positive for ticks and all stations in 2009 were positive for ticks. The three sites negative for ticks occurred within the eastern half of Wisconsin. The results indicate that range expansion of Ixodes scapularis (Say) is continuing and the risk of tick exposure is increasing, especially in the eastern one-third of the state.
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Affiliation(s)
- Xia Lee
- University of Wisconsin, 237 Russell Labs, 1630 Linden Dr., Madison, WI 53706, USA
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184
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Nofchissey RA, Deardorff ER, Blevins TM, Anishchenko M, Bosco-Lauth A, Berl E, Lubelczyk C, Mutebi JP, Brault AC, Ebel GD, Magnarelli LA. Seroprevalence of Powassan virus in New England deer, 1979-2010. Am J Trop Med Hyg 2013; 88:1159-62. [PMID: 23568288 DOI: 10.4269/ajtmh.12-0586] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Powassan virus and its subtype, deer tick virus, are closely related tick-borne flaviviruses that circulate in North America. The incidence of human infection by these agents appears to have increased in recent years. To define exposure patterns among white-tailed deer, potentially useful sentinels that are frequently parasitized by ticks, we screened serum samples collected during 1979-2010 in Connecticut, Maine, and Vermont for neutralizing antibody by using a novel recombinant deer tick virus-West Nile virus chimeric virus. Evidence of exposure was detected in all three states. Overall our results demonstrate that seroprevalence is variable in time and space, suggesting that risk of exposure to Powassan virus is similarly variable.
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185
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Serra AC, Warden PS, Fricker CR, Giese AR. Distribution of Ticks and Prevalence of Borrelia burgdorferi in the Upper Connecticut River Valley of Vermont. Northeast Nat (Steuben) 2013; 20:197-204. [PMID: 25473255 DOI: 10.1656/045.020.0116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ixodes scapularis (Black-legged Tick) has expanded its range in recent decades. To establish baseline data on the abundance of the Black-legged Tick and Borrelia burgdorferi (causative agent of Lyme disease) at the edge of a putative range expansion we collected 1398 ticks from five locations along the Connecticut River in Vermont. Collection locations were approximately evenly distributed between the villages of Ascutney and Guildhall. Relative abundance and distribution by species varied across sites. Black-legged Ticks dominated our collections (n = 1348, 96%), followed by Haemaphysalis leporispalustris (Rabbit Tick, n = 45, 3%) and Dermacentor variabilis (American Dog Tick, n = 5, <1%). Black-legged Tick abundance ranged from 6198 ticks per survey hectare (all life stages combined) at the Thetford site to zero at the Guildhall site. There was little to no overlap of tick species across sites. Phenology of Black-legged Ticks matched published information from other regions of the northeastern USA. Prevalence of B. burgdorferi in adult Black-legged Ticks was 8.9% (n = 112).
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Affiliation(s)
- Abigail C Serra
- Department of Natural Sciences, Lyndon State College, Lyndonville VT, 05851
| | | | | | - Alan R Giese
- Department of Natural Sciences, Lyndon State College, Lyndonville VT, 05851
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186
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Voordouw MJ, Tupper H, Önder Ö, Devevey G, Graves CJ, Kemps BD, Brisson D. Reductions in human Lyme disease risk due to the effects of oral vaccination on tick-to-mouse and mouse-to-tick transmission. Vector Borne Zoonotic Dis 2013; 13:203-14. [PMID: 23428088 DOI: 10.1089/vbz.2012.1003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Vaccinating wildlife is becoming an increasingly popular method to reduce human disease risks from pathogens such as Borrelia burgdorferi, the causative agent of Lyme disease. To successfully limit human disease risk, vaccines targeting the wildlife reservoirs of B. burgdorferi must be easily distributable and must effectively reduce pathogen transmission from infected animals, given that many animals in nature will be infected prior to vaccination. We assessed the efficacy of an easily distributable oral bait vaccine based on the immunogenic outer surface protein A (OspA) to protect uninfected mice from infection and to reduce transmission from previously infected white-footed mice, an important reservoir host of B. burgdorferi. Oral vaccination of white-footed mice effectively reduces transmission of B. burgdorferi at both critical stages of the Lyme disease transmission cycle. First, oral vaccination of uninfected white-footed mice elicits an immune response that protects mice from B. burgdorferi infection. Second, oral vaccination of previously infected mice significantly reduces the transmission of B. burgdorferi to feeding ticks despite a statistically nonsignificant immune response. We used the estimates of pathogen transmission to and from vaccinated and unvaccinated mice to model the efficacy of an oral vaccination campaign targeting wild white-footed mice. Projection models suggest that the effects of the vaccine on both critical stages of the transmission cycle of B. burgdorferi act synergistically in a positive feedback loop to reduce the nymphal infection prevalence, and thus human Lyme disease risk, well below what would be expected from either effect alone. This study suggests that oral immunization of wildlife with an OspA-based vaccine can be a promising long-term strategy to reduce human Lyme disease risk.
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187
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Hamer SA, Goldberg TL, Kitron UD, Brawn JD, Anderson TK, Loss SR, Walker ED, Hamer GL. Wild birds and urban ecology of ticks and tick-borne pathogens, Chicago, Illinois, USA, 2005-2010. Emerg Infect Dis 2013; 18:1589-95. [PMID: 23017244 PMCID: PMC3471635 DOI: 10.3201/eid1810.120511] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
No longer do you have to visit rural areas to find ticks; birds are flying them directly to you. When researchers sampled several thousand birds in Chicago, they found that some carried ticks and that some of these ticks carried the organism that spreads Lyme disease. Although the number of infected ticks on these birds was low, risk for their invading an area and spreading infection to humans cannot be ignored. If conditions are favorable, a few infected ticks can quickly multiply. Migratory birds also carried tick species only known to be established in Central and South America. Limited introduction and successful establishment of ticks and disease-carrying organisms pose a major health risk for humans, wildlife, and domestic animals in urban environments worldwide. Bird-facilitated introduction of ticks and associated pathogens is postulated to promote invasion of tick-borne zoonotic diseases into urban areas. Results of a longitudinal study conducted in suburban Chicago, Illinois, USA, during 2005–2010 show that 1.6% of 6,180 wild birds captured in mist nets harbored ticks. Tick species in order of abundance were Haemaphysalis leporispalustris, Ixodes dentatus, and I. scapularis, but 2 neotropical tick species of the genus Amblyomma were sampled during the spring migration. I. scapularis ticks were absent at the beginning of the study but constituted the majority of ticks by study end and were found predominantly on birds captured in areas designated as urban green spaces. Of 120 ticks, 5 were infected with Borrelia burgdorferi, spanning 3 ribotypes, but none were infected with Anaplasma phagocytophilum. Results allow inferences about propagule pressure for introduction of tick-borne diseases and emphasize the large sample sizes required to estimate this pressure.
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Affiliation(s)
- Sarah A Hamer
- Michigan State University, East Lansing, Michigan, USA.
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188
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Ogden NH, Lindsay LR, Leighton PA. Predicting the rate of invasion of the agent of Lyme disease Borrelia burgdorferi. J Appl Ecol 2013. [DOI: 10.1111/1365-2664.12050] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Nicholas H. Ogden
- Zoonoses Division; Centre for Food-borne, Environmental & Zoonotic Infectious Diseases, Public Health Agency of Canada; Saint-Hyacinthe QC Canada
| | - L. Robbin Lindsay
- Zoonoses & Special Pathogens Division; National Microbiology Laboratory, Public Health Agency of Canada; Winnipeg MB Canada
| | - Patrick A. Leighton
- Faculté de médicine vétérinaire; Université de Montréal; Saint-Hyacinthe QC Canada
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189
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Biodiversity and disease: a synthesis of ecological perspectives on Lyme disease transmission. Trends Ecol Evol 2012. [PMID: 23182683 DOI: 10.1016/j.tree.2012.10.011] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Recent reviews have argued that disease control is among the ecosystem services yielded by biodiversity. Lyme disease (LD) is commonly cited as the best example of the 'diluting' effect of biodiversity on disease transmission, but many studies document the opposite relationship, showing that human LD risk can increase with forestation. Here, we unify these divergent perspectives and find strong evidence for a positive link between biodiversity and LD at broad spatial scales (urban to suburban to rural) and equivocal evidence for a negative link between biodiversity and LD at varying levels of biodiversity within forests. This finding suggests that, across zoonotic disease agents, the biodiversity-disease relationship is scale dependent and complex.
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190
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Pepin KM, Eisen RJ, Mead PS, Piesman J, Fish D, Hoen AG, Barbour AG, Hamer S, Diuk-Wasser MA. Geographic variation in the relationship between human Lyme disease incidence and density of infected host-seeking Ixodes scapularis nymphs in the Eastern United States. Am J Trop Med Hyg 2012; 86:1062-71. [PMID: 22665620 DOI: 10.4269/ajtmh.2012.11-0630] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Prevention and control of Lyme disease is difficult because of the complex biology of the pathogen's (Borrelia burgdorferi) vector (Ixodes scapularis) and multiple reservoir hosts with varying degrees of competence. Cost-effective implementation of tick- and host-targeted control methods requires an understanding of the relationship between pathogen prevalence in nymphs, nymph abundance, and incidence of human cases of Lyme disease. We quantified the relationship between estimated acarological risk and human incidence using county-level human case data and nymphal prevalence data from field-derived estimates in 36 eastern states. The estimated density of infected nymphs (mDIN) was significantly correlated with human incidence (r = 0.69). The relationship was strongest in high-prevalence areas, but it varied by region and state, partly because of the distribution of B. burgdorferi genotypes. More information is needed in several high-prevalence states before DIN can be used for cost-effectiveness analyses.
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Affiliation(s)
- Kim M Pepin
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20892-2220, USA.
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191
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Fryxell RTT, Steelman CD, Szalanski AL, Kvamme KL, Billingsley PM, Williamson PC. Survey of Borreliae in ticks, canines, and white-tailed deer from Arkansas, U.S.A. Parasit Vectors 2012; 5:139. [PMID: 22781030 PMCID: PMC3419661 DOI: 10.1186/1756-3305-5-139] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 07/10/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the Eastern and Upper Midwestern regions of North America, Ixodes scapularis (L.) is the most abundant tick species encountered by humans and the primary vector of B. burgdorferi, whereas in the southeastern region Amblyomma americanum (Say) is the most abundant tick species encountered by humans but cannot transmit B. burgdorferi. Surveys of Borreliae in ticks have been conducted in the southeastern United States and often these surveys identify B. lonestari as the primary Borrelia species, surveys have not included Arkansas ticks, canines, or white-tailed deer and B. lonestari is not considered pathogenic. The objective of this study was to identify Borrelia species within Arkansas by screening ticks (n=2123), canines (n=173), and white-tailed deer (n=228) to determine the identity and locations of Borreliae endemic to Arkansas using PCR amplification of the flagellin (flaB) gene. METHODS Field collected ticks from canines and from hunter-killed white-tailed were identified to species and life stage. After which, ticks and their hosts were screened for the presence of Borrelia using PCR to amplify the flaB gene. A subset of the positive samples was confirmed with bidirectional sequencing. RESULTS In total 53 (21.2%) white-tailed deer, ten (6%) canines, and 583 (27.5%) Ixodid ticks (252 Ixodes scapularis, 161 A. americanum, 88 Rhipicephalus sanguineus, 50 Amblyomma maculatum, 19 Dermacentor variabilis, and 13 unidentified Amblyomma species) produced a Borrelia flaB amplicon. Of the positive ticks, 324 (22.7%) were collected from canines (151 A. americanum, 78 R. sanguineus, 43 I. scapularis, 26 A. maculatum, 18 D. variabilis, and 8 Amblyomma species) and 259 (37.2%) were collected from white-tailed deer (209 I. scapularis, 24 A. maculatum, 10 A. americanum, 10 R. sanguineus, 1 D. variabilis, and 5 Amblyomma species). None of the larvae were PCR positive. A majority of the flaB amplicons were homologous with B. lonestari sequences: 281 of the 296 sequenced ticks, 3 canines, and 27 deer. Only 22 deer, 7 canines, and 15 tick flaB amplicons (12 I. scapularis, 2 A. maculatum, and 1 Amblyomma species) were homologous with B. burgdorferi sequences. CONCLUSIONS Data from this study identified multiple Borreliae genotypes in Arkansas ticks, canines and deer including B. burgdorferi and B. lonestari; however, B. lonestari was significantly more prevalent in the tick population than B. burgdorferi. Results from this study suggest that the majority of tick-borne diseases in Arkansas are not B. burgdorferi.
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192
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193
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In Response. Am J Trop Med Hyg 2012. [PMCID: PMC3366528 DOI: 10.4269/ajtmh.2012.12-0149b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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194
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Synchronous phenology of juvenile Ixodes scapularis, vertebrate host relationships, and associated patterns of Borrelia burgdorferi ribotypes in the midwestern United States. Ticks Tick Borne Dis 2012; 3:65-74. [DOI: 10.1016/j.ttbdis.2011.11.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 11/14/2011] [Accepted: 11/19/2011] [Indexed: 11/20/2022]
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