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Dumas A, Bouchard C, Drapeau P, Lindsay LR, Ogden NH, Leighton PA. The risk of contact between visitors and Borrelia burgdorferi-infected ticks is associated with fine-scale landscape features in a southeastern Canadian nature park. BMC Public Health 2024; 24:1180. [PMID: 38671429 PMCID: PMC11055428 DOI: 10.1186/s12889-024-18673-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 04/21/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Infectious diseases are emerging across temperate regions of the world, and, for some, links have been made between landscapes and emergence dynamics. For tick-borne diseases, public parks may be important exposure sites for people living in urbanized areas of North America and Europe. In most cases, we know more about the ecological processes that determine the hazard posed by ticks as disease vectors than we do about how human population exposure varies in urban natural parks. METHODS In this study, infrared counters were used to monitor visitor use of a public natural park in southern Quebec, Canada. A risk index representing the probability of encounters between humans and infected vectors was constructed. This was done by combining the intensity of visitor trail use and the density of infected nymphs obtained from field surveillance. Patterns of risk were examined using spatial cluster analysis. Digital forest data and park infrastructure data were then integrated using spatially explicit models to test whether encounter risk levels and its components vary with forest fragmentation indicators and proximity to park infrastructure. RESULTS Results suggest that, even at a very fine scales, certain landscape features and infrastructure can be predictors of risk levels. Both visitors and Borrelia burgdorferi-infected ticks concentrated in areas where forest cover was dominant, so there was a positive association between forest cover and the risk index. However, there were no associations between indicators of forest fragmentation and risk levels. Some high-risk clusters contributed disproportionately to the risk distribution in the park relative to their size. There were also two high-risk periods, one in early summer coinciding with peak nymphal activity, and one in early fall when park visitation was highest. CONCLUSIONS Here, we demonstrate the importance of integrating indicators of human behaviour visitation with tick distribution data to characterize risk patterns for tick-borne diseases in public natural areas. Indeed, understanding the environmental determinants of human-tick interactions will allow organisations to deploy more effective risk reduction interventions targeted at key locations and times, and improve the management of public health risks associated with tick-borne diseases in public spaces.
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Affiliation(s)
- Ariane Dumas
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada.
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada.
| | - Catherine Bouchard
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Saint-Hyacinthe, QC, Canada
| | - Pierre Drapeau
- Department of Biological Sciences, Centre for Forest Research, Université du Québec À Montréal, Montreal, QC, Canada
| | - L Robbin Lindsay
- One Health Division, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Nicholas H Ogden
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Saint-Hyacinthe, QC, Canada
| | - Patrick A Leighton
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada
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Yasobant S, Lekha KS, Saxena D. Risk Assessment Tools from the One Health Perspective: A Narrative Review. Risk Manag Healthc Policy 2024; 17:955-972. [PMID: 38645899 PMCID: PMC11032120 DOI: 10.2147/rmhp.s436385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 04/10/2024] [Indexed: 04/23/2024] Open
Abstract
Background 61% of the infections around the world that have emerged to date are zoonotic. Evidence warns that the threat posed by zoonoses is on the rise, and the risk of a new pandemic is higher now than ever. Early identification of risk, populations at risk, and risk of transmission are essential steps towards a prevention, preparation and response to outbreaks. This review aims to look at the tools available for identifying and estimating risks and threats from one health perspective and finally propose a list of indicators which could assess the risk of transmission of disease at the humans, animals and the environment intersection. Methods The databases like PubMed, google scholar, Embase and Scopus were used to extract the relevant articles. A search was carried out using a keyword. A total of 1311 articles were listed initially after the search and reviewed. Out of 1311, only 26 tools which assessed the risk of diseases mainly infectious or were relevant to risk of transmission of any infectious diseases were included in the review. Results The tools included in this review involve risk assessment at the environmental, animal and human dimensions. The tools are used to evaluate the contamination of the environment due to chemicals or toxins or the risk of transmission of infection due to environmental factors like air contamination, to identify the animal diseases like bovine respiratory disease and foot and mouth disease and to estimate the human health risk at the community or individual levels. Conclusion Risk assessment tools are an essential part of the prevention of pandemics. These tools are helpful in assessing the risk of transmission of infections either from human to human, between human and animals, between animals and animals and so on. Thus this review gives us an insight into the existing risk assessment tools and the need for a One Health risk assessment tools to prevent outbreaks in future. It also provides a list of factors that can be included in a one health risk assessment tool.
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Affiliation(s)
- Sandul Yasobant
- Centre for One Health Education, Research & Development (COHERD), Indian Institute of Public Health Gandhinagar (IIPHG), Gandhinagar, Gujarat, India
- School of Epidemiology & Public Health, Datta Meghe Institute of Medical Sciences (DMIMS), Wardha, MH, India
- Global Health, Institute for Hygiene & Public Health, University Hospital Bonn, Bonn, Germany
| | - K Shruti Lekha
- Centre for One Health Education, Research & Development (COHERD), Indian Institute of Public Health Gandhinagar (IIPHG), Gandhinagar, Gujarat, India
| | - Deepak Saxena
- Centre for One Health Education, Research & Development (COHERD), Indian Institute of Public Health Gandhinagar (IIPHG), Gandhinagar, Gujarat, India
- School of Epidemiology & Public Health, Datta Meghe Institute of Medical Sciences (DMIMS), Wardha, MH, India
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McBride SE, Lieberthal BA, Buttke DE, Cronk BD, De Urioste-Stone SM, Goodman LB, Guarnieri LD, Rounsville TF, Gardner AM. Patterns and Ecological Mechanisms of Tick-Borne Disease Exposure Risk in Acadia National Park, Mount Desert Island, Maine, United States. JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:62-72. [PMID: 36271802 DOI: 10.1093/jme/tjac152] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Indexed: 06/16/2023]
Abstract
National parks are unique and significant vector-borne pathogen transmission settings, engaging over 300 million people in outdoor recreation per year. In this study, we integrated vector surveys and ecological habitat feature data in spatial models to characterize tick-borne disease exposure risk in Acadia National Park (ANP), Maine. To determine the broad-scale patterns of blacklegged tick Ixodes scapularis Say (Acari: Ixodidae) densities in ANP, we conducted host-seeking tick collections at 114 sites across the park over two years. Using these tick survey data and geospatial landscape feature data (i.e., land cover, elevation, forest patch size, and aspect) we developed a random forest model of nymphal tick density. We found that host-seeking tick density varies significantly across the park and is particularly high in areas characterized by deciduous forest cover and relatively low elevation. To explore potential fine-scale ecological drivers of tick density spatial patterns, we quantified microclimate conditions, host activity, and vegetation characteristics at a subset of 19 sites. We identified significant differences in microclimate conditions but not host activity or vegetation metrics across broad-scale landscape feature classes. Mean temperature and mean humidity were correlated to nymphal densities and therefore may provide a mechanistic link between landscape features and blacklegged tick densities. Finally, we detected multiple tick-borne pathogens in both ticks and small mammals sampled in ANP, including Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum. Our findings demonstrate the value of using ecological metrics to estimate vector-borne disease exposure risk and provide insight into habitat characteristics that may drive tick-borne disease exposure risk.
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Affiliation(s)
- Sara E McBride
- School of Biology and Ecology, University of Maine, 5722 Deering Hall, Orono, ME 04469, USA
| | - Brandon A Lieberthal
- School of Biology and Ecology, University of Maine, 5722 Deering Hall, Orono, ME 04469, USA
| | - Danielle E Buttke
- National Park Service, 1201 Oakridge Drive, Fort Collins, CO 80525, USA
| | - Brittany D Cronk
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | | | - Laura B Goodman
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Lucy D Guarnieri
- School of Biology and Ecology, University of Maine, 5722 Deering Hall, Orono, ME 04469, USA
| | - Thomas F Rounsville
- Pest Management Unit, University of Maine Cooperative Extension Diagnostic and Research Laboratory, 17 Godfrey Drive, Orono, ME 04473, USA
| | - Allison M Gardner
- School of Biology and Ecology, University of Maine, 5722 Deering Hall, Orono, ME 04469, USA
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Forest-Bérard K, Ripoche M, Irace-Cima A, Thivierge K, Adam-Poupart A. More than ticking boxes: Training Lyme disease education ambassadors to meet outreach and surveillance challenges in Québec, Canada. PLoS One 2021; 16:e0258466. [PMID: 34637465 PMCID: PMC8509862 DOI: 10.1371/journal.pone.0258466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 09/28/2021] [Indexed: 11/18/2022] Open
Abstract
Lyme disease (LD) is an emerging public health threat in Canada, associated with the northward range expansion of the black-legged tick (Ixodes scapularis). To address this, public health authorities have been carrying out surveillance activities and awareness campaigns targeting vulnerable populations such as outdoor workers. Implementing these measures is time-consuming and resource-intensive, prompting the assessment of alternatives. Our goal was to evaluate the feasibility and implementation of a training-of-trainers-inspired approach in raising awareness about LD risk and prevention among workers and general population, as well as to evaluate its potential to contribute to provincial LD surveillance efforts. We trained a group of workers from publicly-accessible outdoor parks of the province of Québec to become "LD education ambassadors". Ambassadors were trained to raise tick and LD awareness, share information on preventive measures in their respective communities, and lead tick sampling activities using a standardised protocol similar to that used by Public Health authorities. Ambassador-led outreach activities, public reach, sampling activities and collected ticks were documented, as well as ambassadors' satisfaction with the training using forms and semi-structured interviews. In total, 18 ambassadors from 12 organizations were trained. Between June and September 2019, they led 28 independent outreach activities, reaching over 1 860 individuals (from occupational and general public settings) in seven public health units. Ambassadors led 28 tick samplings, together collecting 11 I. scapularis ticks. This study suggests that an adapted training-of-trainers is a feasible approach to raising tick and LD risk awareness among Québec outdoor workers and public. Trained ambassadors have the potential of reaching a large portion of the population visiting or working in outdoor parks while also providing much-needed outreach regarding risk and prevention. Pushing this concept further to include other types of workers and jurisdictions may contribute to national LD surveillance efforts.
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Affiliation(s)
- Karl Forest-Bérard
- Direction des risques biologiques et de la santé au travail, Institut national de santé publique du Québec (INSPQ), Montréal, Québec, Canada
| | - Marion Ripoche
- Direction des risques biologiques et de la santé au travail, Institut national de santé publique du Québec (INSPQ), Montréal, Québec, Canada
| | - Alejandra Irace-Cima
- Direction des risques biologiques et de la santé au travail, Institut national de santé publique du Québec (INSPQ), Montréal, Québec, Canada
- École de Santé Publique de l’Université de Montréal (ESPUM), Université de Montréal, Montréal, Québec, Canada
| | - Karine Thivierge
- Laboratoire de santé publique du Québec (LSPQ), Institut national de santé publique du Québec (INSPQ), Montréal, Québec, Canada
- Institute of Parasitology, Faculty of Agricultural and Environmental Sciences, McGill University, Montréal, Québec, Canada
- Groupe de recherche en épidémiologie des zoonoses et santé publique (GREZOSP), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Ariane Adam-Poupart
- Direction des risques biologiques et de la santé au travail, Institut national de santé publique du Québec (INSPQ), Montréal, Québec, Canada
- École de Santé Publique de l’Université de Montréal (ESPUM), Université de Montréal, Montréal, Québec, Canada
- Groupe de recherche en épidémiologie des zoonoses et santé publique (GREZOSP), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
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Dumas A, Bouchard C, Lindsay LR, Ogden NH, Leighton PA. Fine-scale determinants of the spatiotemporal distribution of Ixodes scapularis in Quebec (Canada). Ticks Tick Borne Dis 2021; 13:101833. [PMID: 34600416 DOI: 10.1016/j.ttbdis.2021.101833] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/16/2021] [Accepted: 09/03/2021] [Indexed: 10/20/2022]
Abstract
The tick vector of Lyme disease, Ixodes scapularis, is currently expanding its geographical distribution northward into southern Canada driving emergence of Lyme disease in the region. Despite large-scale studies that attributed different factors such as climate change and changes in land use to the geographical expansion of the tick, a comprehensive understanding of local patterns of tick abundance is still lacking in that region. Using a newly endemic periurban nature park located in Quebec (Canada) as a model, we explored intra-habitat patterns in tick distribution and their relationship with biotic and abiotic factors. We verified the hypotheses that (1) there is spatial heterogeneity in tick densities at the scale of the park and (2) these patterns can be explained by host availability, habitat characteristics and microclimatic conditions. During tick activity season in three consecutive years, tick, deer, rodent and bird abundance, as well as habitat characteristics and microclimatic conditions, were estimated at thirty-two sites. Patterns of tick distribution and abundance were investigated by spatial analysis. Generalised additive mixed models were constructed for each developmental stage of the tick and the relative importance of significant drivers on tick abundance were derived from final models. We found fine-scale spatial heterogeneity in densities of all tick stages across the park, with interannual variability in the location of hotspots. For all stages, the local density was related to the density of the previous stage in the previous season, in keeping with the tick's life cycle. Adult tick density was highest where drainage was moderate (neither waterlogged nor dry). Microclimatic conditions influenced the densities of immature ticks, through the effects of weather at the time of tick sampling (ambient temperature and relative humidity) and of the seasonal microclimate at the site level (degree-days and number of tick adverse moisture events). Seasonal phenology patterns were generally consistent with expected curves for the region, with exceptions in some years that may be attributable to founder events. This study highlights fine scale patterns of tick population dynamics thus providing fundamental knowledge in Lyme disease ecology and information applicable to the development of well-targeted prevention and control strategies for public natural areas affected by this growing problem in southern Canada.
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Affiliation(s)
- Ariane Dumas
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Québec, Canada; Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
| | - Catherine Bouchard
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Québec, Canada; Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Saint-Hyacinthe, Québec, Canada
| | - L Robbin Lindsay
- Zoonotic Diseases and Special Pathogens Division, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Nicholas H Ogden
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Québec, Canada; Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Saint-Hyacinthe, Québec, Canada
| | - Patrick A Leighton
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Québec, Canada; Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Québec, Canada
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Anderson KR, Blekking J, Omodior O. Tick trails: the role of online recreational trail reviews in identifying risk factors and behavioral recommendations associated with tick encounters in Indiana. BMC Public Health 2021; 21:908. [PMID: 33980203 PMCID: PMC8117608 DOI: 10.1186/s12889-021-10940-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/22/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Recreational trails abound across the United States and represent high risk areas for tick exposure. Although online reviews represent a rich source of user information, they have rarely been used in determining the risk of tick exposure during recreational trail use. Based on online user reviews and comments, the purpose of this study was to determine risk factors and behavioral recommendations associated with tick encounters (Tick Presence) on recreational trails in the state of Indiana, U.S. METHODS We reviewed 26,016 user comments left on AllTrails.com for 697 Indiana trails. Reviews were evaluated to determine Tick Presence/Absence, the total number of Tick Presence Reviews per trail, and multiple trail and user behavioral characteristics. We used hot spot (Getis-Ord Gi*) analysis to test the hypothesis of whether there are clusters in the number of Tick Presence Reviews. Pearson chi-square tests of independence evaluated whether tick presence was associated with several trail characteristics. Finally, negative binomial regression evaluated the strength of the association between the number of Tick Presence Reviews and several trail characteristics. RESULTS Tick Presence was recorded at 10% (n = 65) of trails and occurred most frequently in May. Hot spot analysis revealed statistically significant clusters of Tick Presence Reviews on trails in the Southern Indiana State Region. Results of χ2 tests indicated significant associations between Tick Presence Reviews and (a) State Region and (b) Land Management Type; Mann-Whitney U tests detected significant differences in Tick Presence Reviews based on Trail Length and Elevation Gain. Subsequent results of a negative binomial regression model indicated that Southern Indiana State Region, Federal and Private Land Management Type, and Elevation Gain were factors significantly associated with Tick Presence Reviews. Content of user reviews indicated several behaviors employed to prevent tick encounters, particularly Repellent Application and Recreational Deterrence; 25% included a behavior Recommendation to others. CONCLUSIONS Online, user-generated trail reviews have the potential to serve as rich data sources for identifying recreational trails, where 1) the risk of tick exposure is great, 2) more robust active tick and tick-borne pathogen surveillance may be warranted, and 3) tailored prevention interventions are needed.
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Affiliation(s)
- Kristina R Anderson
- Department of Health & Wellness Design, School of Public Health, Indiana University Bloomington, 1025 E. 7th Street, IN, 47405, Bloomington, USA.
| | - Jordan Blekking
- Department of Geography, College of Arts & Sciences, Indiana University Bloomington, 701 E. Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Oghenekaro Omodior
- Department of Health & Wellness Design, School of Public Health, Indiana University Bloomington, 1025 E. 7th Street, IN, 47405, Bloomington, USA
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Burns JE, Metzger ME, Messenger S, Fritz CL, Vilcins IME, Enge B, Bronson LR, Kramer VL, Hu R. Novel Focus of Sin Nombre Virus in Peromyscus eremicus Mice, Death Valley National Park, California, USA. Emerg Infect Dis 2019; 24:1112-1115. [PMID: 29774841 PMCID: PMC6004862 DOI: 10.3201/eid2406.180089] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The deer mouse (Peromyscusmaniculatus) is the primary reservoir for Sin Nombre virus (SNV) in the western United States. Rodent surveillance for hantavirus in Death Valley National Park, California, USA, revealed cactus mice (P. eremicus) as a possible focal reservoir for SNV in this location. We identified SNV antibodies in 40% of cactus mice sampled.
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Curtis-Robles R, Meyers AC, Auckland LD, Zecca IB, Skiles R, Hamer SA. Parasitic interactions among Trypanosoma cruzi, triatomine vectors, domestic animals, and wildlife in Big Bend National Park along the Texas-Mexico border. Acta Trop 2018; 188:225-233. [PMID: 30205082 DOI: 10.1016/j.actatropica.2018.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/03/2018] [Accepted: 09/03/2018] [Indexed: 12/17/2022]
Abstract
National parks attract millions of visitors each year. Park visitors, employees, and pets are at risk of infection with various zoonotic pathogens, including Trypanosoma cruzi, causative agent of Chagas disease. Big Bend National Park is located along the Texas-Mexico border in a region with endemic triatomine insects- vectors of T. cruzi- yet the degree to which the parasite is transmitted in this region is unknown. We collected triatomines for T. cruzi detection and discrete typing unit (DTU) determination, and conducted blood meal analyses to determine recent hosts. As an index of domestic/peridomestic transmission, we tested residential dogs in the Park for exposure to T. cruzi. From 2015 to 2017, 461 triatomines of three species-Triatoma rubida, Triatoma gerstaeckeri, and Triatoma protracta-were collected in and around the Park. Adult triatomine encounters peaked in June of each year (52.8% of collections). We detected an overall infection prevalence of 23.1% in adult triatomines (n = 320) and 4.2% in nymph triatomines (n = 24). DTU TcI was the only T. cruzi strain detected. Of 89 triatomines subjected to blood meal analyses, vertebrate host DNA was successfully amplified from 42 (47.2%); blood meal sources included humans, domestic animals, and avian and mammalian wildlife species. Tested dogs were considered positive if reactive on at least two independent serologic assays; we found 28.6% seroprevalence in 14 dogs. These findings reveal interactions between infected triatomines, humans, dogs, and wildlife in and around Big Bend National Park, with potential risk of human disease.
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Affiliation(s)
- Rachel Curtis-Robles
- College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843, USA.
| | - Alyssa C Meyers
- College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843, USA.
| | - Lisa D Auckland
- College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843, USA.
| | - Italo B Zecca
- College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843, USA.
| | - Raymond Skiles
- Big Bend National Park, P.O. Box 129, Big Bend National Park, TX 79834, USA.
| | - Sarah A Hamer
- College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX, 77843, USA.
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Ripoche M, Lindsay LR, Ludwig A, Ogden NH, Thivierge K, Leighton PA. Multi-Scale Clustering of Lyme Disease Risk at the Expanding Leading Edge of the Range of Ixodes scapularis in Canada. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:E603. [PMID: 29584627 PMCID: PMC5923645 DOI: 10.3390/ijerph15040603] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/17/2018] [Accepted: 03/21/2018] [Indexed: 11/29/2022]
Abstract
Since its detection in Canada in the early 1990s, Ixodes scapularis, the primary tick vector of Lyme disease in eastern North America, has continued to expand northward. Estimates of the tick's broad-scale distribution are useful for tracking the extent of the Lyme disease risk zone; however, tick distribution may vary widely within this zone. Here, we investigated I. scapularis nymph distribution at three spatial scales across the Lyme disease emergence zone in southern Quebec, Canada. We collected ticks and compared the nymph densities among different woodlands and different plots and transects within the same woodland. Hot spot analysis highlighted significant nymph clustering at each spatial scale. In regression models, nymph abundance was associated with litter depth, humidity, and elevation, which contribute to a suitable habitat for ticks, but also with the distance from the trail and the type of trail, which could be linked to host distribution and human disturbance. Accounting for this heterogeneous nymph distribution at a fine spatial scale could help improve Lyme disease management strategies but also help people to understand the risk variation around them and to adopt appropriate behaviors, such as staying on the trail in infested parks to limit their exposure to the vector and associated pathogens.
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Affiliation(s)
- Marion Ripoche
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montréal, 3200 Rue Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada.
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, University of Montréal, 3200 Rue Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada.
| | - Leslie Robbin Lindsay
- Zoonoses and Special Pathogens Division, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3T 2N2, Canada.
| | - Antoinette Ludwig
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, University of Montréal, 3200 Rue Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada.
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, 3200 Rue Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada.
| | - Nicholas H Ogden
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, University of Montréal, 3200 Rue Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada.
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, 3200 Rue Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada.
| | - Karine Thivierge
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, University of Montréal, 3200 Rue Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada.
- Quebec Public Health Laboratory, Quebec Public Health Institute (INSPQ), 20045 Chemin Sainte-Marie, Sainte-Anne-de-Bellevue, QC H9X 3R5, Canada.
- Institute of Parasitology, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.
| | - Patrick A Leighton
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montréal, 3200 Rue Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada.
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculty of Veterinary Medicine, University of Montréal, 3200 Rue Sicotte, Saint-Hyacinthe, QC J2S 2M2, Canada.
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Johnson TL, Graham CB, Boegler KA, Cherry CC, Maes SE, Pilgard MA, Hojgaard A, Buttke DE, Eisen RJ. Prevalence and Diversity of Tick-Borne Pathogens in Nymphal Ixodes scapularis (Acari: Ixodidae) in Eastern National Parks. JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:742-751. [PMID: 28028138 PMCID: PMC5657145 DOI: 10.1093/jme/tjw213] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Indexed: 05/08/2023]
Abstract
Tick-borne pathogens transmitted by Ixodes scapularis Say (Acari: Ixodidae), also known as the deer tick or blacklegged tick, are increasing in incidence and geographic distribution in the United States. We examined the risk of tick-borne disease exposure in 9 national parks across six Northeastern and Mid-Atlantic States and the District of Columbia in 2014 and 2015. To assess the recreational risk to park visitors, we sampled for ticks along frequently used trails and calculated the density of I. scapularis nymphs (DON) and the density of infected nymphs (DIN). We determined the nymphal infection prevalence of I. scapularis with a suite of tick-borne pathogens including Borrelia burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum, and Babesia microti. Ixodes scapularis nymphs were found in all national park units; DON ranged from 0.40 to 13.73 nymphs per 100 m2. Borrelia burgdorferi, the causative agent of Lyme disease, was found at all sites where I. scapularis was documented; DIN with B. burgdorferi ranged from 0.06 to 5.71 nymphs per 100 m2. Borrelia miyamotoi and A. phagocytophilum were documented at 60% and 70% of the parks, respectively, while Ba. microti occurred at just 20% of the parks. Ixodes scapularis is well established across much of the Northeastern and Mid-Atlantic States, and our results are generally consistent with previous studies conducted near the areas we sampled. Newly established I. scapularis populations were documented in two locations: Washington, D.C. (Rock Creek Park) and Greene County, Virginia (Shenandoah National Park). This research demonstrates the potential risk of tick-borne pathogen exposure in national parks and can be used to educate park visitors about the importance of preventative actions to minimize tick exposure.
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Affiliation(s)
- Tammi L Johnson
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Rd., Fort Collins, CO 80521 (; ; ; ; ; ; )
| | - Christine B Graham
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Rd., Fort Collins, CO 80521 (; ; ; ; ; ; )
| | - Karen A Boegler
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Rd., Fort Collins, CO 80521 (; ; ; ; ; ; )
| | - Cara C Cherry
- Biological Resources Division, Wildlife Health Branch and Office of Public Health, National Park Service, 1201 Oakridge Dr., Suite 200, Fort Collins, CO 80525 ( ; )
- Epidemic Intelligence Service, Division of Scientific Education and Professional Development, Center for Surveillance, Epidemiology, and Laboratory Services
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd., Atlanta, GA 30329-4027
| | - Sarah E Maes
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Rd., Fort Collins, CO 80521 (; ; ; ; ; ; )
| | - Mark A Pilgard
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Rd., Fort Collins, CO 80521 (; ; ; ; ; ; )
| | - Andrias Hojgaard
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Rd., Fort Collins, CO 80521 (; ; ; ; ; ; )
| | - Danielle E Buttke
- Biological Resources Division, Wildlife Health Branch and Office of Public Health, National Park Service, 1201 Oakridge Dr., Suite 200, Fort Collins, CO 80525 (; )
| | - Rebecca J Eisen
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Rd., Fort Collins, CO 80521 (; ; ; ; ; ; )
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11
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Sayler K, Rowland J, Boyce C, Weeks E. Borrelia burgdorferi DNA absent, multiple Rickettsia spp. DNA present in ticks collected from a teaching forest in North Central Florida. Ticks Tick Borne Dis 2016; 8:53-59. [PMID: 27720381 DOI: 10.1016/j.ttbdis.2016.09.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/22/2016] [Accepted: 09/23/2016] [Indexed: 01/10/2023]
Abstract
Tick-borne diseases are an emerging public health threat in the United States. In Florida, there has been public attention directed towards the possibility of locally acquired Borrelia burgdorferi sensu stricto, the causative agent of Lyme disease, in association with the lone star tick. The aim of this study was to determine the prevalence of ticks and the pathogens they carry and potentially transmit, such as B. burgdorferi, in a highly utilized teaching and research forest in North Central Florida. Ticks were collected by dragging and flagging methods over a four month period in early 2014, identified, and tested by PCR for multiple pathogens including Anaplasma, Borrelia, Rickettsia, and Ehrlichia species. During the study period the following ticks were collected: 2506 (96.5%) Amblyomma americanum L., 64 (2.5%) Ixodes scapularis Say, 19 (0.7%) Dermacentor variabilis Say, and 5 (0.2%) Ixodes affinis Neuman. Neither Borrelia spp. (0/846) nor Anaplasma spp. (0/69; Ixodes spp. only) were detected by PCR in any of the ticks tested. However, Rickettsia DNA was present in 53.7% (86/160), 62.5% (40/64), 60.0% (3/5) and 31.6% (6/19) of A. americanum, I. scapularis, I. affinis and D. variabilis, respectively. Furthermore, E. chaffeensis and E. ewingii DNA were detected in 1.3% and 4.4% of adult A. americanum specimens tested, respectively. Although receiving an A. americanum bite is likely in wooded areas in North Central Florida due to the abundance of this tick, the risk of contracting a tick-borne pathogen in this specific area during the spring season appears to be low. The potential for pathogen prevalence to be highly variable exists, even within a single geographical site and longitudinal studies are needed to assess how tick-borne pathogen prevalence is changing over time in North Central Florida.
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Affiliation(s)
- Katherine Sayler
- College of Veterinary Medicine, 2015 SW 16th Avenue, Veterinary Academic Building, University of Florida, Gainesville, FL, 32611, USA
| | - Jessica Rowland
- Department of Entomology and Nematology, PO Box 110620, 1881 Natural Area Drive, University of Florida, Gainesville, FL, 32611, USA; Emerging Pathogens Institute, 2055 Mowry Rd, University of Florida, Gainesville, FL, 32611, USA
| | - Carisa Boyce
- College of Veterinary Medicine, 2015 SW 16th Avenue, Veterinary Academic Building, University of Florida, Gainesville, FL, 32611, USA; Department of Entomology and Nematology, PO Box 110620, 1881 Natural Area Drive, University of Florida, Gainesville, FL, 32611, USA
| | - Emma Weeks
- Department of Entomology and Nematology, PO Box 110620, 1881 Natural Area Drive, University of Florida, Gainesville, FL, 32611, USA.
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Wallace JW, Nicholson WL, Perniciaro JL, Vaughn MF, Funkhouser S, Juliano JJ, Lee S, Kakumanu ML, Ponnusamy L, Apperson CS, Meshnick SR. Incident Tick-Borne Infections in a Cohort of North Carolina Outdoor Workers. Vector Borne Zoonotic Dis 2016; 16:302-8. [PMID: 27008102 DOI: 10.1089/vbz.2015.1887] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tick-borne diseases cause substantial morbidity throughout the United States, and North Carolina has a high incidence of spotted fever rickettsioses and ehrlichiosis, with sporadic cases of Lyme disease. The occupational risk of tick-borne infections among outdoor workers is high, particularly those working on publicly managed lands. This study identified incident tick-borne infections and examined seroconversion risk factors among a cohort of North Carolina outdoor workers. Workers from the North Carolina State Divisions of Forestry, Parks and Recreation, and Wildlife (n = 159) were followed for 2 years in a randomized controlled trial evaluating the effectiveness of long-lasting permethrin-impregnated clothing. Antibody titers against Rickettsia parkeri, Rickettsia rickettsii, "Rickettsia amblyommii," and Ehrlichia chaffeensis were measured at baseline (n = 130), after 1 year (n = 82), and after 2 years (n = 73). Titers against Borrelia burgdorferi were measured at baseline and after 2 years (n = 90). Baseline seroprevalence, defined as indirect immunofluorescence antibody titers of 1/128 or greater, was R. parkeri (24%), R. rickettsii (19%), "R. amblyommii" (12%), and E. chaffeensis (4%). Incident infection was defined as a fourfold increase in titer over a 1-year period. There were 40 total seroconversions to at least one pathogen, including R. parkeri (n = 19), "R. amblyommii" (n = 14), R. rickettsii (n = 9), and E. chaffeensis (n = 8). There were no subjects whose sera were reactive to B. burgdorferi C6 antigen. Thirty-eight of the 40 incident infections were subclinical. The overall risk of infection by any pathogen during the study period was 0.26, and the risk among the NC Division of Forest Resources workers was 1.73 times that of workers in other divisions (95% confidence interval [CI]: 1.02, 2.92). The risk of infection was lower in subjects wearing permethrin-impregnated clothing, but not significantly (risk ratio = 0.81; 95% CI: 0.47, 1.39). In summary, outdoor workers in North Carolina are at high risk of incident tick-borne infections, most of which appear to be asymptomatic.
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Affiliation(s)
- John W Wallace
- 1 Department of Epidemiology, University of North Carolina, Gillings School of Global Public Health , Chapel Hill, North Carolina
| | - William L Nicholson
- 2 Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention , Atlanta, Georgia
| | - Jamie L Perniciaro
- 2 Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention , Atlanta, Georgia
| | - Meagan F Vaughn
- 1 Department of Epidemiology, University of North Carolina, Gillings School of Global Public Health , Chapel Hill, North Carolina
| | - Sheana Funkhouser
- 1 Department of Epidemiology, University of North Carolina, Gillings School of Global Public Health , Chapel Hill, North Carolina
| | - Jonathan J Juliano
- 3 Division of Infectious Diseases, University of North Carolina School of Medicine , Chapel Hill, North Carolina
| | - Sangmi Lee
- 4 Department of Entomology, North Carolina State University , Raleigh, North Carolina
| | - Madhavi L Kakumanu
- 4 Department of Entomology, North Carolina State University , Raleigh, North Carolina
| | - Loganathan Ponnusamy
- 4 Department of Entomology, North Carolina State University , Raleigh, North Carolina
| | - Charles S Apperson
- 4 Department of Entomology, North Carolina State University , Raleigh, North Carolina
| | - Steven R Meshnick
- 1 Department of Epidemiology, University of North Carolina, Gillings School of Global Public Health , Chapel Hill, North Carolina
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Marcantonio M, Rizzoli A, Metz M, Rosà R, Marini G, Chadwick E, Neteler M. Identifying the environmental conditions favouring West Nile Virus outbreaks in Europe. PLoS One 2015; 10:e0121158. [PMID: 25803814 PMCID: PMC4372576 DOI: 10.1371/journal.pone.0121158] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/28/2015] [Indexed: 11/29/2022] Open
Abstract
West Nile Virus (WNV) is a globally important mosquito borne virus, with significant implications for human and animal health. The emergence and spread of new lineages, and increased pathogenicity, is the cause of escalating public health concern. Pinpointing the environmental conditions that favour WNV circulation and transmission to humans is challenging, due both to the complexity of its biological cycle, and the under-diagnosis and reporting of epidemiological data. Here, we used remote sensing and GIS to enable collation of multiple types of environmental data over a continental spatial scale, in order to model annual West Nile Fever (WNF) incidence across Europe and neighbouring countries. Multi-model selection and inference were used to gain a consensus from multiple linear mixed models. Climate and landscape were key predictors of WNF outbreaks (specifically, high precipitation in late winter/early spring, high summer temperatures, summer drought, occurrence of irrigated croplands and highly fragmented forests). Identification of the environmental conditions associated with WNF outbreaks is key to enabling public health bodies to properly focus surveillance and mitigation of West Nile virus impact, but more work needs to be done to enable accurate predictions of WNF risk.
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Affiliation(s)
- Matteo Marcantonio
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
- * E-mail:
| | - Annapaola Rizzoli
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Markus Metz
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Roberto Rosà
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Giovanni Marini
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Elizabeth Chadwick
- School of Bioscience, Cardiff University, Cardiff, Wales, United Kingdom
| | - Markus Neteler
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
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Sedda L, Morley DW, Braks MAH, De Simone L, Benz D, Rogers DJ. Risk assessment of vector-borne diseases for public health governance. Public Health 2014; 128:1049-58. [PMID: 25443135 DOI: 10.1016/j.puhe.2014.08.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 08/26/2014] [Accepted: 08/28/2014] [Indexed: 01/13/2023]
Abstract
OBJECTIVES In the context of public health, risk governance (or risk analysis) is a framework for the assessment and subsequent management and/or control of the danger posed by an identified disease threat. Generic frameworks in which to carry out risk assessment have been developed by various agencies. These include monitoring, data collection, statistical analysis and dissemination. Due to the inherent complexity of disease systems, however, the generic approach must be modified for individual, disease-specific risk assessment frameworks. STUDY DESIGN The analysis was based on the review of the current risk assessments of vector-borne diseases adopted by the main Public Health organisations (OIE, WHO, ECDC, FAO, CDC etc…). METHODS Literature, legislation and statistical assessment of the risk analysis frameworks. RESULTS This review outlines the need for the development of a general public health risk assessment method for vector-borne diseases, in order to guarantee that sufficient information is gathered to apply robust models of risk assessment. Stochastic (especially spatial) methods, often in Bayesian frameworks are now gaining prominence in standard risk assessment procedures because of their ability to assess accurately model uncertainties. CONCLUSIONS Risk assessment needs to be addressed quantitatively wherever possible, and submitted with its quality assessment in order to enable successful public health measures to be adopted. In terms of current practice, often a series of different models and analyses are applied to the same problem, with results and outcomes that are difficult to compare because of the unknown model and data uncertainties. Therefore, the risk assessment areas in need of further research are identified in this article.
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Affiliation(s)
- L Sedda
- Department of Zoology, University of Oxford, South Parks Road, OX1 3PS Oxford, United Kingdom.
| | - D W Morley
- Department of Zoology, University of Oxford, South Parks Road, OX1 3PS Oxford, United Kingdom
| | - M A H Braks
- Centre for Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands
| | - L De Simone
- Surveillance and Response Support Unit (SRS), European Centre for Disease Prevention and Control (ECDC), Tomtebodavägen 11 A, 171 83 Stockholm, Sweden
| | - D Benz
- Department of Zoology, University of Oxford, South Parks Road, OX1 3PS Oxford, United Kingdom
| | - D J Rogers
- Department of Zoology, University of Oxford, South Parks Road, OX1 3PS Oxford, United Kingdom
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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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