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Savage JDT, Moore CM. How do host population dynamics impact Lyme disease risk dynamics in theoretical models? PLoS One 2024; 19:e0302874. [PMID: 38722910 PMCID: PMC11081252 DOI: 10.1371/journal.pone.0302874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 04/15/2024] [Indexed: 05/13/2024] Open
Abstract
Lyme disease is the most common wildlife-to-human transmitted disease reported in North America. The study of this disease requires an understanding of the ecology of the complex communities of ticks and host species involved in harboring and transmitting this disease. Much of the ecology of this system is well understood, such as the life cycle of ticks, and how hosts are able to support tick populations and serve as disease reservoirs, but there is much to be explored about how the population dynamics of different host species and communities impact disease risk to humans. In this study, we construct a stage-structured, empirically-informed model with host dynamics to investigate how host population dynamics can affect disease risk to humans. The model describes a tick population and a simplified community of three host species, where primary nymph host populations are made to fluctuate on an annual basis, as commonly observed in host populations. We tested the model under different environmental conditions to examine the effect of environment on the interactions of host dynamics and disease risk. Results show that allowing for host dynamics in the model reduces mean nymphal infection prevalence and increases the maximum annual prevalence of nymphal infection and the density of infected nymphs. Effects of host dynamics on disease measures of nymphal infection prevalence were nonlinear and patterns in the effect of dynamics on amplitude in nymphal infection prevalence varied across environmental conditions. These results highlight the importance of further study of the effect of community dynamics on disease risk. This will involve the construction of further theoretical models and collection of robust field data to inform these models. With a more complete understanding of disease dynamics we can begin to better determine how to predict and manage disease risk using these models.
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Affiliation(s)
- Joseph D. T. Savage
- Biology Department, Colby College, Waterville, Maine, United States of America
- Department of Geography, Graduate Program in Ecology, Evolution, Environment, and Society, Dartmouth College, Hanover, New Hampshire, United States of America
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Habib J, Zenner L, Garel M, Mercier A, Poirel MT, Itty C, Appolinaire J, Amblard T, Benedetti P, Sanchis F, Benabed S, Abi Rizk G, Gibert P, Bourgoin G. Prevalence of tick-borne pathogens in ticks collected from the wild mountain ungulates mouflon and chamois in 4 regions of France. Parasite 2024; 31:21. [PMID: 38602373 PMCID: PMC11008225 DOI: 10.1051/parasite/2024011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 02/09/2024] [Indexed: 04/12/2024] Open
Abstract
Ticks are major vectors of various pathogens of health importance, such as bacteria, viruses and parasites. The problems associated with ticks and vector-borne pathogens are increasing in mountain areas, particularly in connection with global climate change. We collected ticks (n = 2,081) from chamois and mouflon in 4 mountainous areas of France. We identified 6 tick species: Ixodes ricinus, Rhipicephalus bursa, Rh. sanguineus s.l., Haemaphysalis sulcata, H. punctata and Dermacentor marginatus. We observed a strong variation in tick species composition among the study sites, linked in particular to the climate of the sites. We then analysed 791 ticks for DNA of vector-borne pathogens: Babesia/Theileria spp., Borrelia burgdorferi s.l., Anaplasma phagocytophilum, A. marginale, A. ovis, and Rickettsia of the spotted fever group (SFG). Theileria ovis was detected only in Corsica in Rh. bursa. Babesia venatorum (2 sites), Borrelia burgdorferi s.l. (B. afzelii and B. garinii; 2 sites) and Anaplasma phagocytophilum (3 sites) were detected in I. ricinus. Anaplasma ovis was detected at one site in I. ricinus and Rh. sanguineus s.l. SFG Rickettsia were detected at all the study sites: R. monacensis and R. helvetica in I. ricinus at the 3 sites where this tick is present; R. massiliae in Rh. sanguineus s.l. (1 site); and R. hoogstraalii and Candidatus R. barbariae in Rh. bursa in Corsica. These results show that there is a risk of tick-borne diseases for humans and domestic and wild animals frequenting these mountain areas.
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Affiliation(s)
- Jad Habib
- Université de Lyon, VetAgro Sup – Campus Vétérinaire de Lyon, Laboratoire de Parasitologie Vétérinaire 1 avenue Bourgelat BP 83 69280 Marcy-l’Etoile France
- Université de Lyon, Université Lyon 1, CNRS, VetAgro Sup, UMR 5558, Laboratoire de Biométrie et Biologie Évolutive 43 bd du 11 novembre 1918 69622 Villeurbanne France
- Université Libanaise, Faculté d’Agronomie et de Médecine Vétérinaire, Département de Médecine Vétérinaire 3 rue de l'université Beyrouth Lebanon
| | - Lionel Zenner
- Université de Lyon, VetAgro Sup – Campus Vétérinaire de Lyon, Laboratoire de Parasitologie Vétérinaire 1 avenue Bourgelat BP 83 69280 Marcy-l’Etoile France
- Université de Lyon, Université Lyon 1, CNRS, VetAgro Sup, UMR 5558, Laboratoire de Biométrie et Biologie Évolutive 43 bd du 11 novembre 1918 69622 Villeurbanne France
| | - Mathieu Garel
- Office Français de la Biodiversité, Service Anthropisation et Fonctionnement des Écosystèmes Terrestres 5 allée de Bethléem, Z.I. Mayencin 38610 Gières France
| | - Antoine Mercier
- Université de Lyon, VetAgro Sup – Campus Vétérinaire de Lyon, Laboratoire de Parasitologie Vétérinaire 1 avenue Bourgelat BP 83 69280 Marcy-l’Etoile France
- Université de Lyon, Université Lyon 1, CNRS, VetAgro Sup, UMR 5558, Laboratoire de Biométrie et Biologie Évolutive 43 bd du 11 novembre 1918 69622 Villeurbanne France
| | - Marie-Thérèse Poirel
- Université de Lyon, VetAgro Sup – Campus Vétérinaire de Lyon, Laboratoire de Parasitologie Vétérinaire 1 avenue Bourgelat BP 83 69280 Marcy-l’Etoile France
- Université de Lyon, Université Lyon 1, CNRS, VetAgro Sup, UMR 5558, Laboratoire de Biométrie et Biologie Évolutive 43 bd du 11 novembre 1918 69622 Villeurbanne France
| | - Christian Itty
- Office Français de la Biodiversité, Service Appui aux Acteurs et Mobilisation des Territoires, Direction Régionale Occitanie 7 rue du Four, Fagairolles 34610 Castanet-le-Haut France
| | - Joël Appolinaire
- Office Français de la Biodiversité, Service Anthropisation et Fonctionnement des Écosystèmes Terrestres 5 allée de Bethléem, Z.I. Mayencin 38610 Gières France
| | - Thibaut Amblard
- Office Français de la Biodiversité, Service Anthropisation et Fonctionnement des Écosystèmes Terrestres 5 allée de Bethléem, Z.I. Mayencin 38610 Gières France
| | - Pierre Benedetti
- Office Français de la Biodiversité, Unité Espaces Naturels de Corse Funtanella 20218 Moltifao France
| | - Frédéric Sanchis
- Office Français de la Biodiversité, Unité Espaces Naturels de Corse Funtanella 20218 Moltifao France
| | - Slimania Benabed
- Université de Lyon, VetAgro Sup – Campus Vétérinaire de Lyon, Laboratoire de Parasitologie Vétérinaire 1 avenue Bourgelat BP 83 69280 Marcy-l’Etoile France
- Université de Lyon, Université Lyon 1, CNRS, VetAgro Sup, UMR 5558, Laboratoire de Biométrie et Biologie Évolutive 43 bd du 11 novembre 1918 69622 Villeurbanne France
| | - Georges Abi Rizk
- Université Libanaise, Faculté d’Agronomie et de Médecine Vétérinaire, Département de Médecine Vétérinaire 3 rue de l'université Beyrouth Lebanon
| | - Philippe Gibert
- Office Français de la Biodiversité, Service Anthropisation et Fonctionnement des Écosystèmes Terrestres 5 allée de Bethléem, Z.I. Mayencin 38610 Gières France
| | - Gilles Bourgoin
- Université de Lyon, VetAgro Sup – Campus Vétérinaire de Lyon, Laboratoire de Parasitologie Vétérinaire 1 avenue Bourgelat BP 83 69280 Marcy-l’Etoile France
- Université de Lyon, Université Lyon 1, CNRS, VetAgro Sup, UMR 5558, Laboratoire de Biométrie et Biologie Évolutive 43 bd du 11 novembre 1918 69622 Villeurbanne France
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Ferguson LV, El Nabbout A, Adamo SA. Warming, but not infection with Borrelia burgdorferi, increases off-host winter activity in the ectoparasite, Ixodes scapularis. J Therm Biol 2024; 121:103853. [PMID: 38626664 DOI: 10.1016/j.jtherbio.2024.103853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 03/17/2024] [Indexed: 04/18/2024]
Abstract
Warming winters will change patterns of behaviour in temperate and polar arthropods, but we know little about the drivers of winter activity in animals such as ticks. Any changes in behaviour are likely to arise from a combination of both abiotic (e.g. temperature) and biotic (e.g. infection) drivers, and will have important consequences for survival and species interactions. Blacklegged ticks, Ixodes scapularis, have invaded Atlantic Canada and high proportions (30-50%) are infected with the bacteria causing Lyme disease, Borrelia burgdorferi. Infection is correlated with increased overwintering survival of adult females, and ticks are increasingly active in the winter, but it is unclear if infection is associated with activity. Further, we know little about how temperature drives the frequency of winter activity. Here, we exposed wild-caught, adult, female Ixodes scapularis ticks to three different winter temperature regimes (constant low temperatures, increased warming, and increased warming + variability) to determine the thermal and infection conditions that promote or suppress activity. We used automated behaviour monitors to track daily activity in individual ticks and repeated the study with fresh ticks over three years. Following exposure to winter conditions we determined whether ticks were infected with the bacteria B. burgdorferi and if infection was responsible for any patterns in winter activity. Warming conditions promoted increased activity throughout the overwintering period but infection with B. burgdorferi had no impact on the frequency or overall number of ticks active throughout the winter. Individual ticks varied in their levels of activity throughout the winter, such that some were largely dormant for several weeks, while others were active almost daily; however, we do not yet know the drivers behind this individual variation in behaviour. Overall, warming winters will heighten the risk of tick-host encounters.
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Affiliation(s)
- Laura V Ferguson
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, B3H 4J1, Canada.
| | - Amal El Nabbout
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, B3H 4J1, Canada
| | - Shelley A Adamo
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, B3H 4J1, Canada
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Butler RA, Papeş M, Vogt JT, Paulsen DJ, Crowe C, Trout Fryxell RT. Human risk to tick encounters in the southeastern United States estimated with spatial distribution modeling. PLoS Negl Trop Dis 2024; 18:e0011919. [PMID: 38354196 PMCID: PMC10898775 DOI: 10.1371/journal.pntd.0011919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 02/27/2024] [Accepted: 01/14/2024] [Indexed: 02/16/2024] Open
Abstract
Expanding geographic distribution and increased populations of ticks has resulted in an upsurge of human-tick encounters in the United States (US), leading to an increase in tickborne disease reporting. Limited knowledge of the broadscale spatial range of tick species is heightened by a rapidly changing environment. Therefore, we partnered with the Forest Inventory and Analysis (FIA) program of the Forest Service, U.S. Department of Agriculture and used passive tick surveillance to better understand spatiotemporal variables associated with foresters encountering three tick species (Amblyomma americanum L., Dermacentor variabilis Say, and Ixodes scapularis L.) in the southeastern US. Eight years (2014-2021) of tick encounter data were used to fit environmental niche and generalized linear models to predict where and when ticks are likely to be encountered. Our results indicate temporal and environmental partitioning of the three species. Ixodes scapularis were more likely to be encountered in the autumn and winter seasons and associated with soil organic matter, vegetation indices, evapotranspiration, temperature, and gross primary productivity. By contrast, A. americanum and D. variabilis were more likely to be encountered in spring and summer seasons and associated with elevation, landcover, temperature, dead belowground biomass, vapor pressure, and precipitation. Regions in the southeast least suitable for encountering ticks included the Blue Ridge, Mississippi Alluvial Plain, and the Southern Florida Coastal Plain, whereas suitable regions included the Interior Plateau, Central Appalachians, Ozark Highlands, Boston Mountains, and the Ouachita Mountains. Spatial and temporal patterns of different tick species can inform outdoorsmen and the public on tick avoidance measures, reduce tick populations by managing suitable tick habitats, and monitoring areas with unsuitable tick habitat for potential missed encounters.
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Affiliation(s)
- Rebecca A. Butler
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Mona Papeş
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - James T. Vogt
- United States Department of Agriculture Forest Service, Southern Research Station, Knoxville, Tennessee, United States of America
| | - Dave J. Paulsen
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Christopher Crowe
- United States Department of Agriculture Forest Service, Southern Research Station, Knoxville, Tennessee, United States of America
| | - Rebecca T. Trout Fryxell
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, United States of America
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Crandall KE, Millien V, Kerr JT. High-resolution environmental and host-related factors impacting questing Ixodes scapularis at their northern range edge. Ecol Evol 2024; 14:e10855. [PMID: 38384829 PMCID: PMC10879908 DOI: 10.1002/ece3.10855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 01/08/2024] [Accepted: 01/11/2024] [Indexed: 02/23/2024] Open
Abstract
The geographic range of tick populations has expanded in Canada due to climate warming and the associated poleward range shifts of their vertebrate hosts. Abiotic factors, such as temperature, precipitation, and snow, are known to directly affect tick abundance. Yet, biotic factors, such as the abundance and diversity of mammal hosts, may also alter tick abundance and consequent tick-borne disease risk. Here, we incorporated host surveillance data with high-resolution environmental data to evaluate the combined impact of abiotic and biotic factors on questing Ixodes scapularis abundance in Ontario and Quebec, Canada. High-resolution abiotic factors were derived from remote sensing satellites and meteorological towers, while biotic factors related to mammal hosts were derived from active surveillance data that we collected in the field. Generalized additive models were used to determine the relative importance of abiotic and biotic factors on questing I. scapularis abundance. Combinations of abiotic and biotic factors were identified as important drivers of abundances of questing I. scapularis. Positive and negative linear relationships were found for questing I. scapularis abundance with monthly mean precipitation and accumulated snow, but no effect was found for the relative abundance of white-footed mice. Positive relationships were also identified between questing I. scapularis abundance with monthly mean precipitation and mammal species richness. Therefore, future studies that assess I. scapularis should incorporate host surveillance data with high-resolution environmental factors to determine the key drivers impacting the abundance and geographic spread of tick populations and tick-borne pathogens.
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Affiliation(s)
- Kirsten E. Crandall
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
- Department of BiologyMcGill UniversityMontréalQuébecCanada
- Redpath MuseumMcGill UniversityMontréalQuébecCanada
| | - Virginie Millien
- Department of BiologyMcGill UniversityMontréalQuébecCanada
- Redpath MuseumMcGill UniversityMontréalQuébecCanada
| | - Jeremy T. Kerr
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
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Husar K, Pittman DC, Rajala J, Mostafa F, Allen LJS. Lyme Disease Models of Tick-Mouse Dynamics with Seasonal Variation in Births, Deaths, and Tick Feeding. Bull Math Biol 2024; 86:25. [PMID: 38294562 DOI: 10.1007/s11538-023-01248-y] [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: 05/10/2023] [Accepted: 12/19/2023] [Indexed: 02/01/2024]
Abstract
Lyme disease is the most common vector-borne disease in the United States impacting the Northeast and Midwest at the highest rates. Recently, it has become established in southeastern and south-central regions of Canada. In these regions, Lyme disease is caused by Borrelia burgdorferi, which is transmitted to humans by an infected Ixodes scapularis tick. Understanding the parasite-host interaction is critical as the white-footed mouse is one of the most competent reservoir for B. burgdorferi. The cycle of infection is driven by tick larvae feeding on infected mice that molt into infected nymphs and then transmit the disease to another susceptible host such as mice or humans. Lyme disease in humans is generally caused by the bite of an infected nymph. The main aim of this investigation is to study how diapause delays and demographic and seasonal variability in tick births, deaths, and feedings impact the infection dynamics of the tick-mouse cycle. We model tick-mouse dynamics with fixed diapause delays and more realistic Erlang distributed delays through delay and ordinary differential equations (ODEs). To account for demographic and seasonal variability, the ODEs are generalized to a continuous-time Markov chain (CTMC). The basic reproduction number and parameter sensitivity analysis are computed for the ODEs. The CTMC is used to investigate the probability of Lyme disease emergence when ticks and mice are introduced, a few of which are infected. The probability of disease emergence is highly dependent on the time and the infected species introduced. Infected mice introduced during the summer season result in the highest probability of disease emergence.
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Affiliation(s)
- Kateryna Husar
- Department of Statistical Science, Duke University, Durham, NC, 27705, USA.
| | - Dana C Pittman
- Department of Epidemiology and Biostatistics, Texas A &M University, College Station, TX, 77843, USA
| | - Johnny Rajala
- Department of Computer Science, University of Maryland, College Park, MD, 20742, USA
| | - Fahad Mostafa
- Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX, 79409, USA
| | - Linda J S Allen
- Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX, 79409, USA
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Eisen RJ, Eisen L. Evaluation of the association between climate warming and the spread and proliferation of Ixodes scapularis in northern states in the Eastern United States. Ticks Tick Borne Dis 2024; 15:102286. [PMID: 38016209 PMCID: PMC10884982 DOI: 10.1016/j.ttbdis.2023.102286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 11/30/2023]
Abstract
Ixodes scapularis (the blacklegged tick) is widely distributed in forested areas across the eastern United States. The public health impact of I. scapularis is greatest in the north, where nymphal stage ticks commonly bite humans and serve as primary vectors for multiple human pathogens. There were dramatic increases in the tick's distribution and abundance over the last half-century in the northern part of the eastern US, and climate warming is commonly mentioned as a primary driver for these changes. In this review, we summarize the evidence for the observed spread and proliferation of I. scapularis being driven by climate warming. Although laboratory and small-scale field studies have provided insights into how temperature and humidity impact survival and reproduction of I. scapularis, using these associations to predict broad-scale distribution and abundance patterns is more challenging. Numerous efforts have been undertaken to model the distribution and abundance of I. scapularis at state, regional, and global scales based on climate and landscape variables, but outcomes have been ambiguous. Across the models, the functional relationships between seasonal or annual measures of heat, cold, precipitation, or humidity and tick presence or abundance were inconsistent. The contribution of climate relative to landscape variables was poorly defined. Over the last half-century, climate warming occurred in parallel with spread and population increase of the white-tailed deer, the most important reproductive host for I. scapularis adults, in the northern part of the eastern US. There is strong evidence for white-tailed deer playing a key role to facilitate spread and proliferation of I. scapularis in the US over the last century. However, due to a lack of spatially and temporally congruent data, climate, landscape, and host variables are rarely included in the same models, thus limiting the ability to evaluate their relative contributions or interactions in defining the geographic range and abundance patterns of ticks. We conclude that the role of climate change as a key driver for geographic expansion and population increase of I. scapularis in the northern part of the eastern US over the last half-century remains uncertain.
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Affiliation(s)
- Rebecca J Eisen
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521, United States.
| | - Lars Eisen
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521, United States
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Deshpande G, Beetch JE, Heller JG, Naqvi OH, Kuhn KG. Assessing the Influence of Climate Change and Environmental Factors on the Top Tick-Borne Diseases in the United States: A Systematic Review. Microorganisms 2023; 12:50. [PMID: 38257877 PMCID: PMC10821204 DOI: 10.3390/microorganisms12010050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024] Open
Abstract
In the United States (US), tick-borne diseases (TBDs) have more than doubled in the past fifteen years and are a major contributor to the overall burden of vector-borne diseases. The most common TBDs in the US-Lyme disease, rickettsioses (including Rocky Mountain spotted fever), and anaplasmosis-have gradually shifted in recent years, resulting in increased morbidity and mortality. In this systematic review, we examined climate change and other environmental factors that have influenced the epidemiology of these TBDs in the US while highlighting the opportunities for a One Health approach to mitigating their impact. We searched Medline Plus, PUBMED, and Google Scholar for studies focused on these three TBDs in the US from January 2018 to August 2023. Data selection and extraction were completed using Covidence, and the risk of bias was assessed with the ROBINS-I tool. The review included 84 papers covering multiple states across the US. We found that climate, seasonality and temporality, and land use are important environmental factors that impact the epidemiology and patterns of TBDs. The emerging trends, influenced by environmental factors, emphasize the need for region-specific research to aid in the prediction and prevention of TBDs.
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Affiliation(s)
| | | | | | | | - Katrin Gaardbo Kuhn
- Department of Biostatistics & Epidemiology, Hudson College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (G.D.); (J.E.B.); (J.G.H.); (O.H.N.)
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Diyes CP, Dergousoff SJ, Chilton NB. Differences in the reproductive output and larval survival of Rocky Mountain wood ticks (Dermacentor andersoni) and American dog ticks (Dermacentor variabilis) from prairie populations near their northern distributional limits in western Canada. EXPERIMENTAL & APPLIED ACAROLOGY 2023; 91:645-660. [PMID: 38015278 DOI: 10.1007/s10493-023-00856-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 10/12/2023] [Indexed: 11/29/2023]
Abstract
The effects of temperature and relative humidity (RH) on female reproductive output, egg development and larval survival were determined for Rocky Mountain wood ticks (Dermacentor andersoni) from a prairie population (Chin Lakes, Alberta, Canada) near the northern distribution limit of this species. The responses of D. andersoni eggs and unfed larvae to different temperature (25 or 32 °C) and RH (35, 55, 75, 85 or 95%) regimes were compared to our previously published data (Diyes et al. 2021) for a northern prairie population of American dog ticks (Dermacentor variabilis). Oviposition by D. andersoni females took 21-30 days at 25 °C and 95% RH compared to 10-21 days for D. variabilis. The number of eggs laid by female ticks was strongly dependent on their engorgement weight, and D. andersoni females produced more eggs than D. variabilis females of an equivalent body weight. Eggs of D. andersoni took less time to develop at 32 °C than 25 °C with ≥ 85% RH, and hatched faster than those of D. variabilis. Larval survival times declined as temperature increased and RH decreased, but D. andersoni survived longer at 32 °C and ≤ 75% RH than D. variabilis. The interspecific differences in responses to the same temperature and humidity regimes indicate that D. andersoni is xerophilic, whereas D. variabilis is hydrophilic. Hence, 'prairie' populations of the Rocky Mountain wood tick occur in the drier grassland ecoregions but are absent in Aspen Parklands Ecoregion which is located to the north and east of the distributional range of D. andersoni.
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Affiliation(s)
- Chulantha P Diyes
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada
| | - Shaun J Dergousoff
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
| | - Neil B Chilton
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada.
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de Araújo FES, Martins TF, Ramos CCM, Nogueira RMS, Faccini JLH, Tavares MA, de Lima NJ, de Almeida Júnior EB, de Sousa-Paula LC, Dantas-Torres F, da Silva Krawczak F, Costa-Junior LM, Labruna MB, Dall Agnol LT, Luz HR. Seasonal dynamics of Amblyomma cajennense (Fabricius, 1787) sensu stricto in a degraded area of the Amazon biome, with notes on Rickettsia amblyommatis infection. Parasit Vectors 2023; 16:391. [PMID: 37891604 PMCID: PMC10612284 DOI: 10.1186/s13071-023-05978-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 09/23/2023] [Indexed: 10/29/2023] Open
Abstract
BACKGROUND The tick Amblyomma cajennense sensu stricto (A. cajennense s.s.) frequently parasitizes animals and humans in the Amazon biome, in addition to being a vector of Rickettsia amblyommatis. In the present study, we evaluated both the population dynamics of A. cajennense s.s. in a degraded area of the Amazon biome and the presence of rickettsial organisms in this tick population. METHODS The study was carried out in a rural area of the Santa Inês municipality (altitude: 24 m a.s.l.), Maranhão state, Brazil. Ticks were collected from the environment for 24 consecutive months, from June 2021 to May 2023. The region is characterized by two warm seasons: a rainy season (November-May) and a dry season (June-October). We characterized the temporal activity of A. cajennense s.s. on the vegetation by examining questing activity for each life stage (larvae, nymphs, adults [males and females]) in relation to the dry and rainy season. Ticks collected in this study were randomly selected and individually tested by a TaqMan real-time PCR assay that targeted a 147-bp fragment of the rickettsial gltA gene. RESULTS Overall, 1843 (62.4%) adults (52.6% females, 47.4% males), 1110 (37.6%) nymphs and 398 larval clusters were collected. All adult females and nymphs were morphologically identified as A. cajennense s.s. Larval activity was observed from April to December, with a peak from June to September (dry season); nymph abundance peaked from September to November (transition period between dry and rainy seasons); and adult ticks were abundant from October to May (spring/summer/early autumn). The infection rate by R. amblyommatis in A. cajennense s.s. ticks was at least 7% (7/99). CONCLUSION Our data suggest a 1-year generation pattern for A. cajennense s.s., with a well-defined seasonality of larvae, nymphs and adults in the Amazon biome. Larvae predominate during the dry season, nymphs are most abundant in the dry-rainy season transition and adults are most abundant in the rainy season. The presence of R. amblyommatis in adult ticks suggests that animals and humans in the study region are at risk of infection by this species belonging to the spotted fever group of Rickettsia.
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Affiliation(s)
| | - Thiago Fernandes Martins
- Pasteur Institute, São Paulo State Department of Health, São Paulo, SP, Brazil
- Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | | | | | - João Luiz Horacio Faccini
- Post-Graduation Program in Health Sciences, Center of Biological and Health Sciences, Federal University of Maranhão, São Luís, MA, Brazil
| | | | | | - Eduardo Bezerra de Almeida Júnior
- Post-Graduation Program in Biodiversity and Conservation, Center of Biological and Health Sciences, Federal University of Maranhão, São Luís, MA, Brazil
| | - Lucas Christian de Sousa-Paula
- Tick-Pathogen Transmission Unit, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Hamilton, MT, USA
| | - Filipe Dantas-Torres
- Department of Immunology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation (Fiocruz), Recife, PE, Brazil
| | | | - Livio Martins Costa-Junior
- Post-Graduation Program in Northeast Biotechnology Network (RENORBIO), Biodiversity and Conservation, Center of Biological and Health Sciences, Federal University of Maranhão, São Luís, MA, Brazil
| | - Marcelo Bahia Labruna
- Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | | | - Hermes Ribeiro Luz
- Post-Graduation Program in Health and Environment, Federal University of Maranhão, São Luís, MA, Brazil.
- Post-Graduation Program in Northeast Biotechnology Network (RENORBIO), Biodiversity and Conservation, Center of Biological and Health Sciences, Federal University of Maranhão, São Luís, MA, Brazil.
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11
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Tardy O, Acheson ES, Bouchard C, Chamberland É, Fortin A, Ogden NH, Leighton PA. Mechanistic movement models to predict geographic range expansions of ticks and tick-borne pathogens: Case studies with Ixodes scapularis and Amblyomma americanum in eastern North America. Ticks Tick Borne Dis 2023; 14:102161. [PMID: 36996508 DOI: 10.1016/j.ttbdis.2023.102161] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/30/2023]
Abstract
The geographic range of the blacklegged tick, Ixodes scapularis, is expanding northward from the United States into southern Canada, and studies suggest that the lone star tick, Amblyomma americanum, will follow suit. These tick species are vectors for many zoonotic pathogens, and their northward range expansion presents a serious threat to public health. Climate change (particularly increasing temperature) has been identified as an important driver permitting northward range expansion of blacklegged ticks, but the impacts of host movement, which is essential to tick dispersal into new climatically suitable regions, have received limited investigation. Here, a mechanistic movement model was applied to landscapes of eastern North America to explore 1) relationships between multiple ecological drivers and the speed of the northward invasion of blacklegged ticks infected with the causative agent of Lyme disease, Borrelia burgdorferi sensu stricto, and 2) its capacity to simulate the northward range expansion of infected blacklegged ticks and uninfected lone star ticks under theoretical scenarios of increasing temperature. Our results suggest that the attraction of migratory birds (long-distance tick dispersal hosts) to resource-rich areas during their spring migration and the mate-finding Allee effect in tick population dynamics are key drivers for the spread of infected blacklegged ticks. The modeled increases in temperature extended the climatically suitable areas of Canada for infected blacklegged ticks and uninfected lone star ticks towards higher latitudes by up to 31% and 1%, respectively, and with an average predicted speed of the range expansion reaching 61 km/year and 23 km/year, respectively. Differences in the projected spatial distribution patterns of these tick species were due to differences in climate envelopes of tick populations, as well as the availability and attractiveness of suitable habitats for migratory birds. Our results indicate that the northward invasion process of lone star ticks is primarily driven by local dispersal of resident terrestrial hosts, whereas that of blacklegged ticks is governed by long-distance migratory bird dispersal. The results also suggest that mechanistic movement models provide a powerful approach for predicting tick-borne disease risk patterns under complex scenarios of climate, socioeconomic and land use/land cover changes.
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12
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Kjær LJ, Johansson M, Lindgren PE, Asghar N, Wilhelmsson P, Fredlund H, Christensson M, Wallenhammar A, Bødker R, Rasmussen G, Kjellander P. Potential drivers of human tick-borne encephalitis in the Örebro region of Sweden, 2010-2021. Sci Rep 2023; 13:7685. [PMID: 37169798 PMCID: PMC10175290 DOI: 10.1038/s41598-023-34675-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023] Open
Abstract
Incidence of tick-borne encephalitis (TBE) has increased during the last years in Scandinavia, but the underlying mechanism is not understood. TBE human case data reported between 2010 and 2021 were aggregated into postal codes within Örebro County, south-central Sweden, along with tick abundance and environmental data to analyse spatial patterns and identify drivers of TBE. We identified a substantial and continuing increase of TBE incidence in Örebro County during the study period. Spatial cluster analyses showed significant hotspots (higher number of cases than expected) in the southern and northern parts of Örebro County, whereas a cold spot (lower number of cases than expected) was found in the central part comprising Örebro municipality. Generalised linear models showed that the risk of acquiring TBE increased by 12.5% and 72.3% for every percent increase in relative humidity and proportion of wetland forest, respectively, whereas the risk decreased by 52.8% for every degree Celsius increase in annual temperature range. However, models had relatively low goodness of fit (R2 < 0.27). Results suggest that TBE in Örebro County is spatially clustered, however variables used in this study, i.e., climatic variables, forest cover, water, tick abundance, sheep as indicator species, alone do not explain this pattern.
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Affiliation(s)
- Lene Jung Kjær
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Magnus Johansson
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Per-Eric Lindgren
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
- Division of Clinical Microbiology, Department of Laboratory Medicine, Region Jönköping County, Jönköping, Sweden
| | - Naveed Asghar
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Peter Wilhelmsson
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
- Division of Clinical Microbiology, Department of Laboratory Medicine, Region Jönköping County, Jönköping, Sweden
| | - Hans Fredlund
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Örebro County Council, Örebro, Sweden
| | - Madeleine Christensson
- Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences (SLU), Riddarhyttan, Sweden
| | - Amélie Wallenhammar
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - René Bødker
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Gunløg Rasmussen
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Örebro County Council, Örebro, Sweden
| | - Petter Kjellander
- Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences (SLU), Riddarhyttan, Sweden
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13
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Saegerman C, Humblet MF, Leandri M, Gonzalez G, Heyman P, Sprong H, L’Hostis M, Moutailler S, Bonnet SI, Haddad N, Boulanger N, Leib SL, Hoch T, Thiry E, Bournez L, Kerlik J, Velay A, Jore S, Jourdain E, Gilot-Fromont E, Brugger K, Geller J, Studahl M, Knap N, Avšič-Županc T, Růžek D, Zomer TP, Bødker R, Berger TFH, Martin-Latil S, De Regge N, Raffetin A, Lacour SA, Klein M, Lernout T, Quillery E, Hubálek Z, Ruiz-Fons F, Estrada-Peña A, Fravalo P, Kooh P, Etore F, Gossner CM, Purse B. First Expert Elicitation of Knowledge on Possible Drivers of Observed Increasing Human Cases of Tick-Borne Encephalitis in Europe. Viruses 2023; 15:v15030791. [PMID: 36992499 PMCID: PMC10054665 DOI: 10.3390/v15030791] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/11/2023] [Accepted: 03/17/2023] [Indexed: 03/29/2023] Open
Abstract
Tick-borne encephalitis (TBE) is a viral disease endemic in Eurasia. The virus is mainly transmitted to humans via ticks and occasionally via the consumption of unpasteurized milk products. The European Centre for Disease Prevention and Control reported an increase in TBE incidence over the past years in Europe as well as the emergence of the disease in new areas. To better understand this phenomenon, we investigated the drivers of TBE emergence and increase in incidence in humans through an expert knowledge elicitation. We listed 59 possible drivers grouped in eight domains and elicited forty European experts to: (i) allocate a score per driver, (ii) weight this score within each domain, and (iii) weight the different domains and attribute an uncertainty level per domain. An overall weighted score per driver was calculated, and drivers with comparable scores were grouped into three terminal nodes using a regression tree analysis. The drivers with the highest scores were: (i) changes in human behavior/activities; (ii) changes in eating habits or consumer demand; (iii) changes in the landscape; (iv) influence of humidity on the survival and transmission of the pathogen; (v) difficulty to control reservoir(s) and/or vector(s); (vi) influence of temperature on virus survival and transmission; (vii) number of wildlife compartments/groups acting as reservoirs or amplifying hosts; (viii) increase of autochthonous wild mammals; and (ix) number of tick species vectors and their distribution. Our results support researchers in prioritizing studies targeting the most relevant drivers of emergence and increasing TBE incidence.
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Affiliation(s)
- Claude Saegerman
- Fundamental and Applied Research for Animal and Health (FARAH) Center, University of Liege, 4000 Liege, Belgium
- Correspondence:
| | - Marie-France Humblet
- Department for Occupational Protection and Hygiene, Unit Biosafety, Biosecurity and Environmental Licences, University of Liege, 4000 Liege, Belgium
| | - Marc Leandri
- UMI SOURCE, Université Paris-Saclay—UVSQ, 78000 Versailles, France
| | - Gaëlle Gonzalez
- ANSES, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR VIROLOGIE, Laboratoire de Santé Animale, 94700 Maisons-Alfort, France
| | | | - Hein Sprong
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, 3720 MA Bilthoven, The Netherlands
| | - Monique L’Hostis
- Ecole Nationale Vétérinaire Agroalimentaire et de l’Alimentation Nantes-Atlantique, Oniris, 44307 Nantes, France
| | - Sara Moutailler
- ANSES, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR BIPAR, Laboratoire de Santé Animale, 94700 Maisons-Alfort, France
| | - Sarah I. Bonnet
- UMR 2000 Institut Pasteur-CNRS-Université Paris-Cité, Ecology and Emergence of Arthropod-borne Pathogens, 75015 Paris, France
- Animal Health Department, INRAE, 37380 Nouzilly, France
| | - Nadia Haddad
- ANSES, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR BIPAR, Laboratoire de Santé Animale, 94700 Maisons-Alfort, France
| | - Nathalie Boulanger
- UR7290: VBP: Borrelia Group, France and French Reference Centre on Lyme Borreliosis, CHRU, Unversity of Strasbourg, 67000 Strasbourg, France
| | - Stephen L. Leib
- Institute for Infectious Diseases, University of Bern, 3001 Bern, Switzerland
| | | | - Etienne Thiry
- Fundamental and Applied Research for Animal and Health (FARAH) Center, University of Liege, 4000 Liege, Belgium
| | - Laure Bournez
- ANSES, Nancy Laboratory for Rabies and Wildlife, 54220 Malzéville, France
| | - Jana Kerlik
- Department of Epidemiology, Regional Authority of Public Health in Banská Bystrica, 497556 Banská Bystrica, Slovakia
| | - Aurélie Velay
- Unité Mixte de Recherché Immunorhumathologie Moléculaire (UMR IRM_S) 1109, Université de Strasbourg, INSERM, 67000 Strasbourg, France
| | - Solveig Jore
- Zoonotic, Water and Foodborne Infections, The Norwegian Institute for Public Health (NIPH), 0213 Oslo, Norway
| | - Elsa Jourdain
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMR EPIA, Route de Theix, 63122 Saint-Genès-Champanelle, France
| | | | - Katharina Brugger
- Competence Center Climate and Health, Austrian National Institute of Public Health, 1010 Vienna, Austria
| | - Julia Geller
- Department of Virology and Immunology, National Institute for Health Development, 11619 Tallinn, Estonia
| | - Marie Studahl
- Institute of Biomedicine, Department of Infectious Diseases, University of Gothenburg, 41685 Gothenburg, Sweden
| | - Nataša Knap
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, 1000 Ljubljana, Slovenia
| | - Tatjana Avšič-Županc
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, 1000 Ljubljana, Slovenia
| | - Daniel Růžek
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, 37005 Ceske Budejovice, Czech Republic
- Department of Experimental Biology, Faculty of Science, Masaryk University, 62500 Brno, Czech Republic
- Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, 62100 Brno, Czech Republic
| | - Tizza P. Zomer
- Lyme Center Apeldoorn, Gelre Hospital, 7300 DS Apeldoorn, The Netherlands
| | - René Bødker
- Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark
| | - Thomas F. H. Berger
- Agroscope, Risk Evaluation and Risk Mitigation, Schwarzenburgstrasse, 3003 Bern-Liebefeld, Switzerland
| | - Sandra Martin-Latil
- Laboratory for Food Safety, ANSES, University of Paris-EST, 94700 Maisons-Alfort, France
| | - Nick De Regge
- Operational Direction Infectious Diseases in Animals, Unit of Exotic and Vector-borne Diseases, Sciensano, 1180 Brussels, Belgium
| | - Alice Raffetin
- Reference Centre for Tick-Borne Diseases, Paris and Northern Region, Department of Infectious Diseases, General Hospital of Villeneuve-Saint-Georges, 94100 Villeneuve-Saint-Georges, France
| | - Sandrine A. Lacour
- ANSES, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR VIROLOGIE, Laboratoire de Santé Animale, 94700 Maisons-Alfort, France
| | - Matthias Klein
- Neurologische Klinik und Poliklinik, Klinikum der Universität München, LMU München, Marchioninistraße 15, 81377 München, Germany
| | - Tinne Lernout
- Scientific Directorate of Epidemiology and Public Health, Sciensano, 1180 Brussels, Belgium
| | - Elsa Quillery
- ANSES, Risk Assessment Department, 94700 Maisons-Alfort, France
| | - Zdeněk Hubálek
- Institute of Vertebrate Biology, Czech Academy of Sciences, Květná 8, 60365 Brno, Czech Republic
| | - Francisco Ruiz-Fons
- Health & Biotechnology (SaBio) Group, Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCCM, 13071 Ciudad Real, Spain
| | - Agustín Estrada-Peña
- Deptartment of Animal Health, Faculty of Veterinary Medicine, 50013 Zaragoza, Spain
| | - Philippe Fravalo
- Pôle Agroalimentaire, Conservatoire National des Arts et Métiers (Cnam), 75003 Paris, France
| | - Pauline Kooh
- ANSES, Risk Assessment Department, 94700 Maisons-Alfort, France
| | - Florence Etore
- ANSES, Risk Assessment Department, 94700 Maisons-Alfort, France
| | - Céline M. Gossner
- European Centre for Disease Prevention and Control (ECDC), 17183 Solna, Sweden
| | - Bethan Purse
- UK Centre for Ecology & Hydrology, Benson Lane, Crowmarsh Gifford, Oxfordshire OX10 8BB, UK
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14
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Sack A, Naumova EN, Price LL, Xu G, Rich SM. Passive Surveillance of Human-Biting Ixodes scapularis Ticks in Massachusetts from 2015-2019. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:4306. [PMID: 36901316 PMCID: PMC10002092 DOI: 10.3390/ijerph20054306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 02/24/2023] [Accepted: 02/26/2023] [Indexed: 06/18/2023]
Abstract
This study aimed to analyze human-biting Ixodes scapularis ticks submitted to TickReport tick testing service from 2015-2019 in Massachusetts to (1) examine possible patterns of pathogen-positive adult and nymphal ticks over time and (2) explore how socioeconomic factors can influence tick submissions. A passive surveillance data set of ticks and tick-borne pathogens was conducted over 5 years (2015-2019) in Massachusetts. The percentages of four tick-borne pathogens: Borrelia burgdorferi, Anaplasma phagocytophilum, Babesia microti, and Borrelia miyamotoi were determined by Massachusetts county and by month and year. Regression models were used to examine the association between zip-code-level socioeconomic factors and submissions. A total of 13,598 I. scapularis ticks were submitted to TickReport from Massachusetts residents. The infection rate of B. burgdorferi, A. phagocytophilum, and B. microti was 39%, 8%, and 7% in adult ticks; 23%, 6%, and 5% in nymphal ticks, respectively. A relatively higher level of education was associated with high tick submission. Passive surveillance of human-biting ticks and associated pathogens is important for monitoring tick-borne diseases, detecting areas with potentially high risks, and providing public information. Socioeconomic factors should be considered to produce more generalizable passive surveillance data and to target potentially underserved areas.
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Affiliation(s)
- Alexandra Sack
- Clinical and Translational Science Graduate Program, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Elena N. Naumova
- Division of Nutrition Epidemiology and Data Science, Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA 02111, USA
| | - Lori Lyn Price
- Tufts Institute of Clinical and Translational Science, Tufts University, Boston, MA 02111, USA
- Institute of Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA 02111, USA
| | - Guang Xu
- Laboratory of Medical Zoology, Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Stephen M. Rich
- Laboratory of Medical Zoology, Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
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15
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Goren A, Viljugrein H, Rivrud IM, Jore S, Bakka H, Vindenes Y, Mysterud A. The emergence and shift in seasonality of Lyme borreliosis in Northern Europe. Proc Biol Sci 2023; 290:20222420. [PMID: 36809802 PMCID: PMC9943644 DOI: 10.1098/rspb.2022.2420] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
Climate change has had a major impact on seasonal weather patterns, resulting in marked phenological changes in a wide range of taxa. However, empirical studies of how changes in seasonality impact the emergence and seasonal dynamics of vector-borne diseases have been limited. Lyme borreliosis, a bacterial infection spread by hard-bodied ticks, is the most common vector-borne disease in the northern hemisphere and has been rapidly increasing in both incidence and geographical distribution in many regions of Europe and North America. By analysis of long-term surveillance data (1995-2019) from across Norway (latitude 57°58'-71°08' N), we demonstrate a marked change in the within-year timing of Lyme borreliosis cases accompanying an increase in the annual number of cases. The seasonal peak in cases is now six weeks earlier than 25 years ago, exceeding seasonal shifts in plant phenology and previous model predictions. The seasonal shift occurred predominantly in the first 10 years of the study period. The concurrent upsurgence in case number and shift in case timing indicate a major change in the Lyme borreliosis disease system over recent decades. This study highlights the potential for climate change to shape the seasonal dynamics of vector-borne disease systems.
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Affiliation(s)
- Asena Goren
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, Oslo NO-0316, Norway
| | - Hildegunn Viljugrein
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, Oslo NO-0316, Norway.,Norwegian Veterinary Institute, PO Box 64, NO-1431 Ås, Norway
| | - Inger Maren Rivrud
- Norwegian Institute for Nature Research (NINA), Sognsveien 68, NO-0855 Oslo, Norway
| | - Solveig Jore
- Zoonotic, Food and Waterborne Infections, The Norwegian Public Health Institute, PO Box 4404 Nydalen, NO-0403 Oslo, Norway
| | - Haakon Bakka
- Norwegian Veterinary Institute, PO Box 64, NO-1431 Ås, Norway
| | - Yngvild Vindenes
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, Oslo NO-0316, Norway
| | - Atle Mysterud
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, Oslo NO-0316, Norway.,Norwegian Institute for Nature Research (NINA), PO Box 5685 Sluppen, NO-7485 Trondheim, Norway
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16
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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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17
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Hammond-Collins K, Tremblay M, Milord F, Baron G, Bouchard C, Kotchi SO, Lambert L, Leighton P, Ogden NH, Rees EE. An ecological approach to predict areas with established populations of Ixodes scapularis in Quebec, Canada. Ticks Tick Borne Dis 2022; 13:102040. [PMID: 36137391 DOI: 10.1016/j.ttbdis.2022.102040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 08/28/2022] [Accepted: 09/11/2022] [Indexed: 10/31/2022]
Abstract
Public health management of Lyme disease (LD) is a dynamic challenge in Canada. Climate warming is driving the northward expansion of suitable habitat for the tick vector, Ixodes scapularis. Information about tick population establishment is used to inform the risk of LD but is challenged by sampling biases from surveillance data. Misclassifying areas as having no established tick population underestimates the LD risk classification. We used a logistic regression model at the municipal level to predict the probability of I. scapularis population establishment based on passive tick surveillance data during the period of 2010-2017 in southern Quebec. We tested for the effect of abiotic and biotic factors hypothesized to influence tick biology and ecology. Additional variables controlled for sampling biases in the passive surveillance data. In our final selected model, tick population establishment was positively associated with annual cumulative degree-days > 0°C, precipitation and deer density, and negatively associated with coniferous and mixed forest types. Sampling biases from passive tick surveillance were controlled for using municipal population size and public health instructions on tick submissions. The model performed well as indicated by an area under the curve (AUC) of 0.92, sensitivity of 86% and specificity of 81%. Our model enables prediction of I. scapularis population establishment in areas which lack data from passive tick surveillance and may improve the sensitivity of LD risk categorization in these areas. A more sensitive system of LD risk classification is important for increasing awareness and use of protective measures employed against ticks, and decreasing the morbidity associated with LD.
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Affiliation(s)
| | - Mathieu Tremblay
- Direction de santé publique de la Montérégie, 1255 rue Beauregard, Longueuil, QC, Canada
| | - François Milord
- Direction de santé publique de la Montérégie, 1255 rue Beauregard, Longueuil, QC, Canada; Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, QC, Canada
| | - Geneviève Baron
- Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, QC, Canada; Direction de Santé Publique de l'Estrie, 300 rue King Est, Bureau 300, Sherbrooke, QC, Canada
| | - Catherine Bouchard
- Public Health Agency of Canada, 3200 rue Sicotte, Saint-Hyacinthe, QC, Canada; Faculty of Veterinary Medicine, Université de Montréal, 3190 rue Sicotte, Saint-Hyacinthe, QC, Canada; Groupe de Recherche en Épidémiologie des Zoonoses et Santé Publique (GREZOSP), Université de Montréal, 3200 rue Sicotte, Saint-Hyacinthe, QC, Canada
| | - Serge Olivier Kotchi
- Public Health Agency of Canada, 3200 rue Sicotte, Saint-Hyacinthe, QC, Canada; Groupe de Recherche en Épidémiologie des Zoonoses et Santé Publique (GREZOSP), Université de Montréal, 3200 rue Sicotte, Saint-Hyacinthe, QC, Canada
| | - Louise Lambert
- Direction de santé publique de la Montérégie, 1255 rue Beauregard, Longueuil, QC, Canada
| | - Patrick Leighton
- Faculty of Veterinary Medicine, Université de Montréal, 3190 rue Sicotte, Saint-Hyacinthe, QC, Canada; Groupe de Recherche en Épidémiologie des Zoonoses et Santé Publique (GREZOSP), Université de Montréal, 3200 rue Sicotte, Saint-Hyacinthe, QC, Canada
| | - Nicholas H Ogden
- Public Health Agency of Canada, 3200 rue Sicotte, Saint-Hyacinthe, QC, Canada; Groupe de Recherche en Épidémiologie des Zoonoses et Santé Publique (GREZOSP), Université de Montréal, 3200 rue Sicotte, Saint-Hyacinthe, QC, Canada
| | - Erin E Rees
- Public Health Agency of Canada, 3200 rue Sicotte, Saint-Hyacinthe, QC, Canada; Faculty of Veterinary Medicine, Université de Montréal, 3190 rue Sicotte, Saint-Hyacinthe, QC, Canada; Groupe de Recherche en Épidémiologie des Zoonoses et Santé Publique (GREZOSP), Université de Montréal, 3200 rue Sicotte, Saint-Hyacinthe, QC, Canada
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18
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Wu-Chuang A, Obregon D, Estrada-Peña A, Cabezas-Cruz A. Thermostable Keystone Bacteria Maintain the Functional Diversity of the Ixodes scapularis Microbiome Under Heat Stress. MICROBIAL ECOLOGY 2022; 84:1224-1235. [PMID: 34817640 DOI: 10.1007/s00248-021-01929-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/10/2021] [Indexed: 06/13/2023]
Abstract
Variations in the composition and diversity of tick microbiome due to high temperatures may influence the hierarchy of community members as a response to environmental change. Modifications in the community structure are hypothesized to drive alterations in the presence and/or abundance of functional pathways in the bacterial metagenome. In this study, this hypothesis was tested by using published 16S rRNA datasets of Ixodes scapularis males incubated at different temperatures (i.e., 4, 20, 30, and 37 °C) in a laboratory setting. Changes in community structure and functional profiles in response to temperature shifts were measured using co-occurrence networks and metagenome inference. Results from laboratory-reared ticks were then compared with those of field-collected ticks. The results from laboratory-reared ticks showed that high temperature altered the structure of the microbial community and decreased the number of keystone taxa. Notably, four taxa were identified as keystone in all the temperatures, and the functional diversity of the tick microbiome was contained in the four thermostable keystone their associated bacterial taxa. Three of the thermostable keystone taxa were also found in free-living ticks collected in Massachusetts. Moreover, the comparison of functional profiles of laboratory-reared and field-collected ticks revealed the existence of an important set of metabolic pathways that were common among the different datasets. Similar to the laboratory-reared ticks, the keystone taxa identified in field-collected ticks alongside their consortia (co-occurring taxa) were sufficient to retain the majority of the metabolic pathways in the functional profile. These results suggest that keystone taxa are essential in the stability and the functional resiliency of the tick microbiome under heat stress.
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Affiliation(s)
- Alejandra Wu-Chuang
- Anses, INRAE, Ecole Nationale Vétérinaire d'Alfort, UMR BIPAR, Laboratoire de Santé Animale, Maisons-Alfort, F-94700, France
| | - Dasiel Obregon
- School of Environmental Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | | | - Alejandro Cabezas-Cruz
- Anses, INRAE, Ecole Nationale Vétérinaire d'Alfort, UMR BIPAR, Laboratoire de Santé Animale, Maisons-Alfort, F-94700, France.
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19
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Gallagher MR, Kreye JK, Machtinger ET, Everland A, Schmidt N, Skowronski NS. Can restoration of fire-dependent ecosystems reduce ticks and tick-borne disease prevalence in the eastern United States? ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2637. [PMID: 35426200 DOI: 10.1002/eap.2637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/01/2021] [Accepted: 10/13/2021] [Indexed: 06/14/2023]
Abstract
Over the past century, fire suppression has facilitated broad ecological changes in the composition, structure, and function of fire-dependent landscapes throughout the eastern US, which are in decline. These changes have likely contributed mechanistically to the enhancement of habitat conditions that favor pathogen-carrying tick species, key wildlife hosts of ticks, and interactions that have fostered pathogen transmission among them and to humans. While the long-running paradigm for limiting human exposure to tick-borne diseases focuses responsibility on individual prevention, the continued expansion of medically important tick populations, increased incidence of tick-borne disease in humans, and emergence of novel tick-borne diseases highlights the need for additional approaches to stem this public health challenge. Another approach that has the potential to be a cost-effective and widely applied but that remains largely overlooked is the use of prescribed fire to ecologically restore degraded landscapes that favor ticks and pathogen transmission. We examine the ecological role of fire and its effects on ticks within the eastern United States, especially examining the life cycles of forest-dwelling ticks, shifts in regional-scale fire use over the past century, and the concept that frequent fire may have helped moderate tick populations and pathogen transmission prior to the so-called fire-suppression era that has characterized the past century. We explore mechanisms of how fire and ecological restoration can reduce ticks, the potential for incorporating the mechanisms into the broader strategy for managing ticks, and the challenges, limitations, and research needs of prescribed burning for tick reduction.
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Affiliation(s)
| | - Jesse K Kreye
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Erika T Machtinger
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Alexis Everland
- New Jersey Department of Environmental Protection, Forest Fire Service, New Lisbon, New Jersey, USA
| | - Nathaniel Schmidt
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, USA
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20
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Varma A, Szlaszynska M, Ben-Haim A, Ilia N, Tarricone S, Lewandowska-Bejm J, Visentin F, Gadler A. Bearing the Burden of Tick-Borne Encephalitis in Europe, 2012-2020: Rising Cases, Future Predictions and Climate Change. INTERNATIONAL JOURNAL OF MEDICAL STUDENTS 2022. [DOI: 10.5195/ijms.2022.1464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Tick-borne encephalitis (TBE) is a central nervous system disease that is posing a growing public health challenge in Europe. Its disease burden, despite carrying a significant global impact, is still relatively unexplored. This study aims to outline a regression model of how the increasing cases will influence the burden of TBE in the upcoming years, using YLDs (years lived with disability) and DALYs (Disability-adjusted life years), and address climate change as a determinant.
Methods: Information regarding the number of cases, YLDs and DALYs of TBE was collected from European countries using available surveillance data from 2012 to 2020. Number of TBE cases and burden projections were created until 2025, using a linear regression model. The total reported cases of TBE cases in this timeframe, age-group and gender distribution were inserted and modeled in ECDC BCoDE Toolkit, a software application that calculates the burden of communicable diseases, YLDs and DALYs of each year. A non-systematic bibliographic search was conducted exploring the impact of climate change on TBE.
Results: Our findings showed a linear growth in number of TBE cases (74.3% increase), DALYs (71.3%), YLDs (71.75%) in European countries from 2012 to 2020. By 2025, these factors are likely to increase by 141% (95% CI: [108%,175%]), 134% (95% CI: [91%,177%]) and 134% (95% CI: [98%,172%]) compared to 2012, respectively (p<0.0001).
Conclusions: The likelihood of morbidity and mortality increase of TBE, as well as climate-related changes in tick activity, highlight that prompt action is necessary by introducing preventive measures in European populations.
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21
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Burtis JC, Foster E, Schwartz AM, Kugeler KJ, Maes SE, Fleshman AC, Eisen RJ. Predicting distributions of blacklegged ticks (Ixodes scapularis), Lyme disease spirochetes (Borrelia burgdorferi sensu stricto) and human Lyme disease cases in the eastern United States. Ticks Tick Borne Dis 2022; 13:102000. [PMID: 35785605 PMCID: PMC10591441 DOI: 10.1016/j.ttbdis.2022.102000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 06/22/2022] [Accepted: 06/25/2022] [Indexed: 11/27/2022]
Abstract
Lyme disease is the most commonly reported vector-borne disease in the United States (US), with approximately 300,000 -to- 40,000 cases reported annually. The blacklegged tick, Ixodes scapularis, is the primary vector of the Lyme disease-causing spirochete, Borrelia burgdorferi sensu stricto, in high incidence regions in the upper midwestern and northeastern US. Using county-level records of the presence of I. scapularis or presence of B. burgdorferi s.s. infected host-seeking I. scapularis, we generated habitat suitability consensus maps based on an ensemble of statistical models for both acarological risk metrics. Overall accuracy of these suitability models was high (AUC = 0.76 for I. scapularis and 0.86 for B. burgdorferi s.s. infected-I. scapularis). We sought to compare which acarological risk metric best described the distribution of counties reporting high Lyme disease incidence (≥10 confirmed cases/100,000 population) by setting the models to a fixed omission rate (10%). We compared the percent of high incidence counties correctly classified by the two models. The I. scapularis consensus map correctly classified 53% of high and low incidence counties, while the B. burgdorferi s.s. infected-I. scapularis consensus map classified 83% correctly. Counties classified as suitable by the B. burgdorferi s.s. map showed a 91% overlap with high Lyme disease incidence counties with over a 38-fold difference in Lyme disease incidence between high- and low-suitability counties. A total of 288 counties were classified as highly suitable for B. burgdorferi s.s., but lacked records of infected-I. scapularis and were not classified as high incidence. These counties were considered to represent a leading edge for B. burgdorferi s.s. infection in ticks and humans. They clustered in Illinois, Indiana, Michigan, and Ohio. This information can aid in targeting tick surveillance and prevention education efforts in counties where Lyme disease risk may increase in the future.
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Affiliation(s)
- James C Burtis
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, United States.
| | - Erik Foster
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, United States
| | - Amy M Schwartz
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, United States
| | - Kiersten J Kugeler
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, United States
| | - Sarah E Maes
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, United States
| | - Amy C Fleshman
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, United States
| | - Rebecca J Eisen
- Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, United States
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22
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Tian Y, Kaufman PE, Taylor CE, Beati L, Lord CC. Variable Effects of Temperature and Relative Humidity on Rhipicephalus sanguineus s.l. (Acari: Ixodidae) Development. ENVIRONMENTAL ENTOMOLOGY 2022; 51:848-858. [PMID: 35639876 PMCID: PMC9389420 DOI: 10.1093/ee/nvac027] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Indexed: 06/15/2023]
Abstract
Rhipicephalus sanguineus s.l. (Latreille, 1806) can establish populations in residences and may lead to severe domestic and peridomestic infestations. Detection in the early infestation stage is challenging because of their small body size and the lack of visibility when ticks stay in sheltered refugia. The residents may believe that the infestation has been eliminated when no ticks are observed until ticks reappear when seeking hosts. Thus, it is necessary to improve our understanding of tick phenology to achieve more effective infestation management. In this study, the relationships between environmental conditions and tick development were explored in laboratory and using linear and nonlinear models. Three R. sanguineus s.l. strains, from one colony of the temperate lineage and two of the tropical lineage, were evaluated for the development of all life stages and conversion efficiency index (CEI) under five temperatures and four relative humidities (RHs). The development times differed between the three tick strains across stages and were primarily dependent on temperature. The CEIs had little variance explained by temperature, RH, or strains. Compared with the linear and exponential models with temperature as the only variable, the Brière-1 model was the best approximating model for most of the developmental rates. The developmental temperature thresholds for R. sanguineus s.l. development estimated by the Brière-1 model varied inconsistently across strains and life stages. We developed a more predictive relationship between environmental factors and R. sanguineus s.l. development, which can be utilized to predict tick development using temperature and develop appropriate control strategies.
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Affiliation(s)
- Yuexun Tian
- Entomology and Nematology Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
- Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL, USA
| | - Phillip E Kaufman
- Entomology and Nematology Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Caitlin E Taylor
- Entomology and Nematology Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
| | - Lorenza Beati
- U.S. National Tick Collection, Institute for Coastal Plain Science, Georgia Southern University, Statesboro, GA, USA
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23
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Wondim MA, Czupryna P, Pancewicz S, Kruszewska E, Groth M, Moniuszko-Malinowska A. Epidemiological Trends of Trans-Boundary Tick-Borne Encephalitis in Europe, 2000-2019. Pathogens 2022; 11:pathogens11060704. [PMID: 35745558 PMCID: PMC9228375 DOI: 10.3390/pathogens11060704] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/01/2022] [Accepted: 06/14/2022] [Indexed: 02/04/2023] Open
Abstract
Tick-borne encephalitis is a neuroinfection widely distributed in the Euro-Asia region. Primarily, the virus is transmitted by the bite of infected ticks. From 2000-2019, the total number of confirmed cases in Europe reported to the European Centre for Disease Prevention and Control was 51,519. The number of cases decreased in 2014 and 2015; however, since 2015, a growing number of cases have been observed, with the involvement of countries in which TBE has not been previously reported. The determinant factors for the spread of TBE are host population size, weather conditions, movement of hosts, and local regulations on the socioeconomic dynamics of the local and travelling people around the foci areas. The mean incidence rate of tick-borne encephalitis from 2000-2019 in Europe was 3.27, while the age-adjusted mean incidence rate was 2.19 per 100,000 population size. This review used several articles and data sources from the European Centre for Diseases Prevention and Control.
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24
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Effect of Land-Use Change on the Changes in Human Lyme Risk in the United States. SUSTAINABILITY 2022. [DOI: 10.3390/su14105802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The spatial extent and incidence of Lyme disease is increasing in the United States, particularly in the Upper Midwest and Northeast. Many previous studies have explored the drivers of its spatial pattern, however, few studies tried to explore the drivers for the changes of Lyme disease. We here compared the spatial patterns of changes of human Lyme cases and incidence in the Northeast and Upper Midwest between 2003–2005 and 2015–2017, and applied two different approaches (i.e., a statistical regularization approach and model averaging) to investigate the climatic and landscape factors affecting the risk change between the two periods. Our results suggested that changes in land-use variables generally showed different relationships with changes of human Lyme risk between the two regions. Changes of variables related to human-use areas showed opposite correlations in two regions. Besides, forest area and forest edge density generally negatively correlated with the change of human Lyme risk. In the context of ongoing habitat change, we consider this study may provide new insight into understanding the responses of human Lyme disease to these changes, and contribute to a better prediction in the future.
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25
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Witmer FDW, Nawrocki TW, Hahn M. Modeling Geographic Uncertainty in Current and Future Habitat for Potential Populations of Ixodes pacificus (Acari: Ixodidae) in Alaska. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:976-986. [PMID: 35134194 PMCID: PMC9113094 DOI: 10.1093/jme/tjac001] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Indexed: 06/14/2023]
Abstract
Ixodes pacificus Cooley & Kohls is the primary vector of Lyme disease spirochetes to humans in the western United States. Although not native to Alaska, this tick species has recently been found on domestic animals in the state. Ixodes pacificus has a known native range within the western contiguous United States and southwest Canada; therefore, it is not clear if introduced individuals can successfully survive and reproduce in the high-latitude climate of Alaska. To identify areas of suitable habitat within Alaska for I. pacificus, we used model parameters from two existing sets of ensemble habitat distribution models calibrated in the contiguous United States. To match the model input covariates, we calculated climatic and land cover covariates for the present (1980-2014) and future (2070-2100) climatologies in Alaska. The present-day habitat suitability maps suggest that the climate and land cover in Southeast Alaska and portions of Southcentral Alaska could support the establishment of I. pacificus populations. Future forecasts suggest an increase in suitable habitat with considerable uncertainty for many areas of the state. Repeated introductions of this non-native tick to Alaska increase the likelihood that resident populations could become established.
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Affiliation(s)
- Frank D W Witmer
- Department of Computer Science and Engineering, University of Alaska Anchorage, Anchorage, AK, USA
| | - Timm W Nawrocki
- Alaska Center for Conservation Science, University of Alaska Anchorage, Anchorage, AK, USA
| | - Micah Hahn
- Institute for Circumpolar Health Studies, University of Alaska Anchorage, Anchorage, AK, USA
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26
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Tosato M, Zhang X, Wu J. A patchy model for tick population dynamics with patch-specific developmental delays. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2022; 19:5329-5360. [PMID: 35430867 DOI: 10.3934/mbe.2022250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Tick infestation and tick-borne disease spread in a region of multiple adjacent patches with different environmental conditions depend heavily on the host mobility and patch-specific suitability for tick growth. Here we introduce a two-patch model where environmental conditions differ in patches and yield different tick developmental delays, and where feeding adult ticks can be dispersed by the movement of larger mammal hosts. We obtain a coupled system of four delay differential equations with two delays, and we examine how the dynamical behaviours depend on patch-specific basic reproduction numbers and host mobility by using singular perturbation analyses and monotone dynamical systems theory. Our theoretical results and numerical simulations provide useful insights for tick population control strategies.
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Affiliation(s)
- Marco Tosato
- Laboratory for Industrial and Applied Mathematics, York University, Toronto M2J4A6, Canada
| | - Xue Zhang
- Department of Mathematics, Northeastern University, Shenyang 110057, China
| | - Jianhong Wu
- Laboratory for Industrial and Applied Mathematics, York University, Toronto M2J4A6, Canada
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27
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Current and future distribution of Ixodes scapularis ticks in Québec: Field validation of a predictive model. PLoS One 2022; 17:e0263243. [PMID: 35113941 PMCID: PMC8812838 DOI: 10.1371/journal.pone.0263243] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 01/17/2022] [Indexed: 11/19/2022] Open
Abstract
The incidence of Lyme disease is increasing in Québec and is closely linked to the distribution of Ixodes scapularis ticks. A time-to-establishment model developed in 2012 by Leighton and colleagues predicted the year of tick population establishment for each municipality in eastern Canada. To validate if this model correctly predicted tick distribution in Québec, predicted tick establishment was compared to field data from active tick surveillance (2010-2018) using two criteria: i) the detection of at least one tick and ii) the detection of the three questing stages of the tick. The speed of tick establishment and the increase in the exposed human population by 2100 were predicted with the time-to-establishment model. Field observations were consistent with model predictions. Ticks were detected on average 3 years after the predicted year. The probability of tick detection is significantly higher after the predicted year than before (61% vs 27% of collections). The trend was similar for the detection of three tick stages (16% vs 9% of collections). The average speed of tick range expansion was estimated by the model to be 18 km/year in Québec, with 90% of the human population exposed by 2027. The validation of the time-to-establishment model using field data confirmed that it could be used to project I. scapularis range expansion in Québec, and consequently the increase in Lyme disease risk over the coming decades. This will help public health authorities anticipate and adapt preventive measures, especially in areas not yet affected by Lyme disease.
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28
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Bacon EA, Kopsco H, Gronemeyer P, Mateus-Pinilla N, Smith RL. Effects of Climate on the Variation in Abundance of Three Tick Species in Illinois. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:700-709. [PMID: 34875079 PMCID: PMC8924963 DOI: 10.1093/jme/tjab189] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Indexed: 06/01/2023]
Abstract
The range of ticks in North America has been steadily increasing likely, in part, due to climate change. Along with it, there has been a rise in cases of tick-borne disease. Among those medically important tick species of particular concern are Ixodes scapularis Say (Acari: Ixodidae), Dermacentor variabilis Say (Acari: Ixodidae), and Amblyomma americanum Linneaus (Acari: Ixodidae). The aim of this study was to determine if climate factors explain existing differences in abundance of the three aforementioned tick species between two climatically different regions of Illinois (Central and Southern), and if climate variables impact each species differently. We used both zero-inflated regression approaches and Bayesian network analyses to assess relationships among environmental variables and tick abundance. Results suggested that the maximum average temperature and total precipitation are associated with differential impact on species abundance and that this difference varied by region. Results also reinforced a differential level of resistance to desiccation among these tick species. Our findings help to further define risk periods of tick exposure for the general public, and reinforce the importance of responding to each tick species differently.
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Affiliation(s)
- E A Bacon
- College of Veterinary Medicine, University of Illinois, Urbana IL, USA
| | - H Kopsco
- College of Veterinary Medicine, University of Illinois, Urbana IL, USA
| | - P Gronemeyer
- College of Veterinary Medicine, University of Illinois, Urbana IL, USA
| | - N Mateus-Pinilla
- College of Veterinary Medicine, University of Illinois, Urbana IL, USA
| | - R L Smith
- College of Veterinary Medicine, University of Illinois, Urbana IL, USA
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29
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Volk MR, Lubelczyk CB, Johnston JC, Levesque DL, Gardner AM. Microclimate conditions alter Ixodes scapularis (Acari: Ixodidae) overwinter survival across climate gradients in Maine, United States. Ticks Tick Borne Dis 2021; 13:101872. [PMID: 34826798 DOI: 10.1016/j.ttbdis.2021.101872] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 11/02/2021] [Accepted: 11/16/2021] [Indexed: 10/19/2022]
Abstract
The incidence and geographic range of vector-borne diseases have been expanding in recent decades, attributed in part to global climate change. Blacklegged ticks (Ixodes scapularis), the primary vector for multiple tick-borne pathogens in North America, are spreading rapidly beyond their historic post-colonial range and are thought to be constrained mainly by winter temperature at northern latitudes. Our research explored whether winter climate currently limits the distribution of blacklegged ticks and the pathogens they transmit in Maine, U.S.A., by contributing to overwinter mortality of nymphs. We experimentally tested tick overwinter survival across large-scale temperature and snowfall gradients and assessed factors contributing to winter mortality in locations where blacklegged tick populations are currently established and locations where the blacklegged tick has not yet been detected. We also tested the hypothesis that insulation in the tick microhabitat (i.e., by leaf litter and snowpack) can facilitate winter survival of blacklegged tick nymphs despite inhospitable ambient conditions. Overwinter survival was not significantly different in coastal southern compared to coastal and inland northern Maine, most likely due to sufficient snowpack that protected against low ambient temperatures at high latitudes. Snow cover and leaf litter contributed significantly to overwinter survival at sites in both southern and northern Maine. To further assess whether the current distribution of blacklegged ticks in Maine aligns with patterns of overwinter survival, we systematically searched for and collected ticks at seven sites along latitudinal and coastal-inland climate gradients across the state. We found higher densities of blacklegged ticks in coastal southern Maine (90.2 ticks/1000 m2) than inland central Maine (17.8 ticks/1000 m2) and no blacklegged ticks in inland northern Maine. Our results suggest that overwinter survival is not the sole constraint on the blacklegged tick distribution even under extremely cold ambient conditions and additional mechanisms may limit the continued northward expansion of ticks.
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Affiliation(s)
- Michelle R Volk
- School of Biology and Ecology, University of Maine, 5722 Deering Hall, Orono, ME 04469
| | - Charles B Lubelczyk
- Vector-Borne Disease Laboratory, Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME 04074
| | - Jason C Johnston
- College of Arts and Sciences, University of Maine at Presque Isle, 181 Main Street, Presque Isle, ME 04769
| | - Danielle L Levesque
- School of Biology and Ecology, University of Maine, 5722 Deering Hall, Orono, ME 04469
| | - Allison M Gardner
- School of Biology and Ecology, University of Maine, 5722 Deering Hall, Orono, ME 04469.
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Hoy SR, Vucetich LM, Peterson RO, Vucetich JA. Winter Tick Burdens for Moose Are Positively Associated With Warmer Summers and Higher Predation Rates. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.758374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Climate change is expected to modify host-parasite interactions which is concerning because parasites are involved in most food-web links, and parasites have important influences on the structure, productivity and stability of communities and ecosystems. However, the impact of climate change on host–parasite interactions and any cascading effects on other ecosystem processes has received relatively little empirical attention. We assessed host-parasite dynamics for moose (Alces alces) and winter ticks (Dermacentor albipictus) in Isle Royale National Park over a 19-year period. Specifically, we monitored annual tick burdens for moose (estimated from hair loss) and assessed how it covaried with several aspects of seasonal climate, and non-climatic factors, such as moose density, predation on hosts by wolves (Canis lupus) and wolf abundance. Summer temperatures explained half the interannual variance in tick burden with tick burden being greater following hotter summers, presumably because warmer temperatures accelerate the development of tick eggs and increase egg survival. That finding is consistent with the general expectation that warmer temperatures may promote higher parasite burdens. However, summer temperatures are warming less rapidly than other seasons across most regions of North America. Therefore, tick burdens seem to be primarily associated with an aspect of climate that is currently exhibiting a lower rate of change. Tick burdens were also positively correlated with predation rate, which could be due to moose exhibiting risk-sensitive habitat selection (in years when predation risk is high) in such a manner as to increases the encounter rate with questing tick larvae in autumn. However, that positive correlation could also arise if high parasite burdens make moose more vulnerable to predators or because of some other density-dependent process (given that predation rate and moose density are highly correlated). Overall, these results provide valuable insights about interrelationships among climate, parasites, host/prey, and predators.
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31
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Heaney CD, Moon KA, Ostfeld RS, Pollak J, Poulsen MN, Hirsch AG, DeWalle J, Aucott JN, Schwartz BS. Relations of peri-residential temperature and humidity in tick-life-cycle-relevant time periods with human Lyme disease risk in Pennsylvania, USA. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 795:148697. [PMID: 34252768 DOI: 10.1016/j.scitotenv.2021.148697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/22/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
How weather affects tick development and behavior and human Lyme disease remains poorly understood. We evaluated relations of temperature and humidity during critical periods for the tick lifecycle with human Lyme disease. We used electronic health records from 479,344 primary care patients in 38 Pennsylvania counties in 2006-2014. Lyme disease cases (n = 9657) were frequency-matched (5:1) by year, age, and sex. Using daily weather data at ~4 km2 resolution, we created cumulative metrics hypothesized to promote (warm and humid) or inhibit (hot and dry) tick development or host-seeking during nymph development (March 1-May 31), nymph activity (May 1-July 30), and prior year larva activity (Aug 1-Sept 30). We estimated odds ratios (ORs) of Lyme disease by quartiles of each weather variable, adjusting for demographic, clinical, and other weather variables. Exposure-response patterns were observed for higher cumulative same-year temperature, humidity, and hot and dry days (nymph-relevant), and prior year hot and dry days (larva-relevant), with same-year hot and dry days showing the strongest association (4th vs. 1st quartile OR = 0.40; 95% confidence interval [CI] = 0.36, 0.43). Changing temperature and humidity could increase or decrease human Lyme disease risk.
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Affiliation(s)
- Christopher D Heaney
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Katherine A Moon
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | | | - Jonathan Pollak
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Melissa N Poulsen
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Population Health Sciences, Geisinger, Danville, PA, USA.
| | - Annemarie G Hirsch
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Population Health Sciences, Geisinger, Danville, PA, USA.
| | - Joseph DeWalle
- Department of Population Health Sciences, Geisinger, Danville, PA, USA.
| | - John N Aucott
- Johns Hopkins School of Medicine, Department of Medicine, Baltimore, MD, USA.
| | - Brian S Schwartz
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Population Health Sciences, Geisinger, Danville, PA, USA; Johns Hopkins School of Medicine, Department of Medicine, Baltimore, MD, USA.
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Bregnard C, Rais O, Herrmann C, Kahl O, Brugger K, Voordouw MJ. Beech tree masting explains the inter-annual variation in the fall and spring peaks of Ixodes ricinus ticks with different time lags. Parasit Vectors 2021; 14:570. [PMID: 34749794 PMCID: PMC8577035 DOI: 10.1186/s13071-021-05076-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 10/18/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The tick Ixodes ricinus is an important vector of tick-borne diseases including Lyme borreliosis. In continental Europe, the nymphal stage of I. ricinus often has a bimodal phenology with a large spring peak and a smaller fall peak. There is consensus about the origin of the spring nymphal peak, but there are two alternative hypotheses for the fall nymphal peak. In the direct development hypothesis, larvae quest as nymphs in the fall of the same year that they obtained their larval blood meal. In the developmental diapause hypothesis, larvae overwinter in the engorged state and quest as nymphs one year after they obtained their larval blood meal. These two hypotheses make different predictions about the time lags that separate the larval blood meal and the density of questing nymphs (DON) in the spring and fall. METHODS Inter-annual variation in seed production (masting) by deciduous trees is a time-lagged index for the density of vertebrate hosts (e.g., rodents) which provide blood meals for larval ticks. We used a long-term data set on the masting of the European beech tree and a 15-year study on the DON at 4 different elevation sites in western Switzerland to differentiate between the two alternative hypotheses for the origin of the fall nymphal peak. RESULTS Questing I. ricinus nymphs had a bimodal phenology at the three lower elevation sites, but a unimodal phenology at the top elevation site. At the lower elevation sites, the DON in the fall was strongly correlated with the DON in the spring of the following year. The inter-annual variation in the densities of I. ricinus nymphs in the fall and spring was best explained by a 1-year versus a 2-year time lag with the beech tree masting index. Fall nymphs had higher fat content than spring nymphs indicating that they were younger. All these observations are consistent with the direct development hypothesis for the fall peak of I. ricinus nymphs at our study site. Our study provides new insight into the complex bimodal phenology of this important disease vector. CONCLUSIONS Public health officials in Europe should be aware that following a strong mast year, the DON will increase 1 year later in the fall and 2 years later in the spring. Studies of I. ricinus populations with a bimodal phenology should consider that the spring and fall peak in the same calendar year represent different generations of ticks.
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Affiliation(s)
- Cindy Bregnard
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Olivier Rais
- Laboratory of Ecology and Epidemiology of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
- Laboratory of Eco-Epidemiology of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Coralie Herrmann
- Laboratory of Eco-Epidemiology of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Olaf Kahl
- tick-radar GmbH, 10555 Berlin, Germany
| | - Katharina Brugger
- Unit for Veterinary Public Health and Epidemiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria
| | - Maarten J. Voordouw
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
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MacDonald H, Akçay E, Brisson D. The role of host phenology for parasite transmission. THEOR ECOL-NETH 2021; 14:123-143. [PMID: 34721722 PMCID: PMC8549968 DOI: 10.1007/s12080-020-00484-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 09/20/2020] [Indexed: 11/27/2022]
Abstract
Phenology is a fundamental determinant of species distributions, abundances, and interactions. In host–parasite interactions, host phenology can affect parasite fitness due to the temporal constraints it imposes on host contact rates. However, it remains unclear how parasite transmission is shaped by the wide range of phenological patterns observed in nature. We develop a mathematical model of the Lyme disease system to study the consequences of differential tick developmental-stage phenology for the transmission of B. burgdorferi. Incorporating seasonal tick activity can increase B. burgdorferi fitness compared to continuous tick activity but can also prevent transmission completely. B. burgdorferi fitness is greatest when the activity period of the infectious nymphal stage slightly precedes the larval activity period. Surprisingly, B. burgdorferi is eradicated if the larval activity period begins long after the end of nymphal activity due to a feedback with mouse population dynamics. These results highlight the importance of phenology, a common driver of species interactions, for the fitness of a parasite.
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Affiliation(s)
- Hannelore MacDonald
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA
| | - Erol Akçay
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA
| | - Dustin Brisson
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA
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Hacker GM, Jackson BT, Niemela M, Andrews ES, Danforth ME, Pakingan MJ, Novak MG. A Comparison of Questing Substrates and Environmental Factors That Influence Nymphal Ixodes pacificus (Acari: Ixodidae) Abundance and Seasonality in the Sierra Nevada Foothills of California. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1880-1890. [PMID: 33860326 PMCID: PMC8529963 DOI: 10.1093/jme/tjab037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Indexed: 05/08/2023]
Abstract
In California, the western blacklegged tick, Ixodes pacificus Cooley and Kohls, is the principal vector of the Borrelia burgdorferi sensu lato (sl) complex (Spirochaetales: Spirochaetaceae, Johnson et al.), which includes the causative agent of Lyme disease (B. burgdorferi sensu stricto). Ixodes pacificus nymphs were sampled from 2015 to 2017 at one Sierra Nevada foothill site to evaluate our efficiency in collecting this life stage, characterize nymphal seasonality, and identify environmental factors affecting their abundance and infection with B. burgdorferi sl. To assess sampling success, we compared the density and prevalence of I. pacificus nymphs flagged from four questing substrates (logs, rocks, tree trunks, leaf litter). Habitat characteristics (e.g., canopy cover, tree species) were recorded for each sample, and temperature and relative humidity were measured hourly at one location. Generalized linear mixed models were used to assess environmental factors associated with I. pacificus abundance and B. burgdorferi sl infection. In total, 2,033 substrates were sampled, resulting in the collection of 742 I. pacificus nymphs. Seasonal abundance of nymphs was bimodal with peak activity occurring from late March through April and a secondary peak in June. Substrate type, collection year, month, and canopy cover were all significant predictors of nymphal density and prevalence. Logs, rocks, and tree trunks had significantly greater nymphal densities and prevalences than leaf litter. Cumulative annual vapor pressure deficit was the only significant climatic predictor of overall nymphal I. pacificus density and prevalence. No associations were observed between the presence of B. burgdorferi sl in nymphs and environmental variables.
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Affiliation(s)
- Gregory M Hacker
- California Department of Public Health—Vector-Borne Disease Section, Sacramento, CA, USA
- Corresponding author, e-mail:
| | - Bryan T Jackson
- California Department of Public Health—Vector-Borne Disease Section, Sacramento, CA, USA
| | - Michael Niemela
- California Department of Public Health—Vector-Borne Disease Section, Sacramento, CA, USA
| | - Elizabeth S Andrews
- California Department of Public Health—Vector-Borne Disease Section, Sacramento, CA, USA
| | - Mary E Danforth
- California Department of Public Health—Vector-Borne Disease Section, Sacramento, CA, USA
| | - Mary Joyce Pakingan
- California Department of Public Health—Vector-Borne Disease Section, Sacramento, CA, USA
| | - Mark G Novak
- California Department of Public Health—Vector-Borne Disease Section, Sacramento, CA, USA
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35
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Ogden NH, Beard CB, Ginsberg HS, Tsao JI. Possible Effects of Climate Change on Ixodid Ticks and the Pathogens They Transmit: Predictions and Observations. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1536-1545. [PMID: 33112403 PMCID: PMC9620468 DOI: 10.1093/jme/tjaa220] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Indexed: 05/09/2023]
Abstract
The global climate has been changing over the last century due to greenhouse gas emissions and will continue to change over this century, accelerating without effective global efforts to reduce emissions. Ticks and tick-borne diseases (TTBDs) are inherently climate-sensitive due to the sensitivity of tick lifecycles to climate. Key direct climate and weather sensitivities include survival of individual ticks, and the duration of development and host-seeking activity of ticks. These sensitivities mean that in some regions a warming climate may increase tick survival, shorten life-cycles and lengthen the duration of tick activity seasons. Indirect effects of climate change on host communities may, with changes in tick abundance, facilitate enhanced transmission of tick-borne pathogens. High temperatures, and extreme weather events (heat, cold, and flooding) are anticipated with climate change, and these may reduce tick survival and pathogen transmission in some locations. Studies of the possible effects of climate change on TTBDs to date generally project poleward range expansion of geographical ranges (with possible contraction of ranges away from the increasingly hot tropics), upslope elevational range spread in mountainous regions, and increased abundance of ticks in many current endemic regions. However, relatively few studies, using long-term (multi-decade) observations, provide evidence of recent range changes of tick populations that could be attributed to recent climate change. Further integrated 'One Health' observational and modeling studies are needed to detect changes in TTBD occurrence, attribute them to climate change, and to develop predictive models of public- and animal-health needs to plan for TTBD emergence.
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Affiliation(s)
- Nicholas H. Ogden
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, St-Hyacinthe, QC, Canada J2S 2M2
- Groupe de recherche en épidémiologie des zoonoses et santé publique (GREZOSP), Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, QC, Canada J2S 2M2
- Corresponding author,
| | - C. Ben Beard
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - Howard S. Ginsberg
- U.S. Geological Survey, Patuxent Wildlife Research Center, Rhode Island Field Station, University of Rhode Island, Kingston, RI 02881
| | - Jean I. Tsao
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824
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Diuk-Wasser MA, VanAcker MC, Fernandez MP. Impact of Land Use Changes and Habitat Fragmentation on the Eco-epidemiology of Tick-Borne Diseases. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1546-1564. [PMID: 33095859 DOI: 10.1093/jme/tjaa209] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Indexed: 06/11/2023]
Abstract
The incidence of tick-borne diseases has increased in recent decades and accounts for the majority of vector-borne disease cases in temperate areas of Europe, North America, and Asia. This emergence has been attributed to multiple and interactive drivers including changes in climate, land use, abundance of key hosts, and people's behaviors affecting the probability of human exposure to infected ticks. In this forum paper, we focus on how land use changes have shaped the eco-epidemiology of Ixodes scapularis-borne pathogens, in particular the Lyme disease spirochete Borrelia burgdorferi sensu stricto in the eastern United States. We use this as a model system, addressing other tick-borne disease systems as needed to illustrate patterns or processes. We first examine how land use interacts with abiotic conditions (microclimate) and biotic factors (e.g., host community composition) to influence the enzootic hazard, measured as the density of host-seeking I. scapularis nymphs infected with B. burgdorferi s.s. We then review the evidence of how specific landscape configuration, in particular forest fragmentation, influences the enzootic hazard and disease risk across spatial scales and urbanization levels. We emphasize the need for a dynamic understanding of landscapes based on tick and pathogen host movement and habitat use in relation to human resource provisioning. We propose a coupled natural-human systems framework for tick-borne diseases that accounts for the multiple interactions, nonlinearities and feedbacks in the system and conclude with a call for standardization of methodology and terminology to help integrate studies conducted at multiple scales.
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Affiliation(s)
- Maria A Diuk-Wasser
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York
| | - Meredith C VanAcker
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York
| | - Maria P Fernandez
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York
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37
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Hennessy C, Hild K. Are Virginia opossums really ecological traps for ticks? Groundtruthing laboratory observations. Ticks Tick Borne Dis 2021; 12:101780. [PMID: 34298355 DOI: 10.1016/j.ttbdis.2021.101780] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 06/04/2021] [Accepted: 06/28/2021] [Indexed: 11/18/2022]
Abstract
Virginia opossums (Didelphis virginiana) are a common synanthrope in North America, and serve as host to many species of ectoparasites. Research on captive Virginia opossums estimated that opossums eat, on average, 5500 larval ticks (Acari: Ixodidae) per week. To investigate this apparent preference exhibited by opossums for ingesting ticks, we comprehensively analyzed stomach contents of 32 Virginia opossums from central Illinois. Using a dissecting microscope, we searched the contents exhaustively for ticks and tick body parts, without sieving or pre-rinsing the stomach contents. We did not locate any ticks or tick parts in the stomach contents of Virginia opossums. We also performed a vigorous literature search for corroborating evidence of tick ingestion. Our search revealed 23 manuscripts that describe diet analyses of Virginia opossums, 19 of which were conducted on stomach or digestive tract contents and four of which were scat-based analyses. None of the studies identified ticks in their analyses of diet items. We conclude that ticks are not a preferred diet item for Virginia opossums. Considering that wildlife unconditioned to laboratory conditions may exhibit non-typical behaviors, we recommend that lab-based studies of wildlife behavior be groundtruthed with studies based in natural conditions.
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Affiliation(s)
- Cecilia Hennessy
- Division of Math and Sciences, Eureka College, Eureka, IL, United States.
| | - Kaitlyn Hild
- Division of Math and Sciences, Eureka College, Eureka, IL, United States
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38
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Fieler AM, Rosendale AJ, Farrow DW, Dunlevy MD, Davies B, Oyen K, Xiao Y, Benoit JB. Larval thermal characteristics of multiple ixodid ticks. Comp Biochem Physiol A Mol Integr Physiol 2021; 257:110939. [PMID: 33794367 PMCID: PMC8500258 DOI: 10.1016/j.cbpa.2021.110939] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 11/26/2022]
Abstract
Temperature limits the geographic ranges of several tick species. Little is known about the thermal characteristics of these pests outside of a few studies on survival related to thermal tolerance. In this study, thermal tolerance limits, thermal preference, and the impact of temperature on activity levels and metabolic rate were examined in larvae for six species of ixodid ticks. Tolerance of low temperatures ranged from -15 to -24 °C with Dermacentor andersoni surviving the lowest temperatures. High temperature survival ranged from 41 to 47 °C, with Rhipicephalus sanguineus sensu lato having the highest upper lethal limit. Ixodes scapularis showed the lowest survival at both low and high temperatures. Thermal preference temperatures were tested from 0 to 41 °C. The majority of species preferred temperatures between 17 and 22 °C, while Dermacentor variabilis preferred significantly lower temperatures, near 12 °C. Overall activity was measured across a range of temperatures from 10 to 60 °C, and most tick species had the greatest activity near 30 °C. Metabolic rate was the greatest between 30 and 40 °C for all tick species and was relatively stable from 5 to 20 °C. The optimal temperature for tick larvae is likely near the thermal preference for each species, where oxygen consumption is low and activity occurs that will balance questing and conservation of nutrient reserves. In summary, tick species vary greatly in their thermal characteristics, and our results will be critical to predict distribution of these ectoparasites with changing climates.
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Affiliation(s)
- Alicia M Fieler
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Andrew J Rosendale
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA; Department of Biology, Mount St. Joseph University, Cincinnati, OH, USA
| | - David W Farrow
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Megan D Dunlevy
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Benjamin Davies
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Kennan Oyen
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Yanyu Xiao
- Department of Mathematical Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA.
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39
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Zhang X, Wu J. Synchronized Tick Population Oscillations Driven by Host Mobility and Spatially Heterogeneous Developmental Delays Combined. Bull Math Biol 2021; 83:61. [PMID: 33870474 PMCID: PMC8053666 DOI: 10.1007/s11538-021-00874-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 02/23/2021] [Indexed: 12/05/2022]
Abstract
We consider a coupled system of delay differential equations for a single-species tick population dynamics, assuming feeding adult ticks are distributed by their hosts in a spatially heterogeneous environment consisting of two patches where egg ticks produced will complete their life cycles with different, normal and diapause, developmental delays. We show that the mobility of adult tick host and the diapause developmental delay combined drive a synchronized oscillation in the total tick populations around a uniquely defined positive equilibrium, and this synchronization makes the oscillatory patterns much simpler in comparison with multi-peak oscillations exhibited in the absence of host mobility.
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Affiliation(s)
- Xue Zhang
- College of Science, Northeastern University, Shenyang, 110819 Liaoning China
| | - Jianhong Wu
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, ON M3J 1P3 Canada
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40
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Ratti V, Winter JM, Wallace DI. Dilution and amplification effects in Lyme disease: Modeling the effects of reservoir-incompetent hosts on Borrelia burgdorferi sensu stricto transmission. Ticks Tick Borne Dis 2021; 12:101724. [PMID: 33878571 DOI: 10.1016/j.ttbdis.2021.101724] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 11/19/2022]
Abstract
The literature on Lyme disease includes a lively debate about the paradoxical role of changing deer populations. A decrease in the number of deer will both (1) reduce the incidence of Lyme disease by decreasing the host populations for ticks and therefore tick populations, and (2) enhance the incidence of Lyme disease by offering fewer reservoir-incompetent hosts for ticks, forcing the vector to choose reservoir-competent, and therefore possibly diseased, hosts to feed on. A review of field studies exploring the net impact of changing deer populations shows mixed results. In this manuscript, we investigate the hypothesis that the balance of these two responses to changing deer populations depends on the relative population sizes of reservoir-competent vs. reservoir-incompetent hosts and the presence of host preference in larval and adult stages. A temperature driven seasonal model of Borrelia burgdorferi sensu stricto (cause of Lyme disease) transmission among three host types (reservoir-competent infected and uninfected hosts, and reservoir-incompetent hosts) is constructed as a system of nonlinear ordinary differential equations. The model, which produces biologically reasonable results for both the tick vector Ixodes scapularis Say 1921 and the hosts, is used to investigate the effects of reservoir-incompetent host removal on both tick populations and disease prevalence for various relative population sizes of reservoir-competent hosts vs. reservoir-incompetent hosts. In summary, the simulation results show that the model with host preference appears to be more accurate than the one with no host preference. Given these results, we found that removal of adult I. scapularis(Say) hosts is likely to reduce questing nymph populations. At very low levels questing adult abundance may rise with lack of adult hosts. There is a dilution effect at low reservoir-competent host populations and there is an amplification effect at high reservoir-competent host populations.
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Affiliation(s)
- Vardayani Ratti
- Department of Mathematics and Statistics, California State University Chico, CA, United States.
| | - Jonathan M Winter
- Department of Geography, Dartmouth College, Hanover, NH, United States
| | - Dorothy I Wallace
- Department of Mathematics, Dartmouth College, Hanover, NH, United States
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Bregnard C, Rais O, Voordouw MJ. Masting by beech trees predicts the risk of Lyme disease. Parasit Vectors 2021; 14:168. [PMID: 33743800 PMCID: PMC7980658 DOI: 10.1186/s13071-021-04646-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 02/16/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The incidence of Lyme borreliosis and other tick-borne diseases is increasing in Europe and North America. There is currently much interest in identifying the ecological factors that determine the density of infected ticks as this variable determines the risk of Lyme borreliosis to vertebrate hosts, including humans. Lyme borreliosis is caused by the bacterium Borrelia burgdorferi sensu lato (s.l.) and in western Europe, the hard tick Ixodes ricinus is the most important vector. METHODS Over a 15-year period (2004-2018), we monitored the monthly abundance of I. ricinus ticks (nymphs and adults) and their B. burgdorferi s.l. infection status at four different elevations on a mountain in western Switzerland. We collected climate variables in the field and from nearby weather stations. We obtained data on beech tree seed production (masting) from the literature, as the abundance of Ixodes nymphs can increase dramatically 2 years after a masting event. We used generalized linear mixed effects models and AIC-based model selection to identify the ecological factors that influence inter-annual variation in the nymphal infection prevalence (NIP) and the density of infected nymphs (DIN). RESULTS We found that the NIP decreased by 78% over the study period. Inter-annual variation in the NIP was explained by the mean precipitation in the present year, and the duration that the DNA extraction was stored in the freezer prior to pathogen detection. The DIN decreased over the study period at all four elevation sites, and the decrease was significant at the top elevation. Inter-annual variation in the DIN was best explained by elevation site, year, beech tree masting index 2 years prior and the mean relative humidity in the present year. This is the first study in Europe to demonstrate that seed production by deciduous trees influences the density of nymphs infected with B. burgdorferi s.l. and hence the risk of Lyme borreliosis. CONCLUSIONS Public health officials in Europe should be aware that masting by deciduous trees is an important predictor of the risk of Lyme borreliosis.
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Affiliation(s)
- Cindy Bregnard
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Olivier Rais
- Laboratory of Ecology and Epidemiology of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Maarten Jeroen Voordouw
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
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Lumsden GAM, Zakharov EV, Dolynskyj S, Weese JS, Lindsay LR, Jardine C. Temporal Detection Limits of Remnant Larval Bloodmeals in Nymphal Ixodes scapularis (Say, Ixodida: Ixodidae) Using Two Next-Generation Sequencing DNA Barcoding Assays. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:821-829. [PMID: 33095865 DOI: 10.1093/jme/tjaa192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Indexed: 06/11/2023]
Abstract
Using next-generation sequencing DNA barcoding, we aimed to determine: 1) if the larval bloodmeal can be detected in Ixodes scapularis nymphs and 2) the post-moult temporal window for detection of the larval bloodmeal. Subsets of 30 nymphs fed on a domestic rabbit (Oryctolagus cuniculus Linnaeus, Lagomorphia: Leporidae) as larvae were reared and frozen at 11 time points post-moult, up to 150 d. Vertebrate DNA was amplified using novel universal (UP) and species-specific primers (SSP) and sequenced for comparison against cytochrome c oxidase subunit I barcodes to infer host identification. Detectable bloodmeals decreased as time since moult increased for both assays. For the SSP assay, detection of bloodmeals decreased from 96.7% (n = 29/30) in day 0 nymphs to 3.3% (n = 1/30) and 6.7% (n = 2/30) at 4- and 5-mo post-moult, respectively. A shorter temporal detection period was achieved with the UP assay, declining from 16.7% (n = 5/30) in day 0 nymphs to 0/30 in 3-d-old nymphs. Bloodmeal detection was nonexistent for the remaining cohorts, with the exception of 1/30 nymphs at 2-mo post-moult. Host detection was significantly more likely using the SSP assay compared to the UP assay in the first three time cohorts (day 0: χ 2 = 39.1, P < 0.005; day 2: χ 2 = 19.2, P < 0.005; day 3: χ 2 = 23.3, P < 0.005). Regardless of the primer set used, the next-generation sequencing DNA barcoding assay was able to detect host DNA from a larval bloodmeal in the nymphal life stage; however, a short window with a high proportion of detection post-moult was achieved.
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Affiliation(s)
| | - Evgeny V Zakharov
- Canadian Centre for DNA Barcoding, Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada
| | - Sarah Dolynskyj
- Canadian Centre for DNA Barcoding, Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada
| | - J Scott Weese
- Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - L Robbin Lindsay
- Public Health Agency of Canada, National Microbiology Laboratory, Winnipeg, Manitoba, Canada
| | - Claire Jardine
- Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
- Canadian Wildlife Health Cooperative, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
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43
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Alkishe A, Raghavan RK, Peterson AT. Likely Geographic Distributional Shifts among Medically Important Tick Species and Tick-Associated Diseases under Climate Change in North America: A Review. INSECTS 2021; 12:225. [PMID: 33807736 PMCID: PMC8001278 DOI: 10.3390/insects12030225] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 12/15/2022]
Abstract
Ticks rank high among arthropod vectors in terms of numbers of infectious agents that they transmit to humans, including Lyme disease, Rocky Mountain spotted fever, Colorado tick fever, human monocytic ehrlichiosis, tularemia, and human granulocytic anaplasmosis. Increasing temperature is suspected to affect tick biting rates and pathogen developmental rates, thereby potentially increasing risk for disease incidence. Tick distributions respond to climate change, but how their geographic ranges will shift in future decades and how those shifts may translate into changes in disease incidence remain unclear. In this study, we have assembled correlative ecological niche models for eight tick species of medical or veterinary importance in North America (Ixodes scapularis, I. pacificus, I. cookei, Dermacentor variabilis, D. andersoni, Amblyomma americanum, A. maculatum, and Rhipicephalus sanguineus), assessing the distributional potential of each under both present and future climatic conditions. Our goal was to assess whether and how species' distributions will likely shift in coming decades in response to climate change. We interpret these patterns in terms of likely implications for tick-associated diseases in North America.
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Affiliation(s)
- Abdelghafar Alkishe
- Biodiversity Institute, University of Kansas, Lawrence, KS 66045, USA
- Zoology Department, Faculty of Science, University of Tripoli, Tripoli, Libya
| | - Ram K. Raghavan
- Center for Vector-borne and Emerging Infectious Diseases, Departments of Veterinary Pathobiology and Public Health, College of Veterinary Medicine and School of Health Professions, University of Missouri, Columbia, MO 65211, USA;
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44
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Saleh MN, Allen KE, Lineberry MW, Little SE, Reichard MV. Ticks infesting dogs and cats in North America: Biology, geographic distribution, and pathogen transmission. Vet Parasitol 2021; 294:109392. [PMID: 33971481 PMCID: PMC9235321 DOI: 10.1016/j.vetpar.2021.109392] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/20/2021] [Accepted: 02/15/2021] [Indexed: 12/12/2022]
Abstract
A diverse array of ixodid and argasid ticks infest dogs and cats in North America, resulting in skin lesions, blood loss, and disease. The ticks most commonly found on pets in this region are hard ticks of the genera Amblyomma, Dermacentor, Ixodes, and Rhipicephalus, as well as the more recently established Haemaphysalis longicornis. Soft tick genera, especially Otobius and Ornithodoros, are also reported from pets in some regions. In this review, we provide a summary of the complex and diverse life histories, distinct morphologies, and questing and feeding behaviors of the more common ticks of dogs and cats in North America with a focus on recent changes in geographic distribution. We also review pathogens of dogs and cats associated with the different tick species, some of which can cause serious, potentially fatal disease, and describe the zoonotic risk posed by ticks of pets. Understanding the natural history of ticks and the maintenance cycles responsible for providing an ongoing source of tick-borne infections is critical to effectively combatting the challenges ticks pose to the health of pets and people.
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Affiliation(s)
- Meriam N Saleh
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, 74078, United States
| | - Kelly E Allen
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, 74078, United States.
| | - Megan W Lineberry
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, 74078, United States
| | - Susan E Little
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, 74078, United States
| | - Mason V Reichard
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, 74078, United States
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45
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Lumsden GA, Zakharov EV, Dolynskyj S, Weese JS, Lindsay LR, Jardine CM. The application of next-generation sequence-based DNA barcoding for bloodmeal detection in host-seeking wild-caught Ixodes scapularis nymphs. BMC Res Notes 2021; 14:67. [PMID: 33602311 PMCID: PMC7891142 DOI: 10.1186/s13104-021-05481-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 02/10/2021] [Indexed: 11/10/2022] Open
Abstract
Objective Our objective was to apply next-generation sequence-based DNA barcoding to identify the remnant larval bloodmeals in wild-caught host-seeking (unengorged) Ixodes scapularis nymphs (n = 216). To infer host species identification, vertebrate DNA was amplified using universal primers for cytochrome c oxidase subunit I (COI) and sequenced using next-generation sequencing (NGS) for comparison against known barcode references. Results Bloodmeal identification was unsuccessful in most samples (99% of 216 specimens) demonstrating a very low detection rate of this assay. Sequences that surpassed quality thresholds were obtained for 41.7% of nymphs (n = 90) and of those, confident species identification was obtained for 15.6% of nymphs (n = 14). Wild host identifications were only obtained from 2 specimens, where DNA from the eastern grey squirrel (Sciurus carolinensis) was identified. Human and bovine DNA was identified in remaining nymphs and considered to be contaminants. Further optimization of the technique is required to improve detection of remnant bloodmeals in host-seeking nymphs.
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Affiliation(s)
- G A Lumsden
- Ontario Veterinary College, University of Guelph, 50 Stone Road E., Guelph, ON, N1G2W1, Canada.
| | - E V Zakharov
- Canadian Centre for DNA Barcoding, Biodiversity Institute of Ontario, University of Guelph, 579 Gordon St., Guelph, ON, N1G2W1, Canada
| | - S Dolynskyj
- Canadian Centre for DNA Barcoding, Biodiversity Institute of Ontario, University of Guelph, 579 Gordon St., Guelph, ON, N1G2W1, Canada
| | - J S Weese
- Ontario Veterinary College, University of Guelph, 50 Stone Road E., Guelph, ON, N1G2W1, Canada
| | - L R Lindsay
- Public Health Agency of Canada, National Microbiology Laboratory, 1015 Arlington St., Winnipeg, MB, R3E 3R2, Canada
| | - C M Jardine
- Ontario Veterinary College, University of Guelph, 50 Stone Road E., Guelph, ON, N1G2W1, Canada.,Canadian Wildlife Health Cooperative, Ontario Veterinary College, University of Guelph, 50 Stone Road E., Guelph, ON, N1G2W1, Canada
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46
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Couper LI, MacDonald AJ, Mordecai EA. Impact of prior and projected climate change on US Lyme disease incidence. GLOBAL CHANGE BIOLOGY 2021; 27:738-754. [PMID: 33150704 PMCID: PMC7855786 DOI: 10.1111/gcb.15435] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/28/2020] [Indexed: 05/21/2023]
Abstract
Lyme disease is the most common vector-borne disease in temperate zones and a growing public health threat in the United States (US). The life cycles of the tick vectors and spirochete pathogen are highly sensitive to climate, but determining the impact of climate change on Lyme disease burden has been challenging due to the complex ecology of the disease and the presence of multiple, interacting drivers of transmission. Here we incorporated 18 years of annual, county-level Lyme disease case data in a panel data statistical model to investigate prior effects of climate variation on disease incidence while controlling for other putative drivers. We then used these climate-disease relationships to project Lyme disease cases using CMIP5 global climate models and two potential climate scenarios (RCP4.5 and RCP8.5). We find that interannual variation in Lyme disease incidence is associated with climate variation in all US regions encompassing the range of the primary vector species. In all regions, the climate predictors explained less of the variation in Lyme disease incidence than unobserved county-level heterogeneity, but the strongest climate-disease association detected was between warming annual temperatures and increasing incidence in the Northeast. Lyme disease projections indicate that cases in the Northeast will increase significantly by 2050 (23,619 ± 21,607 additional cases), but only under RCP8.5, and with large uncertainty around this projected increase. Significant case changes are not projected for any other region under either climate scenario. The results demonstrate a regionally variable and nuanced relationship between climate change and Lyme disease, indicating possible nonlinear responses of vector ticks and transmission dynamics to projected climate change. Moreover, our results highlight the need for improved preparedness and public health interventions in endemic regions to minimize the impact of further climate change-induced increases in Lyme disease burden.
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Affiliation(s)
- Lisa I Couper
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Andrew J MacDonald
- Earth Research Institute, University of California, Santa Barbara, CA, USA
- Bren School of Environmental Science and Management, University of California, Santa Barbara, CA, USA
| | - Erin A Mordecai
- Department of Biology, Stanford University, Stanford, CA, USA
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47
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Bansal N, Pomroy WE, Heath ACG, Castro I. Aspects of the development of Ixodes anatis under different environmental conditions in the laboratory and in the field. Parasit Vectors 2021; 14:85. [PMID: 33509249 PMCID: PMC7841883 DOI: 10.1186/s13071-021-04601-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 11/19/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Numerous laboratory and fewer field-based studies have found that ixodid ticks develop more quickly and survive better at temperatures between 18 °C and 26 °C and relative humidity (RH) between 75 and 94%. Ixodes anatis Chilton, 1904, is an endophilic, nidicolous species endemic to North Island brown kiwi (Apteryx mantelli) (NIBK) and the tokoeka (Apteryx australis), and little is known about the environmental conditions required for its development. The aims of this study were to determine and compare the conditions of temperature and RH that ensure the best survival of the kiwi tick and the shortest interstadial periods, in laboratory conditions and outdoors inside artificial kiwi burrows. METHODS Free-walking engorged ticks were collected off wild kiwi hosts and placed in the laboratory under various fixed temperature and humidity regimes. In addition, sets of the collected ticks at different developmental stages were placed in artificial kiwi burrows. In both settings, we recorded the times taken for the ticks to moult to the next stage. RESULTS Larvae and nymphs both showed optimum development at between 10 °C and 20 °C, which is lower than the optimum temperature for development in many other species of ixodid ticks. However, larvae moulted quicker and survived better when saturation deficits were < 1-2 mmHg (RH > 94%); in comparison, the optimum saturation deficits for nymph development were 1-10 mmHg. CONCLUSIONS Our results suggest that the kiwi tick has adapted to the stable, but relatively cool and humid conditions in kiwi burrows, reflecting the evolutionary consequences of its association with the kiwi.
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Affiliation(s)
- Natasha Bansal
- School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, New Zealand. .,Wildbase Research, Massey University, Private Bag 11222, Palmerston North, New Zealand.
| | - William E Pomroy
- School of Veterinary Science, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - Allen C G Heath
- AgResearch Ltd, Hopkirk Research Institute, Massey University, Private Bag 11008, Palmerston North, 4442, New Zealand
| | - Isabel Castro
- School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, New Zealand.,Wildbase Research, Massey University, Private Bag 11222, Palmerston North, New Zealand
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48
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Elias SP, Gardner AM, Maasch KA, Birkel SD, Anderson NT, Rand PW, Lubelczyk CB, Smith RP. A Generalized Additive Model Correlating Blacklegged Ticks With White-Tailed Deer Density, Temperature, and Humidity in Maine, USA, 1990-2013. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:125-138. [PMID: 32901284 DOI: 10.1093/jme/tjaa180] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Geographical range expansions of blacklegged tick [Ixodes scapularis Say (Acari: Ixodidae)] populations over time in the United States have been attributed to a mosaic of factors including 20th century reforestation followed by suburbanization, burgeoning populations of the white-tailed deer [Odocoileus virginianus Zimmerman (Artiodactyla: Cervidae)], and, at the northern edge of I. scapularis' range, climate change. Maine, a high Lyme disease incidence state, has been experiencing warmer and shorter winter seasons, and relatively more so in its northern tier. Maine served as a case study to investigate the interacting impacts of deer and seasonal climatology on the spatial and temporal distribution of I. scapularis. A passive tick surveillance dataset indexed abundance of I. scapularis nymphs for the state, 1990-2013. With Maine's wildlife management districts as the spatial unit, we used a generalized additive model to assess linear and nonlinear relationships between I. scapularis nymph abundance and predictors. Nymph submission rate increased with increasing deer densities up to ~5 deer/km2 (13 deer/mi2), but beyond this threshold did not vary with deer density. This corroborated the idea of a saturating relationship between I. scapularis and deer density. Nymphs also were associated with warmer minimum winter temperatures, earlier degree-day accumulation, and higher relative humidity. However, nymph abundance only increased with warmer winters and degree-day accumulation where deer density exceeded ~2 deer/km2 (~6/mi2). Anticipated increases in I. scapularis in the northern tier could be partially mitigated through deer herd management.
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Affiliation(s)
- Susan P Elias
- Maine Medical Center Research Institute, Vector-borne Disease Research Laboratory, Scarborough, ME
| | | | - Kirk A Maasch
- School of Earth and Climate Sciences, University of Maine, Orono, ME
- Climate Change Institute, University of Maine, Orono, ME
| | - Sean D Birkel
- School of Earth and Climate Sciences, University of Maine, Orono, ME
- Climate Change Institute, University of Maine, Orono, ME
| | | | - Peter W Rand
- Maine Medical Center Research Institute, Vector-borne Disease Research Laboratory, Scarborough, ME
| | - Charles B Lubelczyk
- Maine Medical Center Research Institute, Vector-borne Disease Research Laboratory, Scarborough, ME
| | - Robert P Smith
- Maine Medical Center Research Institute, Vector-borne Disease Research Laboratory, Scarborough, ME
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49
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Winter JM, Partridge TF, Wallace D, Chipman JW, Ayres MP, Osterberg EC, Dekker ER. Modeling the Sensitivity of Blacklegged Ticks (Ixodes scapularis) to Temperature and Land Cover in the Northeastern United States. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:416-427. [PMID: 32901803 DOI: 10.1093/jme/tjaa179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Indexed: 06/11/2023]
Abstract
The prevalence of Lyme disease and other tick-borne diseases is dramatically increasing across the United States. While the rapid rise in Lyme disease is clear, the causes of it are not. Modeling Ixodes scapularis Say (Acari: Ixodidae), the primary Lyme disease vector in the eastern United States, presents an opportunity to disentangle the drivers of increasing Lyme disease, including climate, land cover, and host populations. We improved upon a recently developed compartment model of ordinary differential equations that simulates I. scapularis growth, abundance, and infection with Borrelia burgdorferi (Spirochaetales: Spirochaetaceae) by adding land cover effects on host populations, refining the representation of growth stages, and evaluating output against observed data. We then applied this model to analyze the sensitivity of simulated I. scapularis dynamics across temperature and land cover in the northeastern United States. Specifically, we ran an ensemble of 232 simulations with temperature from Hanover, New Hampshire and Storrs, Connecticut, and land cover from Hanover and Cardigan in New Hampshire, and Windsor and Danielson in Connecticut. Consistent with observations, simulations of I. scapularis abundance are sensitive to temperature, with the warmer Storrs climate significantly increasing the number of questing I. scapularis at all growth stages. While there is some variation in modeled populations of I. scapularis infected with B. burgdorferi among land cover distributions, our analysis of I. scapularis response to land cover is limited by a lack of observations describing host populations, the proportion of hosts competent to serve as B. burgdorferi reservoirs, and I. scapularis abundance.
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Affiliation(s)
- Jonathan M Winter
- Department of Geography, Dartmouth College, Hanover, NH
- Department of Earth Sciences, Dartmouth College, Hanover, NH
| | | | | | - Jonathan W Chipman
- Department of Geography, Dartmouth College, Hanover, NH
- Department of Earth Sciences, Dartmouth College, Hanover, NH
| | - Matthew P Ayres
- Department of Biological Sciences, Dartmouth College, Hanover, NH
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50
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Alasmari S, Wall R. Metabolic rate and resource depletion in the tick Ixodes ricinus in response to temperature. EXPERIMENTAL & APPLIED ACAROLOGY 2021; 83:81-93. [PMID: 33175292 PMCID: PMC7736019 DOI: 10.1007/s10493-020-00568-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/04/2020] [Indexed: 05/23/2023]
Abstract
Understanding the effects of temperature on the metabolic activity and the rate of depletion of energy reserves by Ixodes ricinus can represent an important contribution to explaining patterns of tick activity and the likely impacts of environmental change on tick and tick-borne disease risk. Here, a cohort of I. ricinus nymphs, males, and females was collected and placed into incubators at temperatures of between 5 and 30 °C. The protein, carbohydrate, total lipid, neutral lipid, and glycogen levels were measured for nymphs for up to 70 days and adults up to 42 days. In nymphs, at day 0, glycogen was the most abundant metabolite followed by carbohydrate, with relatively low concentrations of protein and lipids. For males, the concentrations of different metabolites were relatively similar. In contrast, for females, concentrations of glycogen and carbohydrate were relatively low compared to those of protein and neutral lipids. Significant exponential declines in metabolite concentrations of all metabolites were detected over time for all life-cycle stages and at all temperatures. Nymphs generally showed lower rates of resource depletion than adults at all temperatures. The lower thresholds for metabolic activity were estimated to be between -10 and -5 °C. The Q10 values, which describe the thermal sensitivity of metabolic rate, were estimated to be relatively low (1.5 for nymphs, 1.71 for males, and 1.63 for females) compared to insects where they are typically around 2.5 (range: 1.5-3), and this is considered to be an adaptation to increase survival during the extended inter-feed intervals.
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Affiliation(s)
- Saeed Alasmari
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.
| | - Richard Wall
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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