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Sirén APK, Berube J, Clarfeld LA, Sullivan CF, Simpson B, Wilson TL. Accounting for missing ticks: Use (or lack thereof) of hierarchical models in tick ecology studies. Ticks Tick Borne Dis 2024; 15:102342. [PMID: 38613901 DOI: 10.1016/j.ttbdis.2024.102342] [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: 10/30/2023] [Revised: 03/20/2024] [Accepted: 04/01/2024] [Indexed: 04/15/2024]
Abstract
Ixodid (hard) ticks play important ecosystem roles and have significant impacts on animal and human health via tick-borne diseases and physiological stress from parasitism. Tick occurrence, abundance, activity, and key life-history traits are highly influenced by host availability, weather, microclimate, and landscape features. As such, changes in the environment can have profound impacts on ticks, their hosts, and the spread of diseases. Researchers recognize that spatial and temporal factors influence activity and abundance and attempt to account for both by conducting replicate sampling bouts spread over the tick questing period. However, common field methods notoriously underestimate abundance, and it is unclear how (or if) tick studies model the confounding effects of factors influencing activity and abundance. This step is critical as unaccounted variance in detection can lead to biased estimates of occurrence and abundance. We performed a descriptive review to evaluate the extent to which studies account for the detection process while modeling tick data. We also categorized the types of analyses that are commonly used to model tick data. We used hierarchical models (HMs) that account for imperfect detection to analyze simulated and empirical tick data, demonstrating that inference is muddled when detection probability is not accounted for in the modeling process. Our review indicates that only 5 of 412 (1 %) papers explicitly accounted for imperfect detection while modeling ticks. By comparing HMs with the most common approaches used for modeling tick data (e.g., ANOVA), we show that population estimates are biased low for simulated and empirical data when using non-HMs, and that confounding occurs due to not explicitly modeling factors that influenced both detection and abundance. Our review and analysis of simulated and empirical data shows that it is important to account for our ability to detect ticks using field methods with imperfect detection. Not doing so leads to biased estimates of occurrence and abundance which could complicate our understanding of parasite-host relationships and the spread of tick-borne diseases. We highlight the resources available for learning HM approaches and applying them to analyzing tick data.
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Affiliation(s)
- Alexej P K Sirén
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA; Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, USA; Department of Environmental Conservation, University of Massachusetts, Amherst, MA, USA.
| | - Juliana Berube
- Department of Environmental Conservation, University of Massachusetts, Amherst, MA, USA
| | - Laurence A Clarfeld
- Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, USA
| | - Cheryl F Sullivan
- Entomology Research Laboratory, University of Vermont, Burlington, VT, USA
| | - Benjamin Simpson
- Penobscot Nation Department of Natural Resources, Indian Island, ME, USA
| | - Tammy L Wilson
- U.S. Geological Survey, Massachusetts Cooperative Fish and Wildlife Research Unit, Department of Environmental Conservation, University of Massachusetts, Amherst, MA, USA
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Giesen C, Cifo D, Gomez-Barroso D, Estévez-Reboredo RM, Figuerola J, Herrador Z. The Role of Environmental Factors in Lyme Disease Transmission in the European Union: A Systematic Review. Trop Med Infect Dis 2024; 9:113. [PMID: 38787046 PMCID: PMC11125681 DOI: 10.3390/tropicalmed9050113] [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: 01/24/2024] [Revised: 04/01/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Lyme disease (LD) is an emergent vector-borne disease caused by Borrelia spp. and transmitted through infected ticks, mainly Ixodes spp. Our objective was to determine meteorological and environmental factors associated with LD transmission in Europe and the effect of climate change on LD. MATERIALS AND METHODS A systematic review following the PRISMA guidelines was performed. We selected studies on LD transmission in the European Union (EU) and the European Economic Area (EEA) published between 2000 and 2022. The protocol was registered in the PROSPERO database. RESULTS We included 81 studies. The impact of environmental, meteorological or climate change factors on tick vectors was studied in 65 papers (80%), and the impact on human LD cases was studied in 16 papers (19%), whereas animal hosts were only addressed in one study (1%). A significant positive relationship was observed between temperature and precipitation and the epidemiology of LD, although contrasting results were found among studies. Other positive factors were humidity and the expansion of anthropized habitats. CONCLUSIONS The epidemiology of LD seems to be related to climatic factors that are changing globally due to ongoing climate change. Unfortunately, the complete zoonotic cycle was not systematically analyzed. It is important to adopt a One Health approach to understand LD epidemiology.
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Affiliation(s)
- Christine Giesen
- Centro de Salud Internacional Madrid Salud, Ayuntamiento de Madrid, 28006 Madrid, Spain;
| | - Daniel Cifo
- Escuela Nacional de Sanidad, Instituto de Salud Carlos III, 28029 Madrid, Spain;
| | - Diana Gomez-Barroso
- Centro Nacional de Epidemiología, Instituto de Salud Carlos III, 28029 Madrid, Spain; (D.G.-B.); (R.M.E.-R.)
- CIBER Epidemiología y Salud Pública (CIBERESP), 28029 Madrid, Spain;
| | - Rosa M. Estévez-Reboredo
- Centro Nacional de Epidemiología, Instituto de Salud Carlos III, 28029 Madrid, Spain; (D.G.-B.); (R.M.E.-R.)
| | - Jordi Figuerola
- CIBER Epidemiología y Salud Pública (CIBERESP), 28029 Madrid, Spain;
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, 41092 Sevilla, Spain
| | - Zaida Herrador
- Centro Nacional de Epidemiología, Instituto de Salud Carlos III, 28029 Madrid, Spain; (D.G.-B.); (R.M.E.-R.)
- CIBER Epidemiología y Salud Pública (CIBERESP), 28029 Madrid, Spain;
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Are Orienteers Protected Enough against Tick Bites? Estimating Human Exposure to Tick Bites through a Participative Science Survey during an Orienteering Competition. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18063161. [PMID: 33803910 PMCID: PMC8003242 DOI: 10.3390/ijerph18063161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 11/17/2022]
Abstract
Mass-participation events in temperate forests are now well-established features of outdoor activities and represent high-risk activities regarding human exposition to tick bites. In this study we used a citizen science approach to quantify the space-time frequency of tick bites and undetected tick bites among orienteers that participated in a 6-day orienteering competition that took place in July 2018 in the forests of Eastern France, and we looked at the use and efficacy of different preventive behaviors. Our study confirms that orienteers are a high-risk population for tick bites, with 62.4% of orienteers bitten at least once during the competition, and 2.4 to 12.1 orienteers per 100 orienteers were bitten by ticks when walking 1 km. In addition, 16.7% of orienteers bitten by ticks had engorged ticks, meaning that they did not detect and remove their ticks immediately after the run. Further, only 8.5% of orienteers systematically used a repellent, and the use of repellent only partially reduced the probability of being bitten by ticks. These results represent the first attempt to quantify the risk of not immediately detecting a tick bite and provide rare quantitative data on the frequency of tick bites for orienteers according to walking distance and time spent in the forest. The results also provide information on the use of repellent, which will be very helpful for modeling risk assessment. The study also shows that prevention should be increased for orienteers in France.
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Burtis JC, Yavitt JB, Fahey TJ, Ostfeld RS. Ticks as Soil-Dwelling Arthropods: An Intersection Between Disease and Soil Ecology. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:1555-1564. [PMID: 31318035 DOI: 10.1093/jme/tjz116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Indexed: 06/10/2023]
Abstract
Ticks are widespread vectors for many important medical and veterinary infections, and a better understanding of the factors that regulate their population dynamics is needed to reduce risk for humans, wildlife, and domestic animals. Most ticks, and all non-nidicolous tick species, spend only a small fraction of their lives associated with vertebrate hosts, with the remainder spent in or on soils and other substrates. Ecological studies of tick-borne disease dynamics have emphasized tick-host interactions, including host associations, burdens, and efficiencies of pathogen transmission, while under emphasizing tick biology during off-host periods. Our ability to predict spatiotemporal trends in tick-borne diseases requires more knowledge of soil ecosystems and their effect on host and tick populations. In this review, we focus on tick species of medical and veterinary concern and describe: 1) the relationships between soil factors and tick densities; 2) biotic and abiotic factors within the soil ecosystem that directly affect tick survival; 3) potential indirect effects on ticks mediated by soil ecosystem influences on their vertebrate hosts; 4) the potential for tick-mediated effects on vertebrate host populations to affect ecosystems; and 5) possible nontarget impacts of tick management on the soil ecosystem. Soils are complex ecosystem components with enormous potential to affect the survival and behavior of ticks during their off-host periods. Hence, tick-borne disease systems present an excellent opportunity for soil ecologists and public health researchers to collaborate and improve understanding of these medically important and ecologically complex disease cycles.
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Affiliation(s)
- James C Burtis
- Department of Natural Resources, Cornell University, Ithaca, NY
- Department of Entomology, Cornell University, Ithaca, NY
| | - Joseph B Yavitt
- Department of Natural Resources, Cornell University, Ithaca, NY
| | - Timothy J Fahey
- Department of Natural Resources, Cornell University, Ithaca, NY
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Khan MD, Thi Vu HH, Lai QT, Ahn JW. Aggravation of Human Diseases and Climate Change Nexus. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E2799. [PMID: 31390751 PMCID: PMC6696070 DOI: 10.3390/ijerph16152799] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 01/24/2023]
Abstract
For decades, researchers have debated whether climate change has an adverse impact on diseases, especially infectious diseases. They have identified a strong relationship between climate variables and vector's growth, mortality rate, reproduction, and spatiotemporal distribution. Epidemiological data further indicates the emergence and re-emergence of infectious diseases post every single extreme weather event. Based on studies conducted mostly between 1990-2018, three aspects that resemble the impact of climate change impact on diseases are: (a) emergence and re-emergence of vector-borne diseases, (b) impact of extreme weather events, and (c) social upliftment with education and adaptation. This review mainly examines and discusses the impact of climate change based on scientific evidences in published literature. Humans are highly vulnerable to diseases and other post-catastrophic effects of extreme events, as evidenced in literature. It is high time that human beings understand the adverse impacts of climate change and take proper and sustainable control measures. There is also the important requirement for allocation of effective technologies, maintenance of healthy lifestyles, and public education.
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Affiliation(s)
- Mohd Danish Khan
- Resources Recycling Department, University of Science and Technology, (UST), 217, Gajeong-ro, Yuseong-gu, Daejeon-34113, Korea
- Center for Carbon Mineralization, Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources (KIGAM), 124 Gwahak-ro, Yuseong-gu, Daejeon-34132, Korea
| | - Hong Ha Thi Vu
- Center for Carbon Mineralization, Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources (KIGAM), 124 Gwahak-ro, Yuseong-gu, Daejeon-34132, Korea
| | - Quang Tuan Lai
- Resources Recycling Department, University of Science and Technology, (UST), 217, Gajeong-ro, Yuseong-gu, Daejeon-34113, Korea
- Center for Carbon Mineralization, Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources (KIGAM), 124 Gwahak-ro, Yuseong-gu, Daejeon-34132, Korea
| | - Ji Whan Ahn
- Center for Carbon Mineralization, Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources (KIGAM), 124 Gwahak-ro, Yuseong-gu, Daejeon-34132, Korea.
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Hauser G, Rais O, Morán Cadenas F, Gonseth Y, Bouzelboudjen M, Gern L. Influence of climatic factors on Ixodes ricinus nymph abundance and phenology over a long-term monthly observation in Switzerland (2000-2014). Parasit Vectors 2018; 11:289. [PMID: 29739424 PMCID: PMC5941567 DOI: 10.1186/s13071-018-2876-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/26/2018] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND One of the major public health challenges in the field of communicable diseases consists of being able to predict where and when a population is at risk of being infected by a pathogen. In the case of vector-borne diseases, such predictions often require strong ecological knowledge of the vector life-cycle and the environmental conditions promoting or preventing its establishment and maintenance. In this study, we analyse how climatic factors influence the abundance and phenology of the Lyme borreliosis vector Ixodes ricinus in a Swiss temperate forest, based on a long-term monthly observation over a period of 15 years (2000 and 2014). RESULTS Our results show that questing nymph density significantly decreased during the study period in the sampling area. Although the analyses of climatic variables point out the relative importance of air temperature, relative humidity and saturation deficit on nymph questing activity, the global trends followed by these variables over the study period failed to fully explain the observed decline. However, nymph phenology was additionally explained by the presence of climatic thresholds that limit the questing behaviours of ticks. Most notably, we found that the presumed upper threshold of air saturation deficit, which strongly limits the increase of questing nymph density and is typically reached in the middle of spring, was reached significantly earlier and earlier over years. CONCLUSIONS In addition to phenology per se, the use of climatic thresholds may help to predict the presence and abundance of questing ticks in Lyme borreliosis endemic areas. Tick sensitivity to temperature or saturation deficit thresholds also suggests that extreme climatic events more than global trends may affect tick population dynamics. These two points may be of high importance in epidemiological short-term as well as long-term predictions. However, the highly unexplained variability in nymph density underlines the need for further studies that include other factors such as tick host abundance or tick microhabitats, two potentially influent factors that were not assessed in the present study.
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Affiliation(s)
- Gaël Hauser
- Institute of Biology, University of Neuchâtel, Emile Argand 11, 2000, Neuchâtel, Switzerland.
| | - Olivier Rais
- Institute of Biology, University of Neuchâtel, Emile Argand 11, 2000, Neuchâtel, Switzerland
| | - Francisca Morán Cadenas
- Institute of Biology, University of Neuchâtel, Emile Argand 11, 2000, Neuchâtel, Switzerland
| | - Yves Gonseth
- Centre Suisse de Cartographie de la Faune, Avenue de Bellevaux 51, 2000, Neuchâtel, Switzerland
| | - Mahmoud Bouzelboudjen
- Service informatique et télématique, University of Neuchâtel, Emile Argand 11, 2000, Neuchâtel, Switzerland
| | - Lise Gern
- Institute of Biology, University of Neuchâtel, Emile Argand 11, 2000, Neuchâtel, Switzerland
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7
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Ehrmann S, Liira J, Gärtner S, Hansen K, Brunet J, Cousins SAO, Deconchat M, Decocq G, De Frenne P, De Smedt P, Diekmann M, Gallet-Moron E, Kolb A, Lenoir J, Lindgren J, Naaf T, Paal T, Valdés A, Verheyen K, Wulf M, Scherer-Lorenzen M. Environmental drivers of Ixodes ricinus abundance in forest fragments of rural European landscapes. BMC Ecol 2017; 17:31. [PMID: 28874197 PMCID: PMC5586062 DOI: 10.1186/s12898-017-0141-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/23/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The castor bean tick (Ixodes ricinus) transmits infectious diseases such as Lyme borreliosis, which constitutes an important ecosystem disservice. Despite many local studies, a comprehensive understanding of the key drivers of tick abundance at the continental scale is still lacking. We analyze a large set of environmental factors as potential drivers of I. ricinus abundance. Our multi-scale study was carried out in deciduous forest fragments dispersed within two contrasting rural landscapes of eight regions, along a macroclimatic gradient stretching from southern France to central Sweden and Estonia. We surveyed the abundance of I. ricinus, plant community composition, forest structure and soil properties and compiled data on landscape structure, macroclimate and habitat properties. We used linear mixed models to analyze patterns and derived the relative importance of the significant drivers. RESULTS Many drivers had, on their own, either a moderate or small explanatory value for the abundance of I. ricinus, but combined they explained a substantial part of variation. This emphasizes the complex ecology of I. ricinus and the relevance of environmental factors for tick abundance. Macroclimate only explained a small fraction of variation, while properties of macro- and microhabitat, which buffer macroclimate, had a considerable impact on tick abundance. The amount of forest and the composition of the surrounding rural landscape were additionally important drivers of tick abundance. Functional (dispersules) and structural (density of tree and shrub layers) properties of the habitat patch played an important role. Various diversity metrics had only a small relative importance. Ontogenetic tick stages showed pronounced differences in their response. The abundance of nymphs and adults is explained by the preceding stage with a positive relationship, indicating a cumulative effect of drivers. CONCLUSIONS Our findings suggest that the ecosystem disservices of tick-borne diseases, via the abundance of ticks, strongly depends on habitat properties and thus on how humans manage ecosystems from the scale of the microhabitat to the landscape. This study stresses the need to further evaluate the interaction between climate change and ecosystem management on I. ricinus abundance.
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Affiliation(s)
- Steffen Ehrmann
- Geobotany, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104, Freiburg, Germany.
| | - Jaan Liira
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005, Tartu, Estonia
| | - Stefanie Gärtner
- Black Forest National Park, Kniebisstraße 67, 77740, Bad Peterstal-Griesbach, Germany
| | - Karin Hansen
- Natural Resources & Environmental Effects, IVL Swedish Environmental Research Institute, Box 210 60, 100 31, Stockholm, Sweden
| | - Jörg Brunet
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 49, 230 53, Alnarp, Sweden
| | - Sara A O Cousins
- Landscape Ecology, Department of Geography and Quaternary Geology, Stockholm University, 106 91, Stockholm, Sweden
| | - Marc Deconchat
- DYNAFOR, Université de Toulouse, INRA, INPT, Chemin de Borde Rouge, CS 52627, 31326, Castanet, France
| | - Guillaume Decocq
- UR "Ecologie et Dynamique des Systèmes Anthropisés" (EDYSAN, FRE 3498 CNRS-UPJV), Jules Verne University of Picardie, 1 rue des Louvels, 80037, Amiens Cedex 1, France.,UF PRiMAX, Clinical Pharmacology Department, CHU Amiens-Picardie, 80054, Amiens Cedex 1, France
| | - Pieter De Frenne
- Forest & Nature Lab, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium.,Department of Plant Production, Ghent University, Proefhoevestraat 22, 9090, Melle, Belgium
| | - Pallieter De Smedt
- Forest & Nature Lab, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Martin Diekmann
- Faculty of Biology/Chemistry (FB 02), Institute of Ecology, Vegetation Ecology and Conservation Biology, University of Bremen, Leobener Str. 5, 28359, Bremen, Germany
| | - Emilie Gallet-Moron
- UR "Ecologie et Dynamique des Systèmes Anthropisés" (EDYSAN, FRE 3498 CNRS-UPJV), Jules Verne University of Picardie, 1 rue des Louvels, 80037, Amiens Cedex 1, France
| | - Annette Kolb
- Faculty of Biology/Chemistry (FB 02), Institute of Ecology, Vegetation Ecology and Conservation Biology, University of Bremen, Leobener Str. 5, 28359, Bremen, Germany
| | - Jonathan Lenoir
- UR "Ecologie et Dynamique des Systèmes Anthropisés" (EDYSAN, FRE 3498 CNRS-UPJV), Jules Verne University of Picardie, 1 rue des Louvels, 80037, Amiens Cedex 1, France
| | - Jessica Lindgren
- Landscape Ecology, Department of Geography and Quaternary Geology, Stockholm University, 106 91, Stockholm, Sweden
| | - Tobias Naaf
- Institute of Land Use Systems, Leibniz-ZALF (e.V.), Eberswalder Str. 84, 15374, Müncheberg, Germany
| | - Taavi Paal
- Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005, Tartu, Estonia
| | - Alicia Valdés
- UR "Ecologie et Dynamique des Systèmes Anthropisés" (EDYSAN, FRE 3498 CNRS-UPJV), Jules Verne University of Picardie, 1 rue des Louvels, 80037, Amiens Cedex 1, France
| | - Kris Verheyen
- Forest & Nature Lab, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Monika Wulf
- Institute of Land Use Systems, Leibniz-ZALF (e.V.), Eberswalder Str. 84, 15374, Müncheberg, Germany
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Kazimírová M, Hamšíková Z, Kocianová E, Marini G, Mojšová M, Mahríková L, Berthová L, Slovák M, Rosá R. Relative density of host-seeking ticks in different habitat types of south-western Slovakia. EXPERIMENTAL & APPLIED ACAROLOGY 2016; 69:205-24. [PMID: 26926874 DOI: 10.1007/s10493-016-0025-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/21/2016] [Indexed: 05/10/2023]
Abstract
Ixodes ricinus is a vector of microbial pathogens of medical and veterinary importance in Europe. Recently, increasing abundance of ticks has been observed in urban and suburban areas. The aim of this study was to investigate the tick species composition and examine correlations between local environmental variables and the relative density of host-seeking I. ricinus in two habitat types. Questing ticks were collected along six 100 m(2) transects in urban/suburban locations of Bratislava town, and in a non-fragmented deciduous forest in the Small Carpathians Mountains (south-western Slovakia) during 2011-2013. In total, 6015 I. ricinus were collected (3435 and 2580 in the urban/suburban and natural habitat, respectively), out of which over 80 % were nymphs. Haemaphysalis concinna comprised 1.3 % of the tick collections. Peak I. ricinus nymph and adult host-seeking activities were registered in April-June. Spatial and temporal variation in tick relative density and differences in the subadult/adult ratio were observed between habitats and between locations within the same habitat type. The relative density of questing I. ricinus nymphs correlated negatively with altitude, geographical aspect and saturation deficit in a 64-day period comprising the 8-day period including the date of tick sampling and previous 56 days. No significant correlation was found between roe deer density and questing nymph density. The study revealed the presence of abundant I. ricinus populations in green areas of Bratislava, suggesting a risk of exposure of town dwellers and domestic and companion animals to potentially infected ticks.
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Affiliation(s)
- Mária Kazimírová
- Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia.
| | - Zuzana Hamšíková
- Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Elena Kocianová
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Giovanni Marini
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010, San Michele all'Adige, TN, Italy
| | - Michala Mojšová
- Department of Zoology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Lenka Mahríková
- Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Lenka Berthová
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Mirko Slovák
- Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Roberto Rosá
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010, San Michele all'Adige, TN, Italy
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9
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Paul REL, Cote M, Le Naour E, Bonnet SI. Environmental factors influencing tick densities over seven years in a French suburban forest. Parasit Vectors 2016; 9:309. [PMID: 27234215 PMCID: PMC4884405 DOI: 10.1186/s13071-016-1591-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 05/12/2016] [Indexed: 12/25/2022] Open
Abstract
Background Worldwide changes in socio-economic and environmental factors and the global climate are recognised causes of variation in tick distribution and density. Thus it is of great importance that new studies address the changing risk of infection for exposed populations. In Europe, Ixodes ricinus ticks are the most common vectors of several pathogens impacting veterinary and public health that have colonised suburban habitats. Methods This study aimed to evaluate longitudinal I. ricinus questing densities and infection rates over 7 years in a French suburban forested area with high human population density. Ticks were collected in spring yearly between 2008 and 2014 and, out of a total of 8594 collected I. ricinus, a representative subset of adult females (n = 259) were individually examined for the presence of several pathogens via PCR. Results Nymph densities peaked in 2009–2011, and then declined in 2012–2014. Changes in monthly temperature only had a modest impact on this variation. In contrast, analysis revealed a complex intra-annual relationship between mean nymph density and both concurrent and lagged mean monthly temperatures. The following pathogens were detected in the studied area: Anaplasma phagocytophilum, Rickettsia helvetica, Babesia venatorum and B. divergens, Francisella tularensis, Borrelia miyamotoi, B. afzelii/valaisiana, B. garinii/lusitaniae and Bartonella spp. Conclusion Our findings reinforce the conclusion that ticks are important vectors of pathogenic microorganisms in suburban forests and suggest that despite complex intra-annual relationships between tick densities and temperature, there is no evidence for a climate-associated increase in infection risk over the 7-year period. Rather, tick densities are likely to be strongly influenced by population density fluctuations in vertebrate host species and wildlife management. Further detailed studies on the impact of climate change on tick population densities are required. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1591-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Richard E L Paul
- Department of Genome and Genetics, Institut Pasteur, Unité de Génétique Fonctionnelle des Maladies Infectieuses, 28 rue du docteur Roux, 75724, Paris, France.,Centre National de la Recherche Scientifique, URA3012, 28 rue du docteur Roux, 75724, Paris, France
| | - Martine Cote
- UMR BIPAR INRA-ANSES-ENVA, 14 rue Pierre et Marie Curie, 94701, Maisons-Alfort cedex, France
| | - Evelyne Le Naour
- UMR BIPAR INRA-ANSES-ENVA, 14 rue Pierre et Marie Curie, 94701, Maisons-Alfort cedex, France
| | - Sarah I Bonnet
- UMR BIPAR INRA-ANSES-ENVA, 14 rue Pierre et Marie Curie, 94701, Maisons-Alfort cedex, France.
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10
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Dantas-Torres F. Climate change, biodiversity, ticks and tick-borne diseases: The butterfly effect. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2015; 4:452-61. [PMID: 26835253 PMCID: PMC4699983 DOI: 10.1016/j.ijppaw.2015.07.001] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 07/22/2015] [Accepted: 07/23/2015] [Indexed: 11/26/2022]
Abstract
We have killed wild animals for obtaining food and decimated forests for many reasons. Nowadays, we are burning fossil fuels as never before and even exploring petroleum in deep waters. The impact of these activities on our planet is now visible to the naked eye and the debate on climate change is warming up in scientific meetings and becoming a priority on the agenda of both scientists and policy decision makers. On the occasion of the Impact of Environmental Changes on Infectious Diseases (IECID) meeting, held in the 2015 in Sitges, Spain, I was invited to give a keynote talk on climate change, biodiversity, ticks and tick-borne diseases. The aim of the present article is to logically extend my rationale presented on the occasion of the IECID meeting. This article is not intended to be an exhaustive review, but an essay on climate change, biodiversity, ticks and tick-borne diseases. It may be anticipated that warmer winters and extended autumn and spring seasons will continue to drive the expansion of the distribution of some tick species (e.g., Ixodes ricinus) to northern latitudes and to higher altitudes. Nonetheless, further studies are advocated to improve our understanding of the complex interactions between landscape, climate, host communities (biodiversity), tick demography, pathogen diversity, human demography, human behaviour, economics, and politics, also considering all ecological processes (e.g., trophic cascades) and other possible interacting effects (e.g., mutual effects of increased greenhouse gas emissions and increased deforestation rates). The multitude of variables and interacting factors involved, and their complexity and dynamism, make tick-borne transmission systems beyond (current) human comprehension. That is, perhaps, the main reason for our inability to precisely predict new epidemics of vector-borne diseases in general. Human development affects the environment and the climate. Environmental and climate changes impacts on biodiversity. Environmental and climate changes alter tick population dynamics. Biodiversity loss affects tick-borne pathogen transmission.
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Affiliation(s)
- Filipe Dantas-Torres
- Department of Immunology, Aggeu Magalhães Research Centre, Oswaldo Cruz Foundation, 50740465 Recife, Pernambuco, Brazil; Department of Veterinary Medicine, University of Bari, 70010 Valenzano, Italy
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Kaizer AM, Foré SA, Kim HJ, York EC. Modeling the biotic and abiotic factors that describe the number of active off-host Amblyomma americanum larvae. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2015; 40:1-10. [PMID: 26047177 DOI: 10.1111/jvec.12126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 08/28/2014] [Indexed: 06/04/2023]
Abstract
Amblyomma americanum (L.) is a three-host tick that spends most of its life off-host and is an important vector of pathogens in the eastern United States. Our objectives were to develop a predictive statistical model that describes the number of active, off-host larvae from 2007 to 2011 and to determine the environmental variables associated with this pattern. Data used in this study came from monitoring conducted in northeast Missouri in which off-host ticks were collected from a permanent plot in a forest and an old field habitat every other week from approximately February to December. Variables examined were day length, degree days, total precipitation prior to sampling, wind speed, saturation deficit, number of adults prior to sampling, and collection site. Of the four regression models tested, the negative binomial model was selected. Fitted candidate models were compared relative to one another using values of eight model selection criteria and model averaging was used to develop a predictive model. The residual plots indicated that the weighted average model performs well in describing the number of larvae. Of the variables considered, the number of larvae was most strongly associated with increasing degree days, the number of active adults prior to sampling, and the forested site.
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Affiliation(s)
- A M Kaizer
- Department of Statistics, Truman State University, Kirksville, MO 63501, U.S.A
| | - S A Foré
- Department of Biology, Truman State University, Kirksville, MO 63501, U.S.A..
| | - H-J Kim
- Department of Statistics, Truman State University, Kirksville, MO 63501, U.S.A
| | - E C York
- Department of Biology, Truman State University, Kirksville, MO 63501, U.S.A
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Imhoff M, Hagedorn P, Schulze Y, Hellenbrand W, Pfeffer M, Niedrig M. Review: Sentinels of tick-borne encephalitis risk. Ticks Tick Borne Dis 2015; 6:592-600. [PMID: 26005107 DOI: 10.1016/j.ttbdis.2015.05.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/15/2015] [Accepted: 05/01/2015] [Indexed: 12/28/2022]
Abstract
Tick-borne encephalitis (TBE) is a viral zoonotic disease endemic in many regions of Eurasia. The definition of TBE risk areas is complicated by the focal nature of the TBE virus transmission. Furthermore, vaccination may reduce case numbers and thus mask infection risk to unvaccinated persons. Therefore, additional risk indicators are sought to complement the current risk assessment solely based on human incidence. We reviewed studies published over the past ten years investigating potential new sentinels of TBE risk to understand the advantages and disadvantages of the various sentinel animal surveys and surrogate indicator methods. Virus prevalence in questing ticks is an unsuitable indicator of TBE infection risk as viral RNA is rarely detected even in large sample sizes collected at known TBE endemic areas. Seroprevalence in domestic animals, on the other hand, showed good spatial correlation with TBE incidence in humans and might also uncover presently unknown TBEV foci.
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Affiliation(s)
- Maren Imhoff
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
| | - Peter Hagedorn
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
| | - Yesica Schulze
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
| | - Wiebke Hellenbrand
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
| | - Martin Pfeffer
- Institute of Animal Hygiene & Veterinary Public Health, Centre of Veterinary Public Health, University of Leipzig, An den Tierkliniken 1, 04103 Leipzig, Germany.
| | - Matthias Niedrig
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
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Tijsse-Klasen E, Koopmans MPG, Sprong H. Tick-borne pathogen - reversed and conventional discovery of disease. Front Public Health 2014; 2:73. [PMID: 25072045 PMCID: PMC4083466 DOI: 10.3389/fpubh.2014.00073] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 06/24/2014] [Indexed: 12/31/2022] Open
Abstract
Molecular methods have increased the number of known microorganisms associated with ticks significantly. Some of these newly identified microorganisms are readily linked to human disease while others are yet unknown to cause human disease. The face of tick-borne disease discovery has changed with more diseases now being discovered in a “reversed way,” detecting disease cases only years after the tick-borne microorganism was first discovered. Compared to the conventional discovery of infectious diseases, reverse order discovery presents researchers with new challenges. Estimating public health risks of such agents is especially challenging, as case definitions and diagnostic procedures may initially be missing. We discuss the advantages and shortcomings of molecular methods, serology, and epidemiological studies that might be used to study some fundamental questions regarding newly identified tick-borne diseases. With increased tick-exposure and improved detection methods, more tick-borne microorganisms will be added to the list of pathogens causing disease in humans in the future.
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Affiliation(s)
- Ellen Tijsse-Klasen
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM) , Bilthoven , Netherlands
| | - Marion P G Koopmans
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM) , Bilthoven , Netherlands ; Erasmus Medical Center , Rotterdam , Netherlands
| | - Hein Sprong
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM) , Bilthoven , Netherlands
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Kiewra D, Kryza M, Szymanowski M. Influence of selected meteorological variables on the questing activity of Ixodes ricinus ticks in Lower Silesia, SW Poland. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2014; 39:138-45. [PMID: 24820566 DOI: 10.1111/j.1948-7134.2014.12080.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 02/28/2014] [Indexed: 05/28/2023]
Abstract
The relationship between climate data and tick questing activity is crucial for estimation of the spatial and temporal distribution of the risk of ticks and tick-borne diseases. This study establishes correlations between selected meteorological variables provided by the Weather Research and Forecasting model (WRF) and the questing activity of Ixodes ricinus nymphs and adults on a regional scale across Lower Silesia, Poland. Application of Generalized Linear Mixed Models (GLMM), built separately for adults and nymphs, showed that solar radiation, air temperature, and saturation deficit appeared to be the meteorological variables of prime importance, whereas the wind speed was less important. However, the effect of meteorological parameters was different for adults and nymphs. The adults are also more influenced by forest cover and the percentage of forest type if compared to nymphs. The WRF model providing meteorological variables separately for each location and day of tick sampling can be useful in studies of questing activity of ticks on a regional scale.
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Affiliation(s)
- Dorota Kiewra
- Department of Microbial Ecology and Environmental Protection, Institute of Genetics and Microbiology, University of Wrocław, Wrocław, Poland.
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