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Tscherne A, Guardado-Calvo P, Clark JJ, Krause R, Krammer F. Puumala orthohantavirus: prevalence, biology, disease, animal models and recent advances in therapeutics development and structural biology. Front Immunol 2025; 16:1575112. [PMID: 40406115 PMCID: PMC12095308 DOI: 10.3389/fimmu.2025.1575112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2025] [Accepted: 03/21/2025] [Indexed: 05/26/2025] Open
Abstract
Puumala orthohantavirus (PUUV) is an emerging zoonotic virus that was first discovered in the Puumala region of Finland in the early 1980s and is the primary etiological agent of nephropathia epidemica (NE), a milder form of a life-threatening disease known as hemorrhagic fever with renal syndrome (HFRS). PUUV and other members of the Old World hantaviruses (OWHVs) predominantly circulate in rodents or insectivores across Eurasia, accounting for several thousand of reported HFRS cases every year (with many more unreported/misdiagnosed cases suspected). The rodent reservoir of PUUV is the common bank vole (Myodes (M.) glareolus), and transmission of the virus to humans occurs via inhalation of contagious aerosols and through contact with contaminated droppings or urine. Although PUUV is the subject of extensive research, due to its potential to cause severe disease outcomes in humans and its considerable economic and social impact, neither licensed vaccines nor specific antiviral treatments are available against PUUV. However, many important advancements have been made in terms of PUUV research over the last years. This included the elucidation of its glycoproteins, the discovery of broadly neutralizing hantavirus antibodies as therapeutic candidates and expanded research on the mRNA vaccine technology which will likely enable the development of strong PUUV vaccine candidates in the near future. Currently, there is still a lack of suitable animal models for the preclinical evaluation of experimental vaccines and antivirals, which hampers vaccine and antiviral development. Current attempts to decrease hantavirus-associated human infections rely primarily on prevention and countermeasures for rodent control, including reduced contact to droppings, saliva and urine, and disinfection of areas that are contaminated with rodent excreta. Here, we review these recent advances and other aspects including PUUV prevalence, virus biology, diagnosis and clinical features, and current animal models for vaccine and treatment development.
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Affiliation(s)
- Alina Tscherne
- Ignaz Semmelweis Institute, Interuniversity Institute for Infection Research, Medical University of Vienna, Vienna, Austria
| | - Pablo Guardado-Calvo
- G5 Unit Structural Biology of Infectious Diseases, Institut Pasteur, Université Paris Cité, Paris, France
| | - Jordan J. Clark
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Robert Krause
- Department of Internal Medicine, Division of Infectious Diseases, Medical University of Graz, Graz, Austria
| | - Florian Krammer
- Ignaz Semmelweis Institute, Interuniversity Institute for Infection Research, Medical University of Vienna, Vienna, Austria
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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2
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Erazo D, Vincenti-Gonzalez MF, Ghisbain G, Faber M, Reusken C, Sauvage V, Wint W, Leirs H, Dellicour S, Tersago K. Impact of Environmental Factors on the Distribution Patterns of Nephropathia Epidemica Cases in Western Europe. ENVIRONMENTAL HEALTH PERSPECTIVES 2025; 133:57023. [PMID: 40261974 DOI: 10.1289/ehp15457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/24/2025]
Abstract
BACKGROUND Environmental factors, such as fluctuations of climatic conditions and land cover, play a pivotal role in driving infectious disease epidemics, particularly those originating from wildlife reservoirs. Orthohantavirus puumalaense, hosted by bank voles in Europe, is the causative agent of a form of hemorrhagic fever and renal syndrome called nephropathia epidemica. Despite two decades of consistent presence in western Europe, nephropathia epidemica outbreaks still pose challenges due to localized periodic occurrences and a lack of understanding of its environmental drivers. OBJECTIVE Our study aims to bridge this gap by investigating the specific ecological and climatic factors influencing nephropathia epidemica outbreaks in western Europe. METHODS We compiled monthly, serologically confirmed nephropathia epidemica case data obtained from public health authorities in Belgium, France, Germany, and the Netherlands for the period 2004-2012. Cases were georeferenced to the finest available administrative unit. We selected 28 covariates, including climatic variables, land cover, tree species distributions, and human population, and implemented a Bayesian spatiotemporal model using integrated nested Laplace approximation (INLA) with zero-inflated Poisson distribution, including fixed effects and spatial, temporal, and nonstructured random effects. RESULTS We identified key triggers for nephropathia epidemica outbreaks, particularly climate-mediated changes in all seasons up to 2 years before, favoring tree mast impacting bank vole abundance. Our findings revealed that while land-cover factors mostly determine hotspot locations, climatic fluctuation patterns rather tend to modulate outbreak intensity. DISCUSSION Crucially, our model allows for the generation of yearly maps showcasing nephropathia epidemica incidence and risk factors, aiding in public health preparedness against climate change-induced disease emergence. This work represents a significant step toward developing targeted forecasting tools for Orthohantavirus puumalaense outbreaks, offering valuable insights for epidemic control strategies. https://doi.org/10.1289/EHP15457.
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Affiliation(s)
- Diana Erazo
- Spatial Epidemiology Lab (SpELL), Université Libre de Bruxelles, Brussels, Belgium
| | | | - Guillaume Ghisbain
- Spatial Epidemiology Lab (SpELL), Université Libre de Bruxelles, Brussels, Belgium
- Laboratory of Zoology, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Mirko Faber
- Department for Infectious Disease Epidemiology, Robert Koch-Institute, Berlin, Germany
| | - Chantal Reusken
- Department Virology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Virginie Sauvage
- Université Paris Cité, Unité Environnement et Risques Infectieux, Centre National de Référence des Hantavirus, Institut Pasteur, Paris, France
| | - William Wint
- Department of Biology, Environmental Research Group Oxford Ltd, Oxford, UK
| | - Herwig Leirs
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
| | - Simon Dellicour
- Spatial Epidemiology Lab (SpELL), Université Libre de Bruxelles, Brussels, Belgium
- Laboratory for Clinical and Epidemiological Virology, Rega Institute, Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
| | - Katrien Tersago
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium
- Epidemiology Unit, Scientific Institute of Public Health, Brussels, Belgium
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Wion AP, Pearse IS, Broxson M, Redmond MD. Mast hindcasts reveal pervasive effects of extreme drought on a foundational conifer species. THE NEW PHYTOLOGIST 2025; 246:450-460. [PMID: 39980122 DOI: 10.1111/nph.20321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Accepted: 11/07/2024] [Indexed: 02/22/2025]
Abstract
Predicting seed production is challenging because many plants produce highly variable crops among years (i.e. masting), but doing so can inform forest management, conservation, and our understanding of ecosystem trajectories in a changing climate. We evaluated the ability of an existing model to forecast masting in an ecologically and culturally important tree species in the southwestern United States, Pinus edulis. Annual seed cone production was predicted using cross-validation techniques on two unique out-of-sample datasets, representing different collection methods and spatial scales (cone scars and cone counts). We then hindcasted this model into the historical past to evaluate whether seed production has declined with the onset of extreme drought conditions in western North America. The evaluated model had fair skill, with root-mean-squared error of 6%. The model had better skill predicting the interannual variability within a site than among sites (i.e. within years). Hindcast analyses indicated recent (2000-2024) mean annual cone production was 30.6% lower than in the past century (1900-1999). Mast forecasts are within reach, but much room remains for improvement. Forecasts may be a powerful tool to anticipate the effects of climate change on forests and woodlands.
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Affiliation(s)
- Andreas P Wion
- U.S. Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, 300 Dinosaur Trail, Santa Fe, NM, 87508, USA
| | - Ian S Pearse
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, 80526, USA
| | - Max Broxson
- University of Colorado, Colorado Springs, CO, 80918, USA
| | - Miranda D Redmond
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
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4
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Fabbri D, Mirolo M, Tagliapietra V, Ludlow M, Osterhaus A, Beraldo P. Ecological determinants driving orthohantavirus prevalence in small mammals of Europe: a systematic review. ONE HEALTH OUTLOOK 2025; 7:15. [PMID: 40134030 PMCID: PMC11938672 DOI: 10.1186/s42522-025-00136-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2024] [Accepted: 01/30/2025] [Indexed: 03/27/2025]
Abstract
Orthohantaviruses are emerging zoonotic pathogens that cause severe human disease and are considered an emerging public health threat globally. Mammalian orthohantaviruses are naturally maintained in rodent species and occasionally in other mammals. The abundance and density of natural orthohantavirus reservoir species are affected by multi annual and seasonal population cycles, community composition, ecosystem variables and climate. Horizontal transmission between host species is mostly density-driven and occurs via contact with infected host excreta, thus, fluctuations in populations and environmental variables often determine the prevalence of hantavirus in natural hosts. Given the zoonotic potential of hantaviruses, ecological factors influencing their spread and persistence in their natural reservoir and population dynamics influencing horizontal transmission require critical evaluation for human infection risk assessment. The present review paper discusses the impacts of natural host population cycles and ecosystem diversity, environmental conditions, and abiotic factors on the epidemiology of rodent-borne hantavirus infections in Europe. While significant efforts have been made to understand the drivers of hantavirus prevalence in natural hosts, we highlight key challenges in evaluating viral prevalence and assessing the role of environmental and population variables in determining hantavirus prevalence in host species.
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Affiliation(s)
- Daniele Fabbri
- Department of Agricultural, Food, Environmental and Animal Sciences (DI4A), University of Udine, Via Sondrio 2/A, Udine, Italy.
- National Biodiversity Future Center (NBFC), Piazza Marina 61, Palermo, Italy.
| | - Monica Mirolo
- Research Centre for Emerging Infections and Zoonoses, University of Veterinary Medicine, Bünteweg 2, Hannover, Germany
| | - Valentina Tagliapietra
- National Biodiversity Future Center (NBFC), Piazza Marina 61, Palermo, Italy
- Research and Innovation Centre, Fondazione Edmund Mach, San Michele All' Adige, Via Edmund Mach 1, Trento, Italy
| | - Martin Ludlow
- Research Centre for Emerging Infections and Zoonoses, University of Veterinary Medicine, Bünteweg 2, Hannover, Germany
| | - Albert Osterhaus
- Research Centre for Emerging Infections and Zoonoses, University of Veterinary Medicine, Bünteweg 2, Hannover, Germany
| | - Paola Beraldo
- Department of Agricultural, Food, Environmental and Animal Sciences (DI4A), University of Udine, Via Sondrio 2/A, Udine, Italy
- National Biodiversity Future Center (NBFC), Piazza Marina 61, Palermo, Italy
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5
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Kazasidis O, Geduhn A, Jacob J. High-resolution early warning system for human Puumala hantavirus infection risk in Germany. Sci Rep 2024; 14:9602. [PMID: 38671000 PMCID: PMC11053085 DOI: 10.1038/s41598-024-60144-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 04/19/2024] [Indexed: 04/28/2024] Open
Abstract
The fluctuation of human infections by the Puumala orthohantavirus (PUUV) in Germany has been linked to weather and phenology parameters that drive the population growth of its host species. We quantified the annual PUUV-outbreaks at the district level by binarizing the reported infections in the period 2006-2021. With these labels we trained a model based on a support vector machine classifier for predicting local outbreaks and incidence well in advance. The feature selection for the optimal model was performed by a heuristic method and identified five monthly weather variables from the previous two years plus the beech flowering intensity of the previous year. The predictive power of the optimal model was assessed by a leave-one-out cross-validation in 16 years that led to an 82.8% accuracy for the outbreak and a 0.457 coefficient of determination for the incidence. Prediction risk maps for the entire endemic area in Germany will be annually available on a freely-accessible permanent online platform of the German Environment Agency. The model correctly identified 2022 as a year with low outbreak risk, whereas its prediction for large-scale high outbreak risk in 2023 was not confirmed.
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Affiliation(s)
- Orestis Kazasidis
- Institute for Epidemiology and Pathogen Diagnostics, Rodent Research, Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Toppheideweg 88, 48161, Münster, Germany.
| | - Anke Geduhn
- Laboratory for Health Pests and Their Control, German Environment Agency, Corrensplatz 1, 14195, Berlin, Germany
| | - Jens Jacob
- Institute for Epidemiology and Pathogen Diagnostics, Rodent Research, Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Toppheideweg 88, 48161, Münster, Germany
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Pearse IS, Wion AP, Gonzalez AD, Pesendorfer MB. Understanding mast seeding for conservation and land management. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200383. [PMID: 34657466 PMCID: PMC8520776 DOI: 10.1098/rstb.2020.0383] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2021] [Indexed: 11/12/2022] Open
Abstract
Masting, the intermittent and synchronous production of large seed crops, can have profound consequences for plant populations and the food webs that are built on their seeds. For centuries, people have recorded mast crops because of their importance in managing wildlife populations. In the past 30 years, we have begun to recognize the importance of masting in conserving and managing many other aspects of the environment: promoting the regeneration of forests following fire or other disturbance, conserving rare plants, conscientiously developing the use of edible seeds as non-timber forest products, coping with the consequences of extinctions on seed dispersal, reducing the impacts of plant invasions with biological control, suppressing zoonotic diseases and preventing depredation of endemic fauna. We summarize current instances and future possibilities of a broad set of applications of masting. By exploring in detail several case studies, we develop new perspectives on how solutions to pressing conservation and land management problems may benefit by better understanding the dynamics of seed production. A lesson common to these examples is that masting can be used to time management, and often, to do this effectively, we need models that explicitly forecast masting and the dynamics of seed-eating animals into the near-term future. This article is part of the theme issue 'The ecology and evolution of synchronized seed production in plants'.
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Affiliation(s)
- Ian S. Pearse
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO 80526, USA
| | - Andreas P. Wion
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO 80523-1177, USA
- Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523-1177, USA
| | - Angela D. Gonzalez
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO 80523-1177, USA
| | - Mario B. Pesendorfer
- Institute of Forest Ecology, University of Natural Resources and Life Sciences, Vienna 1190, Austria
- Smithsonian Conservation Biology Institute, Migratory Bird Center, Washington, DC 20013, USA
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7
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Camp JV, Spruill-Harrell B, Owen RD, Solà-Riera C, Williams EP, Eastwood G, Sawyer AM, Jonsson CB. Mixed Effects of Habitat Degradation and Resources on Hantaviruses in Sympatric Wild Rodent Reservoirs within a Neotropical Forest. Viruses 2021; 13:85. [PMID: 33435494 PMCID: PMC7827808 DOI: 10.3390/v13010085] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/06/2021] [Accepted: 01/06/2021] [Indexed: 12/23/2022] Open
Abstract
Understanding the ecology of rodent-borne hantaviruses is critical to assessing the risk of spillover to humans. Longitudinal surveys have suggested that hantaviral prevalence in a given host population is tightly linked to rodent ecology and correlates with changes in the species composition of a rodent community over time and/or habitat composition. We tested two hypotheses to identify whether resource addition and/or habitat composition may affect hantavirus prevalence among two sympatric reservoir hosts in a neotropical forest: (i) increased food resources will alter the rodent community and thus hantaviral prevalence; and (ii) host abundance and viral seroprevalence will be associated with habitat composition. We established a baseline of rodent-virus prevalence in three grid pairs of distinct habitat compositions and subjected one grid of each pair to resource augmentation. Increased rodent species diversity was observed on grids where food was added versus untreated control grids during the first post-treatment sampling session. Resource augmentation changed species community composition, yet it did not affect the prevalence of hantavirus in the host population over time, nor was there evidence of a dilution effect. Secondly, we show that the prevalence of the virus in the respective reservoir hosts was associated with habitat composition at two spatial levels, independent of resource addition, supporting previous findings that habitat composition is a primary driver of the prevalence of hantaviruses in the neotropics.
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Affiliation(s)
- Jeremy V. Camp
- Institute of Virology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria;
| | - Briana Spruill-Harrell
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA; (B.S.-H.); (E.P.W.)
| | - Robert D. Owen
- Centro para el Desarrollo de la Investigación Científica, Asunción C.P. 1371, Paraguay;
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Carles Solà-Riera
- Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Karolinska University Hospital, 141 86 Stockholm, Sweden;
| | - Evan P. Williams
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA; (B.S.-H.); (E.P.W.)
| | - Gillian Eastwood
- Department of Microbiology, University of Tennessee-Knoxville, Knoxville, TN 37996, USA; (G.E.); (A.M.S.)
| | - Aubrey M. Sawyer
- Department of Microbiology, University of Tennessee-Knoxville, Knoxville, TN 37996, USA; (G.E.); (A.M.S.)
| | - Colleen B. Jonsson
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA; (B.S.-H.); (E.P.W.)
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Faber M, Krüger DH, Auste B, Stark K, Hofmann J, Weiss S. Molecular and epidemiological characteristics of human Puumala and Dobrava-Belgrade hantavirus infections, Germany, 2001 to 2017. ACTA ACUST UNITED AC 2020; 24. [PMID: 31411134 PMCID: PMC6693291 DOI: 10.2807/1560-7917.es.2019.24.32.1800675] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Introduction Two hantavirus species, Puumala (PUUV) and Dobrava-Belgrade (DOBV) virus (genotype Kurkino), are endemic in Germany. Recent PUUV outbreaks raised questions concerning increasing frequency of outbreaks and expansion of PUUV endemic areas. Aims To describe the epidemiology of human PUUV and DOBV infections in Germany. Methods We conducted an observational retrospective study analysing national hantavirus surveillance data notified to the national public health institute and hantavirus nucleotide sequences from patients collected at the national consultation laboratory between 2001 and 2017. Matching molecular sequences with surveillance data, we conducted epidemiological, phylogenetic and phylogeographic analyses. Results In total, 12,148 cases of symptomatic hantavirus infection were notified 2001–17 (mean annual incidence: 0.87/100,000; range: 0.09–3.51). PUUV infections showed a highly variable space-time disease incidence pattern, causing large outbreaks every 2–3 years with peaks in early summer and up to 3,000 annually reported cases. Sex-specific differences in disease presentation were observed. Of 202 PUUV nucleotide sequences obtained from cases, 189 (93.6%) fall into well-supported phylogenetic clusters corresponding to different endemic areas in Germany. DOBV infections caused few, mostly sporadic cases in autumn and winter in the north and east of Germany. Conclusions The frequency of PUUV outbreaks increased between 2001 and 2017 but our data does not support the suggested expansion of endemic areas. The epidemiology of PUUV and DOBV-Kurkino infections differs in several aspects. Moreover, the latter are relatively rare and combining efforts and data of several countries to identify risk factors and develop specific recommendations for prevention could be worthwhile.
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Affiliation(s)
- Mirko Faber
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Detlev H Krüger
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Virology, Berlin, Germany
| | - Brita Auste
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Virology, Berlin, Germany
| | - Klaus Stark
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Jörg Hofmann
- These authors contributed equally and share last authorship.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Virology, Berlin, Germany
| | - Sabrina Weiss
- These authors contributed equally and share last authorship.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Virology, Berlin, Germany
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9
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Krawczyk AI, van Duijvendijk GLA, Swart A, Heylen D, Jaarsma RI, Jacobs FHH, Fonville M, Sprong H, Takken W. Effect of rodent density on tick and tick-borne pathogen populations: consequences for infectious disease risk. Parasit Vectors 2020; 13:34. [PMID: 31959217 PMCID: PMC6971888 DOI: 10.1186/s13071-020-3902-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/08/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Rodents are considered to contribute strongly to the risk of tick-borne diseases by feeding Ixodes ricinus larvae and by acting as amplifying hosts for pathogens. Here, we tested to what extent these two processes depend on rodent density, and for which pathogen species rodents synergistically contribute to the local disease risk, i.e. the density of infected nymphs (DIN). METHODS In a natural woodland, we manipulated rodent densities in plots of 2500 m2 by either supplementing a critical food source (acorns) or by removing rodents during two years. Untreated plots were used as controls. Collected nymphs and rodent ear biopsies were tested for the presence of seven tick-borne microorganisms. Linear models were used to capture associations between rodents, nymphs, and pathogens. RESULTS Investigation of data from all plots, irrespective of the treatment, revealed a strong positive association between rodent density and nymphal density, nymphal infection prevalence (NIP) with Borrelia afzelii and Neoehrlichia mikurensis, and hence DIN's of these pathogens in the following year. The NIP, but not the DIN, of the bird-associated Borrelia garinii, decreased with increasing rodent density. The NIPs of Borrelia miyamotoi and Rickettsia helvetica were independent of rodent density, and increasing rodent density moderately increased the DINs. In addition, NIPs of Babesia microti and Spiroplasma ixodetis decreased with increasing rodent density, which had a non-linear association with DINs of these microorganisms. CONCLUSIONS A positive density dependence for all rodent- and tick-associated tick-borne pathogens was found, despite the observation that some of them decreased in prevalence. The effects on the DINs were variable among microorganisms, more than likely due to contrasts in their biology (including transmission modes, host specificity and transmission efficiency). The strongest associations were found in rodent-associated pathogens that most heavily rely on horizontal transmission. Our results draw attention to the importance of considering transmission mode of a pathogen while developing preventative measures to successfully reduce the burden of disease.
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Affiliation(s)
- Aleksandra I Krawczyk
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands. .,Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands.
| | | | - Arno Swart
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands
| | - Dieter Heylen
- Interuniversity Institute for Biostatistics and statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium.,Department of Ecology and Evolutionary Biology, Princeton University, 106A Guyot Ln, Princeton, NJ, 08544, USA
| | - Ryanne I Jaarsma
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands
| | - Frans H H Jacobs
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Manoj Fonville
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands
| | - Hein Sprong
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands.
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands
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10
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Hartemink N, van Vliet A, Sprong H, Jacobs F, Garcia-Martí I, Zurita-Milla R, Takken W. Temporal-Spatial Variation in Questing Tick Activity in the Netherlands: The Effect of Climatic and Habitat Factors. Vector Borne Zoonotic Dis 2019; 19:494-505. [PMID: 30810501 DOI: 10.1089/vbz.2018.2369] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Longitudinal studies are fundamental in the assessment of the effect of environmental factors on tick population dynamics. In this study, we use data from a 10-year study in 11 different locations in the Netherlands to gauge the effects of climatic and habitat factors on the temporal and spatial variation in questing tick activity. Marked differences in the total number of ticks were found between locations and between years. We investigated which climatic and habitat factors might explain this variation. No effects of climatic factors on the total number of ticks per year were observed, but we found a clear effect of temperature on the onset of tick activity. In addition, we found positive associations between (1) humus layer thickness and densities of all three stages, (2) moss and blackberry abundance and larval densities, and (3) blueberry abundance and densities of larva and nymphs. We conclude that climatic variables do not have a straightforward association with tick density in the Netherlands, but that winter and spring temperatures influence the onset of tick activity. Habitats with apparently similar vegetation types can still differ in tick population densities, indicating that local composition of vegetation and especially of wildlife is likely to contribute considerably to the spatial variation in tick densities.
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Affiliation(s)
- Nienke Hartemink
- 1 Biometris, Wageningen University and Research Centre, Wageningen, the Netherlands.,2 Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - Arnold van Vliet
- 3 Environmental Systems Analysis Group, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - Hein Sprong
- 2 Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, the Netherlands.,4 Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Frans Jacobs
- 2 Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, the Netherlands.,5 Centre for Vector Surveillance, Netherlands Food and Consumer Product Safety Authority, Wageningen, the Netherlands
| | - Irene Garcia-Martí
- 6 Royal Netherlands Meteorological Institute, De Bilt, the Netherlands.,7 Faculty of Geo-Information Science and Earth Observation, University of Twente, Enschede, the Netherlands
| | - Raul Zurita-Milla
- 7 Faculty of Geo-Information Science and Earth Observation, University of Twente, Enschede, the Netherlands
| | - Willem Takken
- 2 Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, the Netherlands
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