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Rousseau R, Mori M, Kabamba B, Vanwambeke SO. Tick abundance and infection with three zoonotic bacteria are heterogeneous in a Belgian peri-urban forest. EXPERIMENTAL & APPLIED ACAROLOGY 2024; 93:49-69. [PMID: 38869724 DOI: 10.1007/s10493-024-00919-2] [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: 10/17/2023] [Accepted: 04/29/2024] [Indexed: 06/14/2024]
Abstract
Ixodes ricinus is a vector of several pathogens of public health interest. While forests are the primary habitat for I. ricinus, its abundance and infection prevalence are expected to vary within forest stands. This study assesses the spatio-temporal variations in tick abundance and infection prevalence with three pathogens in and around a peri-urban forest where human exposure is high. Ticks were sampled multiple times in 2016 and 2018 in multiple locations with a diversity of undergrowth, using the consecutive drags method. Three zoonotic pathogens were screened for, Borrelia burgdorferi s.l., Coxiella burnetii, and Francisella tularensis. The influence of season, type of site and micro-environmental factors on tick abundance were assessed with negative binomial generalized linear mixed-effects models. We collected 1642 nymphs and 181 adult ticks. Ticks were most abundant in the spring, in warmer temperatures, and where undergrowth was higher. Sites with vegetation unaffected by human presence had higher abundance of ticks. Forest undergrowth type and height were significant predictors of the level of tick abundance in a forest. The consecutive drags method is expected to provide more precise estimates of tick abundance, presumably through more varied contacts with foliage. Borrelia burgdorferi s.l. prevalence was estimated from pooled ticks at 5.33%, C. burnetii was detected in six pools and F. tularensis was not detected. Borrelia afzelii was the dominant B. burgdorferi genospecies. Tick abundance and B. burgdorferi s.l. infection prevalence were lower than other estimates in Belgian forests.
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Affiliation(s)
- Raphaël Rousseau
- Earth and Life Institute (ELI), Earth and Climate pole (ELIC), Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium
| | - Marcella Mori
- Bacterial zoonoses unit, Veterinary bacteriology, Sciensano, Ukkel/Uccle, Belgium
| | - Benoît Kabamba
- Institute of Clinical and Experimental Research (IREC), Pôle de Microbiologie Médicale, Université catholique de Louvain (UCLouvain), Brussels, Belgium
| | - Sophie O Vanwambeke
- Earth and Life Institute (ELI), Earth and Climate pole (ELIC), Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium.
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Van Gestel M, Heylen D, Verheyen K, Fonville M, Sprong H, Matthysen E. Recreational hazard: Vegetation and host habitat use correlate with changes in tick-borne disease hazard at infrastructure within forest stands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170749. [PMID: 38340833 DOI: 10.1016/j.scitotenv.2024.170749] [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: 07/21/2023] [Revised: 02/01/2024] [Accepted: 02/04/2024] [Indexed: 02/12/2024]
Abstract
Studies on density and pathogen prevalence of Ixodes ricinus indicate that vegetation and local host community drive much of their variation between green spaces. Contrarily, micro-geographic variation is understudied, although its understanding could reduce disease risk. We studied the density of infectious nymphal Ixodes sp. ("DIN", proxy for disease hazard), density of questing nymphs ("DON") and nymphal infection prevalence ("NIP") near recreational forest infrastructure. Drag sampling within forest stands and at adjacent benches and trails was combined with vegetation surveys, camera trapping hosts and pathogen screening of ticks. We analysed Borrelia burgdorferi s.l. and its genospecies, with complementary analyses on Rickettsia sp., Anaplasma phagocytophilum, Neoehrlichia mikurensis and Borrelia miyamotoi. DIN was highest in forest interior and at trails enclosed by forest. Lower disease hazard was observed at benches and trails at forest edges. This infrastructure effect can be attributed to variation in vegetation characteristics and the habitat use of tick hosts, specifically roe deer, rodents and songbirds. DON is the main driver of DIN at micro-geographic scale and negatively affected by infrastructure and forest edges. A positive association with vegetation cover in understorey and canopy was observed, as were positive trends for local rodent and songbird abundance. NIP of different pathogens was affected by different drivers. Lower B. burgdorferi s.l. prevalence in the interior of forest stands, driven by its most prevalent genospecies B. afzelii, points towards higher density of uninfected hosts there. B. afzelii was positively associated with understorey containing tall species and with high canopy cover, whereas local bird community composition predicts B. garinii prevalence. A positive effect of songbird abundance and a negative effect of pigeons were observed. Our findings support amplification and inhibition mechanisms within forest stands and highlight that the effect of established drivers of DIN may differ based on the considered spatial scale.
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Affiliation(s)
- Mats Van Gestel
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Wilrijk, Belgium; Forest & Nature Lab, Department of Environment, Ghent University, Gontrode, Belgium.
| | - Dieter Heylen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Wilrijk, Belgium; Interuniversity Institute for Biostatistics and statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium
| | - Kris Verheyen
- Forest & Nature Lab, Department of Environment, Ghent University, Gontrode, Belgium
| | - Manoj Fonville
- National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Hein Sprong
- National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Erik Matthysen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Wilrijk, Belgium
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3
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Margos G, Hofmann M, Casjens S, Dupraz M, Heinzinger S, Hartberger C, Hepner S, Schmeusser M, Sing A, Fingerle V, McCoy KD. Genome diversity of Borrelia garinii in marine transmission cycles does not match host associations but reflects the strains evolutionary history. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2023; 115:105502. [PMID: 37716446 DOI: 10.1016/j.meegid.2023.105502] [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: 06/04/2023] [Revised: 08/15/2023] [Accepted: 09/13/2023] [Indexed: 09/18/2023]
Abstract
Borrelia burgdorferi sensu lato is a species complex of spirochetal bacteria that occupy different ecological niches which is reflected in their reservoir host- and vector-associations. Borrelia genomes possess numerous linear and circular plasmids. Proteins encoded by plasmid genes play a major role in host- and vector-interaction and are important for Borrelia niche adaptation. However, the plasmid composition and therewith the gene repertoire may vary even in strains of a single species. Borrelia garinii, one of the six human pathogenic species, is common in Europe (vector Ixodes ricinus), Asia (vector Ixodes persulcatus) and in marine birds (vector Ixodes uriae). For the latter, only a single culture isolate (Far04) and its genome were previously available. The genome was rather small containing only one circular and six linear plasmids with a notable absence of cp32 plasmids. To further investigate B. garinii from marine transmission cycles and to explore i) whether the small number of plasmids found in isolate Far04 is a common feature in B. garinii from marine birds and presents an adaptation to this particular niche and ii) whether there may be a correlation between genome type and host species, we initiated in vitro cultures from live I. uriae collected in 2017 and 2018 from marine avian hosts and their nests. Hosts included common guillemots, Atlantic Puffin, razorbill, and kittiwake. We obtained 17 novel isolates of which 10 were sequenced using Illumina technology, one also with Pacific Bioscience technology. The 10 genomes segregated into five different genome types defined by plasmid types (based on PFam32 loci). We show that the genomes of seabird associated B. garinii contain fewer plasmids (6-9) than B. garinii from terrestrial avian species (generally ≥10), potentially suggesting niche adaptation. However, genome type did not match an association with the diverse avian seabird hosts investigated but matched the clonal complex they originated from, perhaps reflecting the isolates evolutionary history. Questions that should be addressed in future studies are (i) how is plasmid diversity related to host- and/or vector adaptation; (ii) do the different seabird species differ in reservoir host competence, and (iii) can the genome types found in seabirds use terrestrial birds as reservoir hosts.
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Affiliation(s)
- Gabriele Margos
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Markus Hofmann
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Sherwood Casjens
- Pathology Department, School of Medicine, University of Utah, 15 North Medical Drive East Ste. #1100, Salt Lake City, UT 84112, USA.
| | - Marlene Dupraz
- MIVEGEC, University of Montpellier - CNRS - IRD, Centre IRD, Domaine La Valette - 900, rue Jean François BRETON, 34090 Montpellier, France
| | - Susanne Heinzinger
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Christine Hartberger
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Sabrina Hepner
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Mercy Schmeusser
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Andreas Sing
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Volker Fingerle
- National Reference Centre for Borrelia, Bavarian Health and Food Safety Authority, Veterinärstr. 2, 85764 Oberschleissheim, Germany.
| | - Karen D McCoy
- MIVEGEC, University of Montpellier - CNRS - IRD, Centre IRD, Domaine La Valette - 900, rue Jean François BRETON, 34090 Montpellier, France.
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Plasticity in the timing of detachment of an Eurasian-African songbird tick, Ixodes frontalis. Ticks Tick Borne Dis 2022; 13:101966. [DOI: 10.1016/j.ttbdis.2022.101966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/12/2022] [Accepted: 05/02/2022] [Indexed: 11/18/2022]
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The evolving story of Borrelia burgdorferi sensu lato transmission in Europe. Parasitol Res 2022; 121:781-803. [PMID: 35122516 PMCID: PMC8816687 DOI: 10.1007/s00436-022-07445-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 01/19/2022] [Indexed: 12/13/2022]
Abstract
Beside mosquitoes, ticks are well-known vectors of different human pathogens. In the Northern Hemisphere, Lyme borreliosis (Eurasia, LB) or Lyme disease (North America, LD) is the most commonly occurring vector-borne infectious disease caused by bacteria of the genus Borrelia which are transmitted by hard ticks of the genus Ixodes. The reported incidence of LB in Europe is about 22.6 cases per 100,000 inhabitants annually with a broad range depending on the geographical area analyzed. However, the epidemiological data are largely incomplete, because LB is not notifiable in all European countries. Furthermore, not only differ reporting procedures between countries, there is also variation in case definitions and diagnostic procedures. Lyme borreliosis is caused by several species of the Borrelia (B.) burgdorferi sensu lato (s.l.) complex which are maintained in complex networks including ixodid ticks and different reservoir hosts. Vector and host influence each other and are affected by multiple factors including climate that have a major impact on their habitats and ecology. To classify factors that influence the risk of transmission of B. burgdorferi s.l. to their different vertebrate hosts as well as to humans, we briefly summarize the current knowledge about the pathogens including their astonishing ability to overcome various host immune responses, regarding the main vector in Europe Ixodes ricinus, and the disease caused by borreliae. The research shows, that a higher standardization of case definition, diagnostic procedures, and standardized, long-term surveillance systems across Europe is necessary to improve clinical and epidemiological data.
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Geebelen L, Lernout T, Tersago K, Terryn S, Hovius JW, Docters van Leeuwen A, Van Gucht S, Speybroeck N, Sprong H. No molecular detection of tick-borne pathogens in the blood of patients with erythema migrans in Belgium. Parasit Vectors 2022; 15:27. [PMID: 35057826 PMCID: PMC8772185 DOI: 10.1186/s13071-021-05139-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/20/2021] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
A number of tick-borne pathogens circulate in the Belgian tick population in addition to the causative agent of Lyme borreliosis. However, so far, only a few patients with tick-borne diseases other than Lyme borreliosis have been reported in Belgium. The aim of this study was to investigate the occurrence of other human tick-borne infections in Belgium and their possible clinical manifestation.
Methods
Patients with fever (> 37.5 °C) after a tick bite or those with erythema migrans (EM) were included in the study. EDTA-blood samples were screened for the presence of DNA from Borrelia burgdorferi sensu lato, Borrelia miyamotoi, Anaplasma phagocytophilum, Neoehrlichia mikurensis, spotted fever group rickettsiae (genus Rickettsia), Babesia spp., Bartonella spp., Spiroplasma ixodetis and tick-borne encephalitis virus, using multiplex PCR methods. A questionnaire on, among others, demographics and clinical symptoms, was also filled in.
Results
Over a period of 3 years, 119 patients with EM and 14 patients with fever after a recent tick bite were enrolled in the study. Three samples initially tested positive for N. mikurensis by quantitative PCR (qPCR), but the results could not be confirmed by other PCR methods, and repetition of the DNA extraction procedure and qPCR test was not successful. The qPCR test results for the other tick-borne pathogens were negative.
Conclusions
In general, only a few patients with fever after a tick bite could be identified. Although no tick-borne pathogens were detected, their occurrence cannot be excluded based on the limited number of patients and the limitations inherent to current methodologies. This study underscores the possibility of false-positive PCR results and the necessity for the development of multiple independent tools for the sensitive and specific detection of emerging tick-borne pathogens.
Graphical Abstract
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Gandy S, Kilbride E, Biek R, Millins C, Gilbert L. Experimental evidence for opposing effects of high deer density on tick-borne pathogen prevalence and hazard. Parasit Vectors 2021; 14:509. [PMID: 34593023 PMCID: PMC8485466 DOI: 10.1186/s13071-021-05000-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/08/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Identifying the mechanisms driving disease risk is challenging for multi-host pathogens, such as Borrelia burgdorferi sensu lato (s.l.), the tick-borne bacteria causing Lyme disease. Deer are tick reproduction hosts but do not transmit B. burgdorferi s.l., whereas rodents and birds are competent transmission hosts. Here, we use a long-term deer exclosure experiment to test three mechanisms for how high deer density might shape B. burgdorferi s.l. prevalence in ticks: increased prevalence due to higher larval tick densities facilitating high transmission on rodents (M1); alternatively, reduced B. burgdorferi s.l. prevalence because more larval ticks feed on deer rather than transmission-competent rodents (dilution effect) (M2), potentially due to ecological cascades, whereby higher deer grazing pressure shortens vegetation which decreases rodent abundance thus reducing transmission (M3). METHODS In a large enclosure where red deer stags were kept at high density (35.5 deer km-2), we used an experimental design consisting of eight plots of 0.23 ha, four of which were fenced to simulate the absence of deer and four that were accessible to deer. In each plot we measured the density of questing nymphs and nymphal infection prevalence in spring, summer and autumn, and quantified vegetation height and density, and small mammal abundance. RESULTS Prevalence tended to be lower, though not conclusively so, in high deer density plots compared to exclosures (predicted prevalence of 1.0% vs 2.2%), suggesting that the dilution and cascade mechanisms might outweigh the increased opportunities for transmission mechanism. Presence of deer at high density led to shorter vegetation and fewer rodents, consistent with an ecological cascade. However, Lyme disease hazard (density of infected I. ricinus nymphs) was five times higher in high deer density plots due to tick density being 18 times higher. CONCLUSIONS High densities of tick reproduction hosts such as deer can drive up vector-borne disease hazard, despite the potential to simultaneously reduce pathogen prevalence. This has implications for environmental pathogen management and for deer management, although the impact of intermediate deer densities now needs testing.
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Affiliation(s)
- Sara Gandy
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK. .,The James Hutton Institute, Craigiebuckler, Aberdeen, UK.
| | - Elizabeth Kilbride
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Roman Biek
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Caroline Millins
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Lucy Gilbert
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
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Sürth V, Lopes de Carvalho I, Núncio MS, Norte AC, Kraiczy P. Bactericidal activity of avian complement: a contribution to understand avian-host tropism of Lyme borreliae. Parasit Vectors 2021; 14:451. [PMID: 34488849 PMCID: PMC8420066 DOI: 10.1186/s13071-021-04959-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/17/2021] [Indexed: 11/10/2022] Open
Abstract
Complement has been considered as an important factor impacting the host-pathogen association of spirochetes belonging to the Borrelia burgdorferi sensu lato complex, and may play a role in the spirochete's ecology. Birds are known to be important hosts for ticks and in the maintenance of borreliae. Recent field surveys and laboratory transmission studies indicated that certain avian species act as reservoir hosts for different Borrelia species. Nevertheless, our current understanding of the molecular mechanisms determining host tropism of Borrelia is still in its fledgling stage. Concerning the role of complement in avian-host tropism, only a few bird species and Borrelia species have been analysed so far. Here, we performed in vitro serum bactericidal assays with serum samples collected from four bird species including the European robin Erithacus rubecula, the great tit Parus major, the Eurasian blackbird Turdus merula, and the racing pigeon Columba livia, as well as four Borrelia species (B. afzelii, B. garinii, B. valaisiana, and B. burgdorferi sensu stricto). From July to September 2019, juvenile wild birds were caught using mist nets in Portugal. Racing pigeons were sampled in a loft in October 2019. Independent of the bird species analysed, all Borrelia species displayed an intermediate serum-resistant or serum-resistant phenotype except for B. afzelii challenged with serum from blackbirds. This genospecies was efficiently killed by avian complement, suggesting that blackbirds served as dead-end hosts for B. afzelii. In summary, these findings suggest that complement contributes in the avian-spirochete-tick infection cycle and in Borrelia-host tropism.
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Affiliation(s)
- Valerie Sürth
- Institute of Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt, Frankfurt, Germany
| | - Isabel Lopes de Carvalho
- Centre for Vectors and Infectious Diseases Dr. Francisco Cambournac, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal.,Institute of Environmental Health (ISAMB), Lisbon, Portugal
| | - Maria Sofia Núncio
- Centre for Vectors and Infectious Diseases Dr. Francisco Cambournac, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal.,Institute of Environmental Health (ISAMB), Lisbon, Portugal
| | - Ana Cláudia Norte
- Centre for Vectors and Infectious Diseases Dr. Francisco Cambournac, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal. .,Department of Life Sciences, Faculty of Sciences and Technology, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.
| | - Peter Kraiczy
- Institute of Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt, Frankfurt, Germany.
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Dickinson ER, Millins C, Biek R. Sampling scale and season influence the observed relationship between the density of deer and questing Ixodes ricinus nymphs. Parasit Vectors 2020; 13:493. [PMID: 32993763 PMCID: PMC7526098 DOI: 10.1186/s13071-020-04369-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/17/2020] [Indexed: 12/05/2022] Open
Abstract
Background The relationship between environmentally transmitted tick parasites, Ixodes spp., and their main reproductive host, deer, is generally thought to be positive. However, measuring host abundance and density directly can be challenging and indirect methods are often used. The observed relationship between the parasite and host may be affected by sampling scale and season, which could lead to different inferences being made. Here, we aimed to test the effect of sampling scale and season on the relationship between density of deer and the density of questing Ixodes ricinus nymphs. Methods The density of deer (primarily Dama dama) was estimated using line transect distance sampling of deer dung quantified in different seasons (winter and summer) and measured at three different nested scales (site, transect and observation level). Questing nymph density was measured using blanket drag methods and estimates were calculated at the same scales as deer density estimates. General linear models were used to evaluate the relationship between questing nymphs, deer density and other environmental variables at each sampling scale and each season deer density was measured at. Results While a positive relationship between deer density and questing nymph density was detected at the site and transect scale, no relationship was apparent at the observation level. This was likely due to increased variation and reduced precision of deer dung counts at the finest sampling scale. Seasonal changes in deer populations were observed likely reflecting seasonal shifts in habitat usage. The summer estimates of deer density explained questing nymph density whereas winter estimates did not. Conclusions Our results show that the scale of sampling can affect the detectability of the positive association between host and vector species. Furthermore, such associations can be obscured if hosts exhibit seasonal changes in habitat use. Thus, both sampling scale and season are important to consider when investigating the relationship between host and vector species.![]()
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Affiliation(s)
- Eleanor R Dickinson
- Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, 82 Hillhead St, Glasgow, G12 8QQ, Scotland, UK. .,Scottish Centre for Ecology and the Natural Environment, Rowardennan, Glasgow, G63 0AW, Scotland, UK. .,School of Biological Sciences, Queens University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK.
| | - Caroline Millins
- Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, 82 Hillhead St, Glasgow, G12 8QQ, Scotland, UK.,Department of Livestock and One Health, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Brownlow Hill, Liverpool, L69 7TX, UK
| | - Roman Biek
- Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, 82 Hillhead St, Glasgow, G12 8QQ, Scotland, UK
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Heylen DJ, Reinoso-Pérez MT, Goodman L, Dhondt KV, Dhondt AA. Ectoparasitism during an avian disease outbreak: An experiment with Mycoplasma-infected house finches and ticks. Int J Parasitol Parasites Wildl 2020; 12:53-63. [PMID: 32426219 PMCID: PMC7225381 DOI: 10.1016/j.ijppaw.2020.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 04/01/2020] [Accepted: 04/01/2020] [Indexed: 11/18/2022]
Abstract
Hosts are typically co-parasitized by multiple species. Parasites can benefit or suffer from the presence of other parasites, which can reduce or increase the overall virulence due to competition or facilitation. Outcomes of new multi-parasite systems are seldom predictable. In 1994 the bacterium Mycoplasma gallisepticum jumped from poultry to songbirds in which it caused an epidemic throughout North America. Songbirds are often parasitized by hard ticks, and can act as reservoirs for tick-borne pathogens. We tested the hypothesis that Mycoplasma infection in house finches influences North America's most important tick vector Ixodes scapularis, by affecting the tick's feeding success, detachment behaviour and survival to the next stage. Most ticks detached during the daylight hours irrespective of the bird's disease status and time since infestation. Birds incrementally invested in anti-tick resistance mechanisms over the course of the experiment; this investment was made earlier in the Mycoplasma-infected birds. At higher tick densities, the feeding success on birds with more severe conjunctivitis was lower than in the uninfected birds. Throughout the experiment we found positive density dependent effects on the tick's feeding success. More diseased hosts suffered more from the tick infestations, as shown by reduced haematocrits. Three Mycoplasma-infected birds died during the weeks following the experiment, although all birds were kept in optimal housing conditions. Mycoplasma made the bird a less accessible and valuable host for ticks, which is an example of ecological interference. Therefore, Mycoplasma has the potential to ultimately reduce transmission outcomes of tick-borne pathogens via songbird hosts. Songbird hosts show signs of acquired immunological resistance against ticks. Resistance acquisition was accelerated under the influence of Mycoplasma. Mycoplasma infection had no strong effects on diurnal detachments. Mycoplasma made birds a less accessible and valuable host for ticks. Virulence increased under co-parasitism on the same host tissues.
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Affiliation(s)
- Dieter J.A. Heylen
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
- Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium
- Eco-Epidemiology Group, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Corresponding author. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.
| | - María Teresa Reinoso-Pérez
- Laboratory of Ornithology, Cornell University, Ithaca, NY, USA
- Department of Natural Resources, Cornell University, Ithaca, NY, USA
| | - Laura Goodman
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA
| | - Keila V. Dhondt
- Department of Natural Resources, Cornell University, Ithaca, NY, USA
| | - André A. Dhondt
- Laboratory of Ornithology, Cornell University, Ithaca, NY, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
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Lin YP, Diuk-Wasser MA, Stevenson B, Kraiczy P. Complement Evasion Contributes to Lyme Borreliae-Host Associations. Trends Parasitol 2020; 36:634-645. [PMID: 32456964 DOI: 10.1016/j.pt.2020.04.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/17/2020] [Accepted: 04/17/2020] [Indexed: 01/31/2023]
Abstract
Lyme disease is the most common vector-borne disease in the northern hemisphere and is caused by spirochetes of the Borrelia burgdorferi sensu lato complex. Lyme borreliae infect diverse vertebrate reservoirs without triggering apparent manifestations in these animals; however, Lyme borreliae strains differ in their reservoir hosts. The mechanisms that drive those differences are unknown. To survive in vertebrate hosts, Lyme borreliae require the ability to escape from host defense mechanisms, in particular complement. To facilitate the evasion of complement, Lyme borreliae produce diverse proteins at different stages of infection, allowing them to persistently survive without being recognized by hosts and potentially resulting in host-specific infection. This review discusses the current knowledge regarding the ecology and evolutionary mechanisms of Lyme borreliae-host associations driven by complement evasion.
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Affiliation(s)
- Yi-Pin Lin
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Department of Biomedical Science, State University of New York at Albany, NY, USA.
| | - Maria A Diuk-Wasser
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA
| | - Brian Stevenson
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA; Department of Entomology, University of Kentucky, Lexington, KY, USA
| | - Peter Kraiczy
- Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt, Goethe University Frankfurt, D-60596 Frankfurt, Germany.
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12
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Norte AC, Lopes de Carvalho I, Núncio MS, Araújo PM, Matthysen E, Albino Ramos J, Sprong H, Heylen D. Getting under the birds' skin: tissue tropism of Borrelia burgdorferi s.l. in naturally and experimentally infected avian hosts. MICROBIAL ECOLOGY 2020; 79:756-769. [PMID: 31612324 DOI: 10.1007/s00248-019-01442-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 09/11/2019] [Indexed: 06/10/2023]
Abstract
Wild birds are frequently exposed to the zoonotic tick-borne bacteria Borrelia burgdorferi sensu lato (s.l.), and some bird species act as reservoirs for some Borrelia genospecies. Studying the tropism of Borrelia in the host, how it is sequestered in different organs, and whether it is maintained in circulation and/or in the host's skin is important to understand pathogenicity, infectivity to vector ticks and reservoir competency.We evaluated tissue dissemination of Borrelia in blackbirds (Turdus merula) and great tits (Parus major), naturally and experimentally infected with Borrelia genospecies from enzootic foci. We collected both minimally invasive biological samples (feathers, skin biopsies and blood) and skin, joint, brain and visceral tissues from necropsied birds. Infectiousness of the host was evaluated through xenodiagnoses and infection rates in fed and moulted ticks. Skin biopsies were the most reliable method for assessing avian hosts' Borrelia infectiousness, which was supported by the agreement of infection status results obtained from the analysis of chin and lore skin samples from necropsied birds and of their xenodiagnostic ticks, including a significant correlation between the estimated concentration of Borrelia genome copies in the skin and the Borrelia infection rate in the xenodiagnostic ticks. This confirms a dermatropism of Borrelia garinii, B. valaisiana and B. turdi in its avian hosts. However, time elapsed from exposure to Borrelia and interaction between host species and Borrelia genospecies may affect the reliability of skin biopsies. The blood was not useful to assess infectiousness of birds, even during the period of expected maximum spirochetaemia. From the tissues sampled (foot joint, liver, spleen, heart, kidney, gut and brain), Borrelia was detected only in the gut, which could be related with infection mode, genospecies competition, genospecies-specific seasonality and/or excretion processes.
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Affiliation(s)
- Ana Cláudia Norte
- Marine and Environmental Sciences Centre, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal.
- Centre for Vectors and Infectious Diseases Dr. Francisco Cambournac, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal.
| | - Isabel Lopes de Carvalho
- Centre for Vectors and Infectious Diseases Dr. Francisco Cambournac, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal
| | - Maria Sofia Núncio
- Centre for Vectors and Infectious Diseases Dr. Francisco Cambournac, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal
| | - Pedro Miguel Araújo
- Marine and Environmental Sciences Centre, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal
| | - Erik Matthysen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium
| | - Jaime Albino Ramos
- Marine and Environmental Sciences Centre, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal
| | - Hein Sprong
- Centre for Infectious Disease Control (CIb), vhNational Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Dieter Heylen
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
- Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium
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13
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Norte AC, Margos G, Becker NS, Albino Ramos J, Núncio MS, Fingerle V, Araújo PM, Adamík P, Alivizatos H, Barba E, Barrientos R, Cauchard L, Csörgő T, Diakou A, Dingemanse NJ, Doligez B, Dubiec A, Eeva T, Flaisz B, Grim T, Hau M, Heylen D, Hornok S, Kazantzidis S, Kováts D, Krause F, Literak I, Mänd R, Mentesana L, Morinay J, Mutanen M, Neto JM, Nováková M, Sanz JJ, Pascoal da Silva L, Sprong H, Tirri IS, Török J, Trilar T, Tyller Z, Visser ME, Lopes de Carvalho I. Host dispersal shapes the population structure of a tick-borne bacterial pathogen. Mol Ecol 2020; 29:485-501. [PMID: 31846173 DOI: 10.1111/mec.15336] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/02/2019] [Accepted: 12/11/2019] [Indexed: 01/25/2023]
Abstract
Birds are hosts for several zoonotic pathogens. Because of their high mobility, especially of longdistance migrants, birds can disperse these pathogens, affecting their distribution and phylogeography. We focused on Borrelia burgdorferi sensu lato, which includes the causative agents of Lyme borreliosis, as an example for tick-borne pathogens, to address the role of birds as propagation hosts of zoonotic agents at a large geographical scale. We collected ticks from passerine birds in 11 European countries. B. burgdorferi s.l. prevalence in Ixodes spp. was 37% and increased with latitude. The fieldfare Turdus pilaris and the blackbird T. merula carried ticks with the highest Borrelia prevalence (92 and 58%, respectively), whereas robin Erithacus rubecula ticks were the least infected (3.8%). Borrelia garinii was the most prevalent genospecies (61%), followed by B. valaisiana (24%), B. afzelii (9%), B. turdi (5%) and B. lusitaniae (0.5%). A novel Borrelia genospecies "Candidatus Borrelia aligera" was also detected. Multilocus sequence typing (MLST) analysis of B. garinii isolates together with the global collection of B. garinii genotypes obtained from the Borrelia MLST public database revealed that: (a) there was little overlap among genotypes from different continents, (b) there was no geographical structuring within Europe, and (c) there was no evident association pattern detectable among B. garinii genotypes from ticks feeding on birds, questing ticks or human isolates. These findings strengthen the hypothesis that the population structure and evolutionary biology of tick-borne pathogens are shaped by their host associations and the movement patterns of these hosts.
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Affiliation(s)
- Ana Cláudia Norte
- MARE - Marine and Environmental Sciences Centre, University of Coimbra, Coimbra, Portugal.,Center for Vector and Infectious Diseases Research, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal
| | - Gabriele Margos
- German National Reference Centre for Borrelia (NRZ), Bavarian Health and Food Safety Authority (LGL), Oberschleissheim, Germany
| | - Noémie S Becker
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Jaime Albino Ramos
- MARE - Marine and Environmental Sciences Centre, University of Coimbra, Coimbra, Portugal
| | - Maria Sofia Núncio
- Center for Vector and Infectious Diseases Research, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal
| | - Volker Fingerle
- German National Reference Centre for Borrelia (NRZ), Bavarian Health and Food Safety Authority (LGL), Oberschleissheim, Germany
| | - Pedro Miguel Araújo
- MARE - Marine and Environmental Sciences Centre, University of Coimbra, Coimbra, Portugal
| | - Peter Adamík
- Department of Zoology, Palacky University, Olomouc, Czech Republic
| | | | - Emilio Barba
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva (ICBiBE), Universidad de Valencia, Valencia, Spain
| | - Rafael Barrientos
- Department of Biodiversity, Ecology and Evolution, Universidad Complutense de Madrid, Madrid, Spain
| | - Laure Cauchard
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Tibor Csörgő
- Ócsa Bird Ringing Station, Ócsa, Hungary.,Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary
| | - Anastasia Diakou
- Laboratory of Parasitology and Parasitic Diseases, Faculty of Health Sciences, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Niels J Dingemanse
- Behavioural Ecology, Department of Biology, Ludwig Maximilians University of Munich, Planegg-Martinsried, Germany
| | - Blandine Doligez
- CNRS - Department of Biometry and Evolutionary Biology (LBBE) - University Lyon 1, University of Lyon, Villeurbanne, France
| | - Anna Dubiec
- Museum and Institute of Zoology, Polish Academy of Sciences, Warszawa, Poland
| | - Tapio Eeva
- Department of Biology, University of Turku, Turku, Finland
| | - Barbara Flaisz
- Department of Parasitology and Zoology, University of Veterinary Medicine, Budapest, Hungary
| | - Tomas Grim
- Department of Zoology, Palacky University, Olomouc, Czech Republic
| | - Michaela Hau
- Evolutionary Physiology Laboratory, Max Planck Institute for Ornithology, Seewiesen, Germany
| | - Dieter Heylen
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.,Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium
| | - Sándor Hornok
- Department of Parasitology and Zoology, University of Veterinary Medicine, Budapest, Hungary
| | - Savas Kazantzidis
- Forest Research Institute, Hellenic Agricultural Organization "DEMETER", Thesaloniki, Greece
| | - David Kováts
- Ócsa Bird Ringing Station, Ócsa, Hungary.,Hungarian Biodiversity Research Society, Budapest, Hungary
| | | | - Ivan Literak
- Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Raivo Mänd
- Department of Zoology, University of Tartu, Tartu, Estonia
| | - Lucia Mentesana
- Evolutionary Physiology Laboratory, Max Planck Institute for Ornithology, Seewiesen, Germany
| | - Jennifer Morinay
- CNRS - Department of Biometry and Evolutionary Biology (LBBE) - University Lyon 1, University of Lyon, Villeurbanne, France.,Department of Ecology and Evolution, Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Marko Mutanen
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
| | - Júlio Manuel Neto
- Department of Biology, Molecular Ecology and Evolution Lab, University of Lund, Lund, Sweden
| | - Markéta Nováková
- Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic.,Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Juan José Sanz
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
| | - Luís Pascoal da Silva
- Department of Life Sciences, CFE - Centre for Functional Ecology - Science for People & the Planet, University of Coimbra, Coimbra, Portugal.,CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Porto, Portugal
| | - Hein Sprong
- National Institute of Public Health and Environment (RIVM), Laboratory for Zoonoses and Environmental Microbiology, Bilthoven, The Netherlands
| | - Ina-Sabrina Tirri
- Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - János Török
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary
| | - Tomi Trilar
- Slovenian Museum of Natural History, Ljubljana, Slovenia
| | - Zdeněk Tyller
- Department of Zoology, Palacky University, Olomouc, Czech Republic.,Museum of the Moravian Wallachia Region, Vsetín, Czech Republic
| | - Marcel E Visser
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Isabel Lopes de Carvalho
- Center for Vector and Infectious Diseases Research, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal
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14
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Hofmeester TR, Bügel EJ, Hendrikx B, Maas M, Franssen FFJ, Sprong H, Matson KD. Parasite Load and Site-Specific Parasite Pressure as Determinants of Immune Indices in Two Sympatric Rodent Species. Animals (Basel) 2019; 9:ani9121015. [PMID: 31766647 PMCID: PMC6940963 DOI: 10.3390/ani9121015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/15/2019] [Accepted: 11/20/2019] [Indexed: 01/04/2023] Open
Abstract
Wildlife is exposed to parasites from the environment. This parasite pressure, which differs among areas, likely shapes the immunological strategies of animals. Individuals differ in the number of parasites they encounter and host, and this parasite load also influences the immune system. The relative impact of parasite pressure vs. parasite load on different host species, particularly those implicated as important reservoirs of zoonotic pathogens, is poorly understood. We captured bank voles (Myodes glareolus) and wood mice (Apodemus sylvaticus) at four sites in the Netherlands. We sampled sub-adult males to quantify their immune function, infestation load for ecto- and gastrointestinal parasites, and infection status for vector-borne microparasites. We then used regression trees to test if variation in immune indices could be explained by among-site differences (parasite pressure), among-individual differences in infestation intensity and infection status (parasite load), or other intrinsic factors. Regression trees revealed splits among sites for haptoglobin, hemagglutination, and body-mass corrected spleen size. We also found splits based on infection/infestation for haptoglobin, hemolysis, and neutrophil to lymphocyte ratio. Furthermore, we found a split between species for hemolysis and splits based on body mass for haptoglobin, hemagglutination, hematocrit, and body-mass corrected spleen size. Our results suggest that both parasite pressure and parasite load influence the immune system of wild rodents. Additional studies linking disease ecology and ecological immunology are needed to understand better the complexities of host-parasite interactions and how these interactions shape zoonotic disease risk.
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Affiliation(s)
- Tim R. Hofmeester
- Resource Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708PB Wageningen, The Netherlands; (T.R.H.); (E.J.B.); (B.H.)
| | - Esther J. Bügel
- Resource Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708PB Wageningen, The Netherlands; (T.R.H.); (E.J.B.); (B.H.)
| | - Bob Hendrikx
- Resource Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708PB Wageningen, The Netherlands; (T.R.H.); (E.J.B.); (B.H.)
| | - Miriam Maas
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands; (M.M.); (F.F.J.F.); (H.S.)
| | - Frits F. J. Franssen
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands; (M.M.); (F.F.J.F.); (H.S.)
| | - Hein Sprong
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands; (M.M.); (F.F.J.F.); (H.S.)
| | - Kevin D. Matson
- Resource Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708PB Wageningen, The Netherlands; (T.R.H.); (E.J.B.); (B.H.)
- Correspondence:
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15
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Wedekind-Grunert S, Schröder B, Richter D. Basic reproduction number of Lyme disease spirochaetes – modelling various genospecies-host associations in Central Europe. Ecol Modell 2019. [DOI: 10.1016/j.ecolmodel.2019.108821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Gomez-Chamorro A, Battilotti F, Cayol C, Mappes T, Koskela E, Boulanger N, Genné D, Sarr A, Voordouw MJ. Susceptibility to infection with Borrelia afzelii and TLR2 polymorphism in a wild reservoir host. Sci Rep 2019; 9:6711. [PMID: 31040326 PMCID: PMC6491475 DOI: 10.1038/s41598-019-43160-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 04/17/2019] [Indexed: 12/14/2022] Open
Abstract
The study of polymorphic immune genes in host populations is critical for understanding genetic variation in susceptibility to pathogens. Controlled infection experiments are necessary to separate variation in the probability of exposure from genetic variation in susceptibility to infection, but such experiments are rare for wild vertebrate reservoir hosts and their zoonotic pathogens. The bank vole (Myodes glareolus) is an important reservoir host of Borrelia afzelii, a tick-borne spirochete that causes Lyme disease. Bank vole populations are polymorphic for Toll-like receptor 2 (TLR2), an innate immune receptor that recognizes bacterial lipoproteins. To test whether the TLR2 polymorphism influences variation in the susceptibility to infection with B. afzelii, we challenged pathogen-free, lab-born individuals of known TLR2 genotype with B. afzelii-infected ticks. We measured the spirochete load in tissues of the bank voles. The susceptibility to infection with B. afzelii following an infected tick bite was very high (95%) and did not differ between TLR2 genotypes. The TLR2 polymorphism also had no effect on the spirochete abundance in the tissues of the bank voles. Under the laboratory conditions of our study, we did not find that the TLR2 polymorphism in bank voles influenced variation in the susceptibility to B. afzelii infection.
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Affiliation(s)
| | | | - Claire Cayol
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Tapio Mappes
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Esa Koskela
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Nathalie Boulanger
- Facultés de Médecine et de Pharmacie, Université de Strasbourg, Strasbourg, France
| | - Dolores Genné
- Institut de Biologie, Université de Neuchâtel, Neuchâtel, Switzerland
| | - Anouk Sarr
- Institut de Biologie, Université de Neuchâtel, Neuchâtel, Switzerland
| | - Maarten Jeroen Voordouw
- Institut de Biologie, Université de Neuchâtel, Neuchâtel, Switzerland.
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
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17
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Klitgaard K, Højgaard J, Isbrand A, Madsen JJ, Thorup K, Bødker R. Screening for multiple tick-borne pathogens in Ixodes ricinus ticks from birds in Denmark during spring and autumn migration seasons. Ticks Tick Borne Dis 2019; 10:546-552. [DOI: 10.1016/j.ttbdis.2019.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 12/15/2022]
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18
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Genospecies of Borrelia burgdorferi sensu lato detected in 16 mammal species and questing ticks from northern Europe. Sci Rep 2019; 9:5088. [PMID: 30911054 PMCID: PMC6434031 DOI: 10.1038/s41598-019-41686-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 03/14/2019] [Indexed: 12/30/2022] Open
Abstract
Lyme borreliosis is the most common vector-borne zoonosis in the northern hemisphere, and the pathogens causing Lyme borreliosis have distinct, incompletely described transmission cycles involving multiple host groups. The mammal community in Fennoscandia differs from continental Europe, and we have limited data on potential competent and incompetent hosts of the different genospecies of Borrelia burgdorferi sensu lato (sl) at the northern distribution ranges where Lyme borreliosis is emerging. We used qPCR to determine presence of B. burgdorferi sl in tissue samples (ear) from 16 mammalian species and questing ticks from Norway, and we sequenced the 5S-23 S rDNA intergenic spacer region to determine genospecies from 1449 qPCR-positive isolates obtaining 423 sequences. All infections coming from small rodents and shrews were linked to the genospecies B. afzelii, while B. burgdorferi sensu stricto (ss) was only found in red squirrels (Sciurus vulgaris). Red squirrels were also infected with B. afzelii and B. garinii. There was no evidence of B. burgdorferi sl infection in moose (Alces alces), red deer (Cervus elaphus) or roe deer (Capreolus capreolus), confirming the role of cervids as incompetent hosts. In infected questing ticks in the two western counties, B. afzelii (67% and 75%) dominated over B. garinii (27% and 21%) and with only a few recorded B. burgdorferi ss and B. valaisiana. B. burgdorferi ss were more common in adult ticks than in nymphs, consistent with a reservoir in squirrels. Our study identifies potential competent hosts for the different genospecies, which is key to understand transmission cycles at high latitudes of Europe.
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19
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Millins C, Dickinson ER, Isakovic P, Gilbert L, Wojciechowska A, Paterson V, Tao F, Jahn M, Kilbride E, Birtles R, Johnson P, Biek R. Landscape structure affects the prevalence and distribution of a tick-borne zoonotic pathogen. Parasit Vectors 2018; 11:621. [PMID: 30514350 PMCID: PMC6278045 DOI: 10.1186/s13071-018-3200-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/13/2018] [Indexed: 12/13/2022] Open
Abstract
Background Landscape structure can affect pathogen prevalence and persistence with consequences for human and animal health. Few studies have examined how reservoir host species traits may interact with landscape structure to alter pathogen communities and dynamics. Using a landscape of islands and mainland sites we investigated how natural landscape fragmentation affects the prevalence and persistence of the zoonotic tick-borne pathogen complex Borrelia burgdorferi (sensu lato), which causes Lyme borreliosis. We hypothesized that the prevalence of B. burgdorferi (s.l.) would be lower on islands compared to the mainland and B. afzelii, a small mammal specialist genospecies, would be more affected by isolation than bird-associated B. garinii and B. valaisiana and the generalist B. burgdorferi (sensu stricto). Methods Questing (host-seeking) nymphal I. ricinus ticks (n = 6567) were collected from 12 island and 6 mainland sites in 2011, 2013 and 2015 and tested for B. burgdorferi (s.l.). Deer abundance was estimated using dung transects. Results The prevalence of B. burgdorferi (s.l.) was significantly higher on the mainland (2.5%, 47/1891) compared to island sites (0.9%, 44/4673) (P < 0.01). While all four genospecies of B. burgdorferi (s.l.) were detected on the mainland, bird-associated species B. garinii and B. valaisiana and the generalist genospecies B. burgdorferi (s.s.) predominated on islands. Conclusion We found that landscape structure influenced the prevalence of a zoonotic pathogen, with a lower prevalence detected among island sites compared to the mainland. This was mainly due to the significantly lower prevalence of small mammal-associated B. afzelii. Deer abundance was not related to pathogen prevalence, suggesting that the structure and dynamics of the reservoir host community underpins the observed prevalence patterns, with the higher mobility of bird hosts compared to small mammal hosts leading to a relative predominance of the bird-associated genospecies B. garinii and generalist genospecies B. burgdorferi (s.s.) on islands. In contrast, the lower prevalence of B. afzelii on islands may be due to small mammal populations there exhibiting lower densities, less immigration and stronger population fluctuations. This study suggests that landscape fragmentation can influence the prevalence of a zoonotic pathogen, dependent on the biology of the reservoir host. Electronic supplementary material The online version of this article (10.1186/s13071-018-3200-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Caroline Millins
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK. .,The Boyd Orr Centre for Population and Ecosystem Health, University of Glasgow, Glasgow, Scotland, UK. .,School of Veterinary Medicine, University of Glasgow, Glasgow, Scotland, UK.
| | - Eleanor R Dickinson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK
| | - Petra Isakovic
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK.,, Present address: Zakot 43, 8250, Brezice, Slovenia
| | - Lucy Gilbert
- James Hutton Institute, Craigiebuckler, Aberdeen, Scotland, UK
| | - Agnieszka Wojciechowska
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK.,Present address: Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Victoria Paterson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK
| | - Feng Tao
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK.,Present address: Wayne State University, 42 W. Warren Ave, Detroit, MI, 48202, USA
| | - Martin Jahn
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK.,Present address: GEOMAR - Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, D-24105, Kiel, Germany
| | - Elizabeth Kilbride
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK
| | - Richard Birtles
- School of Environment and Life Sciences, University of Salford, Salford, England, UK
| | - Paul Johnson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK.,The Boyd Orr Centre for Population and Ecosystem Health, University of Glasgow, Glasgow, Scotland, UK
| | - Roman Biek
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, UK.,The Boyd Orr Centre for Population and Ecosystem Health, University of Glasgow, Glasgow, Scotland, UK
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20
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Hofmeester TR, Krawczyk AI, van Leeuwen AD, Fonville M, Montizaan MGE, van den Berge K, Gouwy J, Ruyts SC, Verheyen K, Sprong H. Role of mustelids in the life-cycle of ixodid ticks and transmission cycles of four tick-borne pathogens. Parasit Vectors 2018; 11:600. [PMID: 30458847 PMCID: PMC6245527 DOI: 10.1186/s13071-018-3126-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 09/28/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Elucidating which wildlife species significantly contribute to the maintenance of Ixodes ricinus populations and the enzootic cycles of the pathogens they transmit is imperative in understanding the driving forces behind the emergence of tick-borne diseases. Here, we aimed to quantify the relative contribution of four mustelid species in the life-cycles of I. ricinus and Borrelia burgdorferi (sensu lato) in forested areas and to investigate their role in the transmission of other tick-borne pathogens. Road-killed badgers, pine martens, stone martens and polecats were collected in Belgium and the Netherlands. Their organs and feeding ticks were tested for the presence of tick-borne pathogens. RESULTS Ixodes hexagonus and I. ricinus were found on half of the screened animals (n = 637). Pine martens had the highest I. ricinus burden, whereas polecats had the highest I. hexagonus burden. We detected DNA from B. burgdorferi (s.l.) and Anaplasma phagocytophilum in organs of all four mustelid species (n = 789), and Neoehrlichia mikurensis DNA was detected in all species, except badgers. DNA from B. miyamotoi was not detected in any of the investigated mustelids. From the 15 larvae of I. ricinus feeding on pine martens (n = 44), only one was positive for B. miyamotoi DNA, and all tested negative for B. burgdorferi (s.l.), N. mikurensis and A. phagocytophilum. The two feeding larvae from the investigated polecats (n = 364) and stone martens (n = 39) were negative for all four pathogens. The infection rate of N. mikurensis was higher in feeding nymphs collected from mustelids compared to questing nymphs, but not for B. burgdorferi (s.l.), B. miyamotoi or A. phagocytophilum. CONCLUSIONS Although all stages of I. ricinus can be found on badgers, polecats, pine and stone martens, their relative contribution to the life-cycle of I. ricinus in forested areas is less than 1%. Consequently, the relative contribution of mustelids to the enzootic cycles of I. ricinus-borne pathogens is negligible, despite the presence of these pathogens in organs and feeding ticks. Interestingly, all four mustelid species carried all stages of I. hexagonus, potentially maintaining enzootic cycles of this tick species apart from the cycle involving hedgehogs as main host species.
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Affiliation(s)
- Tim R Hofmeester
- Resource Ecology Group, Wageningen University, Wageningen, the Netherlands. .,Present address: Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, Skogsmarksgränd 17, 907 36, Umeå, Sweden.
| | - Aleksandra I Krawczyk
- Centre for Zoonoses and Environmental Microbiology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Arieke Docters van Leeuwen
- Centre for Zoonoses and Environmental Microbiology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Manoj Fonville
- Centre for Zoonoses and Environmental Microbiology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | | | - Koen van den Berge
- Research Institute for Nature and Forest (INBO), Geraardsbergen, Belgium
| | - Jan Gouwy
- Research Institute for Nature and Forest (INBO), Geraardsbergen, Belgium
| | - Sanne C Ruyts
- Forest and Nature Lab, Department of Environment, Ghent University, Geraardsbergsesteenweg 267, 9090, Gontrode, Melle, Belgium
| | - Kris Verheyen
- Forest and Nature Lab, Department of Environment, Ghent University, Geraardsbergsesteenweg 267, 9090, Gontrode, Melle, Belgium
| | - Hein Sprong
- Centre for Zoonoses and Environmental Microbiology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
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21
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Ruyts SC, Landuyt D, Ampoorter E, Heylen D, Ehrmann S, Coipan EC, Matthysen E, Sprong H, Verheyen K. Low probability of a dilution effect for Lyme borreliosis in Belgian forests. Ticks Tick Borne Dis 2018; 9:1143-1152. [PMID: 29716838 DOI: 10.1016/j.ttbdis.2018.04.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 11/16/2022]
Abstract
An increasing number of studies have investigated the consequences of biodiversity loss for the occurrence of vector-borne diseases such as Lyme borreliosis, the most common tick-borne disease in the northern hemisphere. As host species differ in their ability to transmit the Lyme borreliosis bacteria Borrelia burgdorferi s.l. to ticks, increased host diversity can decrease disease prevalence by increasing the proportion of dilution hosts, host species that transmit pathogens less efficiently. Previous research shows that Lyme borreliosis risk differs between forest types and suggests that a higher diversity of host species might dilute the contribution of small rodents to infect ticks with B. afzelii, a common Borrelia genospecies. However, empirical evidence for a dilution effect in Europe is largely lacking. We tested the dilution effect hypothesis in 19 Belgian forest stands of different forest types along a diversity gradient. We used empirical data and a Bayesian belief network to investigate the impact of the proportion of dilution hosts on the density of ticks infected with B. afzelii, and identified the key drivers determining the density of infected ticks, which is a measure of human infection risk. Densities of ticks and B. afzelii infection prevalence differed between forest types, but the model indicated that the density of infected ticks is hardly affected by dilution. The most important variables explaining variability in disease risk were related to the density of ticks. Combining empirical data with a model-based approach supported decision making to reduce tick-borne disease risk. We found a low probability of a dilution effect for Lyme borreliosis in a north-western European context. We emphasize that under these circumstances, Lyme borreliosis prevention should rather aim at reducing tick-human contact rate instead of attempting to increase the proportion of dilution hosts.
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Affiliation(s)
- Sanne C Ruyts
- Forest & Nature Lab, Department of Environment, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Dries Landuyt
- Forest & Nature Lab, Department of Environment, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Evy Ampoorter
- Forest & Nature Lab, Department of Environment, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium
| | - Dieter Heylen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Universiteitsplein 11, 2610, Wilrijk, Belgium
| | - Steffen Ehrmann
- Geobotany, Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Elena C Coipan
- Wageningen University and Research, Plant Sciences Group, Bio-interactions and Plant Health Business Unit, P.O. Box 16, 6700 AA,Wageningen, The Netherlands
| | - Erik Matthysen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Universiteitsplein 11, 2610, Wilrijk, Belgium
| | - Hein Sprong
- Centre for Infectious Disease Control Netherlands, National Institute for Public Health and Environment, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands
| | - Kris Verheyen
- Forest & Nature Lab, Department of Environment, Ghent University, Geraardsbergsesteenweg 267, 9090, Melle-Gontrode, Belgium.
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22
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Van Oosten AR, Duron O, Heylen DJA. Sex ratios of the tick Ixodes arboricola are strongly female-biased, but there are no indications of sex-distorting bacteria. Ticks Tick Borne Dis 2017; 9:307-313. [PMID: 29150322 DOI: 10.1016/j.ttbdis.2017.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/25/2017] [Accepted: 11/09/2017] [Indexed: 11/24/2022]
Abstract
Studies on sex ratio are of fundamental importance for understanding the biology of populations and biological control of pests and pathogens. In most Ixodes tick species, only females feed in the adult stage and, hence, contribute to pathogen transmission. The tree-hole tick Ixodes arboricola infests cavity-nesting birds and has limited dispersal possibilities. It plays an important role in the maintenance of zoonotic disease cycles. Here, we quantified the sex ratio of 718 adult I. arboricola ticks obtained from a laboratory stock at nine distinct periods (cohorts) from 2008 to 2015. In addition, we screened 93 specimens, collected from four study sites in 2011 and 2012, for the presence of six maternally inherited bacterial parasites known to manipulate arthropod sex ratios. We found significantly female-biased sex ratios in seven out of nine cohorts. There were no infections with members of the Wolbachia, Arsenophonus or Cardinium bacterial genera, whereas 96.8% of the screened ticks were infected with Rickettsia vini, 22.6% with Rickettsiella sp., and 14.0% with Spiroplasma ixodetis. Male and female I. arboricola were found equally infected. Our results suggest skewed sex ratios in I. arboricola are not caused by these bacterial infections, although there may be other, untested candidates driving sex ratios. Alternatively, female-biased sex ratios may be an adaptation in females to high local densities and low dispersal, where the production of daughters has a selective advantage because a few sons can fertilise all daughters.
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Affiliation(s)
- A Raoul Van Oosten
- Department of Animal Ecology, VU Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; University of Antwerp, Evolutionary Ecology Group, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
| | - Olivier Duron
- Laboratoire MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle), Centre National de la Recherche Scientifique (CNRS UMR5290), Université de Montpellier, Institut de Recherche pour le Développement (UR224), Montpellier, France
| | - Dieter J A Heylen
- University of Antwerp, Evolutionary Ecology Group, Universiteitsplein 1, B-2610 Wilrijk, Belgium
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23
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Heylen D, Fonville M, Docters van Leeuwen A, Stroo A, Duisterwinkel M, van Wieren S, Diuk-Wasser M, de Bruin A, Sprong H. Pathogen communities of songbird-derived ticks in Europe's low countries. Parasit Vectors 2017; 10:497. [PMID: 29047399 PMCID: PMC5648423 DOI: 10.1186/s13071-017-2423-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/04/2017] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Birds play a major role in the maintenance of enzootic cycles of pathogens transmitted by ticks. Due to their mobility, they affect the spatial distribution and abundance of both ticks and pathogens. In the present study, we aim to identify members of a pathogen community [Borrelia burgdorferi (s.l.), B. miyamotoi, 'Ca. Neoehrlichia mikurensis', Anaplasma phagocytophilum and Rickettsia helvetica] in songbird-derived ticks from 11 locations in the Netherlands and Belgium (2012-2014). RESULTS Overall, 375 infested songbird individuals were captured, belonging to 35 species. Thrushes (Turdus iliacus, T. merula and T. philomelos) were trapped most often and had the highest mean infestation intensity for both Ixodes ricinus and I. frontalis. Of the 671 bird-derived ticks, 51% contained DNA of at least one pathogenic agent and 13% showed co-infections with two or more pathogens. Borrelia burgdorferi (s.l.) DNA was found in 34% of the ticks of which majority belong to so-called avian Borrelia species (distribution in Borrelia-infected ticks: 47% B. garinii, 34% B. valaisiana, 3% B. turdi), but also the mammal-associated B. afzelii (16%) was detected. The occurrence of B. miyamotoi was low (1%). Prevalence of R. helvetica in ticks was high (22%), while A. phagocytophilum and 'Ca. N. mikurensis' prevalences were 5% and 4%, respectively. The occurrence of B. burgdorferi (s.l.) was positively correlated with the occurrence of 'Ca. N. mikurensis', reflecting variation in susceptibility among birds and/or suggesting transmission facilitation due to interactions between pathogens. CONCLUSIONS Our findings highlight the contribution of European songbirds to co-infections in tick individuals and consequently to the exposure of humans to multiple pathogens during a tick bite. Although poorly studied, exposure to and possibly also infection with multiple tick-borne pathogens in humans seems to be the rule rather than the exception.
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Affiliation(s)
- Dieter Heylen
- Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium.
| | - Manoj Fonville
- Centre for Zoonoses & Environmental Microbiology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Arieke Docters van Leeuwen
- Centre for Zoonoses & Environmental Microbiology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Arjan Stroo
- Centre for Monitoring of Vectors, Netherlands Food and Consumer Product Safety Authority, Ministry of Economic Affairs, Wageningen, The Netherlands
| | | | - Sip van Wieren
- Resource Ecology Group, Wageningen University, Wageningen, The Netherlands
| | | | - Arnout de Bruin
- Centre for Zoonoses & Environmental Microbiology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Hein Sprong
- Centre for Zoonoses & Environmental Microbiology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
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24
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Belli A, Sarr A, Rais O, Rego ROM, Voordouw MJ. Ticks infected via co-feeding transmission can transmit Lyme borreliosis to vertebrate hosts. Sci Rep 2017; 7:5006. [PMID: 28694446 PMCID: PMC5503982 DOI: 10.1038/s41598-017-05231-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 05/25/2017] [Indexed: 11/09/2022] Open
Abstract
Vector-borne pathogens establish systemic infections in host tissues to maximize transmission to arthropod vectors. Co-feeding transmission occurs when the pathogen is transferred between infected and naive vectors that feed in close spatiotemporal proximity on a host that has not yet developed a systemic infection. Borrelia afzelii is a tick-borne spirochete bacterium that causes Lyme borreliosis (LB) and is capable of co-feeding transmission. Whether ticks that acquire LB pathogens via co-feeding are actually infectious to vertebrate hosts has never been tested. We created nymphs that had been experimentally infected as larvae with B. afzelii via co-feeding or systemic transmission, and compared their performance over one complete LB life cycle. Co-feeding nymphs had a spirochete load that was 26 times lower than systemic nymphs but both nymphs were highly infectious to mice (i.e., probability of nymph-to-host transmission of B. afzelii was ~100%). The mode of transmission had no effect on the other infection phenotypes of the LB life cycle. Ticks that acquire B. afzelii via co-feeding transmission are highly infectious to rodents, and the resulting rodent infection is highly infectious to larval ticks. This is the first study to show that B. afzelii can use co-feeding transmission to complete its life cycle.
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Affiliation(s)
- Alessandro Belli
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Anouk Sarr
- 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
| | - Ryan O M Rego
- Institute of Parasitology, ASCR, Biology Centre, Ceske Budejovice, Czech Republic
| | - Maarten J Voordouw
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
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25
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Durand J, Jacquet M, Rais O, Gern L, Voordouw MJ. Fitness estimates from experimental infections predict the long-term strain structure of a vector-borne pathogen in the field. Sci Rep 2017; 7:1851. [PMID: 28500292 PMCID: PMC5431797 DOI: 10.1038/s41598-017-01821-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/04/2017] [Indexed: 11/18/2022] Open
Abstract
The populations of many pathogen species consist of a collection of common and rare strains but the factors underlying this strain-specific variation in frequency are often unknown. Understanding frequency variation among strains is particularly challenging for vector-borne pathogens where the strain-specific fitness depends on the performance in both the vertebrate host and the arthropod vector. Two sympatric multiple-strain tick-borne pathogens, Borrelia afzelii and B. garinii, that use the same tick vector, Ixodes ricinus, but different vertebrate hosts were studied. 454-sequencing of the polymorphic ospC gene was used to characterize the community of Borrelia strains in a local population of I. ricinus ticks over a period of 11 years. Estimates of the reproduction number (R0), a measure of fitness, were obtained for six strains of B. afzelii from a previous laboratory study. There was substantial variation in prevalence among strains and some strains were consistently common whereas other strains were consistently rare. In B. afzelii, the strain-specific estimates of R0 in laboratory mice explained over 70% of the variation in the prevalences of the strains in our local population of ticks. Our study shows that laboratory estimates of fitness can predict the community structure of multiple-strain pathogens in the field.
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Affiliation(s)
- Jonas Durand
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Maxime Jacquet
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Olivier Rais
- Laboratory of Eco-Epidemiology of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Lise Gern
- Laboratory of Eco-Epidemiology of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Maarten J Voordouw
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
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26
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Ruyts SC, Frazer-Mendelewska E, Van Den Berge K, Verheyen K, Sprong H. Molecular detection of tick-borne pathogens Borrelia afzelii, Borrelia miyamotoi and Anaplasma phagocytophilum in Eurasian red squirrels (Sciurus vulgaris). EUR J WILDLIFE RES 2017. [DOI: 10.1007/s10344-017-1104-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Heylen D, Krawczyk A, Lopes de Carvalho I, Núncio MS, Sprong H, Norte AC. Bridging of cryptic Borrelia cycles in European songbirds. Environ Microbiol 2017; 19:1857-1867. [PMID: 28152581 DOI: 10.1111/1462-2920.13685] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 01/30/2017] [Indexed: 12/15/2022]
Abstract
The principal European vector for Borrelia burgdorferi s.l., the causative agents of Lyme disease, is the host-generalist tick Ixodes ricinus. Almost all terrestrial host-specialist ticks have been supposed not to contribute to the terrestrial Borrelia transmission cycles. Through an experiment with blackbirds, we show successful transmission by the widespread I. frontalis, an abundant bird-specialized tick that infests a broad range of songbirds. In the first phase of the experiment, we obtained Borrelia-infected I. frontalis (infection rate: 19%) and I. ricinus (17%) nymphs by exposing larvae to wild blackbirds that carried several genospecies (Borrelia turdi, B. valaisiana, B. burgdorferi s.s.). In the second phase, pathogen-free blackbirds were exposed to these infected nymphs. Both tick species were able to infect the birds, as indicated by the analysis of xenodiagnostic I. ricinus larvae which provided evidence for both co-feeding and systemic transmission (infection rates: 10%-60%). Ixodes frontalis was shown to transmit B. turdi spirochetes, while I. ricinus transmitted both B. turdi and B. valaisiana. Neither species transmitted B. burgdorferi s.s. European enzootic cycles of Borrelia between songbirds and their ornithophilic ticks do exist, with I. ricinus potentially acting as a bridging vector towards mammals, including man.
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Affiliation(s)
- Dieter Heylen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Aleksandra Krawczyk
- Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Bilthoven, the Netherlands
| | - Isabel Lopes de Carvalho
- Center for Vector and Infectious Diseases Research, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal
| | - Maria Sofia Núncio
- Center for Vector and Infectious Diseases Research, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal
| | - Hein Sprong
- Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Bilthoven, the Netherlands
| | - Ana Cláudia Norte
- Center for Vector and Infectious Diseases Research, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal.,MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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28
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Inefficient co-feeding transmission of Borrelia afzelii in two common European songbirds. Sci Rep 2017; 7:39596. [PMID: 28054584 PMCID: PMC5214756 DOI: 10.1038/srep39596] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 11/25/2016] [Indexed: 12/26/2022] Open
Abstract
The spirochete bacterium Borrelia afzelii is the most common cause of Lyme borreliosis in Europe. This tick-borne pathogen can establish systemic infections in rodents but not in birds. However, several field studies have recovered larval Ixodes ricinus ticks infected with B. afzelii from songbirds suggesting successful transmission of B. afzelii. We reviewed the literature to determine which songbird species were the most frequent carriers of B. afzelii-infected I. ricinus larvae and nymphs. We tested experimentally whether B. afzelii is capable of co-feeding transmission on two common European bird species, the blackbird (Turdus merula) and the great tit (Parus major). For each bird species, four naïve individuals were infested with B. afzelii-infected I. ricinus nymphal ticks and pathogen-free larval ticks. None of the co-feeding larvae tested positive for B. afzelii in blackbirds, but a low percentage of infected larvae (3.33%) was observed in great tits. Transstadial transmission of B. afzelii DNA from the engorged nymphs to the adult ticks was observed in both bird species. However, BSK culture found that these spirochetes were not viable. Our study suggests that co-feeding transmission of B. afzelii is not efficient in these two songbird species.
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29
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Jacquet M, Margos G, Fingerle V, Voordouw MJ. Comparison of the lifetime host-to-tick transmission between two strains of the Lyme disease pathogen Borrelia afzelii. Parasit Vectors 2016; 9:645. [PMID: 27986081 PMCID: PMC5162089 DOI: 10.1186/s13071-016-1929-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 12/04/2016] [Indexed: 11/10/2022] Open
Abstract
Background Transmission from the vertebrate host to the arthropod vector is a critical step in the life-cycle of any vector-borne pathogen. How the probability of host-to-vector transmission changes over the duration of the infection is an important predictor of pathogen fitness. The Lyme disease pathogen Borrelia afzelii is transmitted by Ixodes ricinus ticks and establishes a chronic infection inside rodent reservoir hosts. The present study compares the temporal pattern of host-to-tick transmission between two strains of B. afzelii. Methods Laboratory mice were experimentally infected via tick bite with one of two strains of B. afzelii: A3 and A10. Mice were repeatedly infested with pathogen-free larval Ixodes ricinus ticks over a period of 4 months. Engorged larval ticks moulted into nymphal ticks that were tested for infection with B. afzelii using qPCR. The proportion of infected nymphs was used to characterize the pattern of host-to-tick transmission over time. Results Both strains of B. afzelii followed a similar pattern of host-to-tick transmission. Transmission decreased from the acute to the chronic phase of the infection by 16.1 and 29.3% for strains A3 and A10, respectively. Comparison between strains found no evidence of a trade-off in transmission between the acute and chronic phase of infection. Strain A10 had higher lifetime fitness and established a consistently higher spirochete load in nymphal ticks than strain A3. Conclusion Quantifying the relationship between host-to-vector transmission and the age of infection in the host is critical for estimating the lifetime fitness of vector-borne pathogens. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1929-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maxime Jacquet
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Gabriele Margos
- National Reference Centre for Borrelia, Munich, Oberschleissheim, Germany.,Bavarian Health and Food Safety Authority, Munich, Oberschleissheim, Germany
| | - Volker Fingerle
- National Reference Centre for Borrelia, Munich, Oberschleissheim, Germany.,Bavarian Health and Food Safety Authority, Munich, Oberschleissheim, Germany
| | - Maarten J Voordouw
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
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30
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Takken W, van Vliet AJH, Verhulst NO, Jacobs FHH, Gassner F, Hartemink N, Mulder S, Sprong H. Acarological Risk of Borrelia burgdorferi Sensu Lato Infections Across Space and Time in The Netherlands. Vector Borne Zoonotic Dis 2016; 17:99-107. [PMID: 27893309 DOI: 10.1089/vbz.2015.1933] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A longitudinal investigation on tick populations and their Borrelia infections in the Netherlands was undertaken between 2006 and 2011 with the aim to assess spatial and temporal patterns of the acarological risk in forested sites across the country and to assess variations in Borrelia genospecies diversity. Ticks were collected monthly in 11 sites and nymphs were examined for Borrelia infections. Tick populations expressed strong seasonal variations, with consistent and significant differences in mean tick densities between sites. Borrelia infections were present in all study sites, with a site-specific mean prevalence per month ranging from 7% to 26%. Prevalence was location-dependent and was not associated with tick densities. Mean Borrelia prevalence was lowest in January (4%), gradually increasing to reach a maximum (24%) in August. Borrelia afzelii represented 70% of all infections, with Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia valaisiana represented with 4%, 8%, and 10%, respectively. The density of infected nymphs and the proportional distribution of the four Borrelia genospecies, were significantly different between sites. The results show a consistent and significant spatial and temporal difference in acarological risk across the Netherlands.
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Affiliation(s)
- Willem Takken
- 1 Laboratory of Entomology, Wageningen University and Research , Wageningen, the Netherlands
| | - Arnold J H van Vliet
- 2 Environmental Systems Analysis Group, Wageningen University , Wageningen, the Netherlands .,3 Foundation for Sustainable Development , Wageningen, the Netherlands
| | - Niels O Verhulst
- 1 Laboratory of Entomology, Wageningen University and Research , Wageningen, the Netherlands
| | - Frans H H Jacobs
- 1 Laboratory of Entomology, Wageningen University and Research , Wageningen, the Netherlands .,4 nVWA Centre for Vector Surveillance , Wageningen, the Netherlands
| | - Fedor Gassner
- 1 Laboratory of Entomology, Wageningen University and Research , Wageningen, the Netherlands .,5 Gassner Biological Risk Consultancy , Houten, the Netherlands
| | - Nienke Hartemink
- 6 Theoretical Ecology Group, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam , Amsterdam, the Netherlands
| | - Sara Mulder
- 2 Environmental Systems Analysis Group, Wageningen University , Wageningen, the Netherlands .,3 Foundation for Sustainable Development , Wageningen, the Netherlands
| | - Hein Sprong
- 1 Laboratory of Entomology, Wageningen University and Research , Wageningen, the Netherlands .,7 Centre for Zoonoses & Environmental Microbiology, Centre for Infectious Disease Control, National Institute for Public Health and the Environment , Bilthoven, the Netherlands
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Diversifying forest communities may change Lyme disease risk: extra dimension to the dilution effect in Europe. Parasitology 2016; 143:1310-9. [DOI: 10.1017/s0031182016000688] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
SUMMARYLyme disease is caused by bacteria of theBorrelia burgdorferigenospecies complex and transmitted by Ixodid ticks. In North America only one pathogenic genospecies occurs, in Europe there are several. According to the dilution effect hypothesis (DEH), formulated in North America, nymphal infection prevalence (NIP) decreases with increasing host diversity since host species differ in transmission potential. We analysedBorreliainfection in nymphs from 94 forest stands in Belgium, which are part of a diversification gradient with a supposedly related increasing host diversity: from pine stands without to oak stands with a shrub layer. We expected changing tree species and forest structure to increase host diversity and decrease NIP. In contrast with the DEH, NIP did not differ between different forest types. Genospecies diversity however, and presumably also host diversity, was higher in oak than in pine stands. Infected nymphs tended to harbourBorrelia afzeliiinfection more often in pine stands whileBorrelia gariniiandBorrelia burgdorferiss. infection appeared to be more prevalent in oak stands. This has important health consequences, since the latter two cause more severe disease manifestations. We show that the DEH must be nuanced for Europe and should consider the response of multiple pathogenic genospecies.
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Heylen D, Fonville M, van Leeuwen AD, Sprong H. Co-infections and transmission dynamics in a tick-borne bacterium community exposed to songbirds. Environ Microbiol 2016; 18:988-96. [DOI: 10.1111/1462-2920.13164] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 11/19/2015] [Accepted: 11/27/2015] [Indexed: 12/14/2022]
Affiliation(s)
- Dieter Heylen
- Evolutionary Ecology Group; Department of Biology; University of Antwerp; Antwerpen Belgium
| | - Manoj Fonville
- Laboratory for Zoonoses and Environmental Microbiology; National Institute for Public Health and Environment (RIVM); Bilthoven the Netherlands
| | - Arieke Docters van Leeuwen
- Laboratory for Zoonoses and Environmental Microbiology; National Institute for Public Health and Environment (RIVM); Bilthoven the Netherlands
| | - Hein Sprong
- Laboratory for Zoonoses and Environmental Microbiology; National Institute for Public Health and Environment (RIVM); Bilthoven the Netherlands
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Multi-trophic interactions driving the transmission cycle of Borrelia afzelii between Ixodes ricinus and rodents: a review. Parasit Vectors 2015; 8:643. [PMID: 26684199 PMCID: PMC4684625 DOI: 10.1186/s13071-015-1257-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 12/10/2015] [Indexed: 11/22/2022] Open
Abstract
The tick Ixodes ricinus is the main vector of the spirochaete Borrelia burgdorferi sensu lato, the causal agent of Lyme borreliosis, in the western Palearctic. Rodents are the reservoir host of B. afzelii, which can be transmitted to I. ricinus larvae during a blood meal. The infected engorged larvae moult into infected nymphs, which can transmit the spirochaetes to rodents and humans. Interestingly, even though only about 1 % of the larvae develop into a borreliae-infected nymph, the enzootic borreliae lifecycle can persist. The development from larva to infected nymph is a key aspect in this lifecycle, influencing the density of infected nymphs and thereby Lyme borreliosis risk. The density of infected nymphs varies temporally and geographically and is influenced by multi-trophic (tick-host-borreliae) interactions. For example, blood feeding success of ticks and spirochaete transmission success differ between rodent species and host-finding success appears to be affected by a B. afzelii infection in both the rodent and the tick. In this paper, we review the major interactions between I. ricinus, rodents and B. afzelii that influence this development, with the aim to elucidate the critical factors that determine the epidemiological risk of Lyme borreliosis. The effects of the tick, rodent and B. afzelii on larval host finding, larval blood feeding, spirochaete transmission from rodent to larva and development from larva to nymph are discussed. Nymphal host finding, nymphal blood feeding and spirochaete transmission from nymph to rodent are the final steps to complete the enzootic B. afzelii lifecycle and are included in the review. It is concluded that rodent density, rodent infection prevalence, and tick burden are the major factors affecting the development from larva to infected nymph and that these interact with each other. We suggest that the B. afzelii lifecycle is dependent on the aggregation of ticks among rodents, which is manipulated by the pathogen itself. Better understanding of the processes involved in the development and aggregation of ticks results in more precise estimates of the density of infected nymphs, and hence predictions of Lyme borreliosis risk.
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Jacquet M, Durand J, Rais O, Voordouw MJ. Strain-specific antibodies reduce co-feeding transmission of the Lyme disease pathogen,Borrelia afzelii. Environ Microbiol 2015; 18:833-45. [DOI: 10.1111/1462-2920.13065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 09/20/2015] [Accepted: 09/20/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Maxime Jacquet
- Laboratory of Ecology and Evolution of Parasites; Institute of Biology; University of Neuchâtel; Emile Argand 11 2000 Neuchâtel Switzerland
| | - Jonas Durand
- Laboratory of Ecology and Evolution of Parasites; Institute of Biology; University of Neuchâtel; Emile Argand 11 2000 Neuchâtel Switzerland
| | - Olivier Rais
- Laboratory of Ecology and Evolution of Parasites; Institute of Biology; University of Neuchâtel; Emile Argand 11 2000 Neuchâtel Switzerland
| | - Maarten J. Voordouw
- Laboratory of Ecology and Evolution of Parasites; Institute of Biology; University of Neuchâtel; Emile Argand 11 2000 Neuchâtel Switzerland
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Cross-reactive acquired immunity influences transmission success of the Lyme disease pathogen, Borrelia afzelii. INFECTION GENETICS AND EVOLUTION 2015; 36:131-140. [DOI: 10.1016/j.meegid.2015.09.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 09/04/2015] [Accepted: 09/13/2015] [Indexed: 11/23/2022]
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36
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Heylen DJA, Müller W, Vermeulen A, Sprong H, Matthysen E. Virulence of recurrent infestations with Borrelia-infected ticks in a Borrelia-amplifying bird. Sci Rep 2015; 5:16150. [PMID: 26553505 PMCID: PMC4639849 DOI: 10.1038/srep16150] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 10/05/2015] [Indexed: 11/10/2022] Open
Abstract
Lyme disease cases caused by Borrelia burgdorferi s.l. bacteria is increasing steadily in Europe, in part due to the expansion of the vector, Ixodes ricinus. Wild reservoir hosts are typically recurrently infested. Understanding the impact of these cumulative parasite exposures on the host's health is, therefore, central to predict the distribution of tick populations and their pathogens. Here, we have experimentally investigated the symptoms of disease caused by recurrent infestations in a common songbird (Parus major). Birds were exposed three times in succession to ticks collected in a Borrelia endemic area. Health and immune measures were analyzed in order to investigate changes in response to tick infestation and Borrelia infection rate. Nitric oxide levels increased with the Borrelia infection rate, but this effect was increasingly counteracted by mounting tick infestation rates. Tick infestations equally reduced haematocrit during each cycle. But birds overcompensated in their response to tick feeding, having higher haematocrit values during tick-free periods depending on the number of ticks they had been previously exposed to. Body condition showed a similar overshooting response in function of the severity of the Borrelia infection. The observed overcompensation increases the bird's energetic needs, which may result in an increase in transmission events.
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Affiliation(s)
- Dieter J. A. Heylen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Belgium
| | - Wendt Müller
- Ethology Group, Department of Biology, University of Antwerp, Belgium
| | - Anke Vermeulen
- Ethology Group, Department of Biology, University of Antwerp, Belgium
| | - Hein Sprong
- Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Bilthoven, the Netherlands
| | - Erik Matthysen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Belgium
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Berret J, Voordouw MJ. Lyme disease bacterium does not affect attraction to rodent odour in the tick vector. Parasit Vectors 2015; 8:249. [PMID: 25928557 PMCID: PMC4417542 DOI: 10.1186/s13071-015-0856-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 04/13/2015] [Indexed: 12/03/2022] Open
Abstract
Background Vector-borne pathogens experience a conflict of interest when the arthropod vector chooses a vertebrate host that is incompetent for pathogen transmission. The qualitative manipulation hypothesis suggests that vector-borne pathogens can resolve this conflict in their favour by manipulating the host choice behaviour of the arthropod vector. Methods European Lyme disease is a model system for studying this conflict because Ixodes ricinus is a generalist tick species that vectors Borrelia pathogens that are specialized on different classes of vertebrate hosts. Avian specialists like B. garinii cannot survive in rodent reservoir hosts and vice versa for rodent specialists like B. afzelii. The present study tested whether Borrelia genospecies influenced the attraction of field-collected I. ricinus nymphs to rodent odours. Results Nymphs were significantly attracted to questing perches that had been scented with mouse odours. However, there was no difference in questing behaviour between nymphs infected with rodent- versus bird-specialized Borrelia genospecies. Conclusion Our study suggests that the tick, and not the pathogen, controls the early stages of host choice behaviour. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-0856-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jérémy Berret
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland.
| | - Maarten Jeroen Voordouw
- Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland.
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An Invasive Mammal (the Gray Squirrel, Sciurus carolinensis) Commonly Hosts Diverse and Atypical Genotypes of the Zoonotic Pathogen Borrelia burgdorferi Sensu Lato. Appl Environ Microbiol 2015; 81:4236-45. [PMID: 25888168 PMCID: PMC4475893 DOI: 10.1128/aem.00109-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/03/2015] [Indexed: 11/29/2022] Open
Abstract
Invasive vertebrate species can act as hosts for endemic pathogens and may alter pathogen community composition and dynamics. For the zoonotic pathogen Borrelia burgdorferisensu lato, the agent of Lyme borreliosis, recent work shows invasive rodent species can be of high epidemiological importance and may support host-specific strains. This study examined the role of gray squirrels (Sciurus carolinensis) (n = 679), an invasive species in the United Kingdom, as B. burgdorferi sensu lato hosts. We found that gray squirrels were frequently infested with Ixodes ricinus, the main vector of B. burgdorferi sensu lato in the United Kingdom, and 11.9% were infected with B. burgdorferi sensu lato. All four genospecies that occur in the United Kingdom were detected in gray squirrels, and unexpectedly, the bird-associated genospecies Borrelia garinii was most common. The second most frequent infection was with Borrelia afzelii. Genotyping of B. garinii and B. afzelii produced no evidence for strains associated with gray squirrels. Generalized linear mixed models (GLMM) identified tick infestation and date of capture as significant factors associated with B. burgdorferi sensu lato infection in gray squirrels, with infection elevated in early summer in squirrels infested with ticks. Invasive gray squirrels appear to become infected with locally circulating strains of B. burgdorferi sensu lato, and further studies are required to determine their role in community disease dynamics. Our findings highlight the fact that the role of introduced host species in B. burgdorferi sensu lato epidemiology can be highly variable and thus difficult to predict.
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Heylen D, Sprong H, van Oers K, Fonville M, Leirs H, Matthysen E. Are the specialized bird ticks, Ixodes arboricola and I. frontalis, competent vectors for Borrelia burgdorferi sensu lato? Environ Microbiol 2013; 16:1081-9. [PMID: 24237635 DOI: 10.1111/1462-2920.12332] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 11/05/2013] [Indexed: 11/30/2022]
Abstract
Our study tested whether two European bird-specialized ticks, Ixodes arboricola and I. frontalis, can act as vectors in the transmission cycles of Borrelia burgdorferi s.l. The ticks have contrasting ecologies but share songbird hosts (such as the great tit, Parus major) with the generalist I. ricinus which may therefore act as a bridging vector. In the first phase of the experiment, we obtained Borrelia-infected ornithophilic nymphs by exposing larvae to great tits that had previously been exposed to I. ricinus nymphs carrying a community of genospecies (Borrelia garinii, valaisiana, afzelii, burgdorferi s.s., spielmanii). Skin samples showed that birds selectively amplified B. garinii and B. valaisiana. The spirochetes were transmitted to the ornithophilic ticks and survived moulting, leading to infection rates of 16% and 27% in nymphs of I. arboricola and I. frontalis respectively. In the second phase, pathogen-free great tits were exposed to the Borrelia-infected ornithophilic nymphs. None of these ticks were able to infect the birds, as indicated by the tissue samples. Analysis of xenodiagnostic I. ricinus larvae found no evidence for co-feeding or systemic transmission of B. burgdorferi s.l. These outcomes do not support the occurrence of enzootic cycles of Borrelia burgdorferi s.l. involving songbirds and their specialized ornithophilic ticks.
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Affiliation(s)
- Dieter Heylen
- Department of Biology, University of Antwerp, Evolutionary Ecology Group, Belgium
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