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Jaenson TGT, Gray JS, Lindgren PE, Wilhelmsson P. Coinfection of Babesia and Borrelia in the Tick Ixodes ricinus-A Neglected Public Health Issue in Europe? Pathogens 2024; 13:81. [PMID: 38251388 PMCID: PMC10818971 DOI: 10.3390/pathogens13010081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/09/2024] [Accepted: 01/15/2024] [Indexed: 01/23/2024] Open
Abstract
Ixodes ricinus nymphs and adults removed from humans, and larvae and nymphs from birds, have been analysed for infection with Babesia species and Borrelia species previously in separately published studies. Here, we use the same data set to explore the coinfection pattern of Babesia and Borrelia species in the ticks. We also provide an overview of the ecology and potential public health importance in Sweden of I. ricinus infected both with zoonotic Babesia and Borrelia species. Among 1952 nymphs and adult ticks removed from humans, 3.1% were PCR-positive for Babesia spp. Of these Babesia-positive ticks, 43% were simultaneously Borrelia-positive. Among 1046 immatures of I. ricinus removed from birds, 2.5% were Babesia-positive, of which 38% were coinfected with Borrelia species. This study shows that in I. ricinus infesting humans or birds in Sweden, potentially zoonotic Babesia protozoa sometimes co-occur with human-pathogenic Borrelia spp. Diagnostic tests for Babesia spp. infection are rarely performed in Europe, and the medical significance of this pathogen in Europe could be underestimated.
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Affiliation(s)
- Thomas G. T. Jaenson
- Evolutionary Biology Centre, Department of Organismal Biology, Uppsala University, Norbyvägen 18d, SE-752 36 Uppsala, Sweden;
| | - Jeremy S. Gray
- UCD School of Biology and Environmental Science, University College Dublin, D04 N2E5 Dublin, Ireland;
| | - Per-Eric Lindgren
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, SE-581 83 Linköping, Sweden;
- Department of Clinical Microbiology, Region Jönköping County, SE-551 11 Jönköping, Sweden
| | - Peter Wilhelmsson
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, SE-581 83 Linköping, Sweden;
- Department of Clinical Microbiology, Region Jönköping County, SE-551 11 Jönköping, Sweden
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Mackenzie LS, Lambin X, Bryce E, Davies CL, Hassall R, Shati AAM, Sutherland C, Telfer SE. Patterns and drivers of vector-borne microparasites in a classic metapopulation. Parasitology 2023; 150:866-882. [PMID: 37519240 PMCID: PMC10577662 DOI: 10.1017/s0031182023000677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 07/07/2023] [Accepted: 07/07/2023] [Indexed: 08/01/2023]
Abstract
Many organisms live in fragmented populations, which has profound consequences on the dynamics of associated parasites. Metapopulation theory offers a canonical framework for predicting the effects of fragmentation on spatiotemporal host–parasite dynamics. However, empirical studies of parasites in classical metapopulations remain rare, particularly for vector-borne parasites. Here, we quantify spatiotemporal patterns and possible drivers of infection probability for several ectoparasites (fleas, Ixodes trianguliceps and Ixodes ricinus) and vector-borne microparasites (Babesia microti, Bartonella spp., Hepatozoon spp.) in a classically functioning metapopulation of water vole hosts. Results suggest that the relative importance of vector or host dynamics on microparasite infection probabilities is related to parasite life-histories. Bartonella, a microparasite with a fast life-history, was positively associated with both host and vector abundances at several spatial and temporal scales. In contrast, B. microti, a tick-borne parasite with a slow life-history, was only associated with vector dynamics. Further, we provide evidence that life-history shaped parasite dynamics, including occupancy and colonization rates, in the metapopulation. Lastly, our findings were consistent with the hypothesis that landscape connectivity was determined by distance-based dispersal of the focal hosts. We provide essential empirical evidence that contributes to the development of a comprehensive theory of metapopulation processes of vector-borne parasites.
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Affiliation(s)
| | - Xavier Lambin
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Emma Bryce
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Claire L. Davies
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Richard Hassall
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Ali A. M. Shati
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Chris Sutherland
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Sandra E. Telfer
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
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3
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Rubel F, Kahl O. The Eurasian shrew and vole tick Ixodes trianguliceps: geographical distribution, climate preference, and pathogens detected. EXPERIMENTAL & APPLIED ACAROLOGY 2023:10.1007/s10493-023-00797-0. [PMID: 37160597 PMCID: PMC10293386 DOI: 10.1007/s10493-023-00797-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/01/2023] [Indexed: 05/11/2023]
Abstract
The Eurasian shrew and vole tick Ixodes trianguliceps Birula lives in the nests and burrows of its small mammalian hosts and is-along with larvae and nymphs of Ixodes ricinus or Ixodes persulcatus-one of the most commonly collected tick species from these hosts in its Eurasian range. Ixodes trianguliceps is a proven vector of Babesia microti. In this study, up-to-date maps depicting the geographical distribution and the climate preference of I. trianguliceps are presented. A dataset was compiled, resulting in 1161 georeferenced locations in Eurasia. This data set covers the entire range of I. trianguliceps for the first time. The distribution area between 8[Formula: see text] W-105[Formula: see text] E and 40-69[Formula: see text] N extends from Northern Spain to Western Siberia. To investigate the climate adaptation of I. trianguliceps, the georeferenced locations were superimposed on a high-resolution map of the Köppen-Geiger climate classification. The Köppen profile for I. trianguliceps, i.e., a frequency distribution of the tick occurrence under different climates, shows two peaks related to the following climates: warm temperate with precipitation all year round (Cfb), and boreal with warm or cold summers and precipitation all year round (Dfb, Dfc). Almost 97% of all known I. trianguliceps locations are related to these climates. Thus, I. trianguliceps prefers climates with warm or cold summers without dry periods. Cold winters do not limit the distribution of this nidicolous tick species, which has been recorded in the European Alps and the Caucasus Mountains up to altitudes of 2400 m. Conversely, I. trianguliceps does not occur in the Mediterranean area with its hot and dry summers.
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Affiliation(s)
- Franz Rubel
- Unit for Veterinary Public Health and Epidemiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria.
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4
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Occhibove F, Kenobi K, Swain M, Risley C. An eco-epidemiological modeling approach to investigate dilution effect in two different tick-borne pathosystems. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2550. [PMID: 35092122 PMCID: PMC9286340 DOI: 10.1002/eap.2550] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 10/20/2021] [Accepted: 10/27/2021] [Indexed: 05/05/2023]
Abstract
Disease (re)emergence appears to be driven by biodiversity decline and environmental change. As a result, it is increasingly important to study host-pathogen interactions within the context of their ecology and evolution. The dilution effect is the concept that higher biodiversity decreases pathogen transmission. It has been observed especially in zoonotic vector-borne pathosystems, yet evidence against it has been found. In particular, it is still debated how the community (dis)assembly assumptions and the degree of generalism of vectors and pathogens affect the direction of the biodiversity-pathogen transmission relationship. The aim of this study was to use empirical data and mechanistic models to investigate dilution mechanisms in two rodent-tick-pathogen systems differing in their vector degree of generalism. A community was assembled to include ecological interactions that expand from purely additive to purely substitutive. Such systems are excellent candidates to analyze the link between vector ecology, community (dis)assembly dynamics, and pathogen transmission. To base our mechanistic models on empirical data, rodent live-trapping, including tick sampling, was conducted in Wales across two seasons for three consecutive years. We have developed a deterministic single-vector, multi-host compartmental model that includes ecological relationships with non-host species, uniquely integrating theoretical and observational approaches. To describe pathogen transmission across a gradient of community diversity, the model was populated with parameters describing five different scenarios differing in ecological complexity; each based around one of the pathosystems: Ixodes ricinus (generalist tick)-Borrelia burgdorferi and I. trianguliceps (small mammals specialist tick)-Babesia microti. The results suggested that community composition and interspecific dynamics affected pathogen transmission with different dilution outcomes depending on the vector degree of generalism. The model provides evidence that dilution and amplification effects are not mutually exclusive in the same community but depend on vector ecology and the epidemiological output considered (i.e., the "risk" of interest). In our scenarios, more functionally diverse communities resulted in fewer infectious rodents, supporting the dilution effect. In the pathosystem with generalist vector we identified a hump shaped relationship between diversity and infections in hosts, while for that characterized by specialist tick, this relationship was more complex and more dependent upon specific parameter values.
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Affiliation(s)
- Flavia Occhibove
- IBERS, Aberystwyth UniversityAberystwythUK
- UK Centre for Ecology & HydrologyWallingfordUK
| | - Kim Kenobi
- Department of MathematicsAberystwyth UniversityAberystwythUK
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Ogden NH, Beard CB, Ginsberg HS, Tsao JI. Possible Effects of Climate Change on Ixodid Ticks and the Pathogens They Transmit: Predictions and Observations. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1536-1545. [PMID: 33112403 PMCID: PMC9620468 DOI: 10.1093/jme/tjaa220] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Indexed: 05/09/2023]
Abstract
The global climate has been changing over the last century due to greenhouse gas emissions and will continue to change over this century, accelerating without effective global efforts to reduce emissions. Ticks and tick-borne diseases (TTBDs) are inherently climate-sensitive due to the sensitivity of tick lifecycles to climate. Key direct climate and weather sensitivities include survival of individual ticks, and the duration of development and host-seeking activity of ticks. These sensitivities mean that in some regions a warming climate may increase tick survival, shorten life-cycles and lengthen the duration of tick activity seasons. Indirect effects of climate change on host communities may, with changes in tick abundance, facilitate enhanced transmission of tick-borne pathogens. High temperatures, and extreme weather events (heat, cold, and flooding) are anticipated with climate change, and these may reduce tick survival and pathogen transmission in some locations. Studies of the possible effects of climate change on TTBDs to date generally project poleward range expansion of geographical ranges (with possible contraction of ranges away from the increasingly hot tropics), upslope elevational range spread in mountainous regions, and increased abundance of ticks in many current endemic regions. However, relatively few studies, using long-term (multi-decade) observations, provide evidence of recent range changes of tick populations that could be attributed to recent climate change. Further integrated 'One Health' observational and modeling studies are needed to detect changes in TTBD occurrence, attribute them to climate change, and to develop predictive models of public- and animal-health needs to plan for TTBD emergence.
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Affiliation(s)
- Nicholas H. Ogden
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, St-Hyacinthe, QC, Canada J2S 2M2
- Groupe de recherche en épidémiologie des zoonoses et santé publique (GREZOSP), Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, QC, Canada J2S 2M2
- Corresponding author,
| | - C. Ben Beard
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - Howard S. Ginsberg
- U.S. Geological Survey, Patuxent Wildlife Research Center, Rhode Island Field Station, University of Rhode Island, Kingston, RI 02881
| | - Jean I. Tsao
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824
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Prevalence of Babesia canis DNA in Ixodes ricinus ticks collected in forest and urban ecosystems in west-central Poland. Ticks Tick Borne Dis 2021; 12:101786. [PMID: 34280697 DOI: 10.1016/j.ttbdis.2021.101786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 05/08/2021] [Accepted: 06/15/2021] [Indexed: 11/24/2022]
Abstract
Babesia canis, a widely distributed European tick-borne protozoan haemoparasite, causes canine babesiosis, the most important tick-borne disease afflicting dogs worldwide. The meadow tick, Dermacentor reticulatus, is considered to be the primary vector of this parasite in central Europe. Females of the more broadly distributed and medically important castor bean tick, Ixodes ricinus, also commonly feed upon dogs, but their role in the enzootic transmission cycle of B. canis is unclear. Here, we screened 1,598 host-seeking I. ricinus ticks collected from two different ecosystems, forest stands vs. urban recreational forests, for the presence of B. canis DNA. Ticks were sampled during their two seasonal peaks of activity, spring (May/June) and late summer (September). Babesia species were identified by amplification and sequencing of a hypervariable 18S rRNA gene fragment. Babesia canis was the only piroplasm detected in 13% of 200 larvae and 8.2% of 324 nymphs in the forest ecosystems. In urban recreational areas, B. canis DNA was found in 1.5% of 460 nymphs, 3.5% of 289 females and 3.2% of 280 males. Additionally, three samples, including one female, one male, and one nymph, were co-infected with B. venatorum and one nymph with B. divergens or B. capreoli. Our findings implicate that B. canis can be transmitted transovarially and maintained transstadially within populations of I. ricinus, but the vector competence of I. ricinus for transmitting B. canis remains to be investigated.
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De Pelsmaeker N, Korslund L, Steifetten Ø. High-elevational occurrence of two tick species, Ixodes ricinus and I. trianguliceps, at their northern distribution range. Parasit Vectors 2021; 14:161. [PMID: 33736666 PMCID: PMC7977262 DOI: 10.1186/s13071-021-04604-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 01/23/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND During the last decades a northward and upward range shift has been observed among many organisms across different taxa. In the northern hemisphere, ticks have been observed to have increased their latitudinal and altitudinal range limit. However, the elevational expansion at its northern distribution range remains largely unstudied. In this study we investigated the altitudinal distribution of the exophilic Ixodes ricinus and endophilic I. trianguliceps on two mountain slopes in Norway by assessing larval infestation rates on bank voles (Myodes glareolus). METHODS During 2017 and 2018, 1325 bank voles were captured during the spring, summer and autumn at ten trapping stations ranging from 100 m to 1000 m.a.s.l. in two study areas in southern Norway. We used generalized logistic regression models to estimate the prevalence of infestation of both tick species along gradients of altitude, considering study area, collection year and season, temperature, humidity and altitude interactions as extrinsic variables, and host body mass and sex as intrinsic predictor variables. RESULTS We found that both I. ricinus and I. trianguliceps infested bank voles at altitudes up to 1000 m.a.s.l., which is a substantial increase in altitude compared to previous findings for I. ricinus in this region. The infestation rates declined more rapidly with increasing altitude for I. ricinus compared to I. trianguliceps, indicating that the endophilic ecology of I. trianguliceps may provide shelter from limiting factors tied to altitude. Seasonal effects limited the occurrence of I. ricinus during autumn, but I. trianguliceps was found to infest rodents at all altitudes during all seasons of both years. CONCLUSIONS This study provides new insights into the altitudinal distribution of two tick species at their northern distribution range, one with the potential to transmit zoonotic pathogens to both humans and livestock. With warming temperatures predicted to increase, and especially so in the northern regions, the risk of tick-borne infections is likely to become a concern at increasingly higher altitudes in the future.
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Affiliation(s)
- Nicolas De Pelsmaeker
- Department of Nature, Health and the Environment, University of South-Eastern Norway, Bø, Norway.
| | - Lars Korslund
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Øyvind Steifetten
- Department of Nature, Health and the Environment, University of South-Eastern Norway, Bø, Norway
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8
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Krawczyk AI, van Duijvendijk GLA, Swart A, Heylen D, Jaarsma RI, Jacobs FHH, Fonville M, Sprong H, Takken W. Effect of rodent density on tick and tick-borne pathogen populations: consequences for infectious disease risk. Parasit Vectors 2020; 13:34. [PMID: 31959217 PMCID: PMC6971888 DOI: 10.1186/s13071-020-3902-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/08/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Rodents are considered to contribute strongly to the risk of tick-borne diseases by feeding Ixodes ricinus larvae and by acting as amplifying hosts for pathogens. Here, we tested to what extent these two processes depend on rodent density, and for which pathogen species rodents synergistically contribute to the local disease risk, i.e. the density of infected nymphs (DIN). METHODS In a natural woodland, we manipulated rodent densities in plots of 2500 m2 by either supplementing a critical food source (acorns) or by removing rodents during two years. Untreated plots were used as controls. Collected nymphs and rodent ear biopsies were tested for the presence of seven tick-borne microorganisms. Linear models were used to capture associations between rodents, nymphs, and pathogens. RESULTS Investigation of data from all plots, irrespective of the treatment, revealed a strong positive association between rodent density and nymphal density, nymphal infection prevalence (NIP) with Borrelia afzelii and Neoehrlichia mikurensis, and hence DIN's of these pathogens in the following year. The NIP, but not the DIN, of the bird-associated Borrelia garinii, decreased with increasing rodent density. The NIPs of Borrelia miyamotoi and Rickettsia helvetica were independent of rodent density, and increasing rodent density moderately increased the DINs. In addition, NIPs of Babesia microti and Spiroplasma ixodetis decreased with increasing rodent density, which had a non-linear association with DINs of these microorganisms. CONCLUSIONS A positive density dependence for all rodent- and tick-associated tick-borne pathogens was found, despite the observation that some of them decreased in prevalence. The effects on the DINs were variable among microorganisms, more than likely due to contrasts in their biology (including transmission modes, host specificity and transmission efficiency). The strongest associations were found in rodent-associated pathogens that most heavily rely on horizontal transmission. Our results draw attention to the importance of considering transmission mode of a pathogen while developing preventative measures to successfully reduce the burden of disease.
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Affiliation(s)
- Aleksandra I Krawczyk
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands. .,Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands.
| | | | - Arno Swart
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands
| | - Dieter Heylen
- Interuniversity Institute for Biostatistics and statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium.,Department of Ecology and Evolutionary Biology, Princeton University, 106A Guyot Ln, Princeton, NJ, 08544, USA
| | - Ryanne I Jaarsma
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands
| | - Frans H H Jacobs
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Manoj Fonville
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands
| | - Hein Sprong
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands.
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands
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Sympatric Ixodes-tick species: pattern of distribution and pathogen transmission within wild rodent populations. Sci Rep 2018; 8:16660. [PMID: 30413762 PMCID: PMC6226450 DOI: 10.1038/s41598-018-35031-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/25/2018] [Indexed: 11/19/2022] Open
Abstract
The generalist tick Ixodes ricinus is the most important vector for tick-borne pathogens (TBP), including Borrelia burgdorferi sensu lato, in Europe. However, the involvement of other sympatric Ixodes ticks, such as the specialist vole tick I. trianguliceps, in the enzootic circulations of TBP remains unclear. We studied the distribution of I. ricinus and I. trianguliceps in Central Finland and estimated the TBP infection likelihood in the most common rodent host in relation with the abundance of the two tick species. Ixodes trianguliceps was encountered in all 16 study sites whereas I. ricinus was frequently observed only at a quarter of the study sites. The abundance of I. ricinus was positively associated with open water coverage and human population density around the study sites. Borrelia burgdorferi s. l.-infected rodents were found only in sites where I. ricinus was abundant, whereas the occurrence of other TBP was independent of I. ricinus presence. These results suggest that I. trianguliceps is not sufficient, at least alone, in maintaining the circulation of B. burgdorferi s. l. in wild hosts. In addition, anthropogenic factors might affect the distribution of I. ricinus ticks and, hence, their pathogens, thus shaping the landscape of tick-borne disease risk for humans.
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10
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Tufts DM, Diuk-Wasser MA. Transplacental transmission of tick-borne Babesia microti in its natural host Peromyscus leucopus. Parasit Vectors 2018; 11:286. [PMID: 29728129 PMCID: PMC5935994 DOI: 10.1186/s13071-018-2875-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/26/2018] [Indexed: 11/21/2022] Open
Abstract
Background Babesia microti is an emerging tick-borne pathogen and the causative agent of human babesiosis. Mathematical modeling of the reproductive rate of B. microti indicates that it cannot persist in nature by horizontal tick-host transmission alone. We hypothesized that transplacental transmission in the reservoir population contributes to B. microti persistence and emergence in North American rodent populations. Methods Peromyscus leucopus were collected from Connecticut and Block Island, Rhode Island and analyzed using a highly specific quantitative PCR (qPCR) assay for infection with B. microti. Results In April, 100% (n = 103) of mice were infected with B. microti. Females exhibited significantly higher parasitemia than their offspring (P < 0.0001) and transplacental transmission was observed in 74.2% of embryos (n = 89). Transplacental transmission of B. microti is thus a viable and potentially important infectious pathway in naturally infected rodent species and should be considered in future theoretical and empirical studies. Conclusions To our knowledge, this study is the first to report transplacental transmission of B. microti occurring in its natural reservoir host, P. leucopus, in the United States and the only study that provides a quantitative estimate of parasitemia. This vector-independent pathway could contribute to the increased geographic range of B. microti or increase its abundance in endemic areas. Electronic supplementary material The online version of this article (10.1186/s13071-018-2875-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Danielle M Tufts
- Ecology, Evolution, and Environmental Biology Department, Columbia University, New York, NY, 10027, USA.
| | - Maria A Diuk-Wasser
- Ecology, Evolution, and Environmental Biology Department, Columbia University, New York, NY, 10027, USA
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11
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Andersson MO, Radbea G, Frangoulidis D, Tomaso H, Rubel F, Nava S, Chitimia-Dobler L. New records and host associations of the tick Ixodes apronophorus and the first detection of Ehrlichia sp. HF in Romania. Parasitol Res 2018; 117:1285-1289. [PMID: 29453647 DOI: 10.1007/s00436-018-5800-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 02/06/2018] [Indexed: 11/27/2022]
Abstract
Ixodes (Ixodes) apronophorus is a neglected tick species and its geographical distribution, host associations, and role as a disease vector are not well known. We collected I. apronophorus from several locations in Romania. Morphological identification of ticks was confirmed by analysis of 16S rDNA and 12S rDNA gene sequences. We report new host associations of I. apronophorus, which was collected from dogs, foxes, and a hare-all new hosts for this tick species in Romania. Furthermore, we report for the first time occurrence of Ehrlichia sp. HF in I. apronophorus. Ehrlichia sp. HF was identified by sequencing a part of the 16S rDNA gene and was found in 16% (3/19) of the tested ticks. Ehrlichia sp. HF has not been previously reported in Eastern Europe and seems to have a much larger geographic distribution than previously known. Currently, it is unknown whether I. apronophorus is a competent vector for Ehrlichia sp. HF, or if the findings in this study represent infection in the hosts, namely dogs and fox.
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Affiliation(s)
- Martin O Andersson
- Center for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, SE-391 82, Kalmar, Sweden
| | - Gabriel Radbea
- Sal-Vet Private Veterinary Clinics, Timisoara, Timis County, Romania
| | - Dimitrios Frangoulidis
- Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, D-80937, Munich, Germany.,German Center of Infection Research (DZIF) Partner Munich, Munich, Germany
| | - Herbert Tomaso
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Naumburger Strasse 96a, 07743, Jena, Germany
| | - Franz Rubel
- Institute for Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Santiago Nava
- Estación Experimental Agropecuaria Rafaela, and Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto Nacional de Tecnología Agropecuaria, Buenos Aires, Argentina
| | - Lidia Chitimia-Dobler
- Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, D-80937, Munich, Germany. .,German Center of Infection Research (DZIF) Partner Munich, Munich, Germany. .,Institute for Diagnosis and Animal Health, Bucharest, Romania.
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12
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Prevalence of ticks and tick-borne pathogens: Babesia and Borrelia species in ticks infesting cats of Great Britain. Vet Parasitol 2017; 244:129-135. [DOI: 10.1016/j.vetpar.2017.07.033] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/22/2017] [Accepted: 07/30/2017] [Indexed: 11/24/2022]
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13
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High prevalence of Babesia microti ‘Munich’ type in small mammals from an Ixodes persulcatus/Ixodes trianguliceps sympatric area in the Omsk region, Russia. Parasitol Res 2016; 115:3619-29. [DOI: 10.1007/s00436-016-5128-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 05/12/2016] [Indexed: 02/07/2023]
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Li LH, Zhu D, Zhang CC, Zhang Y, Zhou XN. Experimental transmission of Babesia microti by Rhipicephalus haemaphysaloides. Parasit Vectors 2016; 9:231. [PMID: 27112141 PMCID: PMC4845380 DOI: 10.1186/s13071-016-1517-2] [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: 01/27/2016] [Accepted: 04/18/2016] [Indexed: 12/22/2022] Open
Abstract
Background Human babesiosis is considered an emerging threat in China. Dozens of human infections with Babesia microti have been reported recently, especially in southern China. However, the transmission vectors of this parasite in these areas are not well understood. Rhipicephalus haemaphysaloides, which is one of the dominant tick species in southern China, is a major vector of bovine babesiosis in China. However, whether this tick has the potential to transmit B. microti has not been tested. The present study experimentally investigated the transmission competence of B. microti through R. haemaphysaloides ticks. Methods Larvae and nymphs of R. haemaphysaloides ticks were fed on laboratory mice infected by B. microti. The infection was detected by PCR at 4 weeks post-molting. BALB/c and NOD/SCID mice were infested by nymphs molting from larvae that ingested the blood of infective mice, and blood samples were then analyzed by PCR. Results Experimental transstadial transmission of R. haemaphysaloides for B. microti was proved in both the larvae to nymph and the nymph to adult transstadial routes. The positive rate of B. microti was 43.8 % in nymphs developed from larvae consumed infected mice and 96.7 % in adults developed from nymphs exposed to positive mice. Among the mice infested by infective nymphs, B. microti was detected in 16.7 % (2/12) of the BALB/c mice and in all of the NOD/SCID (6/6). However, the parasite was not observed to persist beyond more than one molt, and transovarial transmission did not occur. Conclusions This is the first study to demonstrate that B. microti can be transmitted artificially by R. haemaphysaloides. This tick species might be a potential vector of human babesiosis in southern China, which represents a public health concern.
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Affiliation(s)
- Lan-Hua Li
- Key Laboratory of Parasite & Vector Biology, Ministry of Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, 200025, People's Republic of China.,School of Publish Health and Management, Weifang Medical University, Weifang, 261053, PR China
| | - Dan Zhu
- Key Laboratory of Parasite & Vector Biology, Ministry of Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, 200025, People's Republic of China
| | - Chen-Chen Zhang
- Key Laboratory of Parasite & Vector Biology, Ministry of Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, 200025, People's Republic of China
| | - Yi Zhang
- Key Laboratory of Parasite & Vector Biology, Ministry of Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, 200025, People's Republic of China.
| | - Xiao-Nong Zhou
- Key Laboratory of Parasite & Vector Biology, Ministry of Health, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, 200025, People's Republic of China.
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Molecular examinations of Babesia microti in rodents and rodent-attached ticks from urban and sylvatic habitats in Germany. Ticks Tick Borne Dis 2015; 6:445-9. [DOI: 10.1016/j.ttbdis.2015.03.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/02/2015] [Accepted: 03/03/2015] [Indexed: 11/20/2022]
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TURNER AK, BELDOMENICO PM, BOWN K, BURTHE SJ, JACKSON JA, LAMBIN X, BEGON M. Host-parasite biology in the real world: the field voles of Kielder. Parasitology 2014; 141:997-1017. [PMID: 24612619 PMCID: PMC4047648 DOI: 10.1017/s0031182014000171] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 12/20/2013] [Accepted: 01/22/2014] [Indexed: 12/21/2022]
Abstract
Research on the interactions between the field voles (Microtus agrestis) of Kielder Forest and their natural parasites dates back to the 1930s. These early studies were primarily concerned with understanding how parasites shape the characteristic cyclic population dynamics of their hosts. However, since the early 2000s, research on the Kielder field voles has expanded considerably and the system has now been utilized for the study of host-parasite biology across many levels, including genetics, evolutionary ecology, immunology and epidemiology. The Kielder field voles therefore represent one of the most intensely and broadly studied natural host-parasite systems, bridging theoretical and empirical approaches to better understand the biology of infectious disease in the real world. This article synthesizes the body of work published on this system and summarizes some important insights and general messages provided by the integrated and multidisciplinary study of host-parasite interactions in the natural environment.
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Affiliation(s)
- A. K. TURNER
- Institute of Integrative Biology, University of
Liverpool, UK
| | - P. M. BELDOMENICO
- Institute of Integrative Biology, University of
Liverpool, UK
- National Centre for Zoonosis Research, University
of Liverpool, UK
- Laboratorio de Ecología de Enfermedades,
Instituto de Ciencias Veterinarias del Litoral, Universidad Nacional del
Litoral – Consejo de Investigaciones Científicas y Técnicas (UNL – CONICET),
Esperanza, Argentina
| | - K. BOWN
- Institute of Integrative Biology, University of
Liverpool, UK
- School of Environment & Life Sciences,
University of Salford, UK
| | - S. J. BURTHE
- Institute of Integrative Biology, University of
Liverpool, UK
- National Centre for Zoonosis Research, University
of Liverpool, UK
- Centre for Ecology & Hydrology, Natural
Environmental Research Council, Edinburgh,
UK
| | - J. A. JACKSON
- Institute of Integrative Biology, University of
Liverpool, UK
- Institute of Biological, Environmental and Rural
Sciences, University of Aberystwyth, UK
| | - X. LAMBIN
- School of Biological Sciences, University of
Aberdeen, UK
| | - M. BEGON
- Institute of Integrative Biology, University of
Liverpool, UK
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Kallio ER, Begon M, Birtles RJ, Bown KJ, Koskela E, Mappes T, Watts PC. First report of Anaplasma phagocytophilum and Babesia microti in rodents in Finland. Vector Borne Zoonotic Dis 2014; 14:389-93. [PMID: 24848684 DOI: 10.1089/vbz.2013.1383] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Tick-borne diseases pose an increasingly important public health problem in Europe. Rodents are the reservoir host for many tick-transmitted pathogens, including Anaplasma phagocytophilum and Babesia microti, which can cause human granulocytic anaplasmosis and babesiosis, respectively. To estimate the presence of these pathogens in rodents in Finland, we examined blood samples from 151 bank voles (Myodes glareolus) and demonstrate, for the first time, that A. phagocytophilum and B. microti commonly infect bank voles (in 22% and 40% of animals, respectively) in Finland. Sequence analysis of a fragment of 18S rRNA showed that the B. microti strain isolated was identical to the Munich strain, which is considered to be nonzoonotic. The A. phagocytophilum strain (based on a fragment of the msp4 gene) was identical to one found earlier in rodents in the United Kingdom that is transmitted by the tick Ixodes trianguliceps, all the life stages of which feed on small mammals. The infection probability of B. microti in the bank voles was the greater the older the individual was, and males were more often infected than females. A. phagocytophilum infection probability first increased and then decreased with the age of individual without any difference between sexes. While these pathogens presumably pose a limited zoonotic risk to humans in Finland, they might have important interactions with other rodent pathogens and therefore affect infection dynamics of, for example, zoonotic pathogens.
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Affiliation(s)
- Eva R Kallio
- 1 Department of Biological and Environmental Science, University of Jyväskylä , Jyväskylä, Finland
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18
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Yabsley MJ, Shock BC. Natural history of Zoonotic Babesia: Role of wildlife reservoirs. Int J Parasitol Parasites Wildl 2013; 2:18-31. [PMID: 24533312 PMCID: PMC3862492 DOI: 10.1016/j.ijppaw.2012.11.003] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 10/25/2012] [Accepted: 11/06/2012] [Indexed: 11/02/2022]
Abstract
Babesiosis is an emerging zoonotic disease on all inhabited continents and various wildlife species are the principal reservoir hosts for zoonotic Babesia species. The primary vectors of Babesia are Ixodid ticks, with the majority of zoonotic species being transmitted by species in the genus Ixodes. Species of Babesia vary in their infectivity, virulence and pathogenicity for people. Various factors (e.g., increased interactions between people and the environment, increased immunosuppression, changes in landscape and climate, and shifts in host and vector species abundance and community structures) have led to an increase in tick-borne diseases in people, including babesiosis. Furthermore, because babesiosis is now a reportable disease in several states in the United States, and it is the most common blood transfusion-associated parasite, recognized infections are expected to increase. Because of the zoonotic nature of these parasites, it is essential that we understand the natural history (especially reservoirs and vectors) so that appropriate control and prevention measures can be implemented. Considerable work has been conducted on the ecology of Babesia microti and Babesia divergens, the two most common causes of babesiosis in the United States and Europe, respectively. However, unfortunately, for many of the zoonotic Babesia species, the reservoir(s) and/or tick vector(s) are unknown. We review the current knowledge regarding the ecology of Babesia among their reservoir and tick hosts with an emphasis of the role on wildlife as reservoirs. We hope to encourage the molecular characterization of Babesia from potential reservoirs and vectors as well from people. These data are necessary so that informed decisions can be made regarding potential vectors and the potential role of wildlife in the ecology of a novel Babesia when it is detected in a human patient.
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Affiliation(s)
- Michael J. Yabsley
- Corresponding author. Address: The Southeastern Cooperative Wildlife Disease Study, Department of Population Health, 589 DW Brooks Drive, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA. Tel.: +1 706 542 1741; fax: +1 706 542 5865.
| | - Barbara C. Shock
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
- The Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
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Silaghi C, Woll D, Mahling M, Pfister K, Pfeffer M. Candidatus Neoehrlichia mikurensis in rodents in an area with sympatric existence of the hard ticks Ixodes ricinus and Dermacentor reticulatus, Germany. Parasit Vectors 2012; 5:285. [PMID: 23216786 PMCID: PMC3533915 DOI: 10.1186/1756-3305-5-285] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 12/02/2012] [Indexed: 01/17/2023] Open
Abstract
Background Candidatus Neoehrlichia mikurensis (CNM) has been described in the hard tick Ixodes ricinus and rodents as well as in some severe cases of human disease. The aims of this study were to identify DNA of CNM in small mammals, the ticks parasitizing them and questing ticks in areas with sympatric existence of Ixodes ricinus and Dermacentor reticulatus in Germany. Methods Blood, transudate and organ samples (spleen, kidney, liver, skin) of 91 small mammals and host-attached ticks from altogether 50 small mammals as well as questing I. ricinus ticks (n=782) were screened with a real-time PCR for DNA of CNM. Results 52.7% of the small mammals were positive for CNM-DNA. The majority of the infected animals were yellow-necked mice (Apodemus flavicollis) and bank voles (Myodes glareolus). Small mammals with tick infestation were more often infected with CNM than small mammals without ticks. Compared with the prevalence of ~25% in the questing I. ricinus ticks, twice the prevalence in the rodents provides evidence for their role as reservoir hosts for CNM. Conclusion The high prevalence of this pathogen in the investigated areas in both rodents and ticks points towards the need for more specific investigation on its role as a human pathogen.
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Affiliation(s)
- Cornelia Silaghi
- Comparative Tropical Medicine and Parasitology, Ludwig-Maximilians-Universität München, Leopoldstr. 5, D-80802 Munich, Germany.
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20
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Hoch T, Goebel J, Agoulon A, Malandrin L. Modelling bovine babesiosis: a tool to simulate scenarios for pathogen spread and to test control measures for the disease. Prev Vet Med 2012; 106:136-42. [PMID: 22341037 DOI: 10.1016/j.prevetmed.2012.01.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tick-borne diseases are of increasing concern in many countries, particularly as a consequence of changes in land use and climate. Ticks are vectors of numerous pathogens (viruses, bacteria, protozoa) that can be harmful to humans and animals. In the context of animal health, bovine babesiosis poses a recurrent threat to cattle herds. In this study, we use a modeling approach to investigate the spread of babesiosis and evaluate control measures. A previously developed tick population dynamics model (here, Ixodes ricinus) is coupled with a pathogen spread model (here, the protozoan Babesia divergens), which describes pathogen spread in a dairy herd through the following processes: transmission, acquisition, transovarial transmission, transstadial persistence, and clearance of the pathogen. An assessment of the simulated B. divergens prevalence levels in ticks and cattle in the context of existing knowledge and data suggested that the model provides a realistic representation of pathogen spread. The model was then used to evaluate the influence of host density and the effect of acaricides on B. divergens prevalence in cattle. Increasing deer density results in an increase in prevalence in cattle whereas increasing cattle stocking rate results in a slight decrease. A potential increase in deer density would thus have an amplification effect on disease spread due to the increase in the number of infected ticks. Regular use of acaricides produces a reduction in pathogen prevalence in cattle. This model could be adapted to other tick-borne diseases.
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Affiliation(s)
- Thierry Hoch
- INRA, UMR 1300 Bio-Agression, Epidémiologie et Analyse de Risque, Nantes, F-44307, France.
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21
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Abstract
SUMMARYIn the epidemiology of infectious diseases, the basic reproduction number, R0, has a number of important applications, most notably it can be used to predict whether a pathogen is likely to become established, or persist, in a given area. We used the R0model to investigate the persistence of 3 tick-borne pathogens;Babesia microti, Anaplasma phagocytophilumandBorrelia burgdorferisensu lato in anApodemus sylvaticus-Ixodes ricinussystem. The persistence of these pathogens was also determined empirically by screening questing ticks and wood mice by PCR. All 3 pathogens behaved differently in response to changes in the proportion of transmission hosts on whichI. ricinusfed, the efficiency of transmission between the host and ticks and the abundance of larval and nymphal ticks found on small mammals. Empirical data supported theoretical predictions of the R0model. The transmission pathway employed and the duration of systemic infection were also identified as important factors responsible for establishment or persistence of tick-borne pathogens in a given tick-host system. The current study demonstrates how the R0model can be put to practical use to investigate factors affecting tick-borne pathogen persistence, which has important implications for animal and human health worldwide.
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22
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Tick-borne disease systems emerge from the shadows: the beauty lies in molecular detail, the message in epidemiology. Parasitology 2009; 136:1403-13. [PMID: 19366480 DOI: 10.1017/s0031182009005782] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This review focuses on some of the more ground-shifting advances of recent decades, particularly those at the molecular and cellular level that illuminate mechanisms underpinning the natural ecology of tick-host-pathogen interactions and the consequent epidemiology of zoonotic infections in humans. Knowledge of components of tick saliva, now recognized as the central pillar in the tick's ability to complete its blood meal and the pathogen's differential ability to use particular hosts for transmission, has burgeoned with new molecular techniques. Functional studies have linked a few of them to saliva-assisted transmission of non-systemic infections between co-feeding ticks, the quantitative key to persistent cycles of the most significant tick-borne pathogen in Europe. Human activities, however, may be equally important in determining dynamic patterns of infection incidence in humans.
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23
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Relative importance of Ixodes ricinus and Ixodes trianguliceps as vectors for Anaplasma phagocytophilum and Babesia microti in field vole (Microtus agrestis) populations. Appl Environ Microbiol 2008; 74:7118-25. [PMID: 18820068 PMCID: PMC2592922 DOI: 10.1128/aem.00625-08] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The importance of Ixodes ricinus in the transmission of tick-borne pathogens is well recognized in the United Kingdom and across Europe. However, the role of coexisting Ixodes species, such as the widely distributed species Ixodes trianguliceps, as alternative vectors for these pathogens has received little attention. This study aimed to assess the relative importance of I. ricinus and I. trianguliceps in the transmission of Anaplasma phagocytophilum and Babesia microti among United Kingdom field voles (Microtus agrestis), which serve as reservoir hosts for both pathogens. While all instars of I. trianguliceps feed exclusively on small mammals, I. ricinus adults feed primarily on larger hosts such as deer. The abundance of both tick species and pathogen infection prevalence in field voles were monitored at sites surrounded with fencing that excluded deer and at sites where deer were free to roam. As expected, fencing significantly reduced the larval burden of I. ricinus on field voles and the abundance of questing nymphs, but the larval burden of I. trianguliceps was not significantly affected. The prevalence of A. phagocytophilum and B. microti infections was not significantly affected by the presence of fencing, suggesting that I. trianguliceps is their principal vector. The prevalence of nymphal and adult ticks on field voles was also unaffected, indicating that relatively few non-larval I. ricinus ticks feed upon field voles. This study provides compelling evidence for the importance of I. trianguliceps in maintaining these enzootic tick-borne infections, while highlighting the potential for such infections to escape into alternative hosts via I. ricinus.
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Laurenson MK, McKendrick IJ, Reid HW, Challenor R, Mathewson GK. Prevalence, spatial distribution and the effect of control measures on louping-ill virus in the Forest of Bowland, Lancashire. Epidemiol Infect 2007; 135:963-73. [PMID: 17346361 PMCID: PMC2870653 DOI: 10.1017/s0950268806007692] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The complex pathogen-host-vector system of the tick-borne louping-ill virus causes economic losses to sheep and red grouse in upland United Kingdom. This paper examines the spatial distribution, incidence and effect of control measures on louping-ill virus in the Bowland Fells of Lancashire. Seroprevalence in sheep at the beginning of the study varied within the area and was affected significantly by the frequency of acaricide treatment. There was a clear decrease over 5 years in the effective force of infection on farms implementing a vaccination programme, irrespective of acaricide treatment regime, however, only one third of farms apparently eliminated infection. On farms where vaccination did not occur or where vaccination was carried out intermittently, the estimated force of infection was variable or possibly increased. Thus, as befits a complex host-pathogen system, reductions in prevalence were not as dramatic as predicted; we discuss the potential explanations for these observations.
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Affiliation(s)
- M K Laurenson
- Wildlife and Emerging Diseases, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK.
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25
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Siński E, Bajer A, Welc R, Pawełczyk A, Ogrzewalska M, Behnke JM. Babesia microti: prevalence in wild rodents and Ixodes ricinus ticks from the Mazury Lakes District of North-Eastern Poland. Int J Med Microbiol 2006; 296 Suppl 40:137-43. [PMID: 16524774 DOI: 10.1016/j.ijmm.2006.01.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Infections of Babesia microti (Apicomplexa, Piroplasmida), a common erythroparasitic protozoon of Holarctic rodents, are not widely acknowledged in Poland. The presence of this parasite in various species of wild rodents has been well documented throughout the northern temperate zone of North America, Europe, and Eurasia. However, human babesiosis attributable to infection with B. microti has been reported only from the north-eastern and upper midwestern United States and Japan. We recently carried out an epizootiological survey investigating the prevalence of B. microti both in the tick Ixodes ricinus and in wild rodents in North-Eastern Poland. Blood samples were collected from a total of 483 animals comprising three species: Apodemus flavicollis, Microtus arvalis, and Microtus oeconomus trapped at Urwitałt near Mikołajki in the Mazury Lakes District. Questing adult I. ricinus ticks were collected in the study sites by blanket dragging of vegetation in heterogeneous, deciduous woodland, and, in addition, rodents were carefully examined for feeding larvae and nymphs. Altogether, B. microti was detected in 9 out of 1513 I. ricinus ticks (0.6%) examined by PCR. This included 163 adults (92 females and 71 males), 50 nymphs, and 1300 larvae 3%, 8%, and 0% of which were PCR-positive, respectively. Of 85 A. flavicollis, 374 M. arvalis and 24 M. oeconomus, 1%, 12.8%, and 42% were parasitaemic, respectively, as determined by microscopic examination of blood smears stained with Giemsa. B. microti DNA, extracted from 53 M. arvalis and 5 M. oeconomus and examined by nested PCR, targeting a piroplasm-specific portion of the 18S ribosomal DNA, revealed 72% and 40%, respectively, to be PCR positive. Sequence analysis showed that all PCR-positive samples had rDNA sequences identical (100% homology) to that of the Munich B. microti strain isolated from Mus musculus. The results of this study indicate that the B. microti commonly encountered among Microtus spp. rodents is probably not a zoonotic strain and, therefore, that it is most unlikely to represent a risk to public health in the Mazury Lakes District of North-Eastern Poland.
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Affiliation(s)
- Edward Siński
- Department of Parasitology, Institute of Zoology, Warsaw University, Miecznikowa 1 Street, PL-02096 Warsaw, Poland.
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Randolph SE. Tick ecology: processes and patterns behind the epidemiological risk posed by ixodid ticks as vectors. Parasitology 2005; 129 Suppl:S37-65. [PMID: 15938504 DOI: 10.1017/s0031182004004925] [Citation(s) in RCA: 299] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The population ecology of ticks is fundamental to the spatial and temporal variation in the risk of infection by tick-borne pathogens. Tick population dynamics can only be fully understood by quantifying the rates of the demographic processes, which are influenced by both abiotic (climatic) factors acting on the free-living tick stages and biotic (host) responses to the tick as a parasite. Within the framework of a population model, I review methods and results of attempts to quantify (1) rates of tick development and the probability of diapause, (2) the probability of questing for hosts by unfed ticks, (3) the probability of ticks attaching to a host, and (4) tick mortality rates. Biologically, these processes involve the physiological and behavioural response of ticks to temperature, moisture stress and day length that result in specific patterns of seasonal population dynamics and host relationships. Temperate and tropical patterns will be illustrated with reference mostly toIxodes ricinusandRhipicephalus appendiculatus, respectively.
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Affiliation(s)
- S E Randolph
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
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Birkenheuer AJ, Levy MG, Breitschwerdt EB. Efficacy of Combined Atovaquone and Azithromycin for Therapy of Chronic Babesia gibsoni (Asian Genotype) Infections in Dogs. J Vet Intern Med 2004. [DOI: 10.1111/j.1939-1676.2004.tb02573.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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28
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Ogden NH, Casey ANJ, Woldehiwet Z, French NP. Transmission of Anaplasma phagocytophilum to Ixodes ricinus ticks from sheep in the acute and post-acute phases of infection. Infect Immun 2003; 71:2071-8. [PMID: 12654828 PMCID: PMC152096 DOI: 10.1128/iai.71.4.2071-2078.2003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2002] [Revised: 12/14/2002] [Accepted: 01/02/2003] [Indexed: 11/20/2022] Open
Abstract
A total of 60 sheep were exposed to Anaplasma phagocytophilum infection on an enclosed area of Ixodes ricinus-infested pasture in North Wales, United Kingdom, and rapidly acquired acute A. phagocytophilum infections detectable by PCR and blood smear examination. Of the ticks that had engorged in the previous instar on infected sheep, 52% of adult ticks and 28% of nymphs were PCR positive; a significant, 10-fold increase in prevalence compared to that of ticks that engorged on sheep preinfection was observed (P = 0.015). The likelihood that ticks were PCR positive, after feeding on the sheep and molting to the next instar, increased marginally with increasing numbers of infected neutrophils per milliliter of blood of their sheep host (P = 0.068) and increased significantly when they were collected from sheep carrying higher numbers of adult female ticks (P = 0.017), but increasing numbers of feeding nymphs had a significant negative effect on transmission (P = 0.049). The numbers of circulating neutrophils and of infected neutrophils also varied significantly with the numbers of ticks feeding on the sheep when the blood was collected. Our study suggests that ruminants are efficient reservoirs of A. phagocytophilum during the acute and post-acute phases of infection. The risk of ruminant-derived infections may, however, be strongly affected by variations in tick densities, which may influence transmission from acutely infected animals via effects on the numbers of infected cells in the blood and possibly by within-skin modulation of infection.
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Affiliation(s)
- N H Ogden
- Department of Veterinary Preclinical Sciences, University of Liverpool, Liverpool L69 7ZJ, UK.
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29
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Kálmán D, Sréter T, Széll Z, Egyed L. Babesia microti infection of anthropophilic ticks (Ixodes ricinus) in Hungary. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2003; 97:317-9. [PMID: 12803863 DOI: 10.1179/000349803235002272] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- D Kálmán
- Veterinary Research Institute of the Hungarian Academy of Sciences, H-1143 Budapest, Hungária krt. 21, Hungary
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30
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Foppa IM, Krause PJ, Spielman A, Goethert H, Gern L, Brand B, Telford SR. Entomologic and serologic evidence of zoonotic transmission of Babesia microti, eastern Switzerland. Emerg Infect Dis 2002; 8:722-6. [PMID: 12095442 PMCID: PMC3369589 DOI: 10.3201/eid0807.010459] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We evaluated human risk for infection with Babesia microti at a site in eastern Switzerland where several B. microti-infected nymphal Ixodes ricinus ticks had been found. DNA from pooled nymphal ticks amplified by polymerase chain reaction was highly homologous to published B. microti sequences. More ticks carried babesial infection in the lower portion of the rectangular 0.7-ha grid than in the upper (11% vs. 0.8%). In addition, we measured seroprevalence of immunoglobulin (Ig) G antibodies against B. microti antigen in nearby residents. Serum from 1.5% of the 396 human residents of the region reacted to B. microti antigen (>1:64), as determined by indirect immunofluorescence assay (IgG). These observations constitute the first report demonstrating B. microti in a human-biting vector, associated with evidence of human exposure to this agent in a European site.
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Affiliation(s)
- Ivo M. Foppa
- Harvard School of Public Health, Boston, Massachusetts, USA
| | - Peter J. Krause
- Connecticut Children’s Medical Center and University of Connecticut School of Medicine, Hartford, Connecticut, USA
| | | | - Heidi Goethert
- Harvard School of Public Health, Boston, Massachusetts, USA
| | - Lise Gern
- Université de Neuchâtel, Institut de Zoologie, Neuchâtel, Switzerland
| | - Brigit Brand
- Kantonsspital, Blutspendezentrum, Chur, Switzerland
| | - Sam R. Telford
- Harvard School of Public Health, Boston, Massachusetts, USA
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Gray J, von Stedingk LV, Gürtelschmid M, Granström M. Transmission studies of Babesia microti in Ixodes ricinus ticks and gerbils. J Clin Microbiol 2002; 40:1259-63. [PMID: 11923342 PMCID: PMC140393 DOI: 10.1128/jcm.40.4.1259-1263.2002] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to investigate the possible role of Ixodes ricinus as a vector of zoonotic Babesia microti infection in Europe, a European rodent isolate (HK) and a zoonotic American isolate (GI) were studied in transmission experiments. PCR detected B. microti in the blood and spleens of infected gerbils (Meriones unguiculatus) and also in laboratory-induced infections of I. ricinus ticks. B. microti DNA was detected by PCR in all pooled samples of nymphs and the majority of adults that had fed as larvae and nymphs, respectively, on gerbils with acute infection of the European isolate, confirming that I. ricinus could serve as a vector in Europe. The American isolate, GI, proved to be equally infective for larval and nymphal I. ricinus as the HK strain, despite a very different appearance in gerbil erythrocytes. Nymphs infected with the HK and GI strains readily infected gerbils. In contrast to the finding in acute infections, ticks that fed on gerbils with chronic infections of HK and GI did not become infected. It was also found that the HK strain was not transmitted transovarially. The finding that a B. microti strain (GI) from a distant geographical region (United States) can infect and be transmitted by I. ricinus suggests that other European B. microti strains, in addition to the HK strain used here, are probably infective for I. ricinus, supporting the view that infection of humans with European B. microti may be a regular occurrence.
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Affiliation(s)
- Jeremy Gray
- Department of Environmental Resource Management, Faculty of Agriculture, Belfield, Dublin 4, Ireland.
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Duh D, Petrovec M, Avsic-Zupanc T. Diversity of Babesia Infecting European sheep ticks (Ixodes ricinus). J Clin Microbiol 2001; 39:3395-7. [PMID: 11526189 PMCID: PMC88357 DOI: 10.1128/jcm.39.9.3395-3397.2001] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Questing Ixodes ricinus (Acari: Ixodidae) adult and nymphal ticks collected in various parts of Slovenia were tested for the presence of babesial parasites with a PCR assay based on the nuclear small subunit rRNA gene (nss-ribosomal DNA [rDNA]). Thirteen of 135 ticks were found to contain babesial DNA. Sequence determination and analysis of amplified portions of nss-rDNA revealed their identity with Babesia microti and a high degree of homology with Babesia odocoilei and Babesia divergens. The results of this study represent the first genetic evidence of B. microti and B. divergens-like parasites in I. ricinus ticks in Europe.
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Affiliation(s)
- D Duh
- Institute of Microbiology and Immunology, Medical Faculty, Ljubljana, Slovenia
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Abstract
Human babesiosis is an important emerging tick-borne disease. Babesia divergens, a parasite of cattle, has been implicated as the most common agent of human babesiosis in Europe, causing severe disease in splenectomized individuals. In the US, Babesia microti, a babesial parasite of small mammals, has been the cause of over 300 cases of human babesiosis since 1969, resulting in mild to severe disease, even in non-splenectomised patients. Changing ecology has contributed greatly to the increase and expansion of human babesiosis in the US. A relatively recently described babesial parasite, the WA1-type, has been shown to be the causative agent in seven human cases in the western US. This parasite is closely related to babesial parasites isolated from large wild ungulates in California. Like B. microti, WA1-type parasites cause mild to severe disease and the immunopathogenesis of these parasites is distinctly different from each other in experimental infections of hamsters and mice. A B. divergens-like parasite was also identified as the cause of a fatal human babesiosis case in Missouri. Isolated cases of human babesisosis have been described in Africa and Mexico, but the causative parasites were not well characterized. Standard diagnostic techniques for human infection, such as examination of Giemsa-stained thin blood smears and serology, have been complemented with molecular techniques, such as PCR. Current treatment for babesiosis is focused on a regimen of clindamycin and quinine, although new drugs have shown promise. Prevention of infection relies on self-monitoring for the presence of ticks and, in some locations, targeted application of pesticides to decrease tick abundance. Identification of human infection with Babesia spp. will probably increase as physicians and the public become more aware of the disease, as people live and recreate in rural tick-infested areas, and as the numbers of immunocompromised individuals increase.
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Affiliation(s)
- A M Kjemtrup
- University of California, School of Veterinary Medicine, Department of Pathology, Microbiology and Immunology, 1 Shields Avenue, Davis, CA 95616-8736, USA
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Randolph SE. Ticks are not Insects: Consequences of Contrasting Vector Biology for Transmission Potential. ACTA ACUST UNITED AC 1998; 14:186-92. [PMID: 17040748 DOI: 10.1016/s0169-4758(98)01224-1] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Quantitative analyses of vector-borne parasite systems are dominated by insect systems. In attempts to formulate general statements concerning vectors and their indirectly transmitted parasites, ticks are usually ignored or they are implicitly or explicitly assumed to obey the same rules as insects. Here, Sarah Randolph shows that contrasting biological attributes of these two different arthropod classes (ticks and insects) directly affect their performance as vectors. The equations for estimating their respective potential to transmit parasites differ in important respects, as does the relative impact of each factor on these estimates. These conclusions direct attention towards the empirical field data most appropriate for quantifying the spatially and temporally variable risk of infection from these contrasting vector-borne parasite systems.
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Hudson PJ, Norman R, Laurenson MK, Newborn D, Gaunt M, Jones L, Reid H, Gould E, Bowers R, Dobson A. Persistence and transmission of tick-borne viruses: Ixodes ricinus and louping-ill virus in red grouse populations. Parasitology 1995; 111 Suppl:S49-58. [PMID: 8632924 DOI: 10.1017/s0031182000075818] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The population dynamics of tick-borne disease agents and in particular the mechanisms which influence their persistence are examined with reference to the flavivirus that causes louping-ill in red grouse and sheep. Pockets of infection cause heavy mortality and the infection probably persists as a consequence of immigration of susceptible hosts. Seroprevalence is positively associated with temporal variations in vectors per host, although variation between areas is associated with the abundance of mountain hares. The presence of alternative tick hosts, particularly large mammals, provides additional hosts for increasing tick abundance. Grouse alone can not support the vectors and the pathogen but both can persist when a non-viraemic mammalian host supports the tick population and a sufficiently high number of nymphs bite grouse. These alternative hosts may also amplify virus through non-viraemic transmission by the process of co-feeding, although the relative significance of this has yet to be determined. Another possible route of infection is through the ingestion of vectors when feeding or preening. Trans-ovarial transmission is a potentially important mechanism for virus persistence but has not been recorded with louping-ill and Ixodes ricinus. The influence of non-viraemic hosts, both in the multiplication of vectors and the amplification of virus through non-viraemic transmission are considered significant for virus persistence.
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Affiliation(s)
- P J Hudson
- Department of Biological and Molecular Sciences, University of Stirling, UK
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