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Benyedem H, Hajji T, Romdhane R, Obara I, Mhadhbi M, Sebai E, Elati K, Chaari S, Rekik M, Darghouth MA. Genetic diversity of Hyalomma marginatum in Tunisia is not influenced by the bio-climate. Parasitol Res 2023; 122:3013-3025. [PMID: 37823993 DOI: 10.1007/s00436-023-07990-5] [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: 04/24/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023]
Abstract
Ticks are important ectoparasites responsible for the transmission of several pathogens with significant medical, veterinary, and economic impacts. Climate and social changes have generated substantial changes in ticks' distribution, abundance, and activity patterns, including ticks belonging to the Hyalomma marginatum species. Knowledge on the genetic structure and dynamics of H. marginatum populations might contribute to a better understanding of their current and future evolution under the effects of anthropogenic factors and eco-climatic changes. In the present study, we investigated the genetic structure and phylogenetic distribution of H. marginatum across three bioclimatic regions in Tunisia using two mitochondrial markers (16S and 12S rRNA). The molecular investigations were based on 47 adult H. marginatum ticks collected from humid, upper semi-arid, and sub-humid regions of Tunisia. Our results revealed a genetic diversity of 0.278% and 0.809% using the 16S and 12S markers, respectively. The low genetic diversity that we observed raises the hypothesis of a bottleneck event occasioned by a reduction in the size of the tick population under the effects of environmental factors and/or human activities. This hypothesis is supported by the population's demographic history analysis, which revealed a clear deviation from neutrality and supports the occurrence of a bottleneck event followed by a demographic expansion. The fact that most 16S and 12S variability was present in the ticks from the humid bioclimatic zone may suggest that those ticks represent the ancestral population. Overall, the analysis has shown that the phylogenetic clusters do not correspond to the bioclimatic zones.
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Affiliation(s)
- Hayet Benyedem
- Laboratoire de Parasitologie, École Nationale de Médecine Vétérinaire de Sidi Thabet, Institution de La Recherche et de L'Enseignement Supérieur Agricoles and Univ. Manouba, Manouba, Tunisia.
- Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia.
| | - Tarek Hajji
- Laboratory of Biotechnology and Valorization of Bio-Geo-Resources (LR11ES31), Higher Institute of Biotechnology - Sidi Thabet, Univ. Manouba, Ariana, Tunisia
| | - Rihab Romdhane
- Laboratoire de Parasitologie, École Nationale de Médecine Vétérinaire de Sidi Thabet, Institution de La Recherche et de L'Enseignement Supérieur Agricoles and Univ. Manouba, Manouba, Tunisia
| | - Isaiah Obara
- Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-Von-Ostertag-Str. 7, 14163, Berlin, Germany
| | - Moez Mhadhbi
- Laboratoire de Parasitologie, École Nationale de Médecine Vétérinaire de Sidi Thabet, Institution de La Recherche et de L'Enseignement Supérieur Agricoles and Univ. Manouba, Manouba, Tunisia
| | - Essia Sebai
- Laboratoire de Parasitologie, École Nationale de Médecine Vétérinaire de Sidi Thabet, Institution de La Recherche et de L'Enseignement Supérieur Agricoles and Univ. Manouba, Manouba, Tunisia
| | - Khawla Elati
- Laboratoire de Parasitologie, École Nationale de Médecine Vétérinaire de Sidi Thabet, Institution de La Recherche et de L'Enseignement Supérieur Agricoles and Univ. Manouba, Manouba, Tunisia
- Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-Von-Ostertag-Str. 7, 14163, Berlin, Germany
- Veterinary Centre for Resistance Research, Freie Universität Berlin, Robert-Von-Ostertag-Str. 8, Berlin, Germany
| | - Soufiene Chaari
- Laboratoire Pharmaceutique Vétérinaire MEDIVET, Soliman, Tunisia
| | - Mourad Rekik
- International Centre for Agricultural Research in the Dry Areas (ICARDA), Tunis, Tunisia
| | - Mohamed Aziz Darghouth
- Laboratoire de Parasitologie, École Nationale de Médecine Vétérinaire de Sidi Thabet, Institution de La Recherche et de L'Enseignement Supérieur Agricoles and Univ. Manouba, Manouba, Tunisia.
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Celina SS, Černý J, Samy AM. Mapping the potential distribution of the principal vector of Crimean-Congo haemorrhagic fever virus Hyalomma marginatum in the Old World. PLoS Negl Trop Dis 2023; 17:e0010855. [PMID: 38011221 PMCID: PMC10703407 DOI: 10.1371/journal.pntd.0010855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/07/2023] [Accepted: 11/07/2023] [Indexed: 11/29/2023] Open
Abstract
Crimean-Congo haemorrhagic fever (CCHF) is the most widely distributed tick-borne viral disease in humans and is caused by the Crimean-Congo haemorrhagic fever virus (CCHFV). The virus has a broader distribution, expanding from western China and South Asia to the Middle East, southeast Europe, and Africa. The historical known distribution of the CCHFV vector Hyalomma marginatum in Europe includes most of the Mediterranean and the Balkan countries, Ukraine, and southern Russia. Further expansion of its potential distribution may have occurred in and out of the Mediterranean region. This study updated the distributional map of the principal vector of CCHFV, H. marginatum, in the Old World using an ecological niche modeling approach based on occurrence records from the Global Biodiversity Information Facility (GBIF) and a set of covariates. The model predicted higher suitability of H. marginatum occurrences in diverse regions of Africa and Asia. Furthermore, the model estimated the environmental suitability of H. marginatum across Europe. On a continental scale, the model anticipated a widespread potential distribution encompassing the southern, western, central, and eastern parts of Europe, reaching as far north as the southern regions of Scandinavian countries. The distribution of H. marginatum also covered countries across Central Europe where the species is not autochthonous. All models were statistically robust and performed better than random expectations (p < 0.001). Based on the model results, climatic conditions could hamper the successful overwintering of H. marginatum and their survival as adults in many regions of the Old World. Regular updates of the models are still required to continually assess the areas at risk using up-to-date occurrence and climatic data in present-day and future conditions.
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Affiliation(s)
- Seyma S. Celina
- Center for Infectious Animal Diseases, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Czech Republic
| | - Jiří Černý
- Center for Infectious Animal Diseases, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Czech Republic
| | - Abdallah M. Samy
- Entomology Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, Egypt
- Medical Ain Shams Research Institute (MASRI), Faculty of Medicine, Ain Shams University, Cairo, Egypt
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Bonnet SI, Bertagnoli S, Falchi A, Figoni J, Fite J, Hoch T, Quillery E, Moutailler S, Raffetin A, René-Martellet M, Vourc’h G, Vial L. An Update of Evidence for Pathogen Transmission by Ticks of the Genus Hyalomma. Pathogens 2023; 12:pathogens12040513. [PMID: 37111399 PMCID: PMC10146795 DOI: 10.3390/pathogens12040513] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/15/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
Current and likely future changes in the geographic distribution of ticks belonging to the genus Hyalomma are of concern, as these ticks are believed to be vectors of many pathogens responsible for human and animal diseases. However, we have observed that for many pathogens there are no vector competence experiments, and that the level of evidence provided by the scientific literature is often not sufficient to validate the transmission of a specific pathogen by a specific Hyalomma species. We therefore carried out a bibliographical study to collate the validation evidence for the transmission of parasitic, viral, or bacterial pathogens by Hyalomma spp. ticks. Our results show that there are very few validated cases of pathogen transmission by Hyalomma tick species.
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Gillingham EL, Medlock JM, Macintyre H, Phalkey R. Modelling the current and future temperature suitability of the UK for the vector Hyalomma marginatum (Acari: Ixodidae). Ticks Tick Borne Dis 2023; 14:102112. [PMID: 36634470 DOI: 10.1016/j.ttbdis.2022.102112] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 10/20/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022]
Abstract
Hyalomma marginatum is the main vector of Crimean-Congo haemorrhagic fever virus (CCHFV) and spotted fever rickettsiae in Europe. The distribution of H. marginatum is currently restricted to parts of southern Europe, northern Africa and Asia, and one of the drivers limiting distribution is climate, particularly temperature. As temperatures rise with climate change, parts of northern Europe currently considered too cold for H. marginatum to be able to survive may become suitable, including the United Kingdom (UK), presenting a potential public health concern. Here we use a series of modelling methodologies to understand whether mean air temperatures across the UK during 2000-2019 were sufficient for H. marginatum nymphs to moult into adult stages and be able to overwinter in the UK if they were introduced on migratory birds. We then used UK-specific climate projections (UKCP18) to determine whether predicted temperatures would be sufficient to allow survival in future. We found that spring temperatures in parts of the UK during 2000-2019 were warm enough for predicted moulting to occur, but in all years except 2006, temperatures during September to December were too cold for overwintering to occur. Our analysis of the projections data suggests that whilst temperatures in the UK during September to December will increase in future, they are likely to remain below the threshold required for H. marginatum populations to become established.
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Affiliation(s)
| | - Jolyon M Medlock
- Medical Entomology and Zoonoses Ecology, UK Health Security Agency
| | - Helen Macintyre
- Climate Change and Health, UK Health Security Agency; School of Geography, Earth and Environmental Sciences, University of Birmingham
| | - Revati Phalkey
- Climate Change and Health, UK Health Security Agency; Division of Epidemiology and Public Health, University of Nottingham, UK; Heidelberg Institute for Global Health, University of Germany, Germany
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Hoffman T, Olsen B, Lundkvist Å. The Biological and Ecological Features of Northbound Migratory Birds, Ticks, and Tick-Borne Microorganisms in the African-Western Palearctic. Microorganisms 2023; 11:microorganisms11010158. [PMID: 36677450 PMCID: PMC9866947 DOI: 10.3390/microorganisms11010158] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
Identifying the species that act as hosts, vectors, and vehicles of vector-borne pathogens is vital for revealing the transmission cycles, dispersal mechanisms, and establishment of vector-borne pathogens in nature. Ticks are common vectors for pathogens causing human and animal diseases, and they transmit a greater variety of pathogenic agents than any other arthropod vector group. Ticks depend on the movements by their vertebrate hosts for their dispersal, and tick species with long feeding periods are more likely to be transported over long distances. Wild birds are commonly parasitized by ticks, and their migration patterns enable the long-distance range expansion of ticks. The African-Palearctic migration system is one of the world's largest migrations systems. African-Western Palearctic birds create natural links between the African, European, and Asian continents when they migrate biannually between breeding grounds in the Palearctic and wintering grounds in Africa and thereby connect different biomes. Climate is an important geographical determinant of ticks, and with global warming, the distribution range and abundance of ticks in the Western Palearctic may increase. The introduction of exotic ticks and their microorganisms into the Western Palearctic via avian vehicles might therefore pose a greater risk for the public and animal health in the future.
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Affiliation(s)
- Tove Hoffman
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
| | - Björn Olsen
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
- Zoonosis Science Center, Department of Medical Sciences, Uppsala University, 751 85 Uppsala, Sweden
| | - Åke Lundkvist
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
- Correspondence:
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Distribution of Tick-Borne Pathogens in Domestic Animals and Their Ticks in the Countries of the Mediterranean Basin between 2000 and 2021: A Systematic Review. Microorganisms 2022; 10:microorganisms10061236. [PMID: 35744755 PMCID: PMC9228937 DOI: 10.3390/microorganisms10061236] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/10/2022] [Accepted: 06/14/2022] [Indexed: 02/01/2023] Open
Abstract
Tick-borne pathogens (TBPs) include a wide range of bacteria, parasites and viruses that cause a large spectrum of animal, human and zoonotic tick-borne diseases (TBDs). The object of this review was to establish an inventory and an analysis of TBPs found in domestic animals in the countries of the Mediterranean Basin. This geographic area occupies a central position between several continents and is an area of movement for animals, humans and pathogens of interest and their vectors, which is important in terms of animal and human health. In this systematic review, we included a total of 271 publications produced between 2000–2021 concerning TBPs in domestic animals. Among this literature, we found a total of 90 pathogen species (known as TBPs) reported in the 20 countries of the area; these were detected in tick species from domestic animals and were also directly detected in domestic animals. In all, 31 tick species were recorded and 12 domestic animal species, the latter comprising nine livestock and three pet species. More than 50% of the publications were from Western Europe. Island data were extracted and assessed, as islands of the Mediterranean Basin were represented in 16% of the publications and 77.8% of the TBPs reported. Our results show the importance of islands in the monitoring of TBPs, despite the low percentage of publications.
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Kopsco HL, Smith RL, Halsey SJ. A Scoping Review of Species Distribution Modeling Methods for Tick Vectors. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.893016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BackgroundGlobally, tick-borne disease is a pervasive and worsening problem that impacts human and domestic animal health, livelihoods, and numerous economies. Species distribution models are useful tools to help address these issues, but many different modeling approaches and environmental data sources exist.ObjectiveWe conducted a scoping review that examined all available research employing species distribution models to predict occurrence and map tick species to understand the diversity of model strategies, environmental predictors, tick data sources, frequency of climate projects of tick ranges, and types of model validation methods.DesignFollowing the PRISMA-ScR checklist, we searched scientific databases for eligible articles, their references, and explored related publications through a graphical tool (www.connectedpapers.com). Two independent reviewers performed article selection and characterization using a priori criteria.ResultsWe describe data collected from 107 peer-reviewed articles that met our inclusion criteria. The literature reflects that tick species distributions have been modeled predominantly in North America and Europe and have mostly modeled the habitat suitability for Ixodes ricinus (n = 23; 21.5%). A wide range of bioclimatic databases and other environmental correlates were utilized among models, but the WorldClim database and its bioclimatic variables 1–19 appeared in 60 (56%) papers. The most frequently chosen modeling approach was MaxEnt, which also appeared in 60 (56%) of papers. Despite the importance of ensemble modeling to reduce bias, only 23 papers (21.5%) employed more than one algorithm, and just six (5.6%) used an ensemble approach that incorporated at least five different modeling methods for comparison. Area under the curve/receiver operating characteristic was the most frequently reported model validation method, utilized in nearly all (98.9%) included studies. Only 21% of papers used future climate scenarios to predict tick range expansion or contraction. Regardless of the representative concentration pathway, six of seven genera were expected to both expand and retract depending on location, while Ornithodoros was predicted to only expand beyond its current range.ConclusionSpecies distribution modeling techniques are useful and widely employed tools for predicting tick habitat suitability and range movement. However, the vast array of methods, data sources, and validation strategies within the SDM literature support the need for standardized protocols for species distribution and ecological niche modeling for tick vectors.
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González Gordon L, Bessell PR, Nkongho EF, Ngwa VN, Tanya VN, Sander M, Ndip L, Morgan KL, Handel IG, Mazeri S, Bronsvoort BM, Kelly RF. Seroepidemiology of Crimean-Congo Haemorrhagic Fever among cattle in Cameroon: Implications from a One Health perspective. PLoS Negl Trop Dis 2022; 16:e0010217. [PMID: 35312678 PMCID: PMC8936485 DOI: 10.1371/journal.pntd.0010217] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 02/01/2022] [Indexed: 12/17/2022] Open
Abstract
Background Crimean-Congo Haemorrhagic Fever (CCHF) is a tick-borne viral zoonotic disease distributed across several continents and recognized as an ongoing health threat. In humans, the infection can progress to a severe disease with high fatality, raising public health concerns due to the limited prophylactic and therapeutic options available. Animal species, clinically unaffected by the virus, serve as viral reservoirs and amplifier hosts, and can be a valuable tool for surveillance. Little is known about the occurrence and prevalence of Crimean-Congo Haemorrhagic Fever Virus (CCHFV) in Cameroon. Knowledge on CCHFV exposure and the factors associated with its presence in sentinel species are a valuable resource to better understand transmission dynamics and assess local risks for zoonotic disease emergence. Methods and findings We conducted a CCHFV serological survey and risk factor analysis for animal level seropositivity in pastoral and dairy cattle in the North West Region (NWR) and the Vina Division (VD) of the Adamawa Region in Cameroon. Seroprevalence estimates were adjusted for sampling design-effects and test performance. In addition, explanatory multivariable logistic regression mixed-effects models were fit to estimate the effect of animal characteristics, husbandry practices, risk contacts and ecological features on the serological status of pastoral cattle. The overall seroprevalence was 56.0% (95% CI 53.5–58.6) and 6.7% (95% CI 2.6–16.1) among pastoral and dairy cattle, respectively. Animals going on transhumance had twice the odds of being seropositive (OR 2.0, 95% CI 1.1–3.8), indicating that animal movements could be implicated in disease expansion. From an ecological perspective, absolute humidity (OR 0.6, 95% CI 0.4–0.9) and shrub density (OR 2.1, 95% CI 1.4–3.2) were associated with seropositivity, which suggests an underlying viral dynamic connecting vertebrate host and ticks in a complex transmission network. Conclusions This study demonstrated high seroprevalence levels of CCHFV antibodies in cattle in Cameroon indicating a potential risk to human populations. However, current understanding of the underlying dynamics of CCHFV locally and the real risk for human populations is incomplete. Further studies designed using a One Health approach are required to improve local knowledge of the disease, host interactions and environmental risk factors. This information is crucial to better project the risks for human populations located in CCHFV-suitable ecological niches. Crimean-Congo haemorrhagic fever poses an important threat for public health, particularly in endemic locations in Eurasia and parts of Africa. Despite its long-standing recognition, CCHF is considered a neglected disease, with sporadic official case reports and evidence of serological circulation in remote rural areas and less frequently, in peri-urban settings in sub-Saharan Africa. However, the drivers associated with its emergence and the spatial-temporal patterns linked to its circulation and spread are not well-understood. In this study, we identified a high proportion of cattle with CCHFV antibodies suggestive of high levels of viral circulation in the North West and the Adamawa Regions in Cameroon. In pastoral cattle, there was a positive relationship between going on transhumance, older age, higher shrub density and lower absolute humidity and CCHFV individual seropositivity. In contrast, non-indigenous breeds reported a lower risk of being seropositive. These results can be interpreted in connection to the underlying dynamics of CCHFV cycle and underline potential mechanisms linked to disease expansion. From a public health perspective, high levels of exposure to CCHFV in cattle highlight the possibility of unrecognized human infection and therefore, emphasize on the need to remain vigilant to possible disease risks for local groups involved in pastoralism and to dairy smallholders across the region.
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Affiliation(s)
- Lina González Gordon
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom
- * E-mail: (LGG); (BMB); (RFK)
| | - Paul R. Bessell
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom
| | - Egbe F. Nkongho
- School of Life Sciences, University of Lincoln, Lincoln, United Kingdom
| | - Victor N. Ngwa
- School of Veterinary Sciences, University of Ngaoundere, Ngaoundere, Cameroon
| | | | - Melissa Sander
- Tuberculosis Reference Laboratory Bamenda, Bamenda, Cameroon
| | - Lucy Ndip
- Laboratory of Emerging Infectious Diseases, University of Buea, Buea, Cameroon
| | - Kenton L. Morgan
- Institute of Ageing and Chronic Disease and School of Veterinary Science, University of Liverpool, Neston, United Kingdom
| | - Ian G. Handel
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom
| | - Stella Mazeri
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom
| | - Barend MdeC Bronsvoort
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom
- * E-mail: (LGG); (BMB); (RFK)
| | - Robert F. Kelly
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom
- * E-mail: (LGG); (BMB); (RFK)
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Zannou OM, Da Re D, Ouedraogo AS, Biguezoton AS, Abatih E, Yao KP, Farougou S, Lempereur L, Vanwambeke SO, Saegerman C. Modelling habitat suitability of the invasive tick Rhipicephalus microplus in West Africa. Transbound Emerg Dis 2022; 69:2938-2951. [PMID: 34985810 DOI: 10.1111/tbed.14449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 12/25/2021] [Accepted: 12/31/2021] [Indexed: 11/30/2022]
Abstract
Ticks have medical and economic importance due to their ability to transmit pathogens to humans and animals. In tropical and sub-tropical countries, tick-borne diseases (TBD) are among the most important diseases affecting livestock and humans. The fast spread of ticks and TBD requires a quick development and application of efficient prevention and/or control programs. Therefore, prior investigations on TBD and related vectors epidemiology, for instance, through accurate epidemiological models, are mandatory. This study aims to develop models to forecast suitable habitat for Rhipicephalus microplus distribution in West Africa. Tick occurrences were assembled from 10 different studies carried out in six West African countries in the past decade. Six statistical models (maximum entropy in a single model and generalised linear model, generalised additive model, random forest, boosted regression tree and support vector machine model in an ensemble model) were applied and compared to predict the habitat suitability of R. microplus distribution in West Africa. Each model was evaluated with the area under the receiver operating characteristic curve (AUC), the true skill statistic (TSS) and the Boyce index (BI). The selected models had good performance according to their AUC (above .8), TSS (above .7) and BI (above .8). Temperature played a key role in MaxEnt model, whereas normalised difference vegetation index (NDVI) was the most important variable in the ensemble model. The model predictions showed coastal countries of West Africa as more suitable for R. microplus. However, some Sahelian areas seems also favourable. We stress the importance of vector surveillance and control in countries that have not yet detected R. microplus but are in the areas predicted to host suitable habitat. Indeed, awareness-raising and training of different stakeholders must be reinforced for better prevention and control of this tick in these different countries according to their status.
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Affiliation(s)
- Olivier M Zannou
- Research Unit in Epidemiology and Risk Analysis applied to veterinary sciences (UREAR-ULiège), Fundamental and Applied Research for Animal and Health (FARAH) Center, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, Liege, Belgium.,Vector-borne Diseases and Biodiversity Unit (UMaVeB), International Research and Development Center on Livestock in Sub-humid Areas (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Daniele Da Re
- Georges Lemaître Center for Earth and Climate Research, Earth and Life Institute, UCLouvain, Louvain-la-Neuve, Belgium
| | - Achille S Ouedraogo
- Vector-borne Diseases and Biodiversity Unit (UMaVeB), International Research and Development Center on Livestock in Sub-humid Areas (CIRDES), Bobo-Dioulasso, Burkina Faso.,Laboratory of Parasitology and Parasitic Diseases, Fundamental and Applied Research for Animal and Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Abel S Biguezoton
- Vector-borne Diseases and Biodiversity Unit (UMaVeB), International Research and Development Center on Livestock in Sub-humid Areas (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Emmanuel Abatih
- Department of Applied Mathematics, Computer Sciences and Statistics, Ghent University, Gent, Belgium
| | | | - Souaïbou Farougou
- Communicable Diseases Research Unit (URMaT), Polytechnic School of Abomey-Calavi, University of Abomey-Calavi, Cotonou, Republic of Benin
| | - Laetitia Lempereur
- Laboratory of Parasitology and Parasitic Diseases, Fundamental and Applied Research for Animal and Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Sophie O Vanwambeke
- Georges Lemaître Center for Earth and Climate Research, Earth and Life Institute, UCLouvain, Louvain-la-Neuve, Belgium
| | - Claude Saegerman
- Research Unit in Epidemiology and Risk Analysis applied to veterinary sciences (UREAR-ULiège), Fundamental and Applied Research for Animal and Health (FARAH) Center, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, Liege, Belgium
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Hoffman T, Carra LG, Öhagen P, Fransson T, Barboutis C, Piacentini D, Figuerola J, Kiat Y, Onrubia A, Jaenson TGT, Nilsson K, Lundkvist Å, Olsen B. Association between guilds of birds in the African-Western Palaearctic region and the tick species Hyalomma rufipes, one of the main vectors of Crimean-Congo hemorrhagic fever virus. One Health 2021; 13:100349. [PMID: 34825045 PMCID: PMC8605260 DOI: 10.1016/j.onehlt.2021.100349] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 11/29/2022] Open
Abstract
Introduction The ecology of the vertebrate host contributes to the geographical range expansion of ticks. In this study, we investigated which tick taxa that infest and are dispersed by birds along African-Western Palaearctic flyways during northward migration, and whether bird ecology was associated with tick taxa. Materials and methods Ticks were collected from birds trapped at bird observatories in Spain, Italy, Greece, and Israel during the spring migration of 2014 and 2015, using mist nets. The tick-infested bird species were classified into guilds, using different combinations of the variables: migration distance, wintering region, foraging behaviour, and winter habitat. Ticks were molecularly determined to genus and species level by sequencing fragments of the 12S ribosomal DNA (rDNA) gene and by phylogenetic inference, using the Maximum Likelihood algorithm. Data were analysed using descriptive measures, graphs, Chi2 tests, the Tukey-Kramer test, and a parametric linear model (generalized linear model) in order to analyse and adjust for characteristics in the bird guilds and their relationship to collected tick taxa. Results Most (84.2%) of the 10,209 trapped birds were long-distance migrants, of which 2.4% were infested by ticks. The most common tick species was Hyalomma rufipes (77.7%; 447/575), a known vector and reservoir of Crimean-Congo hemorrhagic fever virus. Bird guilds containing only long-distance migrants with wintering areas in Africa were associated with the tick species H. rufipes (p < 0.0001). Furthermore, bird winter habitat was associated with H. rufipes (p = 0.003); with bird species overwintering in open habitat (p = 0.014) and wetlands (p = 0.046) having significantly more H. rufipes as compared to birds with a winter habitat comprising forest and shrubs (p = 0.82). Conclusions With climate change, the likelihood of establishment of permanent Hyalomma populations in central and northern Europe is increasing. Thus, surveillance programs for monitoring the risk of introduction and establishment of H. rufipes in the Western-Palaearctic should be established. Our study suggests that migratory bird species wintering in African open habitats and wetlands are good candidates for monitoring potential introduction.
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Affiliation(s)
- Tove Hoffman
- Department of Medical Biochemistry and Microbiology, Zoonosis Science Center, Uppsala University, Husargatan 3, SE-751 23 Uppsala, Sweden
| | - Laura G Carra
- Department of Medical Biochemistry and Microbiology, Zoonosis Science Center, Uppsala University, Husargatan 3, SE-751 23 Uppsala, Sweden
| | - Patrik Öhagen
- Uppsala Clinical Research Center, Dag Hammarskjölds väg 38, SE-751 85 Uppsala, Sweden
| | - Thord Fransson
- Department of Environmental Research and Monitoring, Swedish Museum of Natural History, Stockholm, Sweden
| | - Christos Barboutis
- Antikythira Bird Observatory, Hellenic Ornithological Society/BirdLife Greece, Athens, Greece
| | | | - Jordi Figuerola
- Estación Biológica de Doñana, CSIC, Avda. Américo Vespucio s/n, 410 92 Sevilla, Spain.,CIBER Epidemiología y Salud Pública (CIBERESP), 280 29 Madrid, Spain
| | - Yosef Kiat
- Israeli Bird Ringing Center (IBRC), Israel Ornithological Center (IOC), Society for the Protection of Nature in Israel (SPNI), Tel-Aviv, Israel
| | | | - Thomas G T Jaenson
- Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18d, SE-752 36 Uppsala, Sweden
| | - Kenneth Nilsson
- Department of Medical Sciences, Section of Clinical Microbiology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Åke Lundkvist
- Department of Medical Biochemistry and Microbiology, Zoonosis Science Center, Uppsala University, Husargatan 3, SE-751 23 Uppsala, Sweden
| | - Björn Olsen
- Department of Medical Sciences, Zoonosis Science Center, Uppsala University, SE-751 85, Uppsala, Sweden
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11
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The impact of climate change and emerging infectious diseases on the blood supply. Transfus Apher Sci 2021; 60:103272. [PMID: 34509385 PMCID: PMC8420088 DOI: 10.1016/j.transci.2021.103272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 11/23/2022]
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12
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Shahhosseini N, Wong G, Babuadze G, Camp JV, Ergonul O, Kobinger GP, Chinikar S, Nowotny N. Crimean-Congo Hemorrhagic Fever Virus in Asia, Africa and Europe. Microorganisms 2021; 9:microorganisms9091907. [PMID: 34576803 PMCID: PMC8471816 DOI: 10.3390/microorganisms9091907] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/26/2021] [Accepted: 08/28/2021] [Indexed: 11/16/2022] Open
Abstract
The global spread of ticks and various tick-borne viruses (TBVs) suggests the possibility of new tick-borne diseases emerging. Crimean-Congo hemorrhagic fever virus (CCHFV) is an emerging TBV of the Nairoviridae family that causes serious disease that can be fatal in humans. CCHFV endemic foci can be found in Africa, Asia, the Middle East, and South-Eastern Europe, and has spread to previously unaffected regions and nations, such as Spain, over the last two decades. In this review, we discuss the current situation of CCHFV in Asia, Africa and Europe based on existing knowledge, and we discuss driving factors in the distribution and transmission of the virus, such as the spread of tick vector species and host reservoirs.
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Affiliation(s)
- Nariman Shahhosseini
- Centre for Vector-Borne Diseases, Canadian Food Inspection Agency, Lethbridge, AB T1H 6P7, Canada;
| | - Gary Wong
- Département de Microbiologie-Infectiologie et d’Immunologie, Université Laval, Québec City, QC G1V 0A6, Canada; (G.W.); (G.P.K.)
- Institut Pasteur of Shanghai, Shanghai 200031, China
| | - George Babuadze
- Department of Biological Sciences, Sunnybrook Research Institute, University of Toronto, Toronto, ON M4N 3M5, Canada;
| | - Jeremy V. Camp
- Center for Virology, Medical University of Vienna, 1090 Vienna, Austria;
| | - Onder Ergonul
- Koç University, School of Medicine and Koç University Iş Bank Center for Infectious Diseases, Istanbul 34450, Turkey;
| | - Gary P. Kobinger
- Département de Microbiologie-Infectiologie et d’Immunologie, Université Laval, Québec City, QC G1V 0A6, Canada; (G.W.); (G.P.K.)
- Department of Medical Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Immunology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sadegh Chinikar
- Pasteur Institute of Tehran, Tehran 1316943551, Iran
- Institute of Virology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
- Correspondence: (S.C.); (N.N.)
| | - Norbert Nowotny
- Institute of Virology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
- Department of Basic Medical Sciences, College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai 505055, United Arab Emirates
- Correspondence: (S.C.); (N.N.)
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13
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Lebon W, Meyer L, Akki FE, Madder M, Beugnet F. Efficacy of a single administration of afoxolaner (NexGard®) or fipronil plus permethrin (Frontline® Tri-Act) against Hyalomma marginatum ticks in dogs. Vet Parasitol Reg Stud Reports 2021; 25:100606. [PMID: 34474799 DOI: 10.1016/j.vprsr.2021.100606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/26/2021] [Accepted: 06/30/2021] [Indexed: 10/21/2022]
Abstract
This study was conducted to assess the acaricidal efficacy of afoxolaner (NexGard®, Boehringer Ingelheim), and fipronil - permethrin (Frontline® Tri-Act, Boehringer Ingelheim) administered once to dogs experimentally infested with Hyalomma marginatum ticks. Twenty-four Beagle dogs were randomly allocated based on a pre-treatment H. marginatum infestation to an untreated control group, a NexGard® or a Frontline® Tri-Act treated groups. Treatments were administered once on Day 0 as per the products' labels. For the efficacy evaluation, dogs were experimentally infested with 30 adult H. marginatum ticks on Days -2, 7, 28 and 36. In-situ counts were performed at 48 h post-treatment on Day 2 and post-infestations on Days 9, 30 and 38. Ticks were removed and counted at 72 h post-treatment on Day 3 and after each tick infestation on Days 10, 31 and 39. The numbers of live ticks counted in the treated groups were significantly different than in the control group at all time-points (p ≤ 0.0006). The efficacy was at least 97% after 48 h, and at least 99% after 72 h for both treatments. In this study both afoxolaner and fipronil/permethrin formulations demonstrated a high efficacy against adult H. marginatum ticks in treated dogs for at least five weeks.
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Affiliation(s)
- Wilfried Lebon
- Boehringer Ingelheim Animal Health, 29 Av. Tony Garnier, 69007 Lyon, France
| | - Leon Meyer
- Clinvet, BP 301, CP 28815 Mohammedia, Morocco
| | | | - Maxime Madder
- ClinVet, PO Box 11186, Universitas, 9321 Bloemfontein, South Africa
| | - Fréderic Beugnet
- Boehringer Ingelheim Animal Health, 29 Av. Tony Garnier, 69007 Lyon, France.
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14
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Ogden NH, Beard CB, Ginsberg HS, Tsao JI. Possible Effects of Climate Change on Ixodid Ticks and the Pathogens They Transmit: Predictions and Observations. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1536-1545. [PMID: 33112403 PMCID: PMC9620468 DOI: 10.1093/jme/tjaa220] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Indexed: 05/09/2023]
Abstract
The global climate has been changing over the last century due to greenhouse gas emissions and will continue to change over this century, accelerating without effective global efforts to reduce emissions. Ticks and tick-borne diseases (TTBDs) are inherently climate-sensitive due to the sensitivity of tick lifecycles to climate. Key direct climate and weather sensitivities include survival of individual ticks, and the duration of development and host-seeking activity of ticks. These sensitivities mean that in some regions a warming climate may increase tick survival, shorten life-cycles and lengthen the duration of tick activity seasons. Indirect effects of climate change on host communities may, with changes in tick abundance, facilitate enhanced transmission of tick-borne pathogens. High temperatures, and extreme weather events (heat, cold, and flooding) are anticipated with climate change, and these may reduce tick survival and pathogen transmission in some locations. Studies of the possible effects of climate change on TTBDs to date generally project poleward range expansion of geographical ranges (with possible contraction of ranges away from the increasingly hot tropics), upslope elevational range spread in mountainous regions, and increased abundance of ticks in many current endemic regions. However, relatively few studies, using long-term (multi-decade) observations, provide evidence of recent range changes of tick populations that could be attributed to recent climate change. Further integrated 'One Health' observational and modeling studies are needed to detect changes in TTBD occurrence, attribute them to climate change, and to develop predictive models of public- and animal-health needs to plan for TTBD emergence.
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Affiliation(s)
- Nicholas H. Ogden
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, St-Hyacinthe, QC, Canada J2S 2M2
- Groupe de recherche en épidémiologie des zoonoses et santé publique (GREZOSP), Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, QC, Canada J2S 2M2
- Corresponding author,
| | - C. Ben Beard
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - Howard S. Ginsberg
- U.S. Geological Survey, Patuxent Wildlife Research Center, Rhode Island Field Station, University of Rhode Island, Kingston, RI 02881
| | - Jean I. Tsao
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824
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15
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Fanelli A, Buonavoglia D. Risk of Crimean Congo haemorrhagic fever virus (CCHFV) introduction and spread in CCHF-free countries in southern and Western Europe: A semi-quantitative risk assessment. One Health 2021; 13:100290. [PMID: 34307823 PMCID: PMC8283130 DOI: 10.1016/j.onehlt.2021.100290] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 11/29/2022] Open
Abstract
Crimean-Congo hemorrhagic fever (CCHF) is a severe tick-borne viral zoonotic disease caused by Crimean-Congo hemorrhagic fever virus (CCHFV). The disease is usually asymptomatic in domestic and wild animals, both of which may act as reservoirs of the virus. CCHF is endemic in parts of Africa, Asia, the Middle East and Eastern Europe. During the last decade, the emergence or re-emergence of CCHF was described in several countries in the Eastern Mediterranean Region, with an increasing risk of extension into new areas. Given the public health importance, this study undertakes a semi-quantitative risk assessment to analyse the likelihood of entry and exposure of CCHFV into 9 CCHF-free countries in Southern and Western Europe. Based on a framework outlining the probability of the virus entry and exposure, the risk estimates were assessed for each individual country. The risk assessment was performed using information from public databases and the available scientific literature. The likelihood of entry was conducted considering 3 main pathways: infected tick vectors, wildlife and livestock. The likelihood of exposure was assessed considering the probability of survival of the infected ticks once introduced in CCHF-free countries (depending on abiotic and biotic factors), and the exposure of resident uninfected susceptible ticks to infected imported wildlife and livestock. The risk estimates (combined CCHFV introduction and exposure) were low for the majority of the countries (Austria, Belgium, Germany, Luxembourg, Netherlands, Slovenia and Switzerland) and medium for France and Italy, if accounting only for animal health consequences. Considering the public health consequences only, the risks were rated low for all the countries, except for Italy where it was assessed to be medium.
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Affiliation(s)
- Angela Fanelli
- Department of Veterinary Medicine, University of Bari, Valenzano (BA), Italy
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16
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Agudelo MS, Grant WE, Wang HH. Effects of white-tailed deer habitat use preferences on southern cattle fever tick eradication: simulating impact on "pasture vacation" strategies. Parasit Vectors 2021; 14:102. [PMID: 33557915 PMCID: PMC7869250 DOI: 10.1186/s13071-021-04590-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 01/11/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Rhipicephalus (Boophilus) annulatus and Rhipicephalus (Boophilus) microplus (southern cattle fever tick; SCFT), collectively known as cattle-fever ticks (CFTs), are vectors of protozoal parasites (Babesia bigemina and Babesia bovis) that cause bovine babesiosis (also known as cattle fever). One traditional strategy for CFT eradication involves the implementation of a "pasture vacation," which involves removing cattle (Bos taurus) from an infested pasture for an extended period of time. However, vacated pastures are often inhabited by wildlife hosts, such as white-tailed deer (WTD; Odocoileus virginianus), which can serve as alternate hosts for questing CFTs. We hypothesized that the distribution of host-seeking larvae among habitat types post-pasture vacation would reflect habitat use patterns of WTD, and in turn, affect the subsequent rate of pasture infestation by CFT. METHODS We adapted a spatially explicit, individual-based model to simulate interactions among SCFT, cattle, and WTD as a tool to investigate the potential effects of WTD habitat use preferences on the efficacy of a pasture vacation. We parameterized the model to represent conditions typical of rangelands in south Texas, USA, simulated a 1-year pasture vacation under different assumptions regarding WTD habitat use preferences, and summarized effects on efficacy through (1) time post-vacation to reach 100% of pre-vacation densities of host-seeking larvae, and (2) the ecological conditions that resulted in the lowest host-seeking larval densities following pasture vacation. RESULTS Larval densities at the landscape scale varied seasonally in a similar manner over the entire simulation period, regardless of WTD habitat use preferences. Following the removal of cattle, larval densities declined sharply to < 100 larvae/ha. Following the return of cattle, larval densities increased to > 60% of pre-vacation densities ≈ 21 weeks post-vacation, and reached pre-vacation levels in less than a year. Trends in larval densities in different habitat types paralleled those at the landscape scale over the entire simulation period, but differed quantitatively from one another during the pasture vacation. Relative larval densities (highest to lowest) shifted from (1) wood/shrub, (2) grass, (3) mixed-brush during the pre-vacation period to (1) mixed-brush, (2) wood/shrub, (3) grass or (1) wood/shrub, (2) mixed-brush, (3) grass during the post-vacation period, depending on WTD habitat use preferences. CONCLUSIONS By monitoring WTD-driven shifts in distributions of SCFT host-seeking larvae among habitat types during simulated pasture vacation experiments, we were able to identify potential SCFT refugia from which recrudescence of infestations could originate. Such information could inform timely applications of acaricides to specific refugia habitats immediately prior to the termination of pasture vacations.
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Affiliation(s)
- M Sofia Agudelo
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX, 77843, USA. .,Western EcoSystems Technology, Inc. (WEST), Bismarck, ND, 58503, USA.
| | - William E Grant
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Hsiao-Hsuan Wang
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, 77843, USA
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17
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Fernández-Ruiz N, Estrada-Peña A. Towards New Horizons: Climate Trends in Europe Increase the Environmental Suitability for Permanent Populations of Hyalomma marginatum (Ixodidae). Pathogens 2021; 10:pathogens10020095. [PMID: 33494140 PMCID: PMC7909578 DOI: 10.3390/pathogens10020095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/16/2021] [Indexed: 01/24/2023] Open
Abstract
Ticks and tick-borne pathogens are changing their current distribution, presumably due to the impact of the climate trends. On a large scale, these trends are changing the environmental suitability of Hyalomma marginatum, the main vector of several pathogens affecting human health. We generated annual models of environmental suitability for the tick in the period 1970-2018, using harmonic regression-derived data of the daily maximum and minimum temperature, soil moisture and water vapor deficit. The results demonstrate an expansion of the suitable area in Mediterranean countries, southeast central Europe and south of the Balkans. Also, the models allowed us to interpret the impact of the ecological variables on these changes. We deduced that (i) maximum temperature was significant for all of the biogeographical categories, (ii) soil humidity has an influence in the Mediterranean climate areas, and (iii) the minimum temperature and deficit water vapor did not influence the environmental suitability of the species. The conclusions clearly show that climate change could create new areas in Europe with suitable climates for H. marginatum, while keeping its "historical" distribution in the Mediterranean. Therefore, it is necessary to further explore possible risk areas for H. marginatum and its associated pathogens.
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Affiliation(s)
- Natalia Fernández-Ruiz
- Faculty of Veterinary Medicine, University of Zaragoza, 50013 Zaragoza, Spain;
- Group of Research on Emerging Zoonoses, Instituto Agroalimentario de Aragón (IA2), 50013 Zaragoza, Spain
- Correspondence:
| | - Agustín Estrada-Peña
- Faculty of Veterinary Medicine, University of Zaragoza, 50013 Zaragoza, Spain;
- Group of Research on Emerging Zoonoses, Instituto Agroalimentario de Aragón (IA2), 50013 Zaragoza, Spain
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18
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First report of human exposure to Hyalomma marginatum in England: Further evidence of a Hyalomma moulting event in north-western Europe? Ticks Tick Borne Dis 2020; 12:101541. [PMID: 33007668 DOI: 10.1016/j.ttbdis.2020.101541] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 07/29/2020] [Accepted: 07/31/2020] [Indexed: 01/08/2023]
Abstract
Hyalomma marginatum is widely distributed across the Mediterranean, Northern Africa and the Middle East. Current climate conditions in Northern Europe are thought to limit the species' ability to moult to the adult stage. It is a vector of several pathogens of human and veterinary concern, including Crimean-Congo haemorrhagic fever virus, for which it is the primary vector in Europe. Here, we report the first human exposure to a locally acquired adult H. marginatum in England, and the second detection in England of Rickettsia aeschlimannii associated with imported Hyalomma.
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19
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Structure and Characterization of Crimean-Congo Hemorrhagic Fever Virus GP38. J Virol 2020; 94:JVI.02005-19. [PMID: 31996434 PMCID: PMC7108853 DOI: 10.1128/jvi.02005-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/26/2020] [Indexed: 12/17/2022] Open
Abstract
Crimean-Congo hemorrhagic fever virus (CCHFV) is a priority pathogen that poses a high risk to public health. Due to the high morbidity and mortality rates associated with CCHFV infection, there is an urgent need to develop medical countermeasures for disease prevention and treatment. CCHFV GP38, a secreted glycoprotein of unknown function unique to the Nairoviridae family, was recently shown to be the target of a protective antibody against CCHFV. Here, we present the crystal structure of GP38, which revealed a novel fold with distant homology to another CCHFV glycoprotein that is suggestive of a gene duplication event. We also demonstrate that antibody 13G8 protects STAT1-knockout mice against heterologous CCHFV challenge using a clinical isolate from regions where CCHFV is endemic. Collectively, these data advance our understanding of GP38 structure and antigenicity and should facilitate future studies investigating its function. Crimean-Congo hemorrhagic fever virus (CCHFV) is the causative agent of the most widespread tick-borne viral infection in humans. CCHFV encodes a secreted glycoprotein (GP38) of unknown function that is the target of a protective antibody. Here, we present the crystal structure of GP38 at a resolution of 2.5 Å, which revealed a novel fold primarily consisting of a 3-helix bundle and a β-sandwich. Sequence alignment and homology modeling showed distant homology between GP38 and the ectodomain of Gn (a structural glycoprotein in CCHFV), suggestive of a gene duplication event. Analysis of convalescent-phase sera showed high titers of GP38 antibodies indicating immunogenicity in humans during natural CCHFV infection. The only protective antibody for CCHFV in an adult mouse model reported to date, 13G8, bound GP38 with subnanomolar affinity and protected against heterologous CCHFV challenge in a STAT1-knockout mouse model. Our data strongly suggest that GP38 should be evaluated as a vaccine antigen and that its structure provides a foundation to investigate functions of this protein in the viral life cycle. IMPORTANCE Crimean-Congo hemorrhagic fever virus (CCHFV) is a priority pathogen that poses a high risk to public health. Due to the high morbidity and mortality rates associated with CCHFV infection, there is an urgent need to develop medical countermeasures for disease prevention and treatment. CCHFV GP38, a secreted glycoprotein of unknown function unique to the Nairoviridae family, was recently shown to be the target of a protective antibody against CCHFV. Here, we present the crystal structure of GP38, which revealed a novel fold with distant homology to another CCHFV glycoprotein that is suggestive of a gene duplication event. We also demonstrate that antibody 13G8 protects STAT1-knockout mice against heterologous CCHFV challenge using a clinical isolate from regions where CCHFV is endemic. Collectively, these data advance our understanding of GP38 structure and antigenicity and should facilitate future studies investigating its function.
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20
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The Potential Role of Migratory Birds in the Rapid Spread of Ticks and Tick-Borne Pathogens in the Changing Climatic and Environmental Conditions in Europe. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17062117. [PMID: 32209990 PMCID: PMC7142536 DOI: 10.3390/ijerph17062117] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/09/2020] [Accepted: 03/17/2020] [Indexed: 12/28/2022]
Abstract
This opinion piece highlights the role of migratory birds in the spread of ticks and their role in the circulation and dissemination of pathogens in Europe. Birds with different lifestyles, i.e., non-migrants residing in a specific area, or short-, medium-, and long-distance migrants, migrating within one or several distant geographical regions are carriers of a number of ticks and tick-borne pathogens. During seasonal migrations, birds that cover long distances over a short time and stay temporarily in different habitats can introduce tick and pathogen species in areas where they have never occurred. An increase in the geographical range of ticks as well as the global climate changes affecting the pathogens, vectors, and their hosts increase the incidence and the spread of emerging tick-borne diseases worldwide. Tick infestations of birds varied between regions depends on the rhythms of tick seasonal activity and the bird migration rhythms determined by for example, climatic and environmental factors. In areas north of latitude ca. 58°N, immature Ixodes ricinus ticks are collected from birds most frequently, whereas ticks from the Hyalomma marginatum group dominate in areas below 42°N. We concluded that the prognosis of hazards posed by tick-borne pathogens should take into account changes in the migration of birds, hosts of many epidemiologically important tick species.
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21
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Okely M, Anan R, Gad-Allah S, Samy AM. Mapping the environmental suitability of etiological agent and tick vectors of Crimean-Congo hemorrhagic fever. Acta Trop 2020; 203:105319. [PMID: 31874130 DOI: 10.1016/j.actatropica.2019.105319] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 11/30/2022]
Abstract
Crimean-Congo hemorrhagic fever (CCHF) is one of the most important public health threats in many regions across Africa, Europe, and Asia. This study used ecological niche modeling analyses to map the environmental suitability of both CCHF virus (CCHFV), and its tick vectors (Amblyomma variegatum, Dermacentor marginatus, Hyalomma marginatum, Hyalomma rufipes, Hyalomma truncatum, Rhipicephalus appendiculatus, and Rhipicephalus evertsi evertsi) in the Old World countries. The CCHFV was anticipated to occur with high environmental suitability across southern and central Europe, northwestern Africa, central Asia, and western Mediterranean region. Ecological niche models of tick vectors anticipated diverse patterns based on the tick species in question; D. marginatus and H. marginatum showed high environmental suitability in southern and central Europe, and North Africa. The remaining vector species were anticipated to occur in Africa. All models were statistically robust and performed better than random (P < 0.001). Finally, we tested the niche similarities between CCHFV and diverse tick vectors and could not reject the null hypotheses of niche similarity in all vector-virus combinations (P > 0.05) except the combinations of CCHFV with A. variegatum, R. evertsi evertsi and R. appendiculatus (P < 0.05).
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Affiliation(s)
- Mohammed Okely
- Entomology Department, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt.
| | - Rabia Anan
- Entomology Department, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt
| | - Sohair Gad-Allah
- Entomology Department, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt
| | - Abdallah M Samy
- Entomology Department, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt.
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22
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First records of adult Hyalomma marginatum and H. rufipes ticks (Acari: Ixodidae) in Sweden. Ticks Tick Borne Dis 2020; 11:101403. [PMID: 32037097 DOI: 10.1016/j.ttbdis.2020.101403] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/20/2019] [Accepted: 01/27/2020] [Indexed: 01/13/2023]
Abstract
From July 2018 to January 2019 we recorded 41 specimens of adult Hyalomma ticks, which had been found on horses, cattle or humans in 14 Swedish provinces. In 20 cases we received tick specimens, which were identified morphologically as adults of H. marginatum (n = 11) or H. rufipes (n = 9). These are the first documented records in Sweden of adults of H. marginatum and H. rufipes. Molecular tests for Crimean-Congo haemorrhagic fever virus and piroplasms (Babesia spp. and Theileria spp.) proved negative; 12 out of 20 tested specimens were positive for rickettsiae (R. aeschlimannii was identified in 11 of the ticks). All ticks originated from people or animals that had not been abroad during the previous two months. These data suggest (i) that the adult Hyalomma ticks originated from immature ticks, which had been brought from the south by migratory birds arriving in Sweden during spring or early summer; and that (ii) due to the exceptionally warm summer of 2018 these immature ticks had been able to develop to the adult stage in the summer and/or autumn of the same year. The rapidly changing climate most likely now permits these two Hyalomma species to develop to the adult, reproductive stage in northern Europe. There is consequently a need to revise the risk maps on the potential geographic occurrence of relevant tick species and related tick-borne pathogens in Sweden and in the neighbouring countries.
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23
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Modelling tick bite risk by combining random forests and count data regression models. PLoS One 2019; 14:e0216511. [PMID: 31821325 PMCID: PMC6903726 DOI: 10.1371/journal.pone.0216511] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 10/30/2019] [Indexed: 12/05/2022] Open
Abstract
The socio-economic and demographic changes that occurred over the past 50 years have dramatically expanded urban areas around the globe, thus bringing urban settlers in closer contact with nature. Ticks have trespassed the limits of forests and grasslands to start inhabiting green spaces within metropolitan areas. Hence, the transmission of pathogens causing tick-borne diseases is an important threat to public health. Using volunteered tick bite reports collected by two Dutch initiatives, here we present a method to model tick bite risk using human exposure and tick hazard predictors. Our method represents a step forward in risk modelling, since we combine a well-known ensemble learning method, Random Forest, with four count data models of the (zero-inflated) Poisson family. This combination allows us to better model the disproportions inherent in the volunteered tick bite reports. Unlike canonical machine learning models, our method can capture the overdispersion or zero-inflation inherent in data, thus yielding tick bite risk predictions that resemble the original signal captured by volunteers. Mapping model predictions enables a visual inspection of the spatial patterns of tick bite risk in the Netherlands. The Veluwe national park and the Utrechtse Heuvelrug forest, which are large forest-urban interfaces with several cities, are areas with high tick bite risk. This is expected, since these are popular places for recreation and tick activity is high in forests. However, our model can also predict high risk in less-intensively visited recreational areas, such as the patchy forests in the northeast of the country, the natural areas along the coastline, or some of the Frisian Islands. Our model could help public health specialists to design mitigation strategies for tick-borne diseases, and to target risky areas with awareness and prevention campaigns.
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24
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Duscher GG, Hodžić A, Hufnagl P, Wille-Piazzai W, Schötta AM, Markowicz MA, Estrada-Peña A, Stanek G, Allerberger F. Adult Hyalomma marginatum tick positive for Rickettsia aeschlimannii in Austria, October 2018. ACTA ACUST UNITED AC 2019; 23. [PMID: 30621821 PMCID: PMC6280420 DOI: 10.2807/1560-7917.es.2018.23.48.1800595] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report on a non-indigenous adult Hyalomma marginatum tick in Austria carrying the human pathogenic Rickettsia aeschlimannii; presumably introduced as a nymph via migratory birds and completed the moulting within the same year. It was negative for Crimean-Congo haemorrhagic fever virus, but the finding of R. aeschlimannii represents a potential threat for humans due to its zoonotic character. Awareness of invasive tick species and carried pathogens should be improved in central and northern Europe.
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Affiliation(s)
| | - Adnan Hodžić
- Institute of Parasitology, University of Veterinary Medicine Vienna, Austria
| | - Peter Hufnagl
- Institute for Medical Microbiology and Hygiene, Austrian Agency for Health and Food Safety Vienna, Austria
| | | | | | | | | | - Gerold Stanek
- Institute for Hygiene and Applied Immunology, Medical University of Vienna, Austria
| | - Franz Allerberger
- Institute for Medical Microbiology and Hygiene, Austrian Agency for Health and Food Safety Vienna, Austria
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25
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Zanzani SA, Pintore E, Olivieri E, Columbano N, Scanu A, Melosu V, Sanna Passino E, Careddu G, Gazzonis AL, Manfredi MT, Garippa G. Ixodid ticks on wild donkeys in a Mediterranean nature reserve (Asinara National Park): diversity and risk factors. MEDICAL AND VETERINARY ENTOMOLOGY 2019; 33:238-246. [PMID: 30569463 DOI: 10.1111/mve.12355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/13/2018] [Accepted: 11/05/2018] [Indexed: 06/09/2023]
Abstract
The Sardinian coloured donkey Equus asinus (Perissodactyla: Equidae) and its albino colour morph represent the wildlife species most typical of the island of Asinara. This Mediterranean island represents a favourable context for ticks and tick-borne diseases; however, knowledge of the tick fauna on Asinara is scarce. A total of 106 Sardinian donkeys were inspected for tick infestation from June to November 2015. All ticks found were collected, classified by stage and sex, and identified to species level. The level of infestation of each donkey was determined; both the overall tick infestation and infestations of each detected species were classified on a scale of 1-3 to give an infestation score (IS). Overall, 256 hard ticks were collected from 60 of 106 donkeys (56.6%). Rhipicephalus bursa, Haemaphysalis punctata and Hyalomma marginatum (all: Ixodida: Ixodidae) infested 26.4%, 28.3% and 6.6% of donkeys, respectively. Different variables affected the IS. With reference to overall tick infestation, a higher IS was observed in donkeys grazing on grassland and Mediterranean shrubland and in albino donkeys compared with coloured donkeys. The collected ticks included species involved in the transmission of pathogens to humans, which highlights the risks for public health in a tourist destination such as Asinara National Park.
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Affiliation(s)
- S A Zanzani
- Department of Veterinary Medicine (DIMEVET), Università degli Studi di Milano, Milan, Italy
| | - E Pintore
- Department of Veterinary Medicine (DIMEVET), Università di Sassari, Sassari, Italy
| | - E Olivieri
- Department of Veterinary Medicine (DIMEVET), Università degli Studi di Milano, Milan, Italy
| | - N Columbano
- Department of Veterinary Medicine (DIMEVET), Università di Sassari, Sassari, Italy
| | - A Scanu
- Department of Veterinary Medicine (DIMEVET), Università di Sassari, Sassari, Italy
| | - V Melosu
- Department of Veterinary Medicine (DIMEVET), Università di Sassari, Sassari, Italy
| | - E Sanna Passino
- Department of Veterinary Medicine (DIMEVET), Università di Sassari, Sassari, Italy
| | - G Careddu
- Parco Nazionale dell'Asinara, Sassari, Italy
| | - A L Gazzonis
- Department of Veterinary Medicine (DIMEVET), Università degli Studi di Milano, Milan, Italy
| | - M T Manfredi
- Department of Veterinary Medicine (DIMEVET), Università degli Studi di Milano, Milan, Italy
| | - G Garippa
- Department of Veterinary Medicine (DIMEVET), Università di Sassari, Sassari, Italy
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26
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Esser HJ, Mögling R, Cleton NB, van der Jeugd H, Sprong H, Stroo A, Koopmans MPG, de Boer WF, Reusken CBEM. Risk factors associated with sustained circulation of six zoonotic arboviruses: a systematic review for selection of surveillance sites in non-endemic areas. Parasit Vectors 2019; 12:265. [PMID: 31133059 PMCID: PMC6537422 DOI: 10.1186/s13071-019-3515-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 05/19/2019] [Indexed: 12/30/2022] Open
Abstract
Arboviruses represent a significant burden to public health and local economies due to their ability to cause unpredictable and widespread epidemics. To maximize early detection of arbovirus emergence in non-endemic areas, surveillance efforts should target areas where circulation is most likely. However, identifying such hotspots of potential emergence is a major challenge. The ecological conditions leading to arbovirus outbreaks are shaped by complex interactions between the virus, its vertebrate hosts, arthropod vector, and abiotic environment that are often poorly understood. Here, we systematically review the ecological risk factors associated with the circulation of six arboviruses that are of considerable concern to northwestern Europe. These include three mosquito-borne viruses (Japanese encephalitis virus, West Nile virus, Rift Valley fever virus) and three tick-borne viruses (Crimean-Congo hemorrhagic fever virus, tick-borne encephalitis virus, and louping-ill virus). We consider both intrinsic (e.g. vector and reservoir host competence) and extrinsic (e.g. temperature, precipitation, host densities, land use) risk factors, identify current knowledge gaps, and discuss future directions. Our systematic review provides baseline information for the identification of regions and habitats that have suitable ecological conditions for endemic circulation, and therefore may be used to target early warning surveillance programs aimed at detecting multi-virus and/or arbovirus emergence.
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Affiliation(s)
- Helen J Esser
- Resource Ecology Group, Wageningen University & Research, Wageningen, The Netherlands. .,Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands.
| | - Ramona Mögling
- Department of Viroscience, WHO CC for arbovirus and viral hemorrhagic fever reference and research, Erasmus University Medical Centre, Rotterdam, The Netherlands
| | - Natalie B Cleton
- Department of Viroscience, WHO CC for arbovirus and viral hemorrhagic fever reference and research, Erasmus University Medical Centre, Rotterdam, The Netherlands.,Centre for Infectious Disease Control, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands
| | - Henk van der Jeugd
- Vogeltrekstation-Dutch Centre for Avian Migration and Demography, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Hein Sprong
- Centre for Infectious Disease Control, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands
| | - Arjan Stroo
- Centre for Monitoring of Vectors (CMV), National Reference Centre (NRC), Netherlands Food and Consumer Product Safety Authority (NVWA), Ministry of Economic Affairs, Wageningen, The Netherlands
| | - Marion P G Koopmans
- Department of Viroscience, WHO CC for arbovirus and viral hemorrhagic fever reference and research, Erasmus University Medical Centre, Rotterdam, The Netherlands
| | - Willem F de Boer
- Resource Ecology Group, Wageningen University & Research, Wageningen, The Netherlands
| | - Chantal B E M Reusken
- Department of Viroscience, WHO CC for arbovirus and viral hemorrhagic fever reference and research, Erasmus University Medical Centre, Rotterdam, The Netherlands.,Centre for Infectious Disease Control, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands
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27
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Chitimia-Dobler L, Schaper S, Rieß R, Bitterwolf K, Frangoulidis D, Bestehorn M, Springer A, Oehme R, Drehmann M, Lindau A, Mackenstedt U, Strube C, Dobler G. Imported Hyalomma ticks in Germany in 2018. Parasit Vectors 2019; 12:134. [PMID: 30909964 PMCID: PMC6434826 DOI: 10.1186/s13071-019-3380-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 03/05/2019] [Indexed: 12/02/2022] Open
Abstract
Background Hyalomma marginatum and Hyalomma rufipes are two-host tick species, which are mainly distributed in southern Europe, Africa and middle-eastern Asia. They are well-known vectors of Crimean Congo hemorrhagic fever (CCHF) virus and other viruses as well as Rickettsia aeschlimannii. In recent years, these tick species have been found sporadically in Germany, but they do not belong to the autochthonous tick fauna in Germany. Methods Ticks with unusual morphology were collected and sent from private persons or public health offices to involve institutions for morphological identification and further testing. All ticks identified as Hyalomma spp. were tested using molecular detection methods for CCHF virus, Rickettsia spp., Coxiella burnetii and Coxiella-like organisms, Babesia spp. and Theileria spp. Results Thirty-five ticks with an unusual appearance or behaviour were reported to us during summer-autumn 2018. For 17 of them, the description or photos implied that they belong to the hard tick genus Hyalomma. The remaining 18 ticks were sent to us and were identified as adult Hyalomma marginatum (10 specimens) or adult Hyalomma rufipes (8 specimens). All ticks tested negative for CCHF virus, Coxiella burnetii, Coxiella-like organisms, Babesia spp. and Theileria spp. The screening for rickettsiae gave positive results in 9 specimens . The Rickettsia species in all cases was identified as R. aeschlimannii. Conclusions These results show that exotic tick species imported into Germany were able to develop from the nymphal to the adult stage under appropriate weather conditions. Fifty percent of the ticks carried R. aeschlimannii, a human pathogen, while CCHF virus or other pathogens were not detected. Imported Hyalomma ticks may be the source of exotic diseases acquired in Germany.
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Affiliation(s)
- Lidia Chitimia-Dobler
- Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, 80937, Munich, Germany.,Department of Parasitology, Institute of Zoology, University of Hohenheim, Emil Wolff-Strasse 34, 70599, Stuttgart, Germany
| | - Sabine Schaper
- Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, 80937, Munich, Germany
| | - Ramona Rieß
- Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, 80937, Munich, Germany
| | - Karin Bitterwolf
- Public Health Office Main-Kinzig, Barbarossastrasse 24, 63571, Gelnhausen, Germany
| | | | - Malena Bestehorn
- Department of Parasitology, Institute of Zoology, University of Hohenheim, Emil Wolff-Strasse 34, 70599, Stuttgart, Germany
| | - Andrea Springer
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Buenteweg 17, 30559, Hanover, Germany
| | - Rainer Oehme
- Baden-Wuerttemberg State Health Office, Stuttgart, Germany
| | - Marco Drehmann
- Department of Parasitology, Institute of Zoology, University of Hohenheim, Emil Wolff-Strasse 34, 70599, Stuttgart, Germany
| | - Alexander Lindau
- Department of Parasitology, Institute of Zoology, University of Hohenheim, Emil Wolff-Strasse 34, 70599, Stuttgart, Germany
| | - Ute Mackenstedt
- Department of Parasitology, Institute of Zoology, University of Hohenheim, Emil Wolff-Strasse 34, 70599, Stuttgart, Germany
| | - Christina Strube
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Buenteweg 17, 30559, Hanover, Germany
| | - Gerhard Dobler
- Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, 80937, Munich, Germany. .,Department of Parasitology, Institute of Zoology, University of Hohenheim, Emil Wolff-Strasse 34, 70599, Stuttgart, Germany.
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28
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Estrada-Peña A, Cutler S, Potkonjak A, Vassier-Tussaut M, Van Bortel W, Zeller H, Fernández-Ruiz N, Mihalca AD. An updated meta-analysis of the distribution and prevalence of Borrelia burgdorferi s.l. in ticks in Europe. Int J Health Geogr 2018; 17:41. [PMID: 30514310 PMCID: PMC6319795 DOI: 10.1186/s12942-018-0163-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 11/27/2018] [Indexed: 12/12/2022] Open
Abstract
Background The bacteria of the group Borrelia burgdorferi s.l. are the etiological agents of Lyme borreliosis in humans, transmitted by bites of ticks. Improvement of control measures requires a solid framework of the environmental traits driving its prevalence in ticks. Methods We updated a previous meta-analysis of the reported prevalence of Borrelia burgdorferi s.l. in questing nymphs of Ixodes ricinus with a literature search from January 2010–June 2017. This resulted in 195 new papers providing the prevalence of Bb for 926 geo-referenced records. Previously obtained data (878 records, years 2000–2010) were appended for modelling. The complete dataset contains data from 82,004 questing nymphs, resulting in 558 records of B. afzelii, 404 of B. burgdorferi s.s. (only 80 after the year 2010), 552 of B. garinii, 78 of B. lusitaniae, 61 of B. spielmanii, and 373 of B. valaisiana. We associated the records with explicit coordinates to environmental conditions and to a categorical definition of European landscapes (LANMAP2) looking for a precise definition of the environmental niche of the most reported species of the pathogen, using models based on different classification methods. Results The most commonly reported species are B. afzelii, B. garinii and B. valaisiana largely overlapping across Europe. Prevalence in ticks is associated with portions of the environmental niche. Highest prevalence occurs in areas of 280°–290° (Kelvin) of mean annual temperature experiencing a small amplitude, steady spring slope, together with high mean values and a moderate spring rise of vegetation vigor. Low prevalence occurs in sites with low and a noteworthy annual amplitude of temperature and the Normalized Difference Vegetation Index (colder areas with abrupt annual changes of vegetation). Models based on support vector machines provided a correct classification rate of the habitat and prevalence of 89.5%. These results confirm the association of prevalence of the three most commonly reported species of B. burgdorferi s.l. in Europe to parts of the environmental niche and provide a statistically tractable framework for analyzing trends under scenarios of climate change. Electronic supplementary material The online version of this article (10.1186/s12942-018-0163-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Agustín Estrada-Peña
- Department of Animal Health, Faculty of Veterinary Medicine, Miguel Servet 177, 50013, Zaragoza, Spain.
| | - Sally Cutler
- School of Health, Sport and Bioscience, University of East London, London, UK
| | - Aleksandar Potkonjak
- Department of Veterinary Medicine, Faculty of Agriculture, University of Novi Sad, Novi Sad, Serbia
| | | | - Wim Van Bortel
- Surveillance and Response Support Unit, Solna, Sweden.,Institute of Tropical Medicine, Unite of Medical Entomology, Antwerp, Belgium
| | - Hervé Zeller
- Office of the Chief Scientist Unit, European Centre for Disease Prevention and Control, Solna, Sweden
| | - Natalia Fernández-Ruiz
- Department of Animal Health, Faculty of Veterinary Medicine, Miguel Servet 177, 50013, Zaragoza, Spain
| | - Andrei Daniel Mihalca
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania
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Modelling the distribution of Rhipicephalus microplus and R. decoloratus in Zimbabwe. VETERINARY PARASITOLOGY- REGIONAL STUDIES AND REPORTS 2018; 14:41-49. [PMID: 31014735 DOI: 10.1016/j.vprsr.2018.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 08/26/2018] [Accepted: 08/28/2018] [Indexed: 10/28/2022]
Abstract
Species distribution modelling is a very useful tool in vector management. Ticks are vectors of various pathogens which cause serious problems in livestock production in tropical countries. They have a high dispersal potential which is mainly facilitated by the movement of animals from one area to another. In light of the observed geographic expansion of Rhipicephalus microplus in Zimbabwe, we used species distribution modelling techniques to identify areas which may provide suitable habitats for the occurrence of this invasive tick species as well as the autochthonous Rhipicephalus decoloratus. Our results suggest that, despite the geographic expansion of R. microplus, climate will continue to be a limiting factor for the further expansion of this tick species. We expect its distribution to be restricted to the most favourable areas in the eastern and northern parts. The greater part of Zimbabwe is suitable for R. decoloratus, although in areas where R. microplus occurs, displacement of the former by the latter will be expected to occur. A heterogeneous climate, unregulated movement of cattle and episodic droughts are suggested to be possible factors for the continued existence of R. microplus and R. decoloratus in Zimbabwe and the partial displacement.
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30
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Abstract
Climate change is expected to impact across every domain of society, including health. The majority of the world's population is susceptible to pathological, infectious disease whose life cycles are sensitive to environmental factors across different physical phases including air, water and soil. Nearly all so-called neglected tropical diseases (NTDs) fall into this category, meaning that future geographic patterns of transmission of dozens of infections are likely to be affected by climate change over the short (seasonal), medium (annual) and long (decadal) term. This review offers an introduction into the terms and processes deployed in modelling climate change and reviews the state of the art in terms of research into how climate change may affect future transmission of NTDs. The 34 infections included in this chapter are drawn from the WHO NTD list and the WHO blueprint list of priority diseases. For the majority of infections, some evidence is available of which environmental factors contribute to the population biology of parasites, vectors and zoonotic hosts. There is a general paucity of published research on the potential effects of decadal climate change, with some exceptions, mainly in vector-borne diseases.
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Affiliation(s)
- Mark Booth
- Newcastle University, Institute of Health and Society, Newcastle upon Tyne, United Kingdom.
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31
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Oliveira SVD, Romero-Alvarez D, Martins TF, Santos JPD, Labruna MB, Gazeta GS, Escobar LE, Gurgel-Gonçalves R. Amblyomma ticks and future climate: Range contraction due to climate warming. Acta Trop 2017; 176:340-348. [PMID: 28865899 DOI: 10.1016/j.actatropica.2017.07.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/26/2017] [Accepted: 07/27/2017] [Indexed: 11/19/2022]
Abstract
Ticks of the Amblyomma cajennense species complex are important vectors of spotted fever in Latin America. Environmental conditions determine the geographic distribution of ticks, such that climate change could influence the distribution of tick-borne diseases. This study aimed to analyze the potential geographic distribution of A. cajennense complex ticks in a Brazil region under present-day and future climate models, assuming dispersal limitations and non-evolutionary adaptation of these tick populations to climate warming. Records of A. cajennense sensu stricto (s.s.) and Amblyomma sculptum were analyzed. Niche models were calibrated using Maxent considering climate variables for 1950-2000 and projecting models to conditions anticipated for 2050 and 2070 under two models of future climate (CCSM4 and HadGEM2-AO). Broad suitable areas for A. cajennense s.s. and A. sculptum were found in present-day climate models, but suitability was reduced when models were projected to future conditions. Our exploration of future climates showed that broad areas had novel climates not existing currently in the study region, including novel extremely high temperatures. Indeed, predicted suitability in these novel conditions would lead to biologically unrealistic results and therefore incorrect forecasts of future tick-distribution. Previous studies anticipating expansions of vectors populations due to climate change should be considered with caution as they assume that model extrapolation anticipates that species would evolve rapidly for adaptation to novel climatic conditions.
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Affiliation(s)
- Stefan Vilges de Oliveira
- Programa de Pós Graduação em Medicina Tropical da Universidade de Brasília, Campus Universitário Darcy Ribeiro, Asa Norte, CEP: 70910-900, Brasília, Brazil; Secretaria de Vigilância em Saúde do Ministério da Saúde do Brasil, Setor de Rádio TV Norte - 701 - Via W5 Norte, Edifício PO 0700, CEP: 70719-040, Brasília, Brazil; Laboratório de Referência Nacional em Vetores das Riquetsioses da Fundação Oswaldo Cruz, Av. Brasil 4365, Manguinhos, CEP: 21040-360, Rio de Janeiro, Brazil.
| | - Daniel Romero-Alvarez
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
| | - Thiago Fernandes Martins
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, Cidade Universitária, CEP: 05508-270, São Paulo, SP, Brazil
| | - Janduhy Pereira Dos Santos
- Departamento de Geografia da Universidade de Brasília, Campus Universitário Darcy Ribeiro, Asa Norte, CEP: 70910-900, Brasília, Brazil
| | - Marcelo B Labruna
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, Cidade Universitária, CEP: 05508-270, São Paulo, SP, Brazil
| | - Gilberto Salles Gazeta
- Laboratório de Referência Nacional em Vetores das Riquetsioses da Fundação Oswaldo Cruz, Av. Brasil 4365, Manguinhos, CEP: 21040-360, Rio de Janeiro, Brazil
| | - Luis E Escobar
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VAN, 24061, USA
| | - Rodrigo Gurgel-Gonçalves
- Laboratório de Parasitologia Médica e Biologia de Vetores da Faculdade de Medicina da Universidade de Brasília, Campus Universitário Darcy Ribeiro, Asa Norte, CEP: 70910-900, Brasília, Brazil
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Abbas T, Xu Z, Younus M, Qayyum A, Riaz MT. Seasonality in hospital admissions of Crimean-Congo hemorrhagic fever and its dependence on ambient temperature-empirical evidence from Pakistan. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2017; 61:1893-1897. [PMID: 28455635 DOI: 10.1007/s00484-017-1359-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 08/31/2016] [Accepted: 04/17/2017] [Indexed: 06/07/2023]
Abstract
Crimean-Congo hemorrhagic fever (CCHF) has been reported from all provinces of Pakistan. Little is known about the seasonal variations in the disease and its association with weather conditions. In this study, we explored time-series data about monthly number of CCHF admissions (2007-2010) in three public sector hospitals of Quetta-the capital city of Baluchistan province of Pakistan. Cosinor analysis was carried out to investigate seasonality in the data. To assess the effect of average monthly ambient temperature (°C) on disease, a distributed lag nonlinear model (DLNM) was applied. Cosinor model revealed statistically significant seasonality in monthly number of CCHF patients admitted to the study hospitals. The estimated amplitude was 3.24 cases per month with phase in mid-June and low point in mid-December. DLNM confirmed nonlinear and delayed effect of temperature on hospital admissions. At a lag of 2 months, the cumulative relative risk was more than 1 at temperature at 18.37 °C and above. In addition, relative risk was significantly high at 60th (21.98 °C), 70th (24.50 °C), 80th (27.33 °C), and 90th (29.25 °C) percentiles of temperature (relative to median value, 18.37 °C). Inclusion of Eid-al-Adha as a predictor did not improve the fitness of DLNM. Based on our analysis, we concluded significant seasonality in CCHF hospital admissions. Our findings also suggested average monthly ambient temperature (°C) as a significant predictor of CCHF hospitalizations. DLNM presented in this study may be improved with inclusion of other possible time-varying predictors particularly meteorological conditions of this region.
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Affiliation(s)
- Tariq Abbas
- University College of Veterinary & Animal Sciences, Islamia University of Bahawalpur, Baghdad-ul-Jadeed Campus, Bahawalpur, Pakistan.
| | - Zhiwei Xu
- School of Public Health, Institute of Health and Biomedical Innovation, Queensland University of Technology, Victoria Park Road, Kelvin Grove, QLD, 4059, Australia
| | - Muhammad Younus
- University of Veterinary & Animal Sciences, Lahore, Pakistan
| | - Abdul Qayyum
- University College of Veterinary & Animal Sciences, Islamia University of Bahawalpur, Baghdad-ul-Jadeed Campus, Bahawalpur, Pakistan
| | - Muhammad T Riaz
- Livestock & Dairy Development Department, Government of Punjab, Lahore, Pakistan
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33
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Zivcec M, Guerrero LIW, Albariño CG, Bergeron É, Nichol ST, Spiropoulou CF. Identification of broadly neutralizing monoclonal antibodies against Crimean-Congo hemorrhagic fever virus. Antiviral Res 2017; 146:112-120. [PMID: 28842265 DOI: 10.1016/j.antiviral.2017.08.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/17/2017] [Accepted: 08/22/2017] [Indexed: 02/07/2023]
Abstract
Despite the serious public health impact of Crimean-Congo hemorrhagic fever (CCHF), the efficacy of antivirals targeting the causative agent, CCHF virus (CCHFV), remains debatable. Neutralizing monoclonal antibodies (MAbs) targeting the CCHFV glycoprotein Gc have been reported to protect mice against challenge with the prototype CCHFV strain, IbAr10200. However, due to extensive sequence diversity of CCHFV glycoproteins, it is unknown whether these MAbs neutralize other CCHFV strains. We initially used a CCHF virus-like particle (VLP) system to generate 11 VLP moieties, each possessing a glycoprotein from a genetically diverse CCHFV strain isolated in either Africa, Asia, the Middle East, or southeastern Europe. We used these VLPs in biosafety level 2 conditions to efficiently screen MAb cross-neutralization potency. Of the 16 MAbs tested, 3 (8A1, 11E7, and 30F7) demonstrated cross-neutralization activity with most CCHF VLPs, with 8A1 neutralizing all VLPs tested. Although binding studies suggest that none of the MAbs compete for the same epitope, combining 11E7, 30F7, or both 11E7 and 30F7 with 8A1 had no additive effect on increasing neutralization in this system. To confirm our findings from the VLP system, the 3 MAbs capable of strain cross-neutralization were confirmed to effectively neutralize 5 diverse CCHFV strains in vitro. Passaging CCHFV strains in the presence of sub-neutralizing concentrations of MAbs did not generate escape mutants resistant to subsequent neutralization. This study demonstrates the utility of the VLP system for screening neutralizing MAbs against multiple CCHFV strains, and provides the first evidence that a single MAb can effectively neutralize a number of diverse CCHFV strains in vitro, which may lead to development of future CCHF therapeutics.
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Affiliation(s)
- Marko Zivcec
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Lisa I W Guerrero
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - César G Albariño
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Éric Bergeron
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Stuart T Nichol
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Christina F Spiropoulou
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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Villar M, Marina A, de la Fuente J. Applying proteomics to tick vaccine development: where are we? Expert Rev Proteomics 2017; 14:211-221. [PMID: 28099817 DOI: 10.1080/14789450.2017.1284590] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Ticks are second to mosquitoes as a vector of human diseases and are the first vector of animal diseases with a great impact on livestock farming. Tick vaccines represent a sustainable and effective alternative to chemical acaricides for the control of tick infestations and transmitted pathogens. The application of proteomics to tick vaccine development is a fairly recent area, which has resulted in the characterization of some tick-host-pathogen interactions and the identification of candidate protective antigens. Areas covered: In this article, we review the application and possibilities of various proteomic approaches for the discovery of tick and pathogen derived protective antigens, and the design of effective vaccines for the control of tick infestations and pathogen infection and transmission. Expert commentary: In the near future, the application of reverse proteomics, immunoproteomics, structural proteomics, and interactomics among other proteomics approaches will likely contribute to improve vaccine design to control multiple tick species with the ultimate goal of controlling tick-borne diseases.
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Affiliation(s)
- Margarita Villar
- a Sabio. Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM , Ciudad Real , Spain
| | - Anabel Marina
- b Centro de Biología Molecular Severo Ochoa CBM-SO (CSIC-UAM) , Cantoblanco , Spain
| | - José de la Fuente
- a Sabio. Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM , Ciudad Real , Spain.,c Department of Veterinary Pathobiology , Center for Veterinary Health Sciences, Oklahoma State University , Stillwater , OK , USA
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Vial L, Stachurski F, Leblond A, Huber K, Vourc’h G, René-Martellet M, Desjardins I, Balança G, Grosbois V, Pradier S, Gély M, Appelgren A, Estrada-Peña A. Strong evidence for the presence of the tick Hyalomma marginatum Koch, 1844 in southern continental France. Ticks Tick Borne Dis 2016; 7:1162-1167. [DOI: 10.1016/j.ttbdis.2016.08.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 08/05/2016] [Accepted: 08/05/2016] [Indexed: 11/29/2022]
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Leblebicioglu H, Ozaras R, Irmak H, Sencan I. Crimean-Congo hemorrhagic fever in Turkey: Current status and future challenges. Antiviral Res 2015; 126:21-34. [PMID: 26695860 DOI: 10.1016/j.antiviral.2015.12.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/09/2015] [Accepted: 12/10/2015] [Indexed: 01/12/2023]
Abstract
Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease of humans that affects a wide geographic area of Africa and Eurasia, including Turkey, Iran, Pakistan, Afghanistan and Russia. Since the first detection of CCHF cases in Turkey in 2002, more than 9700 patients have been reported, with an overall mortality rate just under 5%. This article assesses the present epidemiological situation of CCHF in Turkey, with an updated literature review, describes national practices and summarizes lessons learned in preparation for future outbreaks.
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Affiliation(s)
- Hakan Leblebicioglu
- Department of Infectious Diseases and Clinical Microbiology, Ondokuz Mayis University Medical School, Samsun, Turkey.
| | - Resat Ozaras
- Department of Infectious Diseases and Clinical Microbiology, Istanbul University Cerrahpasa Medical School, Istanbul, Turkey.
| | - Hasan Irmak
- Republic of Turkey Ministry of Health, Ankara, Turkey.
| | - Irfan Sencan
- Department of Infectious Diseases and Clinical Microbiology, Diskapi Yildirim Beyazit Education and Research Hospital, Ankara, Turkey.
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Williams HW, Cross DE, Crump HL, Drost CJ, Thomas CJ. Climate suitability for European ticks: assessing species distribution models against null models and projection under AR5 climate. Parasit Vectors 2015; 8:440. [PMID: 26310856 PMCID: PMC4551698 DOI: 10.1186/s13071-015-1046-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 08/15/2015] [Indexed: 11/20/2022] Open
Abstract
Background There is increasing evidence that the geographic distribution of tick species is changing. Whilst correlative Species Distribution Models (SDMs) have been used to predict areas that are potentially suitable for ticks, models have often been assessed without due consideration for spatial patterns in the data that may inflate the influence of predictor variables on species distributions. This study used null models to rigorously evaluate the role of climate and the potential for climate change to affect future climate suitability for eight European tick species, including several important disease vectors. Methods We undertook a comparative assessment of the performance of Maxent and Mahalanobis Distance SDMs based on observed data against those of null models based on null species distributions or null climate data. This enabled the identification of species whose distributions demonstrate a significant association with climate variables. Latest generation (AR5) climate projections were subsequently used to project future climate suitability under four Representative Concentration Pathways (RCPs). Results Seven out of eight tick species exhibited strong climatic signals within their observed distributions. Future projections intimate varying degrees of northward shift in climate suitability for these tick species, with the greatest shifts forecasted under the most extreme RCPs. Despite the high performance measure obtained for the observed model of Hyalomma lusitanicum, it did not perform significantly better than null models; this may result from the effects of non-climatic factors on its distribution. Conclusions By comparing observed SDMs with null models, our results allow confidence that we have identified climate signals in tick distributions that are not simply a consequence of spatial patterns in the data. Observed climate-driven SDMs for seven out of eight species performed significantly better than null models, demonstrating the vulnerability of these tick species to the effects of climate change in the future. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1046-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hefin Wyn Williams
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales.
| | - Dónall Eoin Cross
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales.
| | - Heather Louise Crump
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales.
| | - Cornelis Jan Drost
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales.
| | - Christopher James Thomas
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales.
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de la Fuente J, Contreras M. Tick vaccines: current status and future directions. Expert Rev Vaccines 2015; 14:1367-76. [DOI: 10.1586/14760584.2015.1076339] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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