| 1. |
- Medlock, Jolyon M, et al.
(författare)
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Driving forces for changes in geographical distribution of Ixodes ricinus ticks in Europe
- 2013
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Ingår i: Parasites & Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 6:1
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Forskningsöversikt (refereegranskat)abstract
- Many factors are involved in determining the latitudinal and altitudinal spread of the important tick vector Ixodes ricinus (Acari: Ixodidae) in Europe, as well as in changes in the distribution within its prior endemic zones. This paper builds on published literature and unpublished expert opinion from the VBORNET network with the aim of reviewing the evidence for these changes in Europe and discusses the many climatic, ecological, landscape and anthropogenic drivers. These can be divided into those directly related to climatic change, contributing to an expansion in the tick’s geographic range at extremes of altitude in central Europe, and at extremes of latitude in Scandinavia; those related to changes in the distribution of tick hosts, particularly roe deer and other cervids; other ecological changes such as habitat connectivity and changes in land management; and finally, anthropogenically induced changes. These factors are strongly interlinked and often not well quantified. Although a change in climate plays an important role in certain geographic regions, for much of Europe it is non-climatic factors that are becoming increasingly important. How we manage habitats on a landscape scale, and the changes in the distribution and abundance of tick hosts are important considerations during our assessment and management of the public health risks associated with ticks and tick-borne disease issues in 21st century Europe. Better understanding and mapping of the spread of I. ricinus (and changes in its abundance) is, however, essential to assess the risk of the spread of infections transmitted by this vector species. Enhanced tick surveillance with harmonized approaches for comparison of data enabling the follow-up of trends at EU level will improve the messages on risk related to tick-borne diseases to policy makers, other stake holders and to the general public.
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| 2. |
- Norte, Ana Cláudia, et al.
(författare)
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Host dispersal shapes the population structure of a tick-borne bacterial pathogen
- 2020
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 29:3, s. 485-501
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Tidskriftsartikel (refereegranskat)abstract
- Birds are hosts for several zoonotic pathogens. Because of their high mobility, especially of longdistance migrants, birds can disperse these pathogens, affecting their distribution and phylogeography. We focused on Borrelia burgdorferi sensu lato, which includes the causative agents of Lyme borreliosis, as an example for tick-borne pathogens, to address the role of birds as propagation hosts of zoonotic agents at a large geographical scale. We collected ticks from passerine birds in 11 European countries. B. burgdorferi s.l. prevalence in Ixodes spp. was 37% and increased with latitude. The fieldfare Turdus pilaris and the blackbird T. merula carried ticks with the highest Borrelia prevalence (92 and 58%, respectively), whereas robin Erithacus rubecula ticks were the least infected (3.8%). Borrelia garinii was the most prevalent genospecies (61%), followed by B. valaisiana (24%), B. afzelii (9%), B. turdi (5%) and B. lusitaniae (0.5%). A novel Borrelia genospecies “Candidatus Borrelia aligera” was also detected. Multilocus sequence typing (MLST) analysis of B. garinii isolates together with the global collection of B. garinii genotypes obtained from the Borrelia MLST public database revealed that: (a) there was little overlap among genotypes from different continents, (b) there was no geographical structuring within Europe, and (c) there was no evident association pattern detectable among B. garinii genotypes from ticks feeding on birds, questing ticks or human isolates. These findings strengthen the hypothesis that the population structure and evolutionary biology of tick-borne pathogens are shaped by their host associations and the movement patterns of these hosts.
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| 3. |
- Saegerman, Claude, et al.
(författare)
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First Expert Elicitation of Knowledge on Possible Drivers of Observed Increasing Human Cases of Tick-Borne Encephalitis in Europe
- 2023
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Ingår i: Viruses. - : MDPI AG. - 1999-4915. ; 15:3
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Tidskriftsartikel (refereegranskat)abstract
- Tick-borne encephalitis (TBE) is a viral disease endemic in Eurasia. The virus is mainly transmitted to humans via ticks and occasionally via the consumption of unpasteurized milk products. The European Centre for Disease Prevention and Control reported an increase in TBE incidence over the past years in Europe as well as the emergence of the disease in new areas. To better understand this phenomenon, we investigated the drivers of TBE emergence and increase in incidence in humans through an expert knowledge elicitation. We listed 59 possible drivers grouped in eight domains and elicited forty European experts to: (i) allocate a score per driver, (ii) weight this score within each domain, and (iii) weight the different domains and attribute an uncertainty level per domain. An overall weighted score per driver was calculated, and drivers with comparable scores were grouped into three terminal nodes using a regression tree analysis. The drivers with the highest scores were: (i) changes in human behavior/activities; (ii) changes in eating habits or consumer demand; (iii) changes in the landscape; (iv) influence of humidity on the survival and transmission of the pathogen; (v) difficulty to control reservoir(s) and/or vector(s); (vi) influence of temperature on virus survival and transmission; (vii) number of wildlife compartments/groups acting as reservoirs or amplifying hosts; (viii) increase of autochthonous wild mammals; and (ix) number of tick species vectors and their distribution. Our results support researchers in prioritizing studies targeting the most relevant drivers of emergence and increasing TBE incidence.
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| 4. |
- Van Lith, Lindy, et al.
(författare)
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A real-time assemblage-specific PCR assay for the detection of Giardia duodenalis assemblages A, B and E in fecal samples
- 2015
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Ingår i: Veterinary parasitology. - : Elsevier BV. - 0304-4017 .- 1873-2550. ; 211:1-2, s. 28-34
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Tidskriftsartikel (refereegranskat)abstract
- Giardiosis is a common gastrointestinal infection caused by the flagellate Giardia duodenalis, and affects both humans and animals, worldwide. Animals are infected with both zoonotic and host-specific G. duodenalis assemblages, and their role in the transmission of the infection to humans has been a subject of intense research and debate. Conventional PCR assays are appropriate to determine G. duodenalis assemblages, but lack sensitivity for the detection of mixed infections. Previous surveys demonstrated the occurrence of mixed infections with G. duodenalis assemblage A and B in humans, and with assemblages A and E in cattle, but are likely to be underestimated. In this study, we designed a set of assemblage-specific primers by exploiting sequence variability in homologous genes from assemblages A, B and E. Primers were designed to amplify fragments of different size that generated different melting curves from each assemblage in real-time PCR (rt-PCR) experiments. The assay has been tested on a large panel of human and farm animal isolates, and shown to possess high specificity (no cross reactions observed) and sensitivity (detection limit close to 20 copies). Therefore, this assay can be useful to detect zoonotic and host-specific G. duodenalis assemblages in fecal samples from farm animals, particularly when a large number of samples is to be tested.
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