| 1. |
- Ivanova, Anna, et al.
(author)
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Detection of Candidatus Neoehrlichia mikurensis and Ehrlichia muris in Estonian ticks
- 2017
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In: Ticks and Tick-borne Diseases. - : Elsevier BV. - 1877-959X .- 1877-9603. ; 8:1, s. 13-17
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Journal article (peer-reviewed)abstract
- So far neglected bacteria like Candidatud Neoehrlichia mikurensis and Ehrlichia muris-like agents get increased attention in the recent past. Ixodid ticks were demonstrated to harbor both of these pathogens. Estonia is populated by two medically important tick species, I. ricinus and I. persulcatus. In this study the presence of E. muris and Candidatus N. mikurensis in these two tick species was investigated. Tick DNA was analyzed by nested PCR and subsequent sequencing for the presence of 16S rRNA of E. muris and Candidatus N. mikurensis. Positive samples were further confirmed by amplification and sequencing of the partial groESL-operon. The obtained partial groESL sequences were used for construction of amaximum likelihood tree. In total, 776 ticks from 36 collection sites situated in 7 counties on the mainland of Estonia and 2 sites situated in one county on the island Saaremaa were collected. 548 were I. ricinus and 228 were 1. persulcatus. Only in 5 counties (11 sites) samples positive for the Anaplasmataceae 16S rRNA gene were found. The percentage of Candidatus N. mikurensis positive ticks varied from 1% to- 9.1% at different sites. In Eastern and South-Eastern Estonia, the area where I. ricinus and 1. persulcatus are sympatric, no Candidatus.N. mikurensis was found. Ticks carrying E. muris were found in three counties, the site-specific percentage of positive ticks varied from 1.2% to 25.6%. This is the first study revealing the presence of Candidatus N. mikurensis and E. muris in Estonian ticks. Candidatus N. mikurensis was found only in the western part of the country exclusively in I. ricinus and the phylogenetic analysis revealed close relatedness of the Estonian sequences to other European Candidatus N. mikurensis strains. E. muris was detected mostly in I. persulcatus and only in one I. ricinus in the sympatric area of both tick species. This is in correspondence with the observation that this pathogen is more often found in I. persulcatus than in I. ricinus. This study demonstrates the presence of Candidatus N. mikurensis and E. muris in Estonian ticks and highlights the necessity to raise awareness of symptoms by healthcare professionals.
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| 2. |
- Ivanova, Anna, et al.
(author)
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Hepatitis E Virus in Domestic Pigs, Wild Boars, Pig Farm Workers, and Hunters in Estonia
- 2015
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In: Food and Environmnetal Virology. - : Springer Science and Business Media LLC. - 1867-0334 .- 1867-0342. ; 7:4, s. 403-412
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Journal article (peer-reviewed)abstract
- While hepatitis E is a growing health concern in Europe, epidemiological data on hepatitis E virus (HEV) in Estonia are scarce. Along with imported HEV infections, autochthonous cases are reported from European countries. Both domestic and wild animals can be a source of human cases of this zoonosis. Here, we investigated the presence of anti-HEV antibodies and HEV RNA in domestic pigs and wild boars, as well as in pig farm workers and hunters in Estonia. Anti-HEV antibodies were detected in 234/380 (61.6 %) of sera from domestic pigs and in all investigated herds, and in 81/471 (17.2 %) of meat juice samples from wild boars. HEV RNA was detected by real-time PCR in 103/449 (22.9 %) of fecal samples from younger domestic pigs and 13/81 (16.0 %) of anti-HEV-positive wild boar samples. Analysis of sera from 67 pig farm workers and 144 hunters revealed the presence of HEV-specific IgG in 13.4 and 4.2 % of the samples, respectively. No HEV RNA was detected in the human serum samples. Phylogenetic analyses of HEV sequences from domestic pigs and wild boars, based on a 245 bp fragment from the open reading frame 2 showed that all of them belonged to genotype 3. The present study demonstrates the presence of HEV in Estonian domestic pig and wild boar populations, as well as in humans who have direct regular contact with these animals. Our results suggest that HEV infections are present in Estonia and require attention.
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| 3. |
- Katargina, Olga, et al.
(author)
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Detection and identification of Rickettsia species in Ixodes tick populations from Estonia
- 2015
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In: Ticks and Tick-borne Diseases. - : Elsevier BV. - 1877-959X .- 1877-9603. ; 6:6, s. 689-694
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Journal article (peer-reviewed)abstract
- A total of 1640 ticks collected in different geographical parts of Estonia were screened for the presence of Rickettsia species DNA by real-time PCR. DNA of Rickettsia was detected in 83 out of 1640 questing ticks with an overall prevalence of 5.1%. The majority of the ticks infected by rickettsiae were Ixodes ricinus (74 of 83), while 9 of the 83 positive ticks were Ixodes persulcatus. For rickettsial species identification, a part of the citrate synthasegltA gene was sequenced. The majority of the positive samples were identified as Rickettsia helvetica (81 out of 83) and two of the samples were identified as Rickettsia monacensis and Candidatus R. tarasevichiae, respectively. Genetic characterization based on the partial gltA gene showed that the Estonian sequences within the R. helvetica, R. monacensis and Candidatus R. tarasevichiae species demonstrated 100% similarity with sequences deposited in GenBank, originating from Rickettsia species distributed over large territories from Europe to Asia.
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| 4. |
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| 5. |
- Saegerman, Claude, et al.
(author)
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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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In: Viruses. - : MDPI AG. - 1999-4915. ; 15:3
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Journal article (peer-reviewed)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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| 6. |
- Värv, Kairi, et al.
(author)
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Identification of I-ricinus, I-persulcatus and I-trianguliceps species by multiplex PCR
- 2017
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In: Ticks and Tick-borne Diseases. - : Elsevier BV. - 1877-959X .- 1877-9603. ; 8:2, s. 235-240
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Journal article (peer-reviewed)abstract
- Correct identification of tick species is an essential requirement for any scientific study engaged in tick associated research. However, morphological identification can lead to misinterpretations, especially when dealing with vector-host research and sub-adult, engorged or damaged specimens. To overcome this "limitation, we developed a novel assay to discriminate between Ixodes ricinus, I. persulcatus and I. trianguliceps species collected from rodents or vegetation, using the second internal transcribed spacer (ITS2) as a genetic marker. This single tube multiplex PCR allows specific amplification of targeted species and produces rapid and accurate results. The specificity was confirmed by sequencing the ITS2 and partial 16S rRNA genes from ticks collected from Estonia, Latvia, Sweden and Russia. We tested the assay in a large-scale experiment, and a total of 1284 ticks removed from rodents and shrews were successfully identified at species level.
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| 7. |
- Kanai, M, et al.
(author)
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- 2023
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swepub:Mat__t
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