Phylogenetic characterization of tick-borne encephalitis virus from Bornholm, Denmark

Bidragets oversatte titel: Fylogenetisk karakteristik af TBE-virus fra Bornholm

Nanna Skaarup Andersen, Malena Bestehorn, Lidia Chitimia-Dobler, Hans Jørn Kolmos, Per Moestrup Jensen, Gerhard Dobler, Sigurdur Skarphédinson

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

The Danish island of Bornholm in the Baltic Sea has been known as a tick-borne encephalitis (TBE) natural focus for more than 60 years. TBE in humans is diagnosed on a regular basis either in inhabitants or tourists of the island. Other areas in Denmark have been suggested as possible risk areas of TBE. Despite the long-known endemicity on Bornholm and the possibility of the virus circulating in other areas, no data on the prevalences of TBE virus (TBEV) in ticks, or adequate molecular characterization and phylogenetic studies are available for the circulating TBEV strains. This study aimed to detect TBEV in ticks collected on the island of Bornholm and other possible risk areas, with the attempt to isolate the circulating viruses for molecular and phylogenetic analysis and confirm the presence of virus in the predicted risk areas.

From 2014 to 2016, 9321 I. ricinus (nymphs, females, and males) were collected by flagging 31 locations in Denmark. The ticks were pooled and tested for TBEV by qPCR. The envelope gene of the detected TBE virus strains was amplified and sequenced by RT-PCR. After successful virus isolation, whole genome sequencing was performed. Phylogenetic analysis of the obtained sequences was done by the Maximum Likelihood method.

One pool of 11 females and one pool of eight males from a total of 34 tick pools collected from the northwestern shore of lake Rubinsøen on Bornholm tested positive, resulting in a local estimated point prevalence of 0.6% [CI95% 0,1–1.85%] in this microfocus. We were not successful in confirming any other of the predicted TBEV-endemic areas. Alignment of the two complete E genes from Bornholm revealed identical sequences. Virus isolation and whole genome sequencing were succeeded from one of the positive samples. Phylogenetic analysis showed that the isolated virus had the closest phylogenetic relationship to TBEV sequences detected in Eastern and Central Europe.
OriginalsprogEngelsk
TidsskriftTicks and Tick-borne Diseases
Vol/bind10
Udgave nummer3
Sider (fra-til)533-539
ISSN1877-959X
DOI
StatusUdgivet - apr. 2019

Fingeraftryk

Tick-borne encephalitis virus
Tick-Borne Encephalitis Viruses
Denmark
Viruses
viruses
phylogeny
tick-borne encephalitis
Tick-Borne Encephalitis
ticks
Islands
Ricinus
Eastern Europe
Nymph
genome
tourists
Eastern European region
Lakes
Baltic Sea
Central European region
nymphs

Citer dette

Andersen, Nanna Skaarup ; Bestehorn, Malena ; Chitimia-Dobler, Lidia ; Kolmos, Hans Jørn ; Jensen, Per Moestrup ; Dobler, Gerhard ; Skarphédinson, Sigurdur. / Phylogenetic characterization of tick-borne encephalitis virus from Bornholm, Denmark. I: Ticks and Tick-borne Diseases. 2019 ; Bind 10, Nr. 3. s. 533-539.
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title = "Phylogenetic characterization of tick-borne encephalitis virus from Bornholm, Denmark",
abstract = "The Danish island of Bornholm in the Baltic Sea has been known as a tick-borne encephalitis (TBE) natural focus for more than 60 years. TBE in humans is diagnosed on a regular basis either in inhabitants or tourists of the island. Other areas in Denmark have been suggested as possible risk areas of TBE. Despite the long-known endemicity on Bornholm and the possibility of the virus circulating in other areas, no data on the prevalences of TBE virus (TBEV) in ticks, or adequate molecular characterization and phylogenetic studies are available for the circulating TBEV strains. This study aimed to detect TBEV in ticks collected on the island of Bornholm and other possible risk areas, with the attempt to isolate the circulating viruses for molecular and phylogenetic analysis and confirm the presence of virus in the predicted risk areas.From 2014 to 2016, 9321 I. ricinus (nymphs, females, and males) were collected by flagging 31 locations in Denmark. The ticks were pooled and tested for TBEV by qPCR. The envelope gene of the detected TBE virus strains was amplified and sequenced by RT-PCR. After successful virus isolation, whole genome sequencing was performed. Phylogenetic analysis of the obtained sequences was done by the Maximum Likelihood method.One pool of 11 females and one pool of eight males from a total of 34 tick pools collected from the northwestern shore of lake Rubins{\o}en on Bornholm tested positive, resulting in a local estimated point prevalence of 0.6{\%} [CI95{\%} 0,1–1.85{\%}] in this microfocus. We were not successful in confirming any other of the predicted TBEV-endemic areas. Alignment of the two complete E genes from Bornholm revealed identical sequences. Virus isolation and whole genome sequencing were succeeded from one of the positive samples. Phylogenetic analysis showed that the isolated virus had the closest phylogenetic relationship to TBEV sequences detected in Eastern and Central Europe.",
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author = "Andersen, {Nanna Skaarup} and Malena Bestehorn and Lidia Chitimia-Dobler and Kolmos, {Hans J{\o}rn} and Jensen, {Per Moestrup} and Gerhard Dobler and Sigurdur Skarph{\'e}dinson",
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Phylogenetic characterization of tick-borne encephalitis virus from Bornholm, Denmark. / Andersen, Nanna Skaarup; Bestehorn, Malena; Chitimia-Dobler, Lidia; Kolmos, Hans Jørn; Jensen, Per Moestrup; Dobler, Gerhard; Skarphédinson, Sigurdur.

I: Ticks and Tick-borne Diseases, Bind 10, Nr. 3, 04.2019, s. 533-539.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Phylogenetic characterization of tick-borne encephalitis virus from Bornholm, Denmark

AU - Andersen, Nanna Skaarup

AU - Bestehorn, Malena

AU - Chitimia-Dobler, Lidia

AU - Kolmos, Hans Jørn

AU - Jensen, Per Moestrup

AU - Dobler, Gerhard

AU - Skarphédinson, Sigurdur

PY - 2019/4

Y1 - 2019/4

N2 - The Danish island of Bornholm in the Baltic Sea has been known as a tick-borne encephalitis (TBE) natural focus for more than 60 years. TBE in humans is diagnosed on a regular basis either in inhabitants or tourists of the island. Other areas in Denmark have been suggested as possible risk areas of TBE. Despite the long-known endemicity on Bornholm and the possibility of the virus circulating in other areas, no data on the prevalences of TBE virus (TBEV) in ticks, or adequate molecular characterization and phylogenetic studies are available for the circulating TBEV strains. This study aimed to detect TBEV in ticks collected on the island of Bornholm and other possible risk areas, with the attempt to isolate the circulating viruses for molecular and phylogenetic analysis and confirm the presence of virus in the predicted risk areas.From 2014 to 2016, 9321 I. ricinus (nymphs, females, and males) were collected by flagging 31 locations in Denmark. The ticks were pooled and tested for TBEV by qPCR. The envelope gene of the detected TBE virus strains was amplified and sequenced by RT-PCR. After successful virus isolation, whole genome sequencing was performed. Phylogenetic analysis of the obtained sequences was done by the Maximum Likelihood method.One pool of 11 females and one pool of eight males from a total of 34 tick pools collected from the northwestern shore of lake Rubinsøen on Bornholm tested positive, resulting in a local estimated point prevalence of 0.6% [CI95% 0,1–1.85%] in this microfocus. We were not successful in confirming any other of the predicted TBEV-endemic areas. Alignment of the two complete E genes from Bornholm revealed identical sequences. Virus isolation and whole genome sequencing were succeeded from one of the positive samples. Phylogenetic analysis showed that the isolated virus had the closest phylogenetic relationship to TBEV sequences detected in Eastern and Central Europe.

AB - The Danish island of Bornholm in the Baltic Sea has been known as a tick-borne encephalitis (TBE) natural focus for more than 60 years. TBE in humans is diagnosed on a regular basis either in inhabitants or tourists of the island. Other areas in Denmark have been suggested as possible risk areas of TBE. Despite the long-known endemicity on Bornholm and the possibility of the virus circulating in other areas, no data on the prevalences of TBE virus (TBEV) in ticks, or adequate molecular characterization and phylogenetic studies are available for the circulating TBEV strains. This study aimed to detect TBEV in ticks collected on the island of Bornholm and other possible risk areas, with the attempt to isolate the circulating viruses for molecular and phylogenetic analysis and confirm the presence of virus in the predicted risk areas.From 2014 to 2016, 9321 I. ricinus (nymphs, females, and males) were collected by flagging 31 locations in Denmark. The ticks were pooled and tested for TBEV by qPCR. The envelope gene of the detected TBE virus strains was amplified and sequenced by RT-PCR. After successful virus isolation, whole genome sequencing was performed. Phylogenetic analysis of the obtained sequences was done by the Maximum Likelihood method.One pool of 11 females and one pool of eight males from a total of 34 tick pools collected from the northwestern shore of lake Rubinsøen on Bornholm tested positive, resulting in a local estimated point prevalence of 0.6% [CI95% 0,1–1.85%] in this microfocus. We were not successful in confirming any other of the predicted TBEV-endemic areas. Alignment of the two complete E genes from Bornholm revealed identical sequences. Virus isolation and whole genome sequencing were succeeded from one of the positive samples. Phylogenetic analysis showed that the isolated virus had the closest phylogenetic relationship to TBEV sequences detected in Eastern and Central Europe.

KW - Bornholm

KW - Denmark

KW - Ixodes ricinus

KW - Phylogenetic analysis

KW - Tick-borne encephalitis virus

U2 - 10.1016/j.ttbdis.2018.12.008

DO - 10.1016/j.ttbdis.2018.12.008

M3 - Journal article

VL - 10

SP - 533

EP - 539

JO - Ticks and Tick-borne Diseases

JF - Ticks and Tick-borne Diseases

SN - 1877-959X

IS - 3

ER -