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Tick-borne encephalitis virus habitats in North East Germany: reemergence of TBEV in ticks after 15 years of inactivity.

Frimmel S, Krienke A, Riebold D, Loebermann M, Littmann M, Fiedler K, Klaus C, Süss J, Reisinger EC - Biomed Res Int (2014)

Bottom Line: Using nested RT-PCR, we were able to confirm the presence of TBEV in ticks for the first time after 15 years.A phylogenetic analysis revealed a close relationship between the sequences we obtained and a TBEV sequence from Mecklenburg-East Pomerania published in 1992 and pointed to the reemergence of a natural focus of TBEV after years of low activity.Our results imply that natural foci of TBEV may either persist at low levels of activity for years or reemerge through the agency of migrating birds.

View Article: PubMed Central - PubMed

Affiliation: Department of Tropical Medicine, Infectious Diseases and Nephrology, University of Rostock Medical School, Ernst-Heydemann-Straße 6, 18057 Rostock, Germany.

ABSTRACT
The incidence of tick-borne encephalitis has risen in Europe since 1990 and the tick-borne encephalitis virus (TBEV) has been documented to be spreading into regions where it was not previously endemic. In Mecklenburg-West Pomerania, a federal state in Northern Germany, TBEV was not detectable in over 16,000 collected ticks between 1992 and 2004. Until 2004, the last human case of TBE in the region was reported in 1985. Following the occurrence of three autochthonous human cases of TBE after 2004, however, we collected ticks from the areas in which the infections were contracted. To increase the chance of detecting TBEV-RNA, some of the ticks were fed on mice. Using nested RT-PCR, we were able to confirm the presence of TBEV in ticks for the first time after 15 years. A phylogenetic analysis revealed a close relationship between the sequences we obtained and a TBEV sequence from Mecklenburg-East Pomerania published in 1992 and pointed to the reemergence of a natural focus of TBEV after years of low activity. Our results imply that natural foci of TBEV may either persist at low levels of activity for years or reemerge through the agency of migrating birds.

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Tick-collection sites from 2007, where autochthonous cases of TBE have appeared in Mecklenburg-West Pomerania since 2004 and natural TBEV foci of 1992.
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fig1: Tick-collection sites from 2007, where autochthonous cases of TBE have appeared in Mecklenburg-West Pomerania since 2004 and natural TBEV foci of 1992.

Mentions: Mecklenburg-West Pomerania had never been declared as an area of risk according to the definition of the public health authority, but few autochthonous cases and TBEV-RNA detection in ticks showed a low activity of the virus in the past: from 1960 to 1985, four human cases of TBE were reported east of the town Neustrelitz in Mecklenburg-West Pomerania [6, 14, 15], and natural foci of TBEV were detected in tick pools in North East Germany using RT-PCR in 1992 [14, 16] (Figure 1). Between 1992 and 2003, a total of 16,089 ticks tested negative for TBEV in Mecklenburg-West Pomerania and it was thought that TBEV had disappeared from this area (Health Department of the State of Mecklenburg-West Pomerania, unpublished data) [17].


Tick-borne encephalitis virus habitats in North East Germany: reemergence of TBEV in ticks after 15 years of inactivity.

Frimmel S, Krienke A, Riebold D, Loebermann M, Littmann M, Fiedler K, Klaus C, Süss J, Reisinger EC - Biomed Res Int (2014)

Tick-collection sites from 2007, where autochthonous cases of TBE have appeared in Mecklenburg-West Pomerania since 2004 and natural TBEV foci of 1992.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109299&req=5

fig1: Tick-collection sites from 2007, where autochthonous cases of TBE have appeared in Mecklenburg-West Pomerania since 2004 and natural TBEV foci of 1992.
Mentions: Mecklenburg-West Pomerania had never been declared as an area of risk according to the definition of the public health authority, but few autochthonous cases and TBEV-RNA detection in ticks showed a low activity of the virus in the past: from 1960 to 1985, four human cases of TBE were reported east of the town Neustrelitz in Mecklenburg-West Pomerania [6, 14, 15], and natural foci of TBEV were detected in tick pools in North East Germany using RT-PCR in 1992 [14, 16] (Figure 1). Between 1992 and 2003, a total of 16,089 ticks tested negative for TBEV in Mecklenburg-West Pomerania and it was thought that TBEV had disappeared from this area (Health Department of the State of Mecklenburg-West Pomerania, unpublished data) [17].

Bottom Line: Using nested RT-PCR, we were able to confirm the presence of TBEV in ticks for the first time after 15 years.A phylogenetic analysis revealed a close relationship between the sequences we obtained and a TBEV sequence from Mecklenburg-East Pomerania published in 1992 and pointed to the reemergence of a natural focus of TBEV after years of low activity.Our results imply that natural foci of TBEV may either persist at low levels of activity for years or reemerge through the agency of migrating birds.

View Article: PubMed Central - PubMed

Affiliation: Department of Tropical Medicine, Infectious Diseases and Nephrology, University of Rostock Medical School, Ernst-Heydemann-Straße 6, 18057 Rostock, Germany.

ABSTRACT
The incidence of tick-borne encephalitis has risen in Europe since 1990 and the tick-borne encephalitis virus (TBEV) has been documented to be spreading into regions where it was not previously endemic. In Mecklenburg-West Pomerania, a federal state in Northern Germany, TBEV was not detectable in over 16,000 collected ticks between 1992 and 2004. Until 2004, the last human case of TBE in the region was reported in 1985. Following the occurrence of three autochthonous human cases of TBE after 2004, however, we collected ticks from the areas in which the infections were contracted. To increase the chance of detecting TBEV-RNA, some of the ticks were fed on mice. Using nested RT-PCR, we were able to confirm the presence of TBEV in ticks for the first time after 15 years. A phylogenetic analysis revealed a close relationship between the sequences we obtained and a TBEV sequence from Mecklenburg-East Pomerania published in 1992 and pointed to the reemergence of a natural focus of TBEV after years of low activity. Our results imply that natural foci of TBEV may either persist at low levels of activity for years or reemerge through the agency of migrating birds.

Show MeSH
Related in: MedlinePlus