Novel variants of tick-borne encephalitis virus from patient and tick samples in Norway

Novel variants of tick-borne encephalitis virus from patient and tick samples in Norway

The annual number of tick-borne encephalitis (TBE) cases in Norway has increased dramatically from 1 case in 1998 to 113 in 2023. Characterization of TBE virus (TBEV) genomes from both clinical samples and tick vectors is necessary to understand disease severity and transmission dynamics. However, c...

Full description

Saved in:
Bibliographic Details
Main Authors: Urusha Maharjan, Hilde Kristin Skudal, Naveed Asghar, Arnulf Soleng, Magnus Johansson, Heidi Elisabeth Heggen Lindstedt, Anita Koskela von Sydow, John H.-O. Pettersson, Wenche Johansen, Børre Fevang, Randi Bjerkreim, Suyog Basnet, Rose Vikse, Åshild K. Andreassen, Kristian Alfsnes
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Ticks and Tick-Borne Diseases
Subjects:
Tick-borne encephalitis virus
Flaviviruses
Whole genome sequencing
Phylogeny
Norway
Tick-borne encephalitis
Online Access:http://www.sciencedirect.com/science/article/pii/S1877959X25000652
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The annual number of tick-borne encephalitis (TBE) cases in Norway has increased dramatically from 1 case in 1998 to 113 in 2023. Characterization of TBE virus (TBEV) genomes from both clinical samples and tick vectors is necessary to understand disease severity and transmission dynamics. However, clinical samples with intact virus are rare because TBE is usually diagnosed by serology in the post-viremic phase, when the viral load is low and undetectable by molecular methods such as polymerase chain reaction (PCR). To date, Mandal-2009 is the only TBEV sequence from Norway with complete virus genome, sequenced directly from the tick vector. We used a combined approach with newly designed overlapping primer pairs and nanopore sequencing together with Sanger sequencing to obtain nearly complete TBEV genomes from both patient and tick samples from Norway. The patient had severe TBE complicated with hemophagocytic lymphohistiocytosis (HLH). The patient and tick samples were collected 16 km apart, from Telemark and Vestfold Counties, respectively. Pairwise genomic comparison showed 99.7 % identity, and phylogenetic analysis revealed that these sequences were closely related to the TBEV strain from Kumlinge in Åland, Finland, rather than to the previously published Norwegian variant Mandal-2009. These findings confirm the existence of novel TBEV variants in the endemic areas of Telemark and Vestfold Counties of Norway. Our findings highlight the need for continuous monitoring and characterization of novel TBEV genomes in Norway and Europe.
ISSN:1877-9603

Similar Items