ABSTRACT
The genomes of two Tick-borne encephalitis virus (TBEV) strains were fully sequenced and compared to those of known Hungarian strains. One was a laboratory strain (KEM-1) isolated in 1952, which had gone through hundreds of passages both on Vero cell cultures and in laboratory mice, while the other was a recent isolate (2019) from questing female ticks. The laboratory strain formed a monophyletic group with the already published 4 Hungarian strains on the evolutionary tree, located relatively close to Finnish (Kumlinge) and Russian (Absettarov) strains. This KEM-1 strain was phylogenetically distantly related both to the geographically close reference strain Neudörfl and the chronologically close Czech isolates from 1953. The 2019 isolate, KEM-195 was related to TBEV isolates from Southern Slovakia and Styria, and had the longest (328 nucleotides) deletion in its 3'-non-coding region among published sequences of strains of European subtype. Our results show that decades of laboratory passage have not altered the viral genome too much and that at least two distinct branches of TBEV strains circulate in Hungary.
Subject(s)
Encephalitis Viruses, Tick-Borne/genetics , Encephalitis, Tick-Borne/virology , Genome, Viral , Encephalitis Viruses, Tick-Borne/classification , Hungary , Phylogeny , Seasons , Time FactorsABSTRACT
Between 2003 and 2007, a yearly average of six cases of West Nile virus neuroinvasive infection were diagnosed in Hungary. In 2008, 14 cases have been confirmed by the end of October. In contrast with previous years the infection has now appeared also in the north-western part of the country which is endemic for tick-borne encephalitis.
