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Molecular epidemiology of tick‐borne encephalitis virus in Ixodes ricinus ticks in Lithuania
Author(s) -
Han Xiuqi,
Juceviciene Aurita,
Uzcategui Nathalie Y.,
BrummerKorvenkontio Henrikki,
Zygutiene Milda,
Jääskeläinen Anu,
Leinikki Pauli,
Vapalahti Olli
Publication year - 2005
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.20444
Subject(s) - tick borne encephalitis virus , virology , biology , encephalitis , virus , population , flavivirus , molecular epidemiology , ixodes ricinus , tick , phylogenetic tree , genotype , gene , genetics , medicine , environmental health
In Lithuania, 171–645 serologically confirmed cases of tick‐borne encephalitis occurred annually [Mickiene et al. (2001): Eur J Clin Microbiol Infect Dis 20:886–888] in 1993–1999, and the tick‐borne encephalitis virus (TBEV) seroprevalence in the general population was found previously to be 3.0% [Juceviciene et al. (2002): J Clin Virol 25:23–27]. To assess the risk for TBEV virus infection in Lithuania and to characterize the agent a panel of 3,234 ticks combined into 436 pools [Juceviciene et al., 2005] were tested for presence of TBEV RNA by a nested RT‐PCR targeting at the NS5 gene. Six pools were confirmed positive and the prevalence of the infected ticks was 0.2% (if one tick per pool [Juceviciene et al., 2005] was considered positive) and the proportion of positive tick pools was 1.4%. The prevalence of the infected ticks in the Panevezys, Siauliai, and Radviliskis regions (in central Lithuania) was 0.1%, 0.4%, and 1.7% corresponding with a higher TBE disease burden in these regions. The 252‐nucleotide NS5‐region amplicons, and a longer sequence (737 nucleotides) obtained from one sample from the PrM‐E gene region, were sequenced. Phylogenetic analysis of the latter showed that all western type TBEV PrM‐E sequences, including the Lithuanian strains, were monophyletic, showed no clustering and had very little variation. The NS5 sequences, although identical within one locality, did not show any mutations common to strains from the two Lithuanian regions, nor could any geographical clustering be found among western type TBEV strains from other areas. J. Med. Virol. 77:249–256, 2005. © 2005 Wiley‐Liss, Inc.