Phylogenetic and Virulence Analysis of Tick-Borne Encephalitis Virus Field Isolates From Switzerland

0359444 - BC 2012 RIV US eng J - Journal Article
Gaumann, R. - Růžek, Daniel - Muhlemann, K. - Strasser, M. - Beuret, C. M.
Phylogenetic and Virulence Analysis of Tick-Borne Encephalitis Virus Field Isolates From Switzerland.
Journal of Medical Virology. Roč. 83, č. 5 (2011), 853-863. ISSN 0146-6615. E-ISSN 1096-9071
R&D Projects: GA ČR GPP302/10/P438; GA MŠMT(CZ) LC06009
Institutional research plan: CEZ:AV0Z60220518
Keywords : molecular epidemiology * envelope protein * neuroinvasiveness/virulence * European subtype * Ixodes ricinus
Subject RIV: EE - Microbiology, Virology
Impact factor: 2.820, year: 2011

Tick-borne encephalitis (TBE) is an endemic disease in Switzerland, with about 110-120 reported human cases each year. In this study, the complete envelope (E) protein sequences and phylogenetic classification of 72 TBE viruses found in Ixodes ricinus ticks sampled at 39 foci throughout Switzerland were analyzed. All isolates belonged to the European subtype and were highly. Sixty-four isolates were characterized in vitro with respect to their plaque phenotype. All of six virus isolates investigated in an in vivo mouse model were highly neurovirulent (100% mortality) but exhibited a relatively low level of neuroinvasiveness, with mouse survival rates ranging from 50% to 100%. Therefore, TBE viruses circulating in Switzerland belong to the European subtype and are closely related. In vitro and in vivo surrogates suggest a high proportion of isolates with a relatively low level of virulence, which is in agreement with a hypothesized high proportion of subclinical or mild TBE infections.
Permanent Link: http://hdl.handle.net/11104/0197233