International Journal of Medical Microbiology 298 (2008) S1, 295–300 Genetic characterisation of a tick-borne encephalitis virus isolated from the brain of a naturally exposed monkey (Macaca sylvanus) Jochen Su¨ss a,Ã , Gerhard Dobler b , Gudrun Zo¨ller b , Sandra Essbauer b , Martin Pfeffer b , Christine Klaus a , Elisabeth M. Liebler-Tenorio a , Ellen Gelpi c , Bernhard Stark d , Helmut Hotzel a a Friedrich-Loeffler-Institute Jena, Naumburger Strasse 96a, D-07743 Jena, Germany b Department of Virology and Rickettsiology, Bundeswehr Institute of Microbiology, Munich, Germany c Institute of Neurology, Medical University of Vienna, Austria d Affenberg Salem, Salem, Germany Accepted 10 February 2008 Abstract In a recently published case study, we have described a clinical case of severe tick-borne encephalitis (TBE) in a monkey (Macaca sylvanus) after natural exposure (tick bite) in a TBE endemic area in Germany. Using histological, immunohistochemical, serological methods, and RT-PCR, the TBE virus infection was confirmed. Here, we describe the isolation of a TBE virus from the brain tissue in Vero-B4 cell cultures and the sequencing of the complete genome of that isolate. The isolated TBE virus strain (named ‘Salem’) is closely related to the Kumlinge strain or strain Neudoerfl, the prototype of the Central European TBE virus subtype. However, a total of 268 nt changes were found in comparison with TBE virus strain Neudoerfl resulting in 28 amino acid changes, none of which affecting any of the known or supposed functional regions of the viral genome. Further investigation of the distribution of viral antigen in brain tissue and characterisation of the host’s inflammatory reactions by immunohistology revealed similarities between the course of the TBE virus infection in the macaque and acute to peracute cases of TBE in humans. r 2008 Elsevier GmbH. All rights reserved. Keywords: Tick-borne encephalitis; TBE virus; Kumlinge strain; Monkey; Clinical case; Glycoprotein E; Nucleotide sequence; Phylogenetic analysis; Central nervous system Introduction Tick-borne encephalitis (TBE) is the most important viral tick-borne disease in Europe and a classical viral zoonosis. TBE virus, a flavivirus, circulates between natural hosts and the vectors, Ixodes (I.) ricinus in Central and Eastern Europe and I. persulcatus in regions east of Latvia. There are also geographical areas where both main vectors were found (Nuttall and Labuda, 1998). Based on molecular biological data, TBE virus can be classified into three subtypes, the European subtype, transmitted mainly by I. ricinus, and the Far Eastern and Siberian subtypes, transmitted mainly by I. persul- catus (Fauquet et al., 2005). The characterisation of viral isolates indicates an overlapping geographical distribu- tion of these subtypes in North-eastern Europe. ARTICLE IN PRESS www.elsevier.de/ijmm 1438-4221/$ - see front matter r 2008 Elsevier GmbH. All rights reserved. doi:10.1016/j.ijmm.2008.02.001 Ã Corresponding author. Tel.: +49 3641 804 248; fax: +49 3641 804 228. E-mail address: jochen.suess@fli.bund.de (J. Su¨ss).