Investigation of ticks-borne Encephalitis virus in Norway

Tick-borne encephalitis (TBE) becomes one of the most important diseases of humans in many parts of Europe and has been currently identified as a major health problem in many countries. In Norway TBE was first diagnosed in 1998 and occurred sporadically, although over the past decade the number of TBE cases has increased and parts of the southern coast have been established as endemic. TBE is a notifiable disease in Norway. According to Norwegian Surveillance System for Communicable Diseases, the annual number of reported cases of TBE in Norway has increased from 2 to 14 cases during the last ten years. The aim of the present study was to confirm the existence of TBEV endemic foci and determine the spread of TBE in different localities of Norway. The ticks were collected at nine locations along the southern coast of Norway during June-July in 2009. A total of 1542 ticks were collected. All collected ticks were identified as Ixodes ricinus. The ticks were pooled according to sampling site, development stage and sex. RNA was extracted from ticks’ pools using RNeasy Mini Plant Kit (Qiagen, Hilden, Germany). For the detection of TBEV specific RNA, primers and a probe of a quantitative real-time RT-PCR protocol according to Schwaiger and Cassinotti (2003) were used. A total of 251 pools were examined and TBEV RNA was detected in 5 pools. These results prove the presence of TBEV in four locations in southern Norway, broaden the current knowledge of tick-borne encephalitis dissemination and will help raise awareness of TBEV infections in NorwayBiologijos katedraVytauto Didžiojo universiteta