Epidemiological and Ecological Studies of Tick-borne Encephalitis Virus

....................................................................................................................................................... 1 Populärvetenskaplig sammanfattning ........................................................................................................ 3 List of papers ................................................................................................................................................ 5 Introduction .................................................................................................................................................. 7 Evolutionary perspectives on parasites and disease ................................................................................ 7 The Tick ..................................................................................................................................................... 9 Life cycle ................................................................................................................................................ 9 The virus .................................................................................................................................................. 11 Replication .......................................................................................................................................... 13 Subtype distribution ........................................................................................................................... 13 Quasispecies........................................................................................................................................ 15 Vector-host transmission .................................................................................................................... 15 Prevalence in ticks ............................................................................................................................... 17 The disease.............................................................................................................................................. 19 History and present epidemiological situation ................................................................................... 19 Pathogenesis ....................................................................................................................................... 21 Clinical picture ..................................................................................................................................... 22 Diagnosis ............................................................................................................................................. 23 Treatment ........................................................................................................................................... 24 Vaccine ................................................................................................................................................ 24 Aims ............................................................................................................................................................ 26 Materials and methods .............................................................................................................................. 27 Ethics ....................................................................................................................................................... 28 The tick-borne diseases STING study ...................................................................................................... 29 Questionnaires ........................................................................................................................................ 31 Tick photo and measurement ................................................................................................................. 31 Development of RNA extraction from ticks ............................................................................................ 32 cDNA synthesis ........................................................................................................................................ 33 Development of real-time PCR for detection and quantification of TBEV ............................................. 33 Extraction and real-time PCR controls .................................................................................................... 36 Cloning .................................................................................................................................................... 36 In vitro transcription ............................................................................................................................... 37 Sequencing and phylogenetic analysis ................................................................................................... 37 Serological methods ................................................................................................................................ 37 Statistics .................................................................................................................................................. 38 Summary of results .................................................................................................................................... 39 Interactions between ticks and humans ................................................................................................. 39 TBEV in ticks detached from humans ..................................................................................................... 42 Dose response of vaccination in older individuals .................................................................................. 44 Quasispecies of TBEV in blood-feeding ticks .......................................................................................... 47 Concluding remarks .................................................................................................................................... 50 Future perspectives .................................................................................................................................... 52 Acknowledgements .................................................................................................................................... 53 References .................................................................................................................................................. 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