About the thesis:
During my PhD study, I investigated tick-borne pathogens in the sheep tick (Ixodes ricinus, “skogflått” in Norwegian) in Norway.
In the first part of the study, we found that a high proportion of ticks in Northern and Southern Norway carry the bacterium Neoehrlichia mikurensis, which causes human neoehrlichiosis. However, along the western coast, the number of infected ticks was much lower. Thus, Northern and Southern Norway are expected to be high-risk areas for neoehrlichiosis, but the risk is lower in Western Norway.
Further, we studied the prevalence of the bacterium Rickettsia helvetica in ticks in Southern Norway and found that it was uncommon but widespread.
Both N. mikurensis and R. helvetica differ significantly in prevalence between regions and countries, which might be explained by climatic factors and tick-host availability.
We also studied tick-borne bacteria in ticks collected from migrating birds in southern Norway. Although the prevalence was low, all the pathogens investigated (N. mikurensis, R. helvetica, Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato) were found. The results indicate that birds are contributors to the spread of many important tick-borne diseases.
Finally, using a novel design strategy, we developed a new PCR test for the detection of tick-borne encephalitis virus (TBEV). This test can detect a much wider range of TBEV types than previous tests, and it will be useful for monitoring the spread of new types of TBE in Norway.