Ph.d.-disputas: Benedikte Nevjen Pedersen

Benedikte Nevjen Pedersen from USN’s PhD program in Ecology will defend her thesis for the degree of PhD: New and emerging tick-borne pathogens in Ixodes ricinus ticks in Norway.

27 Nov

Praktisk informasjon

  • Dato: 27. november 2020
  • Tid: kl. 11.00 - 15.00
  • Sted: Bø, auditorium 5-115 and digitally via Zoom
  • Last ned kalenderfil

  • Påmeldingsfrist: 25. november 2020
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    Both the trial lecture and the defence will be held on Zoom due to the coronavirus situation. 

    Follow the dissertation live.
    (Link will be activated when the program starts.)


    Kl. 11.00: Trial lecture: 'Ecology aspects and transmission dynamics of mosquito-borne viral diseases in a changing climate.'

    Kl. 12.15: Public defence: Benedikte Nevjen Pedersen defends her PhD thesis: 'New and emerging tick-borne pathogens in Ixodes ricinus ticks in Norway.' 

    Evaluation committee:

    • Dr. Hein Sprong, National Institute of Public Health and Environment Centre for Infectious Disease Control, the Netherlands
    • Dr. Eva Kallio, University of Jyväskylä, Finland
    • Professor Andreas Zedrosser, USN


    Leader of the defence:

    • Associate Professor Mona Sæbø, Department of Natural Sciences and Environmental Health, USN

    Main supervisor:

    • Professor Andrew Jenkins, Department of Natural Sciences and Environmental Health, USN


    • Professor Åshild Kristine Andreassen, USN
    • Associate Professor Vivian Kjelland, University of Agder

About the thesis:

Benedikte Nevjen PedersenDuring 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.