Tick-transmitted co-infections among erythema migrans patients in a general practice setting in Norway: a clinical and laboratory follow-up study

Knut Eirik Eliassen*, Lukas Frans Ocias, Karen A. Krogfelt, Peter Wilhelmsson, Susanne Gjeruldsen Dudman, Åshild Andreassen, Morten Lindbak, Per Eric Lindgren

*Corresponding author

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review


Background: Erythema migrans (EM) is the most common manifestation of Lyme borreliosis. Here, we examined EM patients in Norwegian general practice to find the proportion exposed to tick-transmitted microorganisms other than Borrelia, and the impact of co-infection on the clinical manifestations and disease duration. Methods: Skin biopsies from 139/188 EM patients were analyzed using PCR for Neoehrlichia mikurensis, Rickettsia spp., Anaplasma phagocytophilum and Babesia spp. Follow-up sera from 135/188 patients were analyzed for spotted fever group (SFG) Rickettsia, A. phagocytophilum and Babesia microti antibodies, and tested with PCR if positive. Day 0 sera from patients with fever (8/188) or EM duration of ≥ 21 days (69/188) were analyzed, using PCR, for A. phagocytophilum, Rickettsia spp., Babesia spp. and N. mikurensis. Day 14 sera were tested for TBEV IgG. Results: We detected no microorganisms in the skin biopsies nor in the sera of patients with fever or prolonged EM duration. Serological signs of exposure against SFG Rickettsia and A. phagocytophilum were detected in 11/135 and 8/135, respectively. Three patients exhibited both SFG Rickettsia and A. phagocytophilum antibodies, albeit negative PCR. No antibodies were detected against B. microti. 2/187 had TBEV antibodies without prior immunization. There was no significant increase in clinical symptoms or disease duration in patients with possible co-infection. Conclusions: Co-infection with N. mikurensis, A. phagocytophilum, SFG Rickettsia, Babesia spp. and TBEV is uncommon in Norwegian EM patients. Despite detecting antibodies against SFG Rickettsia and A. phagocytophilum in some patients, no clinical implications could be demonstrated.

TidsskriftBMC Infectious Diseases
Udgave nummer1
StatusUdgivet - dec. 2021

Bibliografisk note

Funding Information:
The study was financially supported by the Independent Research Fund Denmark (Grant Number 8020-00344B), ScandTick Innovation (an EU ÖKS Interreg program) and NorthTick, an Interreg project supported by the North Sea Programme of the European Regional Development Fund of the European Union. The TBEV analyses were funded by the Norwegian Institute of Public Health.


  • Antibiotic guidelines
  • Clinical microbiology
  • General practice
  • Tick-borne infections

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