An observational study in Tick Borne Encephalitis (TBE), Lyme Borreliosis and Neoehrlichiosis, sponsored by Turku University Hospital. Recruiting at 3 sites in Finland. Open to participants aged 1 Year and older. Per ClinicalTrials.gov, last updated 2026-10-27.
Sponsored by Turku University Hospital · Observational
Ticks in Finland can carry several microbes that may infect humans. The best known tick-borne diseases are Lyme borreliosis and tick-borne encephalitis (TBE). In recent years, scientists have also found other microbes in Finnish ticks, such as Anaplasma, Rickettsia, Neoehrlichia, Borrelia miyamotoi, and Babesia. Infections caused by these microbes are called emerging tick-borne diseases. Climate change may also increase the number of ticks and expand their range further north. This could lead to more tick-borne diseases in the future.
The public health impact of these emerging infections is still unclear. Some of them may cause severe illness, especially in people with weakened immune systems or without a spleen. However, we still know little about how common these infections are, how they develop in the body, and what symptoms they cause. Some people may have no symptoms, while others may become seriously ill. Good diagnostic tests are also lacking.
More knowledge is also needed about Lyme borreliosis and TBE. Some forms of Lyme disease, such as arthritis, heart inflammation, or eye problems, may be underdiagnosed. In addition, TBE cases have increased in Finland in recent years. This study will examine the symptoms, recovery, and quality of life of patients with these infections.
Another goal is to improve laboratory diagnostics. Current tests for Lyme disease and TBE mainly detect antibodies. These tests cannot always tell when the infection occurred or distinguish a past Lyme borreliosis infection from a current one. This also makes it difficult to detect reinfections in Lyme borreliosis or TBE-infections in vaccinated individuals. By collecting samples from patients, we aim to develop better diagnostic methods.
The main goal of the study is to improve knowledge about tick-borne diseases in Finland. We will study how common emerging infections are, what symptoms they cause, and whether people can have more than one tick-borne infection at the same time. We will also examine how the immune system responds to these infections and how this relates to disease severity and recovery.
This study includes both children and adults who are being examined for a suspected tick-borne disease. Participants will be followed for six months using questionnaires at initiation, one, three, and six months. Blood samples and other samples, depending on the patient's symptoms, will be collected together with routine clinical samples. The samples will be analyzed to detect tick-borne pathogens and antibodies against them. Molecular tests (PCR) will look for the genetic material of the microbes. Researchers will also search for new biological markers of these diseases and study the immune response using advanced laboratory methods.
The study will be conducted in collaboration with the SWETICK study.
51 studies on the registry are indexed under Encephalitis, Tick-Borne; 9 are open to participants now.
This study's planned enrollment of 850 is above the median of 500 across 11 observational studies indexed under Encephalitis, Tick-Borne.
Browse Encephalitis, Tick-Borne studies →Turku University Hospital is the lead sponsor of 287 studies on the registry; 67 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Medical history: tick exposure, tick bite, splenectomy, immunosuppressive treatment (e.g. anti-CD20 or other biological/immunomodulatory drugs, cortisone corresponding to >10 mg prednisolone/day, chemotherapy, hematologic malignancy, other malignancy, rheumatologic disease)
Symptoms/clinical signs: fever after tick bite, fever of unknown origin, skin rashes (single/multiple erythema migrans, lymphocytoma, acrodermatitis chronica atrophicans or other), venous thrombosis, repeated thrombophlebitis, vasculitis, meningitis, encephalitis, myelitis, cranial nerve palsy, radiculitis, peripheral nerve involvement, mono-/oligoarthritis, carditis, ocular or otogenic disturbances of uncertain origin where medical history includes recent tick bite.
Laboratory findings in combination with suspicion of tick-borne disease: leukopenia, thrombocytopenia, anemia, elevated liver enzymes, slightly elevated erythrocyte sedimentation rate and/or C-reactive protein, pleocytosis in CSF or synovial fluid.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Clinical suspicion of tick-borne disease.
Exclusion criteria
Patients with confirmed tick-borne disease
Patients with possible but not confirmed tick-borne disease
Patients investigated for suspected tick-borne disease but diagnosed with another condition (tick-borne disease excluded)
The number of diagnosed neoehrlichiosis cases
The number of patients in whose plasma (EDTA blood sample) Neoehrlichia mikurensis nucleic acid can be detected by a nucleic acid amplification test (NAAT).
Time frame: From enrollment to the end of the follow-up at 6 months.
The number of diagnosed cases with Borrelia miyamotoi -infection
The number of patients in whose blood or cerebrospinal fluid sample Borrelia miyamotoi nucleic acid can be detected by a nucleic acid amplification test (NAAT).
Time frame: From enrollment to the end of follow-up at 6 months
The number of diagnosed babesiosis cases
The number of patients with laboratory evidence of Babesia infection in a blood sample, detected by blood smear microscopy or nucleic acid amplification test.
Time frame: From enrollment to the end of follow-up at 6 months
The number of diagnosed anaplasmosis cases
The number of patients with laboratory-confirmed Anaplasma phagocytophilum infection, demonstrated either by seroconversion in paired serum samples together with symptoms or by detection of nucleic acid in a blood sample using a nucleic acid amplification test (NAAT).
Time frame: From enrollment to the end of follow-up at 6 months
The number of diagnosed rickettsiosis cases
The number of patients with laboratory-confirmed Rickettsia spp. infection, demonstrated either by seroconversion in paired serum samples together with symptoms or by detection of nucleic acid in a blood sample using a nucleic acid amplification test (NAAT).
Time frame: From enrollment to the end of follow-up at 6 months
The number of diagnosed Lyme borreliosis cases
The number of patients diagnosed with Lyme borreliosis according to the European clinical case definitions (Stanek G, Fingerle V, Hunfeld K-P, et al. Lyme borreliosis: clinical case definitions for diagnosis and management in Europe. Clin Microbiol Infect. 2011;17(1):69-79).
Time frame: From enrollment to the end of follow-up at 6 months
The number of diagnosed tick-borne encephalitis cases
The number of patients diagnosed with tick-borne encephalitis (TBE), confirmed either by serology or by a nucleic acid amplification test (NAAT).
Time frame: From enrollment to the end of follow-up at 6 months
EuroQoL-5 Dimension Questionnaire (EQ-5D)
Difference in EQ-5D Health index between study inclusion and at the 6 month-follow-up
Time frame: 6 months
Visual Analogue Scale for Health (VAS) from 0 to 100 (100 best)
Difference between the VAS units at study inclusion and at 6 month-follow-up.
Time frame: 6 months
Plan to share: No — Finnish legislation is very strict regarding the sharing of patient data, and reliable anonymisation of the data requires expertise. Although the patient data are collected without personal identifiers, patients may still be identifiable due to the rarity of their condition. For this reason, we do not share patient-level data.
Started Apr 2025 (actual). Primary completion is estimated for Dec 2034, 116 months after the start.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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