The purpose of the SWEtick project is to increase the knowledge of the various clinical presentations of emerging tick-borne diseases (eTBD), to assess their importance for human health, to develop and validate laboratory methods for diagnosis of eTBD, and to develop recommendations for knowledge-driven management of patients with suspected eTBD within the Swedish healthcare system.

Inclusion Criteria in TBD and Non-TBD groups:

• Clinical suspicion of tick-borne disease (physician's assessment based on medical history, symptoms, clinical findings and sometimes laboratory results)

Exclusion Criteria:

• Incapacitated to understand the study information and make decisions (adults and adolescents >15 years)

1. 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)
2. Symptoms/clinical signs: fever after tick bite, relapsing fever of unknown origin, skin rashes (single/multiple erythema migrans, lymphocytoma, acrodermatitis chronica atrophicans or other), venous thrombosis, repeated thrombophlebitis, meningitis, encephalitis, myelitis, cranial nerve palsy, radiculitis, peripheral nerve involvment, mono-/oligoarthritis, carditis, ocular or otogenic disturbances of uncertain origin where medical history includes recent tick bite.
3. Biochemical findings in combination with factors under a) and b): leukopenia, thrombocytopenia, anemia, elevated liver enzymes, slightly elevated erythrocyte sedimentation rate and/or C-reactive protein, pleocytosis in CSF or synovial fluid.

All IPD that underlie results in a publication can be shared after anonymization, upon request