This is a case report of a 68-year-old woman, who developed malaise after an insect bite. Symptoms subsided, and over weeks progressing difficulty with walking, ataxia and universal areflexia developed. A lumbar puncture showed mononuclear pleocytosis and moderately raised protein levels with no detected viral agents. An MRI of the spinal cord showed leptomeningeal contrast attenuation distally. Serum samples were positive for anti-tick-borne encephalitis (TBE) IgM-antibodies, but not IgG, and showed seroconversion. TBE is endemic in areas of Central Europe and Scandinavia but has earlier only been shown in the eastern part of Denmark.