Introduction: Lyme -borreliosis is a tickborne infectious disease that mainly occurs in coastal areas of Southern Norway. Disseminated Lyme -borreliosis is reported to the Norwegian institute for public health, whereas the skin manifestation erythema migrans (EM) is not reported. Knowledge about the occurrence of EM in Norway is consequently limited.
Objective: To determine the incidence of tick bites and EM in the out of hour services (Norwegian: legevakter) in the four counties Vestfold, Telemark, Aust-Agder and Vest-Agder in the 5-year period 2005-01-01 to 2009-12-31.
Material and methods: 25 out of hour services in the four counties were invited to the study. 14 participated (67 % of those which had technical capability). We made a targeted search through their electronic patient records (EPR) using 16 tick related keywords. All records that included one or more of the keywords where brought out and reviewed manually. Those containing information about tick bite and/or EM were analyzed and coded into five variables: 1. Tick bite present or known 2. EM present 3. Whether the patient had been to a general practitioner prior to this visit 4. Whether there had been taken blood samples for serological testing 5. Whether the patient had been referred to specialist care. The EPR search also gave information about the patients’ gender, year of birth, postal code, diagnosis given, prescribed antibiotics and date of consultation. Altogether we withdrew 13555 consultations in the coarse search, leading to 4097 relevant findings after reviewing the journal texts.
Results: We found the incidence of EM in the out of hour services in Southern Norway to be 0,82 per 1000 residents per year (Range: 0,14-2,85), with the highest incidence found in the coastal municipalities of Farsund, Bamble and Arendal, and the lowest found in the inland municipalities of Notodden and Sauherad. 89,8 % of the patients with EM were treated with antibiotics. In 62,7 % of the cases the patients got phenoxymethylpenicillin, 22,3 % got doxycycline and 1,6 % amoxicillin. The patients present with tick bite, but no EM were treated with antibiotics in 27,8% of the cases. A small majority of men visited the out of hour services with a tick bite and/or EM compared to women. Among the patients older than 40 years, there was a majority of women with EM.