Tick bites in healthy adults from western Norway: occurrence, risk factors, and outcomes

Abstract

The frequency of tick bites, risk factors, as well as simple outcome measures after tick bites in a healthy adult population (blood donors) from Sogn and Fjordane county situated at the western coast of Norway, was assessed. The study was based on cross-sectional data from blood donors at 4 different blood banks in the county during the period January to June 2010. Data on tick bites and potential risk factors were collected from 1213 blood donors using a questionnaire. Among participants, 65.7% had experienced tick bites during their life time, whereas 30% reported recent tick bites (during the latest 12 months). There were fewer tick bites in the eastern, inland part of the county, where the tick Ixodes ricinus is less prevalent compared to the western, coastal regions. The number of total and recent tick bites increased with the respondent's age, hours spent outdoors during summertime, educational level, ownership of domestic animals, and hunting. Women older than 50 years reported more bites than similarly aged men and younger females. Among bitten subjects, 22.7% reported ever having had a rash around a tick bite, whereas 12.7% had seen a medical doctor and 7.7% had received antibiotics owing to tick bite. Avoiding certain locations owing to a fear of tick bites was reported by 15.7% of all respondents, more women than men. In conclusion, tick bites are common in the western part of Norway. The risk of being bitten varies with age and outdoor activities, animal contact, and geography. The consequences in terms of disease seem modest.