Risk of Acquiring Tick Bites in South-eastern Sweden

Abstract

The incidence and the temporal pattern of tick bites were studied in a population frequently out-of-doors in a tick-endemic area in south-eastern Sweden between May 2000 and March 2001. The participants, who were well aware of tick-borne diseases, inspected their skin daily from May until September and completed a diary sheet, registering visited geographical places, time out-of-doors, observed tick bites, etc. The participants were also given questionnaires in both the initial and final stages of the study, asking questions about their earlier history of tick bites, previous tick-borne diseases and out-of-doors activities. The incidence was 0.04 [95% confidence interval (95% CI) 0.02-0.061 tick-bitten participants/10 h spent out-of-doors. In total, the participants registered 1767 tick bites, i.e. an incidence of 0.14 (95% CI 0.10-0.18) tick bites/10 h out-of-doors. Within 6 months after the registration period, 8/235 (3%) had been treated for physician-diagnosed Lyme borreliosis. In conclusion, this study found a 4% risk of being tick-bitten per 10 h spent out-of-doors. The risk of contracting Lyme borreliosis was 1/221 tick bites (0.5%, 95% CI 0.44-0.56). Thus, the results indicate a low risk of acquiring Lyme borreliosis when using daily tick checks and we underline the opinion of not recommending routine prophylactic treatment for observed tick bites.

Five decades of tick–man interaction in Denmark – an analysis

“…The drop in requests in 1999, 2000 and 2001, is likely to be a consequence of the increased access to the internet. The seasonal pattern of requests was similar to the human tick bite distribution indicated by Stjernberg and Berglund (2002) in South-eastern Sweden, which supports the idea that the requests are originating from tick bites. The symptoms of Lyme borreliosis, e.g.…”

“…Small experimental studies have been performed on the interaction between humans and ticks (e.g., Jensen 2000a; Stjernberg and Berglund 2000;Stjernberg and Berglund 2002), but to our knowledge no long term studies have been published and presumably such observations do not exist. The type of study therefore has a 'missing link' status in the knowledge of tick borne diseases.…”

“…Since the vector capacity of ticks was established more than a century ago (Smith and Kilbourne 1893) numerous studies has been performed to assess the risk that tick impose on human health. The studies can be grouped roughly into four different types depending on how evidence of tick activity was measured: (i) Samples of ticks from vegetation (Landbo and Fløng 1992;Kalsbeek and Frandsen 1996;Jensen et al 2000), (ii) Samples of ticks from animals (Humair et al 1993;Kurtenbach et al 1995;L'Hostic et al 1996;Ta¨lleklint 1996;Humair et al 1998Humair et al , 1999, (iii) Epidemiological studies of tick borne diseases from animals (Webster and Frandsen 1994;Wurm et al 1999;Zeman and Januska 1999) and humans (Hansen and Lebech 1992), and finally (iv) Samples of ticks from humans (Stjernberg and Berglund 2000;Stjernberg and Berglund 2002).…”

Prevalence and incidence of Lyme borreliosis among Slovene forestry workers during the period of tick activity

“…The prospective study in the LBendemic area in Sweden established a 0.5% risk of clinical infection with B. burgdorferi s.l. following a tick bite, in spite of a considerable infection of ticks in the area (15-26%) [31], and in a study in the USA the frequency of LB after a recognized tick bite was about 1% [32]. Thus, the risk of symptomatic or asymptomatic infection with B. burgdorferi s.l.…”

A STING from a Tick : Epidemiology, Ecology and Clinical Aspects of Lyme Borreliosis

“…men rather than women may contract more tick bites. However, a study on the risk for people to be infested by ticks in southernmost Sweden found no significant difference between men and women (Stjernberg & Berglund, 2002). A similar study on the western coast of Norway showed that women >50 years actually contracted more tick bites than similarly aged men and younger women (Hjetland et al, 2013).…”