Flåttbårne infeksjoner og selvrapporterte helseplager; en helseundersøkelse i Søgne kommune, Sør-Norge

Abstract

Background: Data on human exposure to tick-borne infections in Norway are scarce, and it is heavily debated whether tick-borne infections can cause chronic subjective health complaints. The main aims of this study were to chart somatic symptom load and seroprevalence of IgG-antibodies to tick-borne microbes in a population living in an area with high abundance of ticks, and assess if exposure to tick-borne infections was associated with increased somatic symptom load.

Materials and methods: All individuals aged 18 - 69 years with residental address in Søgne municipality (n = 7424) were invited to give a bloodsample and answer a questionnaire about their own health. Søgne is a coastal municipality in the southernmost part of Norway, and has a high abundance of ticks. The bloodsamples were analyzed for IgG-antibodies to different tick-borne microbes. The questionnaire PHQ-15 was applied to chart somatic symptom load.

Results: Moderate to severe somatic symptom load (PHQ-15 sum score > 10) was reported by 16.5 % (479/2911). The seroprevalensen of IgG-antibodies to Borrelia burgdorferi sensu lato was 22.0 % (785/3568), TBE-virus 3.1 % (45/1453) (1.4 % (6/419) among individuals not reporting vaccination against TBE-virus and/or yellow fever), Anaplasma phagocytophilum 11.0 % (159/1452), Babesia microti 2.1 % (33/1537), Bartonella henselae/B. quintana 0.1 % (2/1451) og Rickettsia helvetica/R. conorii 4.2 % (60/1445). Presence of serum IgG-antibodies to tick-borne microbes was not associated with self-reported somatic symptom load.

Conclusion: There is a high exposure to Borrelia burgdorferi sensu lato in the general adult population in Søgne, and also exposure to several other tick-borne microbes. However, the study does not support the hypothesis claiming a causal connection between tick-borne infections and subjective health complaints.