Blood donor Borrelia burgdorferi sensu lato seroprevalence and history of tick bites at a northern limit of the vector distribution

Abstract

A-B, Lyng as G, Gray JS, Grude N. Blood donor Borrelia burgdorferi sensu lato seroprevalence and history of tick bites at a northern limit of the vector distribution. APMIS 2017; 125: 717-724.In order to study the antibody seroprevalence of the causal agent of Lyme borreliosis, Borrelia burgdorferi sensu lato (s.l.), and the history of tick bites at a geographical distribution limit of Ixodes ricinus, we compared healthy blood donors in geographically extreme regions: the borreliosis-endemic Vestfold County (59°N) and the region of northern Norway. Blood samples were screened using IgG/VlsE ELISA, and positive/borderline samples were confirmed using C6 ELISA and immunoblot assays. Also, donors completed a questionnaire consisting of several items including the places they have lived, and whether they owned any pets. The seroprevalence was 0.48% (5/1048) in northern Norway and 9.25% (48/519) in Vestfold County. Seven donors (of 1048) had experienced a single tick bite in the southern part of Nordland County (65°N) in northern Norway. This first study on B. burgdorferi s.l. antibody seroprevalence and tick bites on humans and pets in northern Norway showed that the seroprevalence of B. burgdorferi s.l. infection and the risk of tick bite in northern Norway are insignificant; the fact that only five positive IgG samples were detected underscores the very low background seroprevalence. These results suggest that so far I. ricinus has not expanded north of the previously established geographical distribution limit. Borrelia burgdorferi sensu lato (s.l.), the agent of Lyme borreliosis, is transmitted in Europe by the common tick, Ixodes ricinus. The tick is found throughout the region (1), from the southern Europe to Scandinavia except Iceland (2). Although the exact tick distribution limit in northwestern Europe has not been precisely established, it is well known that I. ricinus occurs in the northern region of Norway (3, 4). Hvidsten et al. (5) showed that northwards from the district neighbouring Brønnøy (65°28 0 N) in Nordland County, there was a negative gradient of the number of I. ricinus collected from pets. Furthermore, the prevalence of B. burgdorferi s.l. in ticks was much higher in Brøn-nøy compared with the regions north of Brønnøy: 29% and 4%, respectively. In addition to I. ricinus, two other ixodid tick species undergo a full life cycle in northern Norway: the seabird tick, Ixodes uriae, which is infected with B. burgdorferi s.l. (6), and the rodent tick, Ixodes trianguliceps, which very rarely bites humans and is not known to transmit B. burgdorferi s.l. (7). In Norway, all manifestations of Lyme borreliosis, except erythema migrans, are reported to the This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. 717

Validation of the Rule of 7’s for Identifying Children at Low-risk for Lyme Meningitis

“…17 First, we relied on Lyme disease serology to define a case of Lyme meningitis and serology may be falsely negative in early disease or remain positive after previous infection which may have resulted in patient misclassification (both under and over-diagnosis). [18][19][20][21][22][23] Second, only half of the children with aseptic meningitis had a specific pathogen identified, potentially contributing to misclassification of a child with Lyme meningitis and false-negative serology. Third, we may have missed some children with cranial neuritis because not all children had a fundoscopic examination performed by their treating providers.…”

Incidence and Prevalence of Borrelia burgdorferi Antibodies in Male Professional Football Players

“…41 In a study from Norway again using the same EIA, quite similar 77% had a positive and 82% a positive/equivocal confirmation assay. 42 Based on these differences in confirmation, it is tempting to speculate that competitive sports at such a high level may lead to an unspecific immune arousal through the sympathetic activation, which may lead to a polyclonal B-cell stimulation resulting in low titer antibodies to different antigens. These antibodies might cross react with Borrelia antigens, resulting in false-positive screening assays.…”

“…41 In a study from Norway again using the same EIA, quite similar 77% had a positive and 82% a positive/equivocal confirmation assay. 42…”

Spatial tick bite exposure and associated risk factors in Scandinavia

“…It has additionally been suggested that spatial differences in tick density can be estimated by the number of ticks per pet [ 20 ]. We know that across Europe Ixodes ricinus typically make up 90–100% of all ticks removed from humans [ 8 , 31 – 33 ]. In addition, collected ticks from dogs and cats in Norway showed that 99% was Ixodes ricinus [ 34 ], similar percentage was found also in ticks collected in Sweden [ 20 , 35 ] and Denmark [ 36 ].…”