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- Hvidsten, D., et al.
(författare)
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The distribution limit of the common tick, Ixodes ricinus, and some associated pathogens in north-western Europe
- 2020
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Ingår i: Ticks and Tick-borne Diseases. - : Elsevier. - 1877-959X .- 1877-9603. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- In north-western Europe, the common tick, Ixodes ricinus, is widely established, its distribution appears to be increasing and the spread of tick-borne diseases is of increasing concern. The project Flatt i Nord (Ticks in northern Norway) commenced in spring 2009 with the intention of studying the ticks distribution and that of its pathogens in northern Norway. Several methods were used: cloth-dragging, collecting from trapped small mammals, and collecting from pets. Since 2010, the occurrence of ticks in the region of northern Norway was determined directly by cloth-dragging 167 times in 109 separate locations between the latitudes of 64 degrees N and 70 degrees N (included seven locations in the northern part of Trondelag County). The northernmost location of a permanent I. ricinus population was found to be Nordoyvagen (66.2204 degrees N, 12.59 degrees E) on the Island of Donna. In a sample of 518 nymphal and adult ticks, the Borrelia prevalence collected close to this distribution limit varied but was low (1-15 %) compared with the locations in Trondelag, south of the study area (15-27 %). Five specimens (1 %) were positive for Rickettsia helvetica. The length of the vegetation growing season (GSL) can be used as an approximate index for the presence of established populations of I. ricinus. The present study suggests that the threshold GSL for tick establishment is about 170 days, because the median GSL from 1991 to 2015 was 174-184 days at sites with permanent tick populations, showing a clear increase compared with the period 1961-1990. This apparent manifestation of climate change could explain the northward extension of the range of I. ricinus.
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| 2. |
- Barstad, Bjorn, et al.
(författare)
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Cerebrospinal fluid cytokines and chemokines in children with Lyme neuroborreliosis; pattern and diagnostic utility
- 2020
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Ingår i: Cytokine. - : ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD. - 1043-4666 .- 1096-0023. ; 130
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Tidskriftsartikel (refereegranskat)abstract
- Background: Lyme neuroborreliosis (LNB) is characterized by cerebrospinal fluid (CSF) inflammation with several cytokines/chemokines and B-lymphocytes. Clinically, LNB in children may be difficult to discriminate from non-Lyme aseptic meningitis (NLAM). We aimed to identify CSF cytokine/chemokine patterns in children with LNB, NLAM and controls and elucidate the diagnostic value of these cytokines/chemokines alone or in combination to discriminate between LNB and NLAM. Methods: Children with symptoms suggestive of LNB were included prospectively and categorized as LNB, NLAM or controls (no pleocytosis). Cytokines/chemokines in CSF were measured by multiplex bead assays and levels were compared between the three groups by nonparametric statistical tests. Previous results from the same children on the established biomarker, CXCL13, were included in the statistical analyses. The diagnostic properties of cytokines/chemokines to discriminate between LNB and NLAM were determined by receiver operating characteristic curve analyses with estimates of area under curve (AUC). To explore diagnostic properties of combinations of cytokines/chemokines, prediction models based on logistic regression were used. Results: We included 195 children with LNB (n = 77), NLAM (n = 12) and controls (n = 106). Children with LNB had higher CSF levels of CCL19, CCL22 and CXCL13 compared to NLAM and controls, whereas INF. was higher in NLAM than in LNB and controls. CXCL13 was the superior single cytokine/chemokine to discriminate LNB from NLAM (AUC 0.978). The combination CXCL13/CCL19 (AUC 0.992) may possibly improve the specificity for LNB, especially for children with moderate CXCL13 levels. Conclusions: The intrathecal immune reaction in LNB is characterized by B cell associated chemokines. Whether the combination CXCL13/CCL19 further improves discrimination between LNB and NLAM beyond the diagnostic improvements by CXCL13 alone needs to be tested in new studies.
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