Emerging tick-borne pathogens in the Nordic countries:A clinical and laboratory follow-up study of high-risk tick-bitten individuals

Despite the presence of several microorganisms, other than Borrelia burgdorferi sensu lato (Bbsl) and TBE virus, in Ixodes ricinus ticks from the Nordic countries, data is lacking on their pathogenic potential in humans. In this study, we wanted to investigate the aetiology and clinical manifestations of tick-transmitted infections in individuals seeking medical care following a tick-bite. The sampling frame was participants of a large-scale, prospective, multi-centre, follow-up study of tick-bitten volunteers recruited in Sweden, Finland and Norway in the years 2007-2015. Participants who sought medical care during the three-month follow-up period and from whom blood samples were collected during this healthcare visit (n=92) were tested, using PCR, for exposure to spotted fever group (SFG) Rickettsia spp., Anaplasma phagocytophilum and Babesia spp. Moreover, 86 of these individuals had two serum samples, collected three months apart, tested serologically for six tick-borne microorganisms. The selected organisms-Bbsl, SFG rickettsiae, Anaplasma phagocytophilum, TBE virus, Babesia microti and Bartonella henselae-have all been detected in field-collected ticks from the Nordic countries. Medical records were reviewed and questionnaires were completed to determine clinical manifestations. We found Lyme borreliosis to be the most common tick-transmitted infection as seen in 46 (54%) of the 86 participants with available medical records. Among the 86 participants with paired sera, serological or molecular evidence of recent exposure to other microorganisms than Bbsl could be demonstrated in eight (9%). Five participants (6%) exhibited serological evidence of recent concomitant exposure to more than one tick-borne microorganism. Clinical presentations were mild with one exception (TBE). In conclusion, our data suggest a low risk of infection with tick-borne microorganisms, other than Bbsl, in immunocompetent tick-bitten persons from the examined regions, a low occurrence of co-infection and mostly mild or no overt clinical signs of infection in immunocompetent persons exposed to the studied agents.Funding Agencies|EUEuropean Union (EU) [20200422]; Swedish Research Council Branch of MedicineSwedish Research Council [K2008-58X-14631-06-3]; Medical Research Council of Southeast Sweden; County Council of Ostergotland [LIO-56191]; Independent Research Fund Denmark [8020-00344B]; Wilhelm and Else Stockmann Foundation; Foundation for Aland Medical Research of the Aland Culture Foundation</p

Cerebrospinal fluid findings in adults with acute Lyme neuroborreliosis

Presence of BB-specific antibodies in the cerebrospinal fluid (CSF) with evidence of their intrathecal production in conjunction with the white cell count in the CSF and typical clinical symptoms is the traditional diagnostic gold standard of Lyme neuroborreliosis (LNB). Few data are available on the CSF lactate concentration in European adults with the diagnosis of acute LNB. The objective of the study was to investigate the CSF changes during acute LNB. Routine CSF parameters [leukocyte count, protein, lactate and albumin concentrations, CSF/serum quotients of albumin (QAlb), IgG, IgA and IgM, and oligoclonal IgG bands] and the Borrelia burgdorferi (BB)-specific antibody index were retrospectively studied in relation to the clinical presentation in patients diagnosed with acute LNB. A total of 118 patients with LNB were categorized into the following groups according to their symptoms at presentation; group 1: polyradiculoneuritis (Bannwarth’s syndrome), group 2: isolated facial palsy and group 3: predominantly meningitic course of the disease. In addition to the CSF of patients with acute LNB, CSF of 19 patients with viral meningitis (VM) and 3 with neurolues (NL) were analyzed. There were 97 patients classified with definite LNB, and 21 as probable LNB. Neck stiffness and fever were reported by 15.3% of patients. Most of these patients were younger than 50 years. Polyradiculoneuritis was frequently found in patients older than 50 years. Lymphopleocytosis was found in all patients. Only 5 patients had a CSF lactate ≥3.5 mmol/l, and the mean CSF lactate level was not elevated (2.1 ± 0.6 mmol/l). The patients with definite LNB had significantly higher lactate levels than patients with probable LNB. Elevated lactate levels were accompanied by fever and headache. In the Reiber nomograms, intrathecal immunoglobulin synthesis was found for IgM in 70.2% followed by IgG in 19.5%. Isoelectric focussing detected an intrathecal IgG synthesis in 83 patients (70.3%). Elevated BB AIs in the CSF were found in 97 patients (82.2%). Patients with VM showed lower CSF protein concentration and CSF/serum quotients of albumin than LNB patients. In acute LNB, all patients had elevated cerebrospinal fluid (CSF) leukocyte counts. In contrast to infections by other bacteria, CSF lactate was lower than 3.5 mmol/l in all but 5 patients. The CSF findings did not differ between polyradiculoneuritis, facial palsy, and meningitis. The CSF in LNB patients strongly differed from CSF in VM patients with respect to protein concentration and the CSF/serum albumin quotient