Audun Aase

Background: Persistent symptoms attributed to tick bites or tick-borne diseases are poorly understood. We estimate regionally adjusted prevalence of persistent symptoms, investigate seroprevalence (IgG) and ongoing infections, and examine associated demographic and clinical factors. Methods: Persons aged 18 years or older with persistent symptoms lasting six months or more attributed to tick bites or tick-borne diseases, were recruited into a nationwide cross-sectional study. Demographic data were recorded. Medical records were collected (February 2020 - April 2022) and reviewed for tick bites, tick-borne infections, antibiotic treatment, and clinical findings. Outcome measures included somatic symptoms (PHQ-15), fatigue (Fatigue Severity Scale), physical health (RAND-36), and affective symptoms (HAD Scale). Laboratory assessments included polymerase chain reaction (PCR) analysis of blood samples for Borrelia burgdorferi (Bb) and other known tick-borne pathogens, along with IgG antibody detection. Results: The highest prevalence of persistent symptoms attributed to tick bites or tick-borne diseases was found in southwestern Norway (0.152–0.155%); the lowest was in the north (0.033%), which also had significantly lower Bb -IgG seroprevalence (15.4% compared to the national average 37.5%). Symptom persistence was not associated with confirmed tick exposure or tick-borne infection. Somatic symptoms were associated with low physical activity and comorbidity. Fatigue and poor physical health were strongly associated with underemployment. Fatigue was also associated with depressive symptoms, low activity, sick leave, and comorbidities. Conclusions: Persistent symptoms were most prevalent in tick-endemic regions but were not associated with prior tick exposure or tick-borne infections. Symptom burden was primarily associated with comorbidities, especially physical inactivity and underemployment. Clinical trial number: Not applicable.

The approach to surveillance of Lyme borreliosis varies between countries, depending on the purpose of the surveillance system and the notification criteria used, which prevents direct comparison of national data. In Norway, Lyme borreliosis is notifiable to the Surveillance System for Communicable Diseases (MSIS). The current notification criteria include a combination of clinical and laboratory results for borrelia infection (excluding Erythema migrans) but there are indications that these criteria are not followed consistently by clinicians and by laboratories. Therefore, an evaluation of Lyme borreliosis surveillance in Norway was conducted to describe the purpose of the system and to assess the suitability of the current notification criteria in order to identify areas for improvement. The CDC Guidelines for Evaluation of Surveillance Systems were used to develop the assessment of the data quality, representativeness and acceptability of MSIS for surveillance of Lyme borreliosis. Data quality was assessed through a review of data from 1996 to 2013 in MSIS and a linkage of MSIS data from 2008 to 2012 with data from the Norwegian Patient Registry (NPR). Representativeness and acceptability were assessed through a survey sent to 23 diagnostic laboratories. Completeness of key variables for cases reported to MSIS was high, except for geographical location of exposureThe NPR-MSIS linkage identified 1047 cases in both registries, while 363 were only reported to MSIS and 3914 were only recorded in NPR. A higher proportion of cases found in both registries were recorded as neuroborreliosis in MSIS (84.4 %) than those cases found only in MSIS (20.1 %). The trend (average yearly increase or decrease in reported cases) of neuroborreliosis in MSIS was not significantly different from the trend for all other clinical manifestations recorded in MSIS in negative binomial regression (p = 0.3). The 16 surveyed laboratories (response proportion 70 %) indicated differences in testing practices and low acceptability of the notification criteria. Given the challenges associated with diagnosing Lyme borreliosis, the selected notification criteria should be closely linked with the purpose of the surveillance system. Restricting reportable Lyme borreliosis to neuroborreliosis may increase validity, while a more sensitive case definition (potentially including erythema migrans) may better reflect the true burden of disease. We recommend revising the current notification criteria in Norway to ensure that they are unambiguous for clinicians and laboratories.

Background A modified microscopy protocol (the LM-method) was used to demonstrate what was interpreted as Borrelia spirochetes and later also Babesia sp., in peripheral blood from patients. The method gained much publicity, but was not validated prior to publication, which became the purpose of this study using appropriate scientific methodology, including a control group. Methods Blood from 21 patients previously interpreted as positive for Borrelia and/or Babesia infection by the LM-method and 41 healthy controls without known history of tick bite were collected, blinded and analysed for these pathogens by microscopy in two laboratories by the LM-method and conventional method, respectively, by PCR methods in five laboratories and by serology in one laboratory. Results Microscopy by the LM-method identified structures claimed to be Borrelia- and/or Babesia in 66% of the blood samples of the patient group and in 85% in the healthy control group. Microscopy by the conventional method for Babesia only did not identify Babesia in any samples. PCR analysis detected Borrelia DNA in one sample of the patient group and in eight samples of the control group; whereas Babesia DNA was not detected in any of the blood samples using molecular methods. Conclusions The structures interpreted as Borrelia and Babesia by the LM-method could not be verified by PCR. The method was, thus, falsified. This study underlines the importance of doing proper test validation before new or modified assays are introduced.

Enterotoxigenic Escherichia coli (ETEC) is an important cause of childhood diarrhea in resource-limited regions. It is also an important cause of diarrhea in travellers to these areas. To evaluate the protective efficacy of new ETEC vaccines that are under development, there is a need to increase the capacity to undertake Phase IIB (human challenge) clinical trials and to develop suitable challenge models. An in-hospital study was performed where fasting adult volunteers were experimentally infected with 1 × 10⁶ to 1 × 10⁹ colony forming units (CFUs) of the wild-type ETEC strain TW10598, which had been isolated from a child with diarrhea in West Africa in 1997. We recorded symptoms and physical signs and measured serum immune response to the TW10598 bacterium. We included 30 volunteers with mean age 22.8 (range 19.8, 27.4) years. The most common symptoms were diarrhea (77%), abdominal pain (67%), nausea (63%), and abdominal cramping (53%). Seven subjects (23%) experienced fever, none were hypotensive. Most of the volunteers responded with a substantial rise in the level of serum IgA antibodies against the challenge strain. We established the capacity and methods for safely undertaking challenge studies to measure the efficacy of ETEC vaccine candidates in a hospital ward. Strain TW10598 elicited both clinical symptoms and an immune response across the doses given.

Waning vaccine-induced immunity againstBordetella pertussisis observed among adolescents and adults. A high incidence of pertussis has been reported in this population, which serves as a reservoir forB. pertussis. A fifth dose of reduced antigen of diphtheria-tetanus-acellular-pertussis and inactivated polio vaccine was given as a booster dose to healthy teenagers. The antibody activity againstB. pertussisantigens was measured prior to and 4 to 8 weeks after the booster by different assays: enzyme-linked immunosorbent assays (ELISAs) of IgG and IgA against pertussis toxin (PT) and filamentous hemagglutinin (FHA), IgG against pertactin (PRN), opsonophagocytic activity (OPA), and IgG binding to liveB. pertussis. There was a significant increase in the IgG activity against PT, FHA, and PRN following the booster immunization (P< 0.001). The prebooster sera showed a geometric mean OPA titer of 65.1 and IgG binding to live bacteria at a geometric mean concentration of 164.9 arbitrary units (AU)/ml. Following the fifth dose, the OPA increased to a titer of 360.4, and the IgG concentration against live bacteria increased to 833.4 AU/ml (P< 0.001 for both). The correlation analyses between the different assays suggest that antibodies against FHA and PRN contribute the most to the OPA and IgG binding.

Bordetella pertussisis the causative agent of pertussis (whooping cough). Despite high vaccination coverage, pertussis remains a significant disease in many countries. Besides vaccination, transient carriage ofBordetellaspp. or other cross-reacting organisms adds to the immunity against pertussis. However, the various immunological mechanisms conferring protection remain largely unknown. In this study, paired serum samples from 464 healthy Norwegian military recruits were collected, the first at enrolment and the second about 8 months later. The prevalence of pertussis during military service was examined by comparing the paired serum samples for immunoglobulin G (IgG) antibodies against pertussis toxin (PT) by enzyme-linked immunosorbent assay (ELISA). Seventy-eight percent of the recruits had low levels of IgG antibodies against PT in both samples. Conversely, 8.4% of the recruits demonstrated high anti-PT IgG levels in the first sample, indicative of recent pertussis prior to enrolment. One recruit experienced seroconversion, indicating pertussis during service. A subset of 248 serum samples with low, medium, and high anti-PT IgG titers were analyzed by a different ELISA kit for IgG and IgA antibodies against PT and filamentous hemagglutinin (FHA) and for opsonophagocytic activity (OPA), for induction of C3b deposition products, and for IgG binding with liveB. pertussisas the antigen. We observed high correlations between OPA and IgG against live bacteria (r= 0.83), between OPA and IgG anti-FHA (r= 0.79), between OPA and anti-PT IgG (r= 0.68), and between OPA and C3b binding (r= 0.70) (P< 0.0001 for all). Anti-PT IgA did not correlate closely with the other assays.