Subjective health complaints are not associated with tick bites or antibodies to Borrelia burgdorferi sensu lato in blood donors in western Norway: a cross-sectional study

Persistent Anti-Borrelia IgM Antibodies without Lyme Borreliosis in the Clinical and Immunological Context

The aim of the study was to investigate the etiology of persistent IgM antibodies against Borrelia burgdorferi sensu lato (sl) and to analyze their association with nonspecific symptoms. The study group comprised individuals with persistent IgM antibodies in the absence of IgG. The relation between ELISA values and time elapsed since past erythema migrans (EM) was analyzed. Previous antibiotic treatments were assessed. The association between persistent IgM and nonspecific symptoms was evaluated statistically. Specificity of IgM antibodies for outer surface protein C (OspC) of B. burgdorferi sl was examined by immunoblotting. Further, we investigated the cross-reactivity with Borrelia-unrelated proteins. Fifty-nine patients (46 women; 78%) were included in the study group. The mean IgM-ELISA values did not change significantly during follow-up (median 6.2 months). The mean ELISA value in the study group was dependent on time elapsed since past EM. Nonspecific symptoms improved significantly more often in patients with lower IgM ELISA results. Persistent IgM antibodies were specific for the C-terminal PKKP motif of OspC. Cross-reacting C-terminal PKKP antigens from both human and prokaryotic origins were identified. We demonstrate that the C-terminal PKKP motif plays a main role for the reactivity of persistent Borrelia IgM toward OspC. However, cross-reactivity to other eukaryotic and/or prokaryotic antigens may hamper the specificity of OspC in the serological diagnosis of Lyme borreliosis. Lack of improvement of nonspecific symptoms was associated with higher IgM ELISA values.

IMPORTANCE The reactivity of human IgM with the outer surface protein C (OspC) of Borrelia burgdorferi sensu lato is frequently used to detect Borrelia specific IgM in commercial immunoassays, and such antibodies usually occur in the early phase of the infection. We identified a group of individuals with persistent Borrelia IgM without symptoms of Lyme borreliosis. We used their sera to demonstrate that the C-terminal epitope of OspC binds the IgM. Strikingly, we found that the same epitope occurs also in certain proteins of human and environmental origin; the latter include other bacteria and food plants. Our experimental data show that these Borrelia-unrelated proteins cross-react with the OpsC-specific IgM. This knowledge is important for the development of serologic assays for Lyme borreliosis and provides a cross-reactive explanation for the persistence of Borrelia-IgM.

Subjective health complaints and exposure to tick-borne infections in southern Norway

OBJECTIVES

Whether tick-borne infections can cause chronic subjective health complaints is heavily debated. If such a causal connection exists, one would expect to find more health complaints among individuals exposed to tick-borne infections than among non-exposed. In this study, we aimed to assess if exposure to tick-borne infections earlier in life, evaluated by examination of serum for IgG antibodies to tick-borne microbes, was associated with self-reported somatic symptom load.

MATERIALS & METHODS

All individuals with residential address in Søgne municipality in southern Norway, aged 18-69 years, were invited to participate in the study. Blood samples were analyzed for IgG antibodies to different tick-borne microbes, and somatic symptom load was charted by the Patient Health Questionnaire-15 (PHQ-15).

RESULTS

Out of 7424 invited individuals, 2968 (40.0%) were included in the study. We detected IgG antibodies to Borrelia burgdorferi sensu lato (Bb) in 22.9% (95% CI 21.4-24.4). Bb seropositive individuals reported less frequently moderate to severe somatic symptom load (ie, PHQ-15 sum score ≥ 10) than seronegative individuals (12.5% versus 17.7%, difference 5.2% [95% 2.1-8.0]). However, when adjusting for several other variables in a multivariable linear regression model, presence of serum IgG antibodies to Bb was not associated with somatic symptom load. Presence of IgG antibodies to other tick-borne microbes than Bb, or seropositivity to at least two microbes, was also not associated with somatic symptom load.

CONCLUSION

Presence of serum IgG antibodies to tick-borne microbes was not associated with self-reported somatic symptom load.

Nonspecific Symptoms in Children Referred to a Lyme Borreliosis Center

BACKGROUND

Nonspecific symptoms in children suspected of Lyme borreliosis (LB) are challenging for clinicians. We assessed whether nonspecific symptoms are more prevalent among children with positive immunoglobulin G (IgG) serology or a history of clinical LB.

METHODS

We included children (<18 years) suspected of LB who visited the Lyme Center Apeldoorn of Gelre Hospital between 2008 and 2017. Serum samples were taken, and questionnaires on nonspecific symptoms completed. Clinical data were collected from patients' medical records. The prevalence of nonspecific symptoms was compared between patients with positive versus negative IgG serology and between patients with versus without previous LB with the χ and Fisher exact tests with Bonferroni correction. A history of LB was anamnestically determined. Patients with active Lyme manifestations were excluded.

RESULTS

Included were 149 children (66% female; median age 13 years); 29 (19%) had positive IgG serology; 36 (24%) had previous LB; 12 (8%) had both. Common nonspecific symptoms were sleep disturbances (58%), severe fatigue (57%) and headache (42%). The prevalence of nonspecific symptoms was similar in children with positive versus negative IgG serology. None of the nonspecific symptoms occurred more frequently in children with previous LB compared with children without. More prevalent in children without previous LB were sleep disturbances (40 vs. 66%; P = 0.002) and tingling (6 vs. 34%; P < 0.001).

CONCLUSIONS

Nonspecific symptoms were not more prevalent in children with positive IgG serology nor in children with previous LB, where some were significantly less prevalent. Hence, questionnaires on nonspecific symptoms cannot be used to identify children for serologic testing in Lyme centers.

Association of Seropositivity to Borrelia burgdorferi With the Risk of Neuropsychiatric Disorders and Functional Decline in Older Adults: The Aging Multidisciplinary Investigation Study

Importance

Exposure to Borrelia burgdorferi (Bb) has been reported to be associated with certain neuropsychiatric disorders.

Objective

To establish the association between seropositivity to Bb and incidental neuropsychiatric disorders (eg, cognitive decline, incident dementia, and depressive symptoms) as well as functional decline.

Design, Setting, and Participants

This prospective, 6-year follow-up cohort study was conducted in a rural southwestern region of France and included 689 retired farmers 65 years or older randomly recruited from the Farmer Health Insurance System who agreed to submit a blood sample and were participants in the Aging Multidisciplinary Investigation study, an ongoing epidemiological prospective study of aging initiated in 2007. The data were analyzed from April to May 2019.

Exposures

Borrelia burgdorferi serology testing was performed in a 2-tiered approach. During the follow-up period, cognitive decline, incident dementia, depressive symptoms, and functional decline were repeatedly assessed.

Main Outcomes and Measures

Diagnosis of dementia relied on a 3-step procedure; cognitive decline was determined using the Mini-Mental State Examination and depressive symptomatology was assessed using the Center for Epidemiologic Studies Depression scale. For disability, scores on instrumental and basic activities of daily living were investigated.

Results

Of 689 participants, 432 (62.2%) were men and the mean (SD) age was 75.8 (6.4) years. The seroprevalence rate of Bb was 6.5%. At baseline, compared with Bb- participants, those who were Bb+ were older, predominantly men, and had lower depressive symptoms. No association between seropositivity and any of the studied outcomes (ie, cognitive decline, depressive symptoms, or functional decline) was found in the crude analysis and after adjusting for confounding variables. Regarding incident dementia, no increased risk was found among Bb+ participants (hazard ratio, 0.42; 95% CI, 0.1-1.17; adjusted for diverse confounders).

Conclusions and Relevance

To our knowledge, this is one of the few longitudinal studies exploring the risk of neuropsychiatric disorders and functional decline associated with exposure to Bb. Despite its limitations (eg, a lack of information if clinical manifestations of Lyme borreliosis existed, date of exposure, or treatment received), this study suggests that seropositivity to Bb is not a risk factor for incidental neuropsychiatric disorders and functional decline.

Somatic symptoms and fatigue in a Norwegian population with high exposure to ticks

BACKGROUND

It is heavily debated whether tick-borne infections cause chronic subjective health complaints. If the hypothesis of a major causal connection is true, one would expect to find more subjective health complaints in a population with high exposure to ticks than in a population with less exposure. In the current study we aimed to assess somatic symptoms and fatigue in a Norwegian population with high exposure to ticks, compare our findings to normative data, and assess predictors of somatic symptom load.

MATERIAL AND METHODS

All individuals aged 18-69 years with residential address in Søgne municipality in southern Norway were in the period June 2015 to June 2016 invited to participate in the study. Somatic symptoms were assessed by the Patient Health Questionnaire-15 (PHQ-15) and fatigue by the Fatigue Severity Scale (FSS). A multivariable regression analysis was performed to assess predictors of somatic symptom load.

RESULTS

Out of 7424 invited individuals, 2971 (40.0%) returned the questionnaire. 85.1% of 2950 responders reported exposure to tick-bite. PHQ-15 mean sum score was 5.3, and 16.5% reported moderate to severe somatic symptom load (i.e. ≥ 10). FSS mean score was 3.2, and 29.8% scored above the cut-off value for fatigue (i.e. ≥ 4.0). All gender and age groups in our study population had equal or lower mean sum score on PHQ-15 than reported in Swedish normative data, and lower mean score on FSS than reported in Norwegian normative data. In multivariable regression the following factors were associated with higher somatic symptom load (listed in order of descending beta coefficient): Anxiety and depression, number of other diseases, female gender, younger age, recruitment when visiting general practitioner's office, ≤ 6 years education after primary school, tick-bite earlier in life, erythema migrans earlier in life, less physical activity, and modern health worries.

CONCLUSION

The study population reported high exposure to tick-bites, but less or equal level of somatic symptoms and less fatigue than found in normative data. There was a weak association between somatic symptom load and exposure to tick-bite and erythema migrans, possibly related to selection bias. Our findings do not support the hypothesis of a major causal connection between tick-borne infections and subjective health complaints.

Lyme disease: diagnosis and management

Lyme disease (borreliosis) is a tick-borne bacterial infection caused by the spirochaete Borrelia burgdoferi, transmitted by hard-backed Ixodes ticks. Actual numbers of cases are increasing and it appears that the distribution across the UK is widening; however, it occurs most frequently in area of woodland, with temperate climate. It typically presents in mid to late summer. Lyme disease is a multisystem disease. The nervous system is the second most commonly affected system after the skin. Other systemic manifestations, such as carditis, keratitis, uveitis and inflammatory arthritis, rarely occur in European Lyme disease. In 2018, the National Institute for Health and Care Excellence has updated its guidelines on the diagnosis and management of Lyme disease. Here, we highlight important aspects of this guidance and provide a more detailed review of the clinical spectrum of neuroborreliosis, illustrated by cases we have seen.

Diagnosing Borreliosis

Borrelia species fall into two groups, the Borrelia burgdorferi sensu lato (Bbsl) complex, the cause of Lyme borreliosis (also known as Lyme disease), and the relapsing fever group. Both groups exhibit inter- and intraspecies diversity and thus have variations in both clinical presentation and diagnostic approaches. A further layer of complexity is derived from the fact that ticks may carry multiple infectious agents and are able to transmit them to the host during blood feeding, with potential overlapping clinical manifestations. Besides this, pathogens like Borrelia have developed strategies to evade the host immune system, which allows them to persist within the host, including humans. Diagnostics can be applied at different times during the clinical course and utilize sample types, each with their own advantages and limitations. These differing methods should always be considered in conjunction with potential exposure and compatible clinical features. Throughout this review, we aim to explore different approaches providing the reader with an overview of methods appropriate for various situations. This review will cover human pathogenic members of Bbsl and relapsing fever borreliae, including newly recognized Borrelia miyamotoi spirochetes.

Symptom load and general function among patients with erythema migrans: a prospective study with a 1-year follow-up after antibiotic treatment in Norwegian general practice

OBJECTIVE

Promptly treated erythema migrans (EM) has good prognosis. However, some patients report persistent symptoms. Do patients with EM have more symptoms than the general population? We describe individual symptoms and general function in EM-patients at time of diagnosis and one year after treatment.

DESIGN

Prospective study with 1-year follow up after treatment. Questionnaires included a modified version of the Subjective Health Complaints Inventory, comprising three additional Lyme borreliosis (LB) related symptoms. General function was assessed using a five-point scale modified from the COOP/WONCA charts.

SETTING

Norwegian general practice.

SUBJECTS

A total of 188 patients were included in a randomized controlled trial comparing three antibiotic regimens for EM, of whom 139 had complete data for this study.

MAIN OUTCOME MEASURES

Individual symptoms, symptom load and general function.

RESULTS

Mild symptoms were common, reported by 84.9% at baseline and by 85.6% at follow-up. At baseline, patients reported a mean of 5.4 symptoms, compared with 6.2 after one year. Severely bothersome symptoms and severely impaired general function were rare. Tiredness was the most reported symptom both at baseline and at follow-up. Palsy (other than facial) was the least reported symptom, but the only one with a significant increase. However, this was not associated to the EM.

CONCLUSION

The symptom load was comparable to that reported in the general population. We found an increase in symptom load at follow-up that did not significantly affect general function.

IMPLICATION

Monitoring patients' symptom loads prior to treatment reduce the probability of attributing follow-up symptoms to LB. Key points Erythema migrans has a good prognosis.Patients treated for erythema migrans have a slight increase in symptom load one year after treatment. This increase does not affect general function. The levels of subjective health complaints in patients treated for erythema migrans are comparable to the background population.