Surveillance perspective on Lyme borreliosis across the European Union and European Economic Area

Lyme borreliosis in pediatric population: Clinical, diagnostic and therapeutic features

INTRODUCTION

Lyme borreliosis (LB) in the paediatric population is an understudied entity with certain peculiarities. The objective of this study is to describe the characteristics of paediatric patients with LB, and their diagnostic and therapeutic processes.

METHODS

Descriptive and retrospective study in patients up to 14 years old with suspected or confirmed LB between 2015 and 2021.

RESULTS

A total of 21 patients were studied: 18 with confirmed LB (50% women; median age 6.4 years old) and 3 false positive of the serology. Clinical features in the 18 patients with LB were: neurological (3, neck stiffness; 6, facial nerve palsy), dermatological (6, erythema migratory), articular (1), and non-specific manifestations (5). Serological diagnosis was confirmatory in 83.3% of cases. A total of 94.4% patients received antimicrobial treatment (median duration, 21 days). All recovered with resolution of symptoms.

CONCLUSIONS

LB diagnosis is difficult in the paediatric population and presents clinical and therapeutic peculiarities, with favourable prognosis.

Identifying Potential Lyme Disease Cases Using Self-Reported Worldwide Tweets: Deep Learning Modeling Approach Enhanced With Sentimental Words Through Emojis

BACKGROUND

Lyme disease is among the most reported tick-borne diseases worldwide, making it a major ongoing public health concern. An effective Lyme disease case reporting system depends on timely diagnosis and reporting by health care professionals, and accurate laboratory testing and interpretation for clinical diagnosis validation. A lack of these can lead to delayed diagnosis and treatment, which can exacerbate the severity of Lyme disease symptoms. Therefore, there is a need to improve the monitoring of Lyme disease by using other data sources, such as web-based data.

OBJECTIVE

We analyzed global Twitter data to understand its potential and limitations as a tool for Lyme disease surveillance. We propose a transformer-based classification system to identify potential Lyme disease cases using self-reported tweets.

METHODS

Our initial sample included 20,000 tweets collected worldwide from a database of over 1.3 million Lyme disease tweets. After preprocessing and geolocating tweets, tweets in a subset of the initial sample were manually labeled as potential Lyme disease cases or non-Lyme disease cases using carefully selected keywords. Emojis were converted to sentiment words, which were then replaced in the tweets. This labeled tweet set was used for the training, validation, and performance testing of DistilBERT (distilled version of BERT [Bidirectional Encoder Representations from Transformers]), ALBERT (A Lite BERT), and BERTweet (BERT for English Tweets) classifiers.

RESULTS

The empirical results showed that BERTweet was the best classifier among all evaluated models (average F1-score of 89.3%, classification accuracy of 90.0%, and precision of 97.1%). However, for recall, term frequency-inverse document frequency and k-nearest neighbors performed better (93.2% and 82.6%, respectively). On using emojis to enrich the tweet embeddings, BERTweet had an increased recall (8% increase), DistilBERT had an increased F1-score of 93.8% (4% increase) and classification accuracy of 94.1% (4% increase), and ALBERT had an increased F1-score of 93.1% (5% increase) and classification accuracy of 93.9% (5% increase). The general awareness of Lyme disease was high in the United States, the United Kingdom, Australia, and Canada, with self-reported potential cases of Lyme disease from these countries accounting for around 50% (9939/20,000) of the collected English-language tweets, whereas Lyme disease-related tweets were rare in countries from Africa and Asia. The most reported Lyme disease-related symptoms in the data were rash, fatigue, fever, and arthritis, while symptoms, such as lymphadenopathy, palpitations, swollen lymph nodes, neck stiffness, and arrythmia, were uncommon, in accordance with Lyme disease symptom frequency.

CONCLUSIONS

The study highlights the robustness of BERTweet and DistilBERT as classifiers for potential cases of Lyme disease from self-reported data. The results demonstrated that emojis are effective for enrichment, thereby improving the accuracy of tweet embeddings and the performance of classifiers. Specifically, emojis reflecting sadness, empathy, and encouragement can reduce false negatives.

Citizen Science on Lyme Borreliosis in Spain Reveals Disease-Associated Risk Factors and Control Interventions

Background: Lyme borreliosis (LB) caused by Borrelia burgdorferi sensu lato complex spirochetes is one of the tick-borne diseases with high prevalence and social/economic burden in the United States, Spain, and other European countries. The objective is to address limited information available about the incidence, prevalence, and symptoms of LB, current prevention, and treatment interventions that are not adequately focused and thus not very effective against this disease. Methods: To address these limitations, in this study, we used a citizen science approach to evaluate the LB-associated risks and implementation of control interventions in Spain. A total of 405 participants in the survey were included in the analysis. Responses to the questionnaire were received during January-July 2022. The questionnaire contained qualitative and quantitative questions. Homogeneity among binary variables was analyzed using a Fisher's exact test. Results: Despite limitations of the study associated with response to the questionnaire and information on tick species, the results evidenced the effect of factors such as age, gender, tick bites, disease clinical signs, comorbidities such as alpha-gal syndrome, health care services, and treatment effectiveness affecting LB. Conclusions: The main conclusions of the study highlight the need for better surveillance of tick infestations, pathogen infection, and diagnosis of LB and related comorbidities. To advance in disease prevention, diagnosis, and treatment, new interventions need to be developed and implemented in both public and private health care services. Providing access to these results to the society, health care system, and scientists is important to further advance in disease surveillance, diagnosis, control, and prevention.

Identification of a novel transport system in Borrelia burgdorferi that links the inner and outer membranes

Borrelia burgdorferi, the spirochete that causes Lyme disease, is a diderm organism that is similar to Gram-negative organisms in that it contains both an inner and outer membrane. Unlike typical Gram-negative organisms, however, B. burgdorferi lacks lipopolysaccharide (LPS). Using computational genome analyses and structural modeling, we identified a transport system containing six proteins in B. burgdorferi that are all orthologs to proteins found in the lipopolysaccharide transport (LPT) system that links the inner and outer membranes of Gram-negative organisms and is responsible for placing LPS on the surface of these organisms. While B. burgdorferi does not contain LPS, it does encode over 100 different surface-exposed lipoproteins and several major glycolipids, which like LPS are also highly amphiphilic molecules, though no system to transport these molecules to the borrelial surface is known. Accordingly, experiments supplemented by molecular modeling were undertaken to determine whether the orthologous LPT system identified in B. burgdorferi could transport lipoproteins and/or glycolipids to the borrelial outer membrane. Our combined observations strongly suggest that the LPT transport system does not transport lipoproteins to the surface. Molecular dynamic modeling, however, suggests that the borrelial LPT system could transport borrelial glycolipids to the outer membrane.

Seroepidemiology of Borrelia burgdorferi s.l. among German National Cohort (NAKO) Participants, Hanover

Lyme borreliosis is the leading tick-related illness in Europe, caused by Borrelia Burgdorferi s.l. Lower Saxony, Germany, including its capital, Hanover, has a higher proportion of infected ticks than central European countries, justifying a research focus on the potential human consequences. The current knowledge gap on human incident infections, particularly in Western Germany, demands serological insights, especially regarding a potentially changing climate-related tick abundance and activity. We determined the immunoglobulin G (IgG) and immunoglobulin M (IgM) serostatuses for 8009 German National Cohort (NAKO) participants from Hanover, examined in 2014-2018. We used an enzyme-linked immunosorbent assay (ELISA) as the screening and a line immunoblot as confirmation for the Borrelia Burgdorferi s.l. antibodies. We weighted the seropositivity proportions to estimate general population seropositivity and estimated the force of infection (FOI). Using logistic regression, we investigated risk factors for seropositivity. Seropositivity was 3.0% (IgG) and 2.1% (IgM). The FOI varied with age, sharply increasing in participants aged ≥40 years. We confirmed advancing age and male sex as risk factors. We reported reduced odds for seropositivity with increasing body mass index and depressive symptomatology, respectively, pointing to an impact of lifestyle-related behaviors. The local proportion of seropositive individuals is comparable to previous estimates for northern Germany, indicating a steady seroprevalence.

When the patient is making the (wrong?) diagnosis: a biographical approach to patients consulting for presumed Lyme disease

BACKGROUND

Media coverage of Lyme disease (LD) has led to an increase in consultations for presumed LD in Europe. However, LD is confirmed in only 10%-20% of patients, with a significant number remaining in a diagnostic dead-end.

OBJECTIVES

To reach a deeper understanding of how patients themselves contribute to the diagnostic process. To describe the genesis of the LD hypothesis in care pathways.

METHODS

In 2019, 30 patients from a prospective cohort consulting in the infectious diseases department at University Hospital in Marseille for presumed LD were recruited for semistructured interviews. The inclusion criteria were: suffering from subjective symptoms for 6 months, no clinical or paraclinical argument suggesting current LD. The patients' medical trajectories were collected using a biographical approach.

RESULTS

The diagnosis of LD was primarily triggered by identification with personal testimonies found on the Internet. Most of patients were leading their own diagnostic investigation. The majority of participants were convinced they had LD despite the lack of medical evidence and the scepticism of their referring GP.

CONCLUSION

GPs should first systematically explore patients' aetiologic representations in order to improve adherence to the diagnosis especially in the management of medically unexplained symptoms. Long COVID-19 syndrome challenge offers an opportunity to promote active patient involvement in diagnosis.

A One Health Evaluation of the Surveillance Systems on Tick-Borne Diseases in the Netherlands, Spain and Italy

Simple Summary

Ixodid ticks and tick-borne diseases are expanding their geographical range, but surveillance activities vary among countries. We analysed the surveillance systems in place in the Netherlands, Spain and Italy, to identify ideal elements to monitor tick-borne diseases, by using a One Health evaluation protocol. We identified differences among the three surveillance systems, with the Dutch initiative showing a high level of transdisciplinary collaboration, good identification of the actors and engagement of the public in research and education. Measurable outcomes have been generated, such as the reduction in tick bites and the discovery of new pathogens and tick species. In Italy and Spain, surveillance systems are based on compulsory notification to health authorities; legislation seems relevant but law enforcement alongside the availability of economic resources is rather fragmented and limited to the most severe diseases. The non-scientific community is marginally considered and collaborations are limited to local initiatives. Research activities in both countries have mostly contributed to gaining knowledge on the distribution of tick species and the discovery of new pathogens. Although all TBD surveillance plans comply with the EU regulations, the initiatives characterised by trans-disciplinary collaboration may be more effective for the surveillance and prevention of tick-transmitted diseases.

Abstract

To identify ideal elements for the monitoring and prevention of tick-borne diseases (TBD), we analysed the surveillance systems in place in the Netherlands, Spain and Italy. We applied a semi-quantitative evaluation to identify outcomes and assess the degree of One Health implementation. Differences emerged in the surveillance initiatives, as well as the One Health scores. The Dutch surveillance is dominated by a high level of transdisciplinary and trans-sectoral collaboration, enabling communication and data sharing among actors. Different project-based monitoring, research and educational activities are centrally coordinated and the non-scientific community is actively involved. All this yielded measurable health outcomes. In Italy and Spain, TBD surveillance and reporting systems are based on compulsory notification. Law enforcement, alongside dedicated time and availability of economic resources, is fragmented and limited to the most severe health issues. Veterinary and human medicine are the most involved disciplines, with the first prevailing in some contexts. Stakeholders are marginally considered and collaborations limited to local initiatives. Research activities have mostly contributed to gaining knowledge on the distribution of tick vectors and discovery of new pathogens. Although all TBD surveillance plans comply with EU regulations, initiatives characterised by transdisciplinary collaboration may be more effective for the surveillance and prevention of TBD.

Epidemiology of Lyme Disease

Lyme disease is the most common vector-borne illness in North America and Europe. The etiologic agent, Borrelia burgdorferi sensu lato, is transmitted to humans by certain species of Ixodes ticks, which are found widely in temperate regions of the Northern hemisphere. Clinical features are diverse but death is rare. The risk of human infection is determined by the distribution and abundance of vector ticks, ecologic factors influencing tick infection rates, and human behaviors that promote tick bite. Rates of infection are highest among children aged 5 to 15 years and adults aged more than 50 years. In the northeastern United States where disease is most common, exposure occurs primarily in areas immediately around the home. Knowledge of disease epidemiology is important for patient management and proper diagnosis.

Meta-analysis: A useful tool to assess infection prevalence and disease ecology of Borrelia burgdorferi sensu lato in nymphal ticks in North-Western Europe with recommendations for a standardised approach to future studies

Lyme borreliosis is a vector-borne disease of concern in Europe. While neuroborreliosis data are reportable at EU level, it can nevertheless be difficult to make comparisons of disease risk between neighbouring countries. This study used proportion meta-analyses to compare environmental markers of disease risk between woodland sites in two countries in North-Western Europe (Ireland, Scotland). 73 site-visits from 12 publications were analysed, resulting in a significantly higher pooled nymphal infection prevalence (NIP) in Ireland (8.2% (95% CI: 5.9–11.4%)) than Scotland (1.7%(95% CI 1.1–2.5%)). All other analysed parameters of disease risk were also higher in Ireland than Scotland. Subgroup-meta-analyses and meta-regressions were used to assess the influence of environmental variables on NIP. NIP increased significantly with increasing woodland size in Ireland, but not Scotland, which may be accounted for by Ireland's highly fragmented landscape.

Assuming the application of strict inclusion/exclusion criteria and control of variables, proportion meta-analysis can provide useful insights in disease ecology, as it allows for the achievement of high study powers incorporating samples collected across multiple sites, which is otherwise often a prohibitively difficult and resource-heavy feat in environmental studies in disease ecology. A standardised approach to data collection is recommended to achieve more robust meta-analyses in future in conjunction with additional research on environmental factors affecting Lyme borreliosis risk in Europe, particularly pertaining to the impact of host species on NIP.

The Diagnostic Challenges and Clinical and Serological Outcome in Patients Hospitalized for Suspected Lyme Neuroborreliosis

The aim of our study was to evaluate the differential diagnosis and clinical/serological outcome to antibiotic treatment in patients hospitalized for suspected Lyme neuroborreliosis (LNB). A prospective study included patients hospitalized in a Romanian hospital between March 2011 and October 2012 with neurological symptoms, positive laboratory tests for Borrelia burgdorferi, cerebrospinal fluid (CSF) analysis, and no previous treatment for LNB. A questionnaire was completed for each patient at admission, at the end of treatment, and 3 months later. Patients were treated with antibiotic therapy (ceftriaxone/cefotaxime), irrespective of CSF analysis results. A symptomatic scoring scale was used for the follow-up. Out of the 42 patients included, no patient fulfilled criteria for definite LNB; 7 patients were classified as possible LNB; and in 33 patients, LNB was excluded. Two patients could not be classified (insufficient amount of CSF). Clinical follow-up suggested a better response to therapy in the group of patients with possible LNB than in the group with LNB excluded. The patients’ differential diagnosis and serological follow-up are presented. Patients investigated for suspected LNB present diverse clinical manifestations and comorbidities that complicate differential diagnosis. LNB may be misdiagnosed if CSF analysis is not performed.

Comparison of national surveillance systems for Lyme disease in humans in Europe and North America: a policy review

BACKGROUND

Lyme disease incidence is increasing in Europe, the USA, and Canada. In 2010, a comparison of surveillance systems for Lyme disease (LD) in humans in 28 European countries showed that systems highly varied, making epidemiological comparisons difficult. Details by country were not published. In 2018, one of LD clinical manifestations, neuroborreliosis, was added under European Union (EU) surveillance to standardise definitions. In this study, we identified and compared, 10 years after the European inventory, the characteristics of national surveillance systems and policies for LD in humans, with additional countries.

METHODS

Thirty-four European and North American countries were included. Information on national "traditional" systems (which compile data reported by clinicians and laboratories) and "public participatory" websites and mobile applications (which collect information directly from the public) were searched in MEDLINE, a systematic evidence map, and Google. An existing framework on LD surveillance was adapted to capture information on the administration level, indicators, reporting entities, coverage, and obligation to report.

RESULTS

A surveillance system was found for 29 (85%) countries. Twenty-four had a traditional system alone, one had a public participatory system alone, and the remaining had both. Among countries with traditional systems, 23 (82%) administered them at the national level. Nineteen (68%) required mandatory reporting. Sixteen (57%) used both clinicians and laboratories as reporting entities. Eighteen (64%) employed case definitions, most of which considered both neuroborreliosis and erythema migrans (n = 14). Others monitored the number of positive laboratory tests and/or patient consultations. Public participatory systems were only implemented in countries employing either also sentinels or voluntary surveys, or no traditional system, suggesting their use as a complementary tool. Only 56% of EU countries had neuroborreliosis as an indicator.

CONCLUSION

The situation remains similar to 2010 with persisting heterogeneity between systems, suggesting that countries prioritise different surveillance objectives for LD. Without a common indicator in Europe, it is difficult to get a clear epidemiological picture. We discuss four factors that potentially influence LD surveillance strategies: perceptions of severity, burden on resources, two-way communication, and the medical conflicts about LD. Addressing these with countries might help moving towards the adoption of common practices.

Predictive Model of Lyme Disease Epidemic Process Using Machine Learning Approach

Lyme disease is the most prevalent tick-borne disease in Eastern Europe. This study focuses on the development of a machine learning model based on a neural network for predicting the dynamics of the Lyme disease epidemic process. A retrospective analysis of the Lyme disease cases reported in the Kharkiv region, East Ukraine, between 2010 and 2017 was performed. To develop the neural network model of the Lyme disease epidemic process, a multilayered neural network was used, and the backpropagation algorithm or the generalized delta rule was used for its learning. The adequacy of the constructed forecast was tested on real statistical data on the incidence of Lyme disease. The learning of the model took 22.14 s, and the mean absolute percentage error is 3.79%. A software package for prediction of the Lyme disease incidence on the basis of machine learning has been developed. Results of the simulation have shown an unstable epidemiological situation of Lyme disease, which requires preventive measures at both the population level and individual protection. Forecasting is of particular importance in the conditions of hostilities that are currently taking place in Ukraine, including endemic territories.

The evolving story of Borrelia burgdorferi sensu lato transmission in Europe

Beside mosquitoes, ticks are well-known vectors of different human pathogens. In the Northern Hemisphere, Lyme borreliosis (Eurasia, LB) or Lyme disease (North America, LD) is the most commonly occurring vector-borne infectious disease caused by bacteria of the genus Borrelia which are transmitted by hard ticks of the genus Ixodes. The reported incidence of LB in Europe is about 22.6 cases per 100,000 inhabitants annually with a broad range depending on the geographical area analyzed. However, the epidemiological data are largely incomplete, because LB is not notifiable in all European countries. Furthermore, not only differ reporting procedures between countries, there is also variation in case definitions and diagnostic procedures. Lyme borreliosis is caused by several species of the Borrelia (B.) burgdorferi sensu lato (s.l.) complex which are maintained in complex networks including ixodid ticks and different reservoir hosts. Vector and host influence each other and are affected by multiple factors including climate that have a major impact on their habitats and ecology. To classify factors that influence the risk of transmission of B. burgdorferi s.l. to their different vertebrate hosts as well as to humans, we briefly summarize the current knowledge about the pathogens including their astonishing ability to overcome various host immune responses, regarding the main vector in Europe Ixodes ricinus, and the disease caused by borreliae. The research shows, that a higher standardization of case definition, diagnostic procedures, and standardized, long-term surveillance systems across Europe is necessary to improve clinical and epidemiological data.

Seroprevalence of antibodies against Borrelia burgdorferi sensu lato in healthy blood donors in Romania: an update

BACKGROUND

The Borrelia burgdorferi sensu lato (s.l.) genogroup is the causative agent responsible for Lyme borreliosis, a common tick-borne infectious disease in some temperate regions of the Northern Hemisphere. In humans, the clinical manifestations of Lyme borreliosis vary from dermatological infection to severe systemic manifestations. In Romania, data on the seroprevalence of Lyme borreliosis and associated risk factors are scarce and outdated, as the only seroprevalence study with a large dataset was published more than 20 years ago. Therefore, the aim of the present study was to evaluate the seroprevalence for Borrelia burgdorferi s.l. in healthy blood donors from six Romanian counties and identify the associated risk factors.

METHODS

The study was conducted among 1200 healthy blood donors aged between 18 and 65 years during November 2019 and September 2020 from six counties in the northwestern and central parts of Romania. A two-tiered testing strategy was applied. Positive and equivocal immunoenzymatic test results for IgG and IgM antibodies were further confirmed by Western blot.

RESULTS

Serum samples from 20% of the blood donors had positive or equivocal IgG and IgM ELISA index values. In total, 2.3% of the serum samples for IgG and 1.8% for IgM were positive by Western blot. The seroprevalence for both antibodies varied between 1.5% (Satu-Mare) and 6.5% (Bistrița-Năsăud) in the six counties investigated. The highest seroprevalence was observed in men (4.7%), in blood donors performing their professional activities outdoors (4.2%), and in those aged  ≥ 56 years (8%).

CONCLUSIONS

These findings confirm the presence of specific IgG and IgM antibodies to B. burgdorferi s.l. among healthy blood donors from Romania. Furthermore, potential risk factors, such as gender, age, and behavior, associated with the presence of positive B. burgdorferi s.l. antibodies among healthy blood donors were identified.

Occurrence and Identification of Ixodes ricinus Borne Pathogens in Northeastern Italy

In Europe, Ixodes ricinus is the main vector for tick-borne pathogens (TBPs), the most common tick species in Italy, particularly represented in pre-alpine and hilly northern areas. From 2011 to 2017, ticks were collected by dragging in Belluno province (northeast Italy) and analyzed by molecular techniques for TBP detection. Several species of Rickettsia spp. and Borrelia spp. Anaplaspa phagocitophilum, Neoerlichia mikurensis and Babesia venatorum, were found to be circulating in the study area carried by I. ricinus (n = 2668, all stages). Overall, 39.1% of screened pools were positive for at least one TBP, with a prevalence of 12.25% and 29.2% in immature stages and adults, respectively. Pathogens were detected in 85% of the monitored municipalities, moreover the presence of TBPs varied from one to seven different pathogens in the same year. The annual TBPs prevalence fluctuations observed in each municipality highlights the necessity of performing continuous tick surveillance. In conclusion, the observation of TBPs in ticks remains an efficient strategy for monitoring the circulation of tick-borne diseases (TBDs) in a specific area.

In vitro efficacy of antibiotics against different Borrelia isolates

In the present study, the effectiveness of six antimicrobial agents have been tested against 24 borrelia strains isolated from Ixodes ricinus ticks (11 Borrelia lusitaniae, eight Borrelia afzelii, three Borrelia garinii and two Borrelia valaisiana) and one B. lusitaniae strain isolated from human skin. The minimum inhibitory concentration range of antimicrobial agents was as follows: amoxicillin, 0.125-2 mg/L; doxycycline, 0.125-1 mg/L, ceftriaxone, 0.016-0.063 mg/L; cefuroxime, 0.063-1 mg/L; azithromycin, 0.0017-0.11 mg/L; amikacin 32-512 mg/L. Potentially pathogenic B. lusitaniae and B. valaisiana species were more susceptible to amoxicillin and azithromycin than pathogenic B. afzelii and B. garinii (P < 0.05); B. garinii, B. lusitaniae and B. valaisiana were more susceptible to doxycycline than B. afzelii (P < 0.05) while all species showed same susceptibility to ceftriaxone and cefuroxime (P > 0.05). This study is the first report on in vitro susceptibility of isolates from Serbia to antimicrobial agents and the first report on susceptibility of larger number of isolates of potentially pathogenic species B. lusitaniae. We showed that antimicrobial agents in vitro inhibit growth of borrelia strains very effectively, indicating the potential of their equally beneficial use in the treatment of Lyme borreliosis.

Lyme Neuroborreliosis: Mechanisms of B. burgdorferi Infection of the Nervous System

Lyme borreliosis is the most prevalent tick-borne disease in the United States, infecting ~476,000 people annually. Borrelia spp. spirochetal bacteria are the causative agents of Lyme disease in humans and are transmitted by Ixodes spp ticks. Clinical manifestations vary depending on which Borrelia genospecies infects the patient and may be a consequence of distinct organotropism between species. In the US, B. burgdorferi sensu stricto is the most commonly reported genospecies and infection can manifest as mild to severe symptoms. Different genotypes of B. burgdorferi sensu stricto may be responsible for causing varying degrees of clinical manifestations. While the majority of Lyme borreliae-infected patients fully recover with antibiotic treatment, approximately 15% of infected individuals experience long-term neurological and psychological symptoms that are unresponsive to antibiotics. Currently, long-term antibiotic treatment remains the only FDA-approved option for those suffering from these chronic effects. Here, we discuss the current knowledge pertaining to B. burgdorferi sensu stricto infection in the central nervous system (CNS), termed Lyme neuroborreliosis (LNB), within North America and specifically the United States. We explore the molecular mechanisms of spirochete entry into the brain and the role B. burgdorferi sensu stricto genotypes play in CNS infectivity. Understanding infectivity can provide therapeutic targets for LNB treatment and offer public health understanding of the B. burgdorferi sensu stricto genotypes that cause long-lasting symptoms.

Evaluation of factors influencing tick bites and tick-borne infections: a longitudinal study

BACKGROUND

Various tick-borne infections like borreliosis and rickettsiosis pose a health risk to humans in many parts of the world. We investigated seroprevalence of and seroconversion to Borrelia burgdorferi and Rickettsia spp. and relation to tick-bites, weather and clinical manifestations in Denmark.

METHODS

Blood donors were enrolled at the Hospital of Southern Jutland in June-July with follow-up November-February of 2018 and 2019. Blood samples were collected, and a questionnaire regarding tick bites, potential exposures and symptoms was completed at each visit. Samples were tested for presence of IgM and IgG antibodies directed against B. burgdorferi and Rickettsia spp. using R. helvetica and R. felis as antigens. Data were examined for correlation between tick bites, serological results, potential exposures and symptoms.

RESULTS

Two-hundred and fourteen (93 follow-ups) and 130 (38 follow-ups) blood donors were included in 2018 and 2019, respectively. The total borrelia seroconversion rate was 6.3% (CI 2.1-10.5), while the prevalence of IgM and IgG antibodies was 7.8% (CI 4.9-10.6) and 6.7% (CI 4-9.3), respectively. Seroconversion to Rickettsia spp. was detected in one participant. Tick bites and seroconversion were not significantly associated with the reported unspecific symptoms, but unspecific symptoms were common in the study population. There was no significant difference in number of tick bites or seroconversion/prevalence between seasons with highly alternating weather.

CONCLUSIONS

Results suggest that weather conditions in an individual year have a limited impact. Anti-Borrelia-antibodies do not seem to persist in serum for several years. Rickettsiosis is of limited concern in Denmark.

Exploratory Space-Time Analyses of Reported Lyme Borreliosis Cases in France, 2016-2019

In recent decades, the incidence of Lyme borreliosis (LB) in Europe seems to have increased, underpinning a growing public health concern. LB surveillance systems across the continent are heterogeneous, and the spatial and temporal patterns of LB reports have been little documented. In this study, we explored the spatio-temporal patterns of LB cases reported in France from 2016 to 2019, to describe high-risk clusters and generate hypotheses on their occurrence. The space–time K-function and the Kulldorf’s scan statistic were implemented separately for each year to evaluate space–time interaction between reported cases and searching clusters. The results show that the main spatial clusters, of radius size up to 97 km, were reported in central and northeastern France each year. In 2017–2019, spatial clusters were also identified in more southern areas (near the Alps and the Mediterranean coast). Spatio-temporal clustering occurred between May and August, over one-month to three-month windows in 2016–2017 and in 2018–2019. A strong spatio-temporal interaction was identified in 2018 within 16 km and seven days, suggesting a potential local and intense pathogen transmission process. Ongoing improved surveillance and accounting for animal hosts, vectors, meteorological factors and human behaviors are keys to further elucidate LB spatio-temporal patterns.

First Data on Human Lyme Borreliosis in Kosovo: Prospective Evaluation of the Disease from a Tick Bite Perspective

Purpose: Lyme borreliosis (LB) occurs throughout Europe. No clinical and seroprevalence studies for LB in Kosovo have been publicly available thus far. Therefore, this study aimed to investigate LB from a tick bite perspective in the Pristina region, Kosovo. Methods: This single-center prospective observational study enrolled consecutive adult participants (≥18 years of age) with tick bite (embedded tick in the skin), who were examined at the Clinic of Infectious Diseases, Pristina, between January 2015 and August 2018. At the first visit related to the index tick bite, ticks (the complete ticks or parts of the ticks) were removed from the skin, blood samples were taken for serological tests, and antibiotic treatment was started when deemed necessary. The complete, undamaged ticks removed were proceeded for entomological identification. Participants were followed up at 2 months (serological tests were repeated) and 6 months after the index event for the development of clinical manifestations of LB and/or seroconversion against Borrelia burgdorferi. Results: A total of 380 subjects were included in the study. Most cases were seen in May and June in all study years. All 117 preserved ticks were identified as Ixodes ricinus. Immunoglobulin G seroprevalence among subjects during the first visit in the study was 28/380 (7.4%). Erythema migrans (EM) was clinically diagnosed in 74/380 patients (19.5%, 95% confidence interval 15.6-23.8). Only 15 clinically diagnosed EM (in seronegative patients) were serologically confirmed with seroconversion (2 months later), 3.9% of all subjects included in the study. There were three cases with clinical manifestation between the second and third visit: EM recidivans, multiple erythema, or several nonspecific systemic symptoms. Doxycycline and amoxicillin were mainly used for the treatment of borrelial skin lesions. Conclusion: This assessment can help indicate the need for disease awareness and reinforce the importance of primary prevention measures, early diagnosis, and appropriate treatment.

Lyme Disease in Humans

Lyme disease (Lyme borreliosis) is a tick-borne, zoonosis of adults and children caused by genospecies of the Borrelia burgdorferi sensu lato complex. The ailment, widespread throughout the Northern Hemisphere, continues to increase globally due to multiple environmental factors, coupled with increased incursion of humans into habitats that harbor the spirochete. B. burgdorferi sensu lato is transmitted by ticks from the Ixodes ricinus complex. In North America, B. burgdorferi causes nearly all infections; in Europe, B. afzelii and B. garinii are most associated with human disease. The spirochete's unusual fragmented genome encodes a plethora of differentially expressed outer surface lipoproteins that play a seminal role in the bacterium's ability to sustain itself within its enzootic cycle and cause disease when transmitted to its incidental human host. Tissue damage and symptomatology (i.e., clinical manifestations) result from the inflammatory response elicited by the bacterium and its constituents. The deposition of spirochetes into human dermal tissue generates a local inflammatory response that manifests as erythema migrans (EM), the hallmark skin lesion. If treated appropriately and early, the prognosis is excellent. However, in untreated patients, the disease may present with a wide range of clinical manifestations, most commonly involving the central nervous system, joints, or heart. A small percentage (~10%) of patients may go on to develop a poorly defined fibromyalgia-like illness, post-treatment Lyme disease (PTLD) unresponsive to prolonged antimicrobial therapy. Below we integrate current knowledge regarding the ecologic, epidemiologic, microbiologic, and immunologic facets of Lyme disease into a conceptual framework that sheds light on the disorder that healthcare providers encounter.

Lyme borreliosis in Finland: a register-based linkage study

Background

In Finland, the routine surveillance of Lyme borreliosis (LB) is laboratory-based. In addition, we have well established national health care registers where countrywide data from patient visits in public health care units are collected. In our previous study based on these registers, we reported an increasing incidence of both microbiologically confirmed and clinically diagnosed LB cases in Finland during the past years. Here, we evaluated our register data, refined LB incidence estimates provided in our previous study, and evaluated treatment practices considering LB in the primary health care.

Methods

Three national health care registers were used. The Register for Primary Health Care Visits (Avohilmo) and the National Hospital Discharge Register (Hilmo) collect physician-recorded data from the outpatient and inpatient health care visits, respectively, whereas the National Infectious Diseases Register (NIDR) represents positive findings in LB diagnostics notified electronically by microbiological laboratories. We used a personal identification number in register-linkage to identify LB cases on an individual level in the study year 2014. In addition, antibiotic purchase data was retrieved from the Finnish Social Insurance Institution in order to evaluate the LB treatment practices in the primary health care in Finland.

Results

Avohilmo was found to be useful in monitoring clinically diagnosed LB (i.e. erythema migrans (EM) infections), whereas Hilmo did not add much value next to existing laboratory-based surveillance of disseminated LB. However, Hilmo gave valuable information about uncertainties related to physician-based surveillance of disseminated LB and the total annual number of EM infections in our country. Antibiotic purchases associated with the LB-related outpatient visits in the primary health care indicated a good compliance with the recommended treatment guidelines.

Conclusions

Avohilmo and laboratory-based NIDR together are useful in monitoring LB incidence in Finland. A good compliance was observed with the recommended treatment guidelines of clinically diagnosed LB in the primary health care. In 2018, Avohilmo was introduced in the routine surveillance of LB in Finland next to laboratory-based surveillance of disseminated LB.

Efficacy of Double-Dose Dapsone Combination Therapy in the Treatment of Chronic Lyme Disease/Post-Treatment Lyme Disease Syndrome (PTLDS) and Associated Co-infections: A Report of Three Cases and Retrospective Chart Review

Three patients with multi-year histories of relapsing and remitting Lyme disease and associated co-infections despite extended antibiotic therapy were each given double-dose dapsone combination therapy (DDD CT) for a total of 7–8 weeks. At the completion of therapy, all three patients’ major Lyme symptoms remained in remission for a period of 25–30 months. A retrospective chart review of 37 additional patients undergoing DDD CT therapy (40 patients in total) was also performed, which demonstrated tick-borne symptom improvements in 98% of patients, with 45% remaining in remission for 1 year or longer. In conclusion, double-dose dapsone therapy could represent a novel and effective anti-infective strategy in chronic Lyme disease/post-treatment Lyme disease syndrome (PTLDS), especially in those individuals who have failed regular dose dapsone combination therapy (DDS CT) or standard antibiotic protocols. A randomized, blinded, placebo-controlled trial is warranted to evaluate the efficacy of DDD CT in those individuals with chronic Lyme disease/PTLDS.

Seroprevalence, spatial distribution and risk factors of Borrelia burgdorferi sensu lato in Jordan

Lyme borreliosis has not been studied in Jordan or in much of the Middle East. However, limited research indicates that the tick vector, Ixodes ricinus, exists in the region. This study examined the seroprevalence of B. burgdorferi s.l. in Jordan and potential demographic and zoonotic risk factors for seropositivity. Serum samples of 824 apparently healthy participants from 11 governorates in Jordan were tested for B. burgdorferi s.l. using Enzygnost Lyme link VlsE/IgG enzyme-linked immunosorbent assay. A validated questionnaire was used to collect demographic and animal exposure data. Univariate and multivariate logistic regression were used to identify factors associated with seropositivity. The results showed that 11.7 % (95 % CI, 9.3-14.0 %) of the participants were seropositive for B. burgdorferi s.l.. There was a bimodal age distribution of seroprevalence with higher seroprevalence among individuals <20 and>60 years old. After controlling for governorate of residence, females had 2.77 (95 % CI 1.53-5.00) times greater odds of seropositivity compared to males. Individuals living in the southeastern part of Jordan (Ma'an) had 2.32 (95 % CI, 1.02-5.31) greater odds of seropositivity compared to those living in Amman, the Capital of Jordan, while those living in the northeast had significantly lower odds of seropositivity. This study presents the first evidence of B. burgdorferi s.l. seropositivity in Jordan and suggests several risk factors which were reported in studies conducted elsewhere. This study suggests that Lyme borreliosis should be considered in the differential diagnosis for patients presenting with skin lesions in Jordan.

Classification of patients referred under suspicion of tick-borne diseases, Copenhagen, Denmark

To provide better care for patients suspected of having a tick-transmitted infection, the Clinic for Tick-borne Diseases at Rigshospitalet, Copenhagen, Denmark was established. The aim of this prospective cohort study was to evaluate diagnostic outcome and to characterize demographics and clinical presentations of patients referred between the 1st of September 2017 to 31st of August 2019. A diagnosis of Lyme borreliosis was based on medical history, symptoms, serology and cerebrospinal fluid analysis. The patients were classified as definite Lyme borreliosis, possible Lyme borreliosis or post-treatment Lyme disease syndrome. Antibiotic treatment of Lyme borreliosis manifestations was initiated in accordance with the national guidelines. Patients not fulfilling the criteria of Lyme borreliosis were further investigated and discussed with an interdisciplinary team consisting of specialists from relevant specialties, according to individual clinical presentation and symptoms. Clinical information and demographics were registered and managed in a database. A total of 215 patients were included in the study period. Median age was 51 years (range 17-83 years), and 56 % were female. Definite Lyme borreliosis was diagnosed in 45 patients, of which 20 patients had erythema migrans, 14 patients had definite Lyme neuroborreliosis, six had acrodermatitis chronica atrophicans, four had multiple erythema migrans and one had Lyme carditis. Furthermore, 12 patients were classified as possible Lyme borreliosis and 12 patients as post-treatment Lyme disease syndrome. A total of 146 patients (68 %) did not fulfil the diagnostic criteria of Lyme borreliosis. Half of these patients (73 patients, 34 %) were diagnosed with an alternative diagnosis including inflammatory diseases, cancer diseases and two patients with a tick-associated disease other than Lyme borreliosis. A total of 73 patients (34 %) were discharged without sign of somatic disease. Lyme borreliosis patients had a shorter duration of symptoms prior to the first hospital encounter compared to patients discharged without a specific diagnosis (p<0.001). When comparing symptoms at presentation, patients discharged without a specific diagnosis suffered more often from general fatigue and cognitive dysfunction. In conclusion, 66 % of all referred patients were given a specific diagnosis after ended outpatient course. A total of 32 % was diagnosed with either definite Lyme borreliosis, possible Lyme borreliosis or post-treatment Lyme disease syndrome; 34 % was diagnosed with a non-tick-associated diagnosis. Our findings underscore the complexity in diagnosing Lyme borreliosis and the importance of ruling out other diseases through careful examination.

Lyme neuroborreliosis epidemiology in Sweden 2010 to 2014: clinical microbiology laboratories are a better data source than the hospital discharge diagnosis register

BackgroundIn a study from 2013 that prioritised communicable diseases for surveillance in Sweden, we identified Lyme borreliosis as one of the diseases with highest priority. In 2014, when the present study was designed, there were also plans to make neuroborreliosis notifiable within the European Union.AimWe compared possibilities of surveillance of neuroborreliosis in Sweden through two different sources: the hospital discharge register and reporting from the clinical microbiology laboratories.MethodsWe examined the validity of ICD-10 codes in the hospital discharge register by extracting personal identification numbers for all cases of neuroborreliosis, defined by a positive cerebrospinal fluid-serum anti-Borrelia antibody index, who were diagnosed at the largest clinical microbiology laboratory in Sweden during 2014. We conducted a retrospective observational study with a questionnaire sent to all clinical microbiology laboratories in Sweden requesting information on yearly number of cases, age group and sex for the period 2010 to 2014.ResultsAmong 150 neuroborreliosis cases, 67 (45%) had received the ICD-10 code A69.2 (Lyme borreliosis) in combination with G01.9 (meningitis in bacterial diseases classified elsewhere), the combination that the Swedish National Board of Health and Welfare recommends for neuroborreliosis. All 22 clinical laboratories replied to our questionnaire. Based on laboratory reporting, the annual incidence of neuroborreliosis in Sweden was 6.3 cases per 100,000 in 2014.ConclusionThe hospital discharge register was unsuitable for surveillance of neuroborreliosis, whereas laboratory-based reporting was a feasible alternative. In 2018, the European Commission included Lyme neuroborreliosis on the list of diseases under epidemiological surveillance.

Catalogue of stage-specific transcripts in Ixodes ricinus and their potential functions during the tick life-cycle

Background

The castor bean tick Ixodes ricinus is an important vector of several clinically important diseases, whose prevalence increases with accelerating global climate changes. Characterization of a tick life-cycle is thus of great importance. However, researchers mainly focus on specific organs of fed life stages, while early development of this tick species is largely neglected.

Methods

In an attempt to better understand the life-cycle of this widespread arthropod parasite, we sequenced the transcriptomes of four life stages (egg, larva, nymph and adult female), including unfed and partially blood-fed individuals. To enable a more reliable identification of transcripts and their comparison in all five transcriptome libraries, we validated an improved-fit set of five I. ricinus-specific reference genes for internal standard normalization of our transcriptomes. Then, we mapped biological functions to transcripts identified in different life stages (clusters) to elucidate life stage-specific processes. Finally, we drew conclusions from the functional enrichment of these clusters specifically assigned to each transcriptome, also in the context of recently published transcriptomic studies in ticks.

Results

We found that reproduction-related transcripts are present in both fed nymphs and fed females, underlining the poorly documented importance of ovaries as moulting regulators in ticks. Additionally, we identified transposase transcripts in tick eggs suggesting elevated transposition during embryogenesis, co-activated with factors driving developmental regulation of gene expression. Our findings also highlight the importance of the regulation of energetic metabolism in tick eggs during embryonic development and glutamate metabolism in nymphs.

Conclusions

Our study presents novel insights into stage-specific transcriptomes of I. ricinus and extends the current knowledge of this medically important pathogen, especially in the early phases of its development.

Could climate trends disrupt the contact rates between Ixodes ricinus (Acari, Ixodidae) and the reservoirs of Borrelia burgdorferi s.l.?

This study addresses the modifications that future climate conditions could impose on the transmission cycles of Borrelia burgdorferi s.l. by the tick Ixodes ricinus in Europe. Tracking the distribution of foci of a zoonotic agent transmitted by vectors as climate change shapes its spatial niche is necessary to issue self-protection measures for the human population. We modeled the current distribution of the tick and its predicted contact rates with 18 species of vertebrates known to act as reservoirs of the pathogen. We approached an innovative way for estimating the possibility of permanent foci of Borrelia afzelii or Borrelia garinii tracking separately the expected spatial overlap among ticks and reservoirs for these pathogens in Europe. Environmental traits were obtained from MODIS satellite images for the years 2002-2017 (baseline) and projected on scenarios for the years 2030 and 2050. The ratio between MODIS baseline/current interpolated climatologies (WorldClim), and the ratio between MODIS-projected year 2050 with five climate change scenarios for that year (WorldClim) revealed no significant differences, meaning that projections from MODIS are reliable. Models predict that contact rates between the tick and reservoirs of either B. garinii or B. afzelii are spatially different because those have different habitats overlap. This is expected to promote different distribution patterns because of the different responses of both groups of reservoirs to environmental variables. Models for 2030 predict an increase in latitude, mainly in the circulation of B. garinii, with large areas of expected permanent contact between vector and reservoirs in Nordic countries and central Europe. However, climate projections for the year 2050 predict an unexpected scenario of contact disruption. Though large areas in Europe would be suitable for circulation of the pathogens, the predicted lack of niche overlap among ticks and reservoirs could promote a decrease in permanent foci. This development represents a proof-of-concept for the power of jointly modeling both the vector and reservoirs in a common framework. A deeper understanding of the unanticipated result regarding the year 2050 is needed.

Lyme borreliosis: diagnosis and management

Lyme borreliosis is the most common vectorborne disease in the northern hemisphere. It usually begins with erythema migrans; early disseminated infection particularly causes multiple erythema migrans or neurologic disease, and late manifestations predominantly include arthritis in North America, and acrodermatitis chronica atrophicans (ACA) in Europe. Diagnosis of Lyme borreliosis is based on characteristic clinical signs and symptoms, complemented by serological confirmation of infection once an antibody response has been mounted. Manifestations usually respond to appropriate antibiotic regimens, but the disease can be followed by sequelae, such as immune arthritis or residual damage to affected tissues. A subset of individuals reports persistent symptoms, including fatigue, pain, arthralgia, and neurocognitive symptoms, which in some people are severe enough to fulfil the criteria for post-treatment Lyme disease syndrome. The reported prevalence of such persistent symptoms following antimicrobial treatment varies considerably, and its pathophysiology is unclear. Persistent active infection in humans has not been identified as a cause of this syndrome, and randomized treatment trials have invariably failed to show any benefit of prolonged antibiotic treatment. For prevention of Lyme borreliosis, post-exposure prophylaxis may be indicated in specific cases, and novel vaccine strategies are under development.

Comparison of motif-based and whole-unique-sequence-based analyses of phage display library datasets generated by biopanning of anti-Borrelia burgdorferi immune sera

Detection of protection-associated epitopes via reverse vaccinology is the first step for development of subunit vaccines against microbial pathogens. Mapping subunit vaccine targets requires high throughput methods, which would allow delineation of epitopes recognized by protective antibodies on a large scale. Phage displayed random peptide library coupled to Next Generation Sequencing (PDRPL/NGS) is the universal platform that enables high-yield identification of peptides that mimic epitopes (mimotopes). Despite being unsurpassed as a tool for discovery of polyclonal serum mimotopes, the PDRPL/NGS is far inferior as a quantitative method of immune response. Difficult-to-control fluctuations in amounts of antibody-bound phages after rounds of selection and amplification diminish the quantitative capacity of the PDRPL/NGS. In an attempt to improve the accuracy of the PDRPL/NGS method, we compared the discriminating capacity of two approaches for PDRPL/NGS data analysis. The whole-unique-sequence-based analysis (WUSA) involved generation of 7-mer peptide profiles and comparison of the numbers of sequencing reads for unique peptide sequences between serum samples. The motif-based analysis (MA) included identification of 4-mer consensus motifs unifying unique 7-mer sequences and comparison of motifs between serum samples. The motif comparison was based not on the numbers of sequencing reads, but on the numbers of distinct 7-mers constituting the motifs. Our PDRPL/NGS datasets generated from biopanning of protective and non-protective anti-Borrelia burgdorferi sera of New Zealand rabbits were used to contrast the two approaches. As a result, the principle component analyses (PCA) showed that the discriminating powers of the WUSA and MA were similar. In contrast, the unsupervised hierarchical clustering obtained via the MA classified the preimmune, non-protective, and protective sera better than the WUSA-based clustering. Also, a total number of discriminating motifs was higher than that of discriminating 7-mers. In sum, our results indicate that MA approach improves the accuracy and quantitative capacity of the PDRPL/NGS method.

Knowledge, Attitudes, and Practices on Tick-Borne Human Diseases and Tick-Borne Encephalitis Vaccine among Farmers from North-Eastern Italy (2017)

Objectives: Tick-borne diseases (T-BD) represent a potential health threat for outdoor workers in endemic areas, such as the Autonomous Province of Trento (APT). We conducted a questionnaire-based survey to assess T-BD knowledge, attitudes, and preventive practices among APT farmers, specifically focusing on the use of protective habits and the uptake of the tick-borne encephalitis (TBE) vaccine.Methods: A convenience sample of 106 farmers (all males, mean age 47.3 ± 13.6 years) attending pesticide training courses (12/2016-03/2017) completed the anonymous survey. Binary regression analysis, calculations of multivariate odds ratios (mOR) and 95% confidence intervals were used to assess knowledge, attitudes, and risk perceptions as predictors of preventive measures.Results: Though general understanding of T-BD was fairly low, the majority of the participants perceived TBE infection as a frequent (73.6%) and severe disease (61.3%). Overall, 43.3% of participants knew a TBE vaccine was available, and 24.5% had been vaccinated. Protective habits were reported by 53.8% of respondents, with self-checks for tick bites particularly low at 2.8% of participants. Better knowledge of T-BD and favorable attitudes toward vaccinations were associated with TBE immunization (mOR 4.708; 95%CI 1.273-17.409 and mOR 3.555; 95%CI 1.175-10.760, respectively), while previous history of tick bite and any interaction with T-BD significantly predicted adherence to protective measures (mOR 4.458; 95%CI 1.808-10.991, and mOR 9.433; 95%CI 1.127-78.973, respectively).Conclusions: Adherence to preventive measures (TBE vaccine) and protective habits was unsatisfactory in our sampled group, being a possible consequence of significant knowledge gaps. Public health communication on T-BD in farmers should, therefore, target understanding of health issues and appropriate preventive measures.

The demographics and geographic distribution of laboratory-confirmed Lyme disease cases in England and Wales (2013-2016): an ecological study

OBJECTIVE

Lyme disease is a tick-borne disease of increasing incidence and public concern across the Northern Hemisphere. However, the socio-demographics and geographic distribution of the population affected in England and Wales are poorly understood. Therefore, the proposed study was designed to describe the demographics and distribution of laboratory-confirmed cases of Lyme disease from a national testing laboratory.

DESIGN

An ecological study of routinely collected laboratory surveillance data.

SETTING

Public Health England's national Lyme disease testing laboratory.

PARTICIPANTS

3986 laboratory-confirmed cases of Lyme disease between 2013 and 2016.

RESULTS

In England and Wales, the incidence of laboratory-confirmed Lyme disease rose significantly over the study period from 1.62 cases per 100 000 in 2013 to 1.95 cases per 100 000 in 2016. There was a bimodal age distribution (with peaks at 6-10 and 61-65 years age bands) with a predominance of male patients. A significant clustering of areas with high Lyme disease incidence was located in southern England. An association was found between disease incidence and socioeconomic status, based on the patient's resident postcode, with more cases found in less deprived areas. Cases were disproportionately found in rural areas compared with the national population distribution.

CONCLUSIONS

These results suggest that Lyme disease patients originate from areas with higher socioeconomic status and disproportionately in rural areas. Identification of the Lyme disease hotspots in southern England, alongside the socio-demographics described, will enable a targeted approach to public health interventions and messages.

Delineating Surface Epitopes of Lyme Disease Pathogen Targeted by Highly Protective Antibodies of New Zealand White Rabbits

Lyme disease (LD), the most prevalent vector-borne illness in the United States and Europe, is caused by Borreliella burgdorferi No vaccine is available for humans. Dogmatically, B. burgdorferi can establish a persistent infection in the mammalian host (e.g., mice) due to a surface antigen, VlsE. This antigenically variable protein allows the spirochete to continually evade borreliacidal antibodies. However, our recent study has shown that the B. burgdorferi spirochete is effectively cleared by anti-B. burgdorferi antibodies of New Zealand White rabbits, despite the surface expression of VlsE. Besides homologous protection, the rabbit antibodies also cross-protect against heterologous B. burgdorferi spirochetes and significantly reduce the pathology of LD arthritis in persistently infected mice. Thus, this finding that NZW rabbits develop a unique repertoire of very potent antibodies targeting the protective surface epitopes, despite abundant VlsE, prompted us to identify the specificities of the protective rabbit antibodies and their respective targets. By applying subtractive reverse vaccinology, which involved the use of random peptide phage display libraries coupled with next-generation sequencing and our computational algorithms, repertoires of nonprotective (early) and protective (late) rabbit antibodies were identified and directly compared. Consequently, putative surface epitopes that are unique to the protective rabbit sera were mapped. Importantly, the relevance of newly identified protection-associated epitopes for their surface exposure has been strongly supported by prior empirical studies. This study is significant because it now allows us to systematically test the putative epitopes for their protective efficacy with an ultimate goal of selecting the most efficacious targets for development of a long-awaited LD vaccine.

The value of seroprevalence data as surveillance tool for Lyme borreliosis in the general population: the experience of Belgium

BACKGROUND

Serological surveillance, based on the measurement of the presence of specific antibodies in a given population, can be used in addition to traditional and routine disease surveillance methods. The added value of this has been largely documented for vaccine-preventable diseases, but to a lesser extent for vector-borne diseases. This study aimed to evaluate the utility of seroprevalence data as additional source of information on the epidemiology of Lyme borreliosis in Belgium.

METHODS

In total, 3215 residual blood samples collected in 2013-2015 were analysed with Liaison® Borrelia IgG kit (DiaSorin S.p.A, Saluggia, Italy). Positive and equivocal results were further examined with immunoblotting (recomLine Borrelia IgG kit, Mikrogen, Neuried, Germany). Crude prevalence estimates of equivocal and seropositive results were calculated and further adjusted accounting for clustered sampling and standardized for age, sex and population per province, according to the Belgian population structure in 2014. The effect of age, sex and region on seropositivity was assessed using log-binomial regression.

RESULTS

The overall weighted national seroprevalence for Borrelia burgdorferi sensu lato, adjusted for clustered sampling, age, sex and province was 1.06% (95%CI 0.67-1.67). Although not statistically significant, the highest prevalences were observed in men and in those younger than 15 years or older than 59 years of age. At provincial level, the seroprevalence estimates do not follow the geographical distribution of tick bites and diagnoses of Lyme borreliosis as detected through other surveillance systems.

CONCLUSIONS

Although the use of residual samples for seroprevalence estimates has several advantages, it seems to be a limited tool for serological surveillance of Lyme borreliosis in Belgium, other than follow-up of trends if repeated over time. A population-based sampling strategy might provide a more representative nationwide sample, but would be very time intensive and expensive. Seroprevalence studies within risk groups or risk areas in Belgium could provide a useful alternative approach to complement routine surveillance data of Lyme borreliosis.

[Ecology of Lyme disease]

Diseases spread by ticks are complex and typically come under the One Health approach because the implications for human, animal and environmental health are so intricately interconnected. In Europe and North America, these diseases, particularly the emblematic case of Lyme disease, are constantly on the rise. They are associated with a very strong emotional element in Western societies, where citizens are preoccupied by this upsurge and call on governments and health services to act. There is no vaccine against Lyme disease. This is the backdrop against which scientists are looking for alternative solutions based on the identification of ecological factors that are liable to better control tick populations and the movements of pathogens within ecosystems. This article describes the main knowledge already acquired about the ecology of Lyme disease and then provides a list of a number of instruments that can be leveraged to limit the risks and improve control.

Epidemiology of Lyme borreliosis through two surveillance systems: the national Sentinelles GP network and the national hospital discharge database, France, 2005 to 2016

BACKGROUND

Lyme borreliosis (LB) is the most frequent vector-borne disease in France. Since 2009, surveillance of LB is conducted by a sentinel network of general practitioners (GPs). This system, in conjunction with the national hospitalisation database was used to estimate the incidence and describe the characteristics of LB in France.

AIM

To describe the estimated incidence and trends in GP consultations and hospital admissions for LB in France and identify risk groups and high-incidence regions.

RESULTS

From 2011 to 2016, the mean yearly incidence rate of LB cases was 53 per 100,000 inhabitants (95% CI: 41-65) ranging from 41 in 2011 to 84 per 100 000 in 2016. A mean of 799 cases per year were hospitalised with LB associated diagnoses 2005-16. The hospitalisation incidence rate (HIR) ranged from 1.1 cases per 100,000 inhabitants in 2005 to 1.5 in 2011 with no statistically significant trend. We observed seasonality with a peak during the summer, important inter-regional variations and a bimodal age distribution in LB incidence and HIR with higher incidence between 5 and 9 year olds and those aged 60 years. Erythema migrans affected 633/667 (95%) of the patients at primary care level. Among hospitalised cases, the most common manifestation was neuroborreliosis 4,906/9,594 (51%).

CONCLUSION

Public health strategies should focus on high-incidence age groups and regions during the months with the highest incidences and should emphasise prevention measures such as regular tick checks after exposure and prompt removal to avoid infection.

Prevalence of Borrelia Burgdorferi Sensu Lato in Ticks from the Ternopil Region in Ukraine

Introduction

Lyme borreliosis/Lyme disease is caused by Borrelia burgdorferi and is one of the most common vector-borne diseases transmitted by ticks.

Material and Methods

A total of 136 Ixodes ricinus ticks, collected in the Ternopil (Ukraine) region, including 126 adults (70 females and 56 males), and 10 nymphs were examined. The identification of the species and their developmental form was based on morphological characteristics.

Results

PCR with B5S-Bor and 23S-Bor primers resulted in Borrelia burgdorferi sensu lato DNA amplification among six ticks (4.4%). The detailed analysis based on the DNA sequencing showed the presence of DNA of Borrelia afzelii in four samples; the remaining two represented Borrelia burgdorferi sensu lato complex, although their genospecies were not determined. The research confirmed the dominance of Borrelia afzelii genospecies in the ticks from Ukraine.

Conclusion

It seems reasonable to undertake similar research in ticks from other regions of Ukraine. Knowledge in this field can be useful for public health and planning the prevention of tick-borne diseases.

The Emerging Role of Microbial Biofilm in Lyme Neuroborreliosis

Lyme borreliosis (LB) is the most common tick-borne disease caused by the spirochete Borrelia burgdorferi in North America and Borrelia afzelii or Borrelia garinii in Europe and Asia, respectively. The infection affects multiple organ systems, including the skin, joints, and the nervous system. Lyme neuroborreliosis (LNB) is the most dangerous manifestation of Lyme disease, occurring in 10-15% of infected individuals. During the course of the infection, bacteria migrate through the host tissues altering the coagulation and fibrinolysis pathways and the immune response, reaching the central nervous system (CNS) within 2 weeks after the bite of an infected tick. The early treatment with oral antimicrobials is effective in the majority of patients with LNB. Nevertheless, persistent forms of LNB are relatively common, despite targeted antibiotic therapy. It has been observed that the antibiotic resistance and the reoccurrence of Lyme disease are associated with biofilm-like aggregates in B. burgdorferi, B. afzelii, and B. garinii, both in vitro and in vivo, allowing Borrelia spp. to resist to adverse environmental conditions. Indeed, the increased tolerance to antibiotics described in the persisting forms of Borrelia spp., is strongly reminiscent of biofilm growing bacteria, suggesting a possible role of biofilm aggregates in the development of the different manifestations of Lyme disease including LNB.

Highlights from the 20th International Symposium on HIV and Emerging Infectious Diseases (ISHEID) 16-18 May 2018, Marseille, France: from HIV and comorbidities to global health

The 20th International Symposium on HIV and Emerging Infectious Diseases took place in Marseille, France. It had a refreshing European look with reinforced partnerships with the European AIDS Clinical Society and the British HIV Association and with international speakers and participants. Topics included HIV and global health, HIV and hepatitis cure, the microbiome and immunotherapies, clinical research and methodology, as well as chemsex, pre-exposure prophylaxis, sexually transmitted infections and emerging infectious diseases. Novel areas of research were also described, such as electronic technology in order to improve HIV management, and the expert patient.

Control of Lyme borreliosis and other Ixodes ricinus-borne diseases

Lyme borreliosis (LB) and other Ixodes ricinus-borne diseases (TBDs) are diseases that emerge from interactions of humans and domestic animals with infected ticks in nature. Nature, environmental and health policies at (inter)national and local levels affect the risk, disease burden and costs of TBDs. Knowledge on ticks, their pathogens and the diseases they cause have been increasing, and resulted in the discovery of a diversity of control options, which often are not highly effective on their own. Control strategies involving concerted actions from human and animal health sectors as well as from nature managers have not been formulated, let alone implemented. Control of TBDs asks for a “health in all policies” approach, both at the (inter)national level, but also at local levels. For example, wildlife protection and creating urban green spaces are important for animal and human well-being, but may increase the risk of TBDs. In contrast, culling or fencing out deer decreases the risk for TBDs under specific conditions, but may have adverse effects on biodiversity or may be societally unacceptable. Therefore, in the end, nature and health workers together must carry out tailor-made control options for the control of TBDs for humans and animals, with minimal effects on the environment. In that regard, multidisciplinary approaches in environmental, but also medical settings are needed. To facilitate this, communication and collaboration between experts from different fields, which may include patient representatives, should be promoted.

A concise overview on tick-borne human infections in Europe: a focus on Lyme borreliosis and tick-borne Rickettsia spp

Ticks are blood-feeding external parasites of mammals. Almost all ticks belong to one of two major families, the Ixodidae or hard ticks, and the Argasidae or soft ticks. Ticks are responsible of transmitting many diseases called ‘tick-borne diseases'. Borrelia and Rickettsia spp., are the most important tick-transmitted bacterial pathogens circulating in Europe. In this review we will focus on the two tick-borne diseases caused by these bacterial pathogens, their vector, epidemiology, clinical diagnosis and symptoms.