The evolving story of Borrelia burgdorferi sensu lato transmission in Europe

Molecular Typing of Tick-Borne Pathogens in Ixodids of Bosnia and Herzegovina

Ticks are key vectors of zoonotic pathogens, and their expanding distribution in Europe heightens public health concerns. In Bosnia and Herzegovina, while tick distribution is well documented, molecular data on tick-borne pathogens remain limited. This study aimed to illustrate the presence and diversity of these pathogens, focusing on areas with high human activity. Ticks (n = 556) were collected in April 2022 from eight diverse locations, including urban parks, private properties, and rural sites. PCR-based screening was employed to detect Anaplasmataceae, Borrelia, Francisella, Piroplasmida, Rickettsia, and tick-borne encephalitis virus (TBEV), with subsequent sequencing to confirm results. Further characterization of Borrelia burgdorferi sensu lato was achieved via reverse line blotting (RLB) hybridization and sequencing. Ixodes ricinus was the most prevalent species, followed by Dermacentor marginatus and D. reticulatus. Our analysis revealed an overall infection rate of 22.1% in questing ticks, with Rickettsia spp. and Borrelia spp. predominating. Notably, seven Borrelia species were identified in I. ricinus, alongside Anaplasma phagocytophilum, Rickettsia helvetica, and R. monacensis, with co-infections mainly observed in peri-urban areas. This study provides the first molecular evidence of multiple tick-borne pathogens in the region, underscoring the need for further surveillance and risk assessment of tick-borne diseases in the region.

Two decades of research on Borrelia burgdorferi sensu lato in questing Ixodes ricinus ticks in Slovakia

Introduction

In Europe, Borrelia burgdorferi sensu lato (s.l.), the causative agent of Lyme borreliosis is transmitted by the castor bean tick, Ixodes ricinus. In the last decades, global changes affect the spread of ticks and also their bionomics. The aim of this study was summarization of a large dataset obtained during 20 years of research.

Methods

The research was carried out in 1999-2019 at 16 localities in Slovakia that were continuously monitored. In total, 17,249 questing I. ricinus ticks were tested for the presence of B. burgdorferi s.l.

Results

The total prevalence of infected ticks was 18.8% (3,248/17,249), with 15.1% (1,557/10,302) infected nymphs and 24.3% (1,691/6,947) infected adults. Nine species of B. burgdorferi s.l. were identified. Borrelia afzelii (37.1%), B. garinii/bavariensis (24.7%), and B. valaisiana (15.4%) were the most frequent and were present at all study sites, followed by B. lusitaniae (12.6%), B. burgdorferi sensu stricto (4.1%) and B. spielmanii (1.6%). Borrelia bavariensis was confirmed only in four samples (0.1%), however, detection of this species has been performed only since 2017. Borrelia bissettii and B. kurtenbachii were both recorded in one case. The total prevalence differed significantly among four habitat types (urban, suburban, natural, agricultural). The highest infection prevalence was confirmed in natural habitat (22.0%), the lowest in urban habitat (13.2%). In addition, molecular analysis was carried out on part of the collected ticks previously morphologically identified as I. ricinus. The analysis did not confirm the occurrence of Ixodes inopinatus in Slovakia.

Conclusion

Long-term monitoring of the abundance and spread of ticks as well as the prevalence and genetic variability of tick-borne pathogens can reveal the impact of global climatic and socio-economic changes on different habitats, including natural foci of tick-borne pathogens.

Lyme borreliosis in Brazil: a critical review on the Baggio-Yoshinari syndrome (Brazilian Lyme-like disease)

SUMMARYLyme borreliosis or Lyme disease is the most frequently reported tick-borne disease in the Northern Hemisphere. In countries of the Southern Hemisphere, such as Brazil, since the early 1990s, some researchers have argued for the existence of an autochthonous Lyme-like borreliosis, known locally as the Baggio-Yoshinari syndrome (BYS), an alleged "Brazilian borreliosis" supposedly caused by a different strain of Borrelia burgdorferi and transmitted by hard ticks. Currently, the existence of BYS in Brazil is still accepted by a large part of the human health care workers, scientists, medical societies, and patients. In fact, this alleged "Brazilian borreliosis" has been the tick-borne zoonotic disease with the greatest number of reported cases and published studies in Brazil during this century, second only to Brazilian spotted fever. In this manuscript, we reviewed all manuscripts directly related to BYS that have been published in Brazil during the last 35 years. This analysis included 199 individual human cases that have been reported in Brazil since 1989, plus multiple studies on ticks, domestic, and wild animals. Our revision aimed to provide a critical opinion on whether the current published works allow healthcare workers, public health agencies, and patients to accept the existence of Lyme disease, BYS, or other Lyme borreliosis-related disease in Brazil. For this purpose, we evaluated the strengths and weaknesses of each published study, considering the diagnostic methods used, such as serological, microbiological, and molecular analyses. Based on these evaluations, we conclude that there is not enough evidence to support the occurrence of Lyme borreliosis in Brazil or that BYS (Brazilian Lyme-like disease) is caused by a bacterium of the genus Borrelia. This assumption is based on the inaccuracy, unreliability, and misinterpretation of the different diagnostic methods that have been used in Brazil. Recognizing the lack of technical evidence for the occurrence of Lyme borreliosis in Brazil has highly relevant implications. For example, it becomes imperative to raise awareness among the country's medical profession, as they have adopted unnecessary and extreme therapies recommended for patients with a supposed borrelial infection, including BYS, in Brazil. Finally, the technical analyses carried out in this study could be applied to other countries in the Southern Hemisphere (e.g., Argentina, South Africa, Australia), where cases classified and alleged as Lyme disease have been reported.

Temporal Changes in Tick-Borne Pathogen Prevalence in Questing Ixodes ricinus Across Different Habitats in the North-Eastern Italian Alps

Changes in land use, climate, and host community are leading to increased complexity in eco-epidemiological relationships and the emergence of zoonoses. This study investigates the changes in the prevalence of several Ixodes ricinus-transmitted pathogens in questing ticks over a 10-year interval (2011-2013, 2020) in natural and agricultural habitats of the Autonomous Province of Trento (North-eastern Alps), finding an average prevalence of infection of 27.1%. Analysis of 2652 ticks, investigating four infectious agents (Borrelia burgdorferi sensu lato, Anaplasma spp., Rickettsia spp., and Babesia spp.), revealed the circulation of 11 different zoonotic pathogens, with varying infection rates across different years and habitats. In 2020, we found a decrease in Anaplasma phagocytophilum, associated with agricultural habitats, and Rickettsia spp., found in all habitats. In the same year, Babesia spp. increased in both habitats, similar to Borrelia burgdorferi sensu stricto, which was related to natural habitats. Co-infections were identified in 8% of positive-tested ticks with different spatiotemporal associations, primarily in natural settings. Our results provide new evidence that the risk of infection with tick-borne pathogens in the Alpine region varies over time and in different environments, broadening the current information on co-infection rates and the circulation of zoonotic pathogens, previously not reported in this area.

Proposed Immunopathogenetic Mechanisms Underlying Lyme Arthritis

ABSTRACT

Lyme disease is commonly associated with musculoskeletal features, inflammatory and noninflammatory. The precise pathogenesis of the clinical features of this infection are complex and often multiple. A better understanding of how Borrelia burgdorferi causes these musculoskeletal manifestations is necessary in order to determine the proper treatment and eschew that which is unlikely to work, often associated with toxicities. The following review seeks to summarize the various immunopathogenic mechanisms that may cause these features of Lyme disease and suggests a series of approaches based on the most likely underlying mechanism(s).

Prevalence and genotyping of Toxoplasma gondii in questing Ixodes ricinus ticks from forest areas of Northern Poland

Toxoplasma gondii occurs in a wide range of intermediate hosts, whose blood may be a meal for different tick species. A few studies have examined the role of ticks in the life cycle of T. gondii. This one includes the largest number and all stages of Ixodes ricinus collected from the widest area, covering seven recreational localities within a forest biotope in Northern Poland. This study aimed to determine the prevalence of T. gondii DNA in 2144 collected questing ticks to establish whether they may be involved in T. gondii life cycle. The additional goal was to genotype the detected T. gondii, as knowledge about its genotypes occurring in European ticks is insufficient. A further purpose was to detect coinfection with T. gondii and Borreliaceae in the collected ticks, as all of them have previously been tested for the presence of bacteria DNA. Nested PCR and sequencing of the obtained B1 gene fragment were conducted. T. gondii DNA was detected in 0.9% of all ticks (1.1% of nymphs and 0.7% of larvae). The presence of T. gondii in unfed larvae and nymphs may indicate the possibility of its vertical transmission. The prevalence of T. gondii DNA in ticks collected from individual sites was focal (0-4.3%) and seems to depend on local climatic conditions. Among all examined ticks, 0.3% were coinfected with T. gondii and Borreliella spp., vs. 0.6% of specimens with a single T. gondii infection. The obtained B1 sequences showed the greatest similarity (99.71-100%) to the sequence representing type III.

Pathogens transmitted by Ixodes ricinus

Ixodes ricinus is the most important tick vector in central and western Europe and one of the most researched parasites. However, in the published literature on the tick and the pathogens it transmits, conjecture about specific transmission cycles and the clinical significance of certain microbes is not always clearly separated from confirmed facts. This article aims to present up-to-date, evidence-based information about the well-researched human pathogens tick-borne encephalitis virus, louping-ill virus, Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato and several Babesia species, with a focus on their development in the tick, transmission dynamics and the reservoir hosts that support their circulation in the environment. Borrelia miyamotoi, Neoehrlichia mikurensis, Rickettsia helvetica and Rickettsia monacensis, which are much less common causes of disease but may affect immunocompromised patients, are also briefly discussed. Finally, the possible role of I. ricinus in the transmission of Coxiella burnetii, Francisella tularensis, Bartonella spp. and Spiroplasma ixodetis is reviewed.

Twenty Years of Lyme Borreliosis in the Netherlands: Temporal Trends in Seroprevalence and Risk Factors

Lyme borreliosis (LB) is not notifiable in many European countries, and the patchwork of surveillance strategies in Europe perpetuates knowledge gaps. In the Netherlands, LB incidence has been estimated from recurring general practitioner surveys since the 1990s. To complement the incidence data, this study aimed to estimate the prevalence of antibodies against Borrelia burgdorferi sensu lato in the general population of the Netherlands in 1995/1996, identify risk factors for seropositivity, and compare these findings to data from 2016/2017 to identify temporal trends. Sera from participants (n = 8041, aged 0-80 years) in a cross-sectional nationwide surveillance study were assessed for the presence of antibodies against B. burgdorferi s.l., using a screening ELISA and immunoblot confirmation. Risk factors associated with seropositivity were evaluated using multivariable analysis. A significant difference in weighted seroprevalence was observed between 1995/1996 (2.8%) and 2016/2017 (4.3%). In both cohorts, the seroprevalence was significantly higher among men than among women, and increased with age and tick bite frequency. The upward trend in age-specific seropositivity in individuals over 50 was steeper in 2016/2017 than in 1995/1996, possibly due to improved fitness among contemporary elderly, allowing increased outdoor activities. This study highlights significant trends in the seroprevalence of B. burgdorferi s.l. antibodies in the general population of the Netherlands over 20 years. The doubling of seroprevalence underscores the increasing burden of LB, and the importance of continued surveillance. Targeted interventions, particularly for elderly populations, may help raise awareness to the risks of tick bites and reduce the growing disease burden and societal costs associated with LB.

A metalloprotease secreted by an environmentally acquired gut bacterium hinders Borrelia afzelii colonization in Ixodes ricinus

Although the importance of the microbiome in the context of tick biology and vector competence has recently come into a broader research focus, the field is still in its infancy and the complex ecological interactions between the tick residential bacteria and pathogens are obscure. Here, we show that an environmentally acquired gut bacterium has the potential to impair Borrelia afzelii colonization within the tick vector through a secreted metalloprotease. Oral introduction of either Bacillus cereus LTG-1 isolate or its purified enhancin (BcEnhancin) protein significantly reduces B. afzelii burden in the guts of Ixodes ricinus ticks. This effect is attributed to the ability of BcEnhancin to degrade a glycan-rich peritrophic matrix (PM), which is a gut protective barrier essential for Borrelia survival. Our study highlights the importance of the gut microbiome in determining tick vector competence and provides a deeper mechanistic insight into the complex network of interactions between Borrelia, the tick, and the tick microbiome.

Emerging patterns in rodent-borne zoonotic diseases

Rodents are ubiquitous and typically unwelcome dwellers in human habitats worldwide, infesting homes, farm fields, and agricultural stores and potentially shedding disease-causing microbes into the most human-occupied of spaces. Of the vertebrate animal taxa that share pathogens with us, rodents are the most abundant and diverse, with hundreds of species of confirmed zoonotic hosts, some of which have nearly global distributions. However, only 12% of rodent species are known to be sources of pathogens that also infect people, and those rodents that do are now recognized as tending to share a suite of predictable traits. Here, we characterize those traits and explore them in the context of three emerging or reemerging rodent-borne zoonotic diseases of people: Lassa fever, Lyme disease, and plague.

New BB0108, BB0126, BB0298, BB0323, and BB0689 Chromosomally Encoded Recombinant Proteins of Borrelia burgdorferi sensu lato for Serodiagnosis of Lyme Disease

Five chromosomally encoded proteins, BB0108, BB0126, BB0298, BB0323, and BB0689, from Borrelia burgdorferi sensu lato (s.l.), were obtained in three variants each, representing the most common genospecies found in Europe (Borrelia afzelii, Borrelia burgdorferi sensu stricto (s.s.), and Borrelia garinii). The reactivity of these recombinant proteins with the IgM and IgG antibodies present in human serum was assessed using Western blot (WB) and the ELISA. In IgG-WB, the proteins exhibited varying reactivity, peaking at approximately 40-50% for BB0108 and BB0689. However, none of these proteins were recognized by specific antibodies in the IgM-WB. The sensitivity of IgG-ELISA based on three variants of BB0108 and BB0323 ranged from 71% to 82% and from 62% to 72%, respectively. Conversely, the specificity of both tested proteins was consistently above 82%. Tests utilizing single variants of BB0323 did not yield any diagnostic value in detecting IgM antibodies. However, BB0108 demonstrated recognition by antibodies present in 52% to 63% of the tested sera. These antigens appear advantageous due to the consistent reactivity observed across their variants. This observation suggests that appropriate selection of antigens conserved within B. burgdorferi s.l. could offer a solution to the issue of variable sensitivity encountered in serodiagnostic tests across Europe.

The first molecular record of Borrelia afzelii, B. garinii, B. valaisiana, B. burgdorferi s.s. and B. bavariensis in Bosnia and Herzegovina

Borrelia burgdorferi sensu lato complex comprises 20 species, from which B. afzelii, B. garinii, B. burgdorferi sensu stricto, B. bavariensis, and B. spielmanii are directly associated with Lyme borreliosis, while B. bissettiae, B. lusitaniae, and B. valaisiana were detected in individual cases. Their main vector in Europe is the hard tick species Ixodes ricinus. To date, two species, B. spielmanii and B. lusitaniae, have been molecularly detected in Bosnia and Herzegovina. To test for the presence of other Borrelia species, we performed nested PCR targeting intergenic region rrf (5S) - rrl (23S) on DNA isolates from 49 ticks collected from vegetation by flagging method and 43 removed from humans in The Center for Emergency Medical Assistance of the Sarajevo Canton and The Healthcare Centers of the Sarajevo Canton. Borrelia species were detected by one-directional Sanger sequencing of the amplified region using the same forward primer as in PCR. Out of six Borrelia species detected in the present study, this is the first record of B. afzelii, B. garinii, B. burgdorferi s.s. B. bavariensis, and B. valaisiana in Bosnia and Herzegovina.

Ticks and spirochetes of the genus Borrelia in urban areas of Central-Western Poland

Due to the extensive use of green urban areas as recreation places, city residents are exposed to tick-borne pathogens. The objectives of our study were (i) to determine the occurrence of ticks in urban green areas, focussing on areas used by humans such as parks, schools and kindergartens, and urban forests, and (ii) to assess the prevalence of Borrelia infections in ticks in Zielona Góra, a medium-sized city in western Poland. A total of 161 ticks representing the two species Ixodes ricinus (34 males, 51 females, 30 nymphs) and Dermacentor reticulatus (20 males, 26 females) were collected from 29 of 72 (40.3%) study sites. In total, 26.1% of the ticks (85.7% of I. ricinus and 14.3% of D. reticulatus) yielded DNA of Borrelia. The difference in the infection rate between I. ricinus and D. reticulatus was significant. Among infected ticks, the most frequent spirochete species were B. lusitaniae (50.0%) and B. afzelii (26.2%), followed by B. spielmanii (9.5%), B. valaisiana (7.1%), B. burgdorferi sensu stricto, (4.8%) and B. miyamotoi (2.4%). No co-infections were found. We did not observe a correlation in the occurrence of Borrelia spirochetes in ticks found in individual study sites that differed in terms of habitat type and height of vegetation. Our findings demonstrate that the Borrelia transmission cycles are active within urban habitats, pointing the need for monitoring of tick-borne pathogens in public green areas. They could serve as guidelines for authorities for the proper management of urban green spaces in a way that may limit tick populations and the potential health risks posed by tick-borne pathogens.

Tick-Borne Bacterial Diseases in Europe: Threats to public health

BACKGROUND

Tick-borne diseases, caused by bacterial pathogens, pose a growing threat to public health in Europe. This paper provides an overview of the historical context of the discovery of the most impactful pathogens transmitted by ticks, including Borrelia burgdorferi sensu lato, Rickettsia spp., Anaplasma spp., Francisella spp., Ehrlichia spp., and Neoehrlichia mikurensis. Understanding the historical context of their discovery provides insight into the evolution of our understanding of these pathogens.

METHODS AND RESULTS

Systematic investigation of the prevalence and transmission dynamics of these bacterial pathogens is provided, highlighting the intricate relationships among ticks, host organisms, and the environment. Epidemiology is explored, providing an in-depth analysis of clinical features associated with infections. Diagnostic methodologies undergo critical examination, with a spotlight on technological advancements that enhance detection capabilities. Additionally, the paper discusses available treatment options, addressing existing therapeutic strategies and considering future aspects.

CONCLUSIONS

By integrating various pieces of information on these bacterial species, the paper aims to provide a comprehensive resource for researchers and healthcare professionals addressing the impact of bacterial tick-borne diseases in Europe. This review underscores the importance of understanding the complex details influencing bacterial prevalence and transmission dynamics to better combat these emerging public health threats.

A crucial nexus: Phylogenetic versus ecological support of the life-cycle of Ixodes ricinus (Ixodoidea: Ixodidae) and Borrelia spp. amplification

The tick Ixodes ricinus parasitizes a wide range of vertebrates. These hosts vary in the relative contribution to the feeding of the different tick life stages, and their interplay is pivotal in the transmission dynamics of tick-borne pathogens. We aimed to know if there is a phylogenetic signal in the feeding and propagation hosts of I. ricinus, independently of other traits, as well as in the amplification of Borrelia burgdorferi (s.l.) in feeding larvae. We used a compilation of 1127 published field surveys in Europe, providing data for 96,586 hosts, resulting in 265,124 larvae, 72,080 nymphs and 37,726 adults. The load of immature ticks on hosts showed a significant phylogenetic signal towards the genera Psammodromus, Podarcis, and Lacerta (nymphs only). We hypothesize that such signal is the background hallmark of the primitive hosts associations of I. ricinus, probably in the glaciation refugia. A secondary phylogenetic signal for tick immatures appeared for some genera of Rodentia and Eulipotyphla. Results suggest the notion that the tick gained these hosts after spread from glaciation refugia. Analyses support a phylogenetic signal in the tick adults, firmly linked to Cetartiodactyla, but not to Carnivora or Aves. This study provides the first demonstration of host preferences in the generalist tick I. ricinus. We further demonstrate that combinations of vertebrates contribute in different proportions supporting the tick life-cycle in biogeographical regions of the Western Palaearctic as each region has unique combinations of dominant hosts. Analysis of the amplification of B. burgdorferi (s.l.) demonstrated that each genospecies is better amplified by competent reservoirs with which a strong phylogenetic signal exists. These vertebrates are the same along the spatial range: environmental traits do not change the reservoirs along the large territory studied. The transmission of B. burgdorferi (s.l.) is amplified by a few species of vertebrates, that share biogeographical regions with the tick vector in variable proportions.

The role of wildlife in the epidemiology of tick-borne diseases in Slovakia

Tick-borne diseases (TBD) represent an important challenge for human and veterinary medicine. In Slovakia, studies on the epidemiology of tick-borne pathogens (TBP) regarding reservoir hosts have focused on small mammals and to a lesser extent on birds or lizards, while knowledge of the role of the remaining vertebrate groups is limited. Generally, wild ungulates, hedgehogs, small- and medium-sized carnivores, or squirrels are important feeding hosts for ticks and serve as reservoirs for TBP. Importantly, because they carry infected ticks and/or are serologically positive, they can be used as sentinels to monitor the presence of ticks and TBP in the environment. With their increasing occurrence in urban and suburban habitats, wild ungulates, hedgehogs or foxes are becoming an important component in the developmental cycle of Ixodes ricinus and of TBP such as Anaplasma phagocytophilum or Babesia spp. On the other hand, it has been postulated that cervids may act as dilution hosts for Borrelia burgdorferi (sensu lato) and tick-borne encephalitis virus. In southwestern Slovakia, a high prevalence of infection with Theileria spp. (100%) was observed in some cervid populations, while A. phagocytophilum (prevalence of c.50%) was detected in cervids and wild boars. The following pathogens were detected in ticks feeding on free-ranging ungulates, birds, and hedgehogs: A. phagocytophilum, Rickettsia spp., Coxiella burnetii, Neoehrlichia mikurensis, B. burgdorferi (s.l.), and Babesia spp. The growing understanding of the role of wildlife as pathogen reservoirs and carriers of pathogen-infected ticks offers valuable insights into the epidemiology of TBP, providing a foundation for reducing the risk of TBD.

Prevalence of Lyme Disease and Relapsing Fever Borrelia spp. in Vectors, Animals, and Humans within a One Health Approach in Mediterranean Countries

The genus Borrelia has been divided into Borreliella spp., which can cause Lyme Disease (LD), and Borrelia spp., which can cause Relapsing Fever (RF). The distribution of genus Borrelia has broadened due to factors such as climate change, alterations in land use, and enhanced human and animal mobility. Consequently, there is an increasing necessity for a One Health strategy to identify the key components in the Borrelia transmission cycle by monitoring the human-animal-environment interactions. The aim of this study is to summarize all accessible data to increase our understanding and provide a comprehensive overview of Borrelia distribution in the Mediterranean region. Databases including PubMed, Google Scholar, and Google were searched to determine the presence of Borreliella and Borrelia spp. in vectors, animals, and humans in countries around the Mediterranean Sea. A total of 3026 were identified and screened and after exclusion of papers that did not fulfill the including criteria, 429 were used. After examination of the available literature, it was revealed that various species associated with LD and RF are prevalent in vectors, animals, and humans in Mediterranean countries and should be monitored in order to effectively manage and prevent potential infections.

Italian peninsula as a hybridization zone of Ixodes inopinatus and I. ricinus and the prevalence of tick-borne pathogens in I. inopinatus, I. ricinus, and their hybrids

BACKGROUND

Ixodes inopinatus was described from Spain on the basis of morphology and partial sequencing of 16S ribosomal DNA. However, several studies suggested that morphological differences between I. inopinatus and Ixodes ricinus are minimal and that 16S rDNA lacks the power to distinguish the two species. Furthermore, nuclear and mitochondrial markers indicated evidence of hybridization between I. inopinatus and I. ricinus. In this study, we tested our hypothesis on tick dispersal from North Africa to Southern Europe and determined the prevalence of selected tick-borne pathogens (TBPs) in I. inopinatus, I. ricinus, and their hybrids.

METHODS

Ticks were collected in Italy and Algeria by flagging, identified by sequencing of partial TROSPA and COI genes, and screened for Borrelia burgdorferi s.l., B. miyamotoi, Rickettsia spp., and Anaplasma phagocytophilum by polymerase chain reaction and sequencing of specific markers.

RESULTS

Out of the 380 ticks, in Italy, 92 were I. ricinus, 3 were I. inopinatus, and 136 were hybrids of the two species. All 149 ticks from Algeria were I. inopinatus. Overall, 60% of ticks were positive for at least one TBP. Borrelia burgdorferi s.l. was detected in 19.5% of ticks, and it was significantly more prevalent in Ixodes ticks from Algeria than in ticks from Italy. Prevalence of Rickettsia spotted fever group (SFG) was 51.1%, with significantly greater prevalence in ticks from Algeria than in ticks from Italy. Borrelia miyamotoi and A. phagocytophilum were detected in low prevalence (0.9% and 5.2%, respectively) and only in ticks from Italy.

CONCLUSIONS

This study indicates that I. inopinatus is a dominant species in Algeria, while I. ricinus and hybrids were common in Italy. The higher prevalence of B. burgdorferi s.l. and Rickettsia SFG in I. inopinatus compared with that in I. ricinus might be due to geographical and ecological differences between these two tick species. The role of I. inopinatus in the epidemiology of TBPs needs further investigation in the Mediterranean Basin.

Seropositivity of Borrelia burgdorferi s.l. in Germany-an analysis across four German National Cohort (NAKO) study sites

Lyme borreliosis (LB) is caused by the transmission of Borrelia burgdorferi s.l. from ticks to humans. Climate affects tick abundance, and climate change is projected to promote shifts in abundance in Europe, potentially increasing human exposure. We analyzed serum samples collected between the years 2014-2019 from German National Cohort (NAKO) participants at four study sites (Augsburg, Berlin, Hanover, Münster) for immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies using an enzyme-linked immunosorbent assay (ELISA) and line blot immunoassay as confirmatory test for positive and equivocal ELISA samples. We reported crude and weighted seropositivity proportions for local estimates. We used mixed model analysis to investigate associated factors, such as age, sex, migration background, or animal contacts. We determined the serostatus of 14,207 participants. The weighted seropositivity proportions were 3.4% (IgG) and 0.4% (IgM) in Augsburg, 4.1% (IgG) and 0.6% (IgM) in northern Berlin, 3.0% (IgG) and 0.9% (IgM) in Hanover, and 2.7% (IgG) and 0.6% (IgM) in Münster. We found higher odds for IgG seropositivity with advancing age (p < 0.001), among males compared to females (p < 0.001) and reduced odds among participants with migration background compared to those without (p = 0.001). We did not find evidence for an association between serostatus and depression, children within the household, or animal contact, respectively. We found low seropositivity proportions and indications of differences across the study locations, although between-group comparisons did not yield significant results. Comparisons to earlier research are subject to important limitations; however, our results indicate no major increases in seropositivity over time. Nevertheless, monitoring of seropositivity remains critical in light of potential climate-related Borrelia exposure.

Hazard potential of Swiss Ixodes ricinus ticks: Virome composition and presence of selected bacterial and protozoan pathogens

Ticks play an important role in transmitting many different emerging zoonotic pathogens that pose a significant threat to human and animal health. In Switzerland and abroad, the number of tick-borne diseases, in particular tick-borne encephalitis (TBE), has been increasing over the last few years. Thus, it remains essential to investigate the pathogen spectrum of ticks to rapidly detect emerging pathogens and initiate the necessary measures. To assess the risk of tick-borne diseases in different regions of Switzerland, we collected a total of 10'286 ticks from rural and urban areas in ten cantons in 2021 and 2022. Ticks were pooled according to species, developmental stage, gender, and collection site, and analyzed using next generation sequencing (NGS) and quantitative polymerase chain reaction (qPCR). The metagenomic analysis revealed for the first time the presence of Alongshan virus (ALSV) in Swiss ticks. Interestingly, the pool-prevalence of ALSV was higher than that of tick-borne encephalitis virus (TBEV). Furthermore, several TBEV foci have been identified and pool prevalence of selected non-viral pathogens determined.

Multimodal imaging for the management of Lyme-associated uveitis: A case report from an Italian tertiary center

INTRODUCTION

Lyme borreliosis may present with different systemic manifestations and also the ocular involvement may be difficult to diagnose because of its multifaceted presentation. Considering the growing incidence of Lyme disease in European countries, ophthalmologist should be trained to distinguish ocular borreliosis.

CASE REPORT

Several clinical presentations have been previously described, including uveitis, unilateral or bilateral chorioretinitis, keratitis, episcleritis, papillitis and ischemic optic neuropathy, retinal vasculitis and acute posterior multifocal placoid pigment epitheliopathy (APMPPE); however our case report showed a rare presentation with the presence of unilateral uveitis with vitreitis and multiple, patchy, yellowish lesions, in association with retinal vasculitis. This clinical picture was to be considered in differential diagnosis with ocular Toxoplasmosis.

CONCLUSIONS

The appropriate management of this patient was made possible by the combination of multimodal imaging and appropriate laboratory tests, representing the optimal process in the diagnostic and therapeutic pathway in high-risk patients for ocular Lyme disease.

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.

Recombinant protein immunoblots for differential diagnosis of tick-borne relapsing fever and Lyme disease

Lyme disease (LD) is caused by a group of tick-borne bacteria of the genus Borrelia termed Lyme disease Borreliae (LDB). The detection of serum antibodies to specific LDB antigens is widely used to support diagnosis of LD. Recent findings highlight a need for serological tests that can differentiate LD from tick-borne relapsing fever (TBRF) caused by a separate group of Borrelia species termed relapsing fever Borreliae. This is because LD and TBRF share some clinical symptoms and can occur in overlapping locations. The development of serological tests for TBRF is at an early stage compared with LD. This article reviews the application of line immunoblots (IBs), where recombinant proteins applied as lines on nitrocellulose membrane strips are used to detect antibodies in patient sera, for the diagnosis and differentiation of LD and TBRF.

Emergency Department Syndromic Surveillance to Monitor Tick-Borne Diseases: A 6-Year Small-Area Analysis in Northeastern Italy

Tick-borne diseases (TBD) are endemic in Europe. However, surveillance is currently incomplete. Alternative strategies need to be considered. The aim of this study was to test an Emergency Department Syndromic Surveillance (EDSyS) system as a complementary data source to describe the impact of tick bites and TBD using a small-area analysis approach and to monitor the risk of TBD to target prevention. ED databases in the Local Health Authority 8 District (Veneto, Italy) were queried for tick-bite and TBD-related visits between January 2017 and December 2022. Hospitalisations were also collected. Events involving the resident population were used to calculate incidence rates. A total of 4187 ED visits for tick-bite and 143 for TBD were recorded; in addition, 62 TBD-related hospitalisations (of which 72.6% in over 50 s and 22.6% in over 65 s). ED visits peaked in spring and in autumn, followed by a 4-week lag in the increase in hospital admissions. The small-area analysis identified two areas at higher risk of bites and TBD. The use of a EDSyS system allowed two natural foci to be identified. This approach proved useful in predicting temporal and geographic risk of TBD and in identifying local endemic areas, thus enabling an effective multidisciplinary prevention strategy.

Tick-Borne Encephalitis Virus and Borrelia burgdorferi Seroprevalence in Balkan Tick-Infested Individuals: A Two-Centre Study

Lyme borreliosis (LB) and tick-borne encephalitis (TBE) are important tick-borne diseases in Europe. This study aimed to investigate the seroreactivity against Borrelia burgdorferi and TBE virus (TBEV) in tick-infested individuals in North Macedonia and Serbia. Serum samples were collected from tick-infested individuals and from healthy individuals in the same regions. Samples were tested for anti-Borrelia IgG reactivity and TBEV-neutralizing antibodies. Results showed higher seroreactivity against Borrelia antigens in patients and healthy donors from Novi Sad compared to those from the Skopje region. However, there was no statistically significant difference between tick-infested patients and healthy donors within each region. No TBEV-neutralizing antibodies were detected in participants from Novi Sad or in the control groups, except for one person from North Macedonia who had a moderate TBEV-neutralizing reaction. The study highlights the need for improved surveillance and diagnostic capabilities for LB and TBE in these regions. It also suggests the potential existence of TBEV foci in North Macedonia. The findings provide a complementary understanding of the LB and TBE epidemiology in the studied regions; however, further research is needed to investigate the presence and distribution of Borrelia spp. and TBEV in ticks to assess the significance of detected seroreactivity.

Spatial and Temporal Variability in Prevalence Rates of Members of the Borrelia burgdorferi Species Complex in Ixodes ricinus Ticks in Urban, Agricultural and Sylvatic Habitats in Slovakia

Lyme borreliosis (LB) is the most prevalent tick-borne human infection in Europe, with increasing incidence during the latest decades. Abundant populations of Ixodes ricinus, the main vector of the causative agent, spirochetes from the Borrelia burgdorferi sensu lato (Bbsl) complex, have been observed in urban and suburban areas of Europe, in general, and Slovakia, particularly. Understanding the spread of infectious diseases is crucial for implementing effective control measures. Global changes affect contact rates of humans and animals with Borrelia-infected ticks and increase the risk of contracting LB. The aim of this study was to investigate spatial and temporal variation in prevalence of Bbsl and diversity of its species in questing I. ricinus from three sites representing urban/suburban, natural and agricultural habitat types in Slovakia. Ixodes ricinus nymphs and adults were collected by dragging the vegetation in green areas of Bratislava town (urban/suburban habitat), in the Small Carpathians Mountains (natural habitat) (south-western Slovakia) and in an agricultural habitat at Rozhanovce in eastern Slovakia. Borrelia presence in ticks was detected by PCR and Bbsl species were identified by restriction fragment length polymorphism (RFLP). Borrelia burgdorferi s.l. species in coinfected ticks were identified by reverse line blot. Significant spatial and temporal variability in prevalence of infected ticks was revealed in the explored habitats. The lowest total prevalence was detected in the urban/suburban habitat, whereas higher prevalence was found in the natural and agricultural habitat. Six Bbsl species were detected by RFLP in each habitat type -B. burgdorferi sensu stricto (s.s.), B. afzelii, B. garinii, B. valaisiana, B. lusitaniae and B. spielmanii. Coinfections accounted for 3% of the total infections, whereby B. kurtenbachii was identified by RLB and sequencing in mixed infection with B. burgdorferi s.s, B. garinii and B. valaisiana. This finding represents the first record of B. kurtenbachii in questing I. ricinus in Slovakia and Europe. Variations in the proportion of Bbsl species were found between nymphs and adults, between years and between habitat types. Spatial variations in prevalence patterns and proportion of Bbsl species were also confirmed between locations within a relatively short distance in the urban habitat. Habitat-related and spatial variations in Borrelia prevalence and distribution of Bbsl species are probably associated with the local environmental conditions and vertebrate host spectrum. Due to the presence of Borrelia species pathogenic to humans, all explored sites can be ranked as areas with high epidemiological risk.

Annular dermatoses with rheumatologic implications

A wide variety of cutaneous disorders present with annular (ringlike) skin lesions, and some of them carry rheumatologic implications because they may involve the joints or belong to the spectrum of connective tissue diseases. The diagnosis of an annular rheumatologic skin disease is possible with a correct clinicopathologic correlation, with a correct anamnesis of the patient, with the evaluation of systemic symptoms, laboratory and instrumental investigations, and finally with a cutaneous biopsy.

Neuroborreliosis and Post-Treatment Lyme Disease Syndrome: Focus on Children

Neuroborreliosis is a form of Lyme Borreliosis (LB) that affects various structures of the central and peripheral nervous system. Although most cases of LB can be cured with a course of antibiotics, some children can present prolonged symptoms, which may constitute post-treatment Lyme disease syndrome (PTLDS). The aim of our analysis was the long-term observation of children with NB and the determination of their risk of PTLDS. The clinical observation was supplemented by a laboratory study based on the assessment of the dynamics of anti-VlsE (variable major protein-like sequence, expressed) IgG antibodies in children with NB after antibiotic therapy. The prospective survey based on 40 children presented 1-2 forms of NB. The control group consisted of 36 patients with analogical symptoms for whom LB was excluded. Our long-term observation showed a low risk of developing long-term complications in children who received antibiotic therapy in accordance with the recommendations. The concentration of anti-VlsE IgG demonstrates a statistical significance for differences between the control and the study groups for each measurement period. Higher values of anti-VlsE IgG were observed in the study group, and the concentration decreased from the first measurement period to the next. The article emphasizes the importance of the long-term follow-up of children with neuroborreliosis.

Is Borrelia burgdorferi Sensu Stricto in South America? First Molecular Evidence of Its Presence in Colombia

The genus Borrelia encompasses spirochetal species that are part of three well-defined groups. Two of these groups contain pathogens that affect humans: the group causing Lyme disease (LDG) and the relapsing fever group (RFG). Lyme disease is caused by Borrelia burgdorferi s.l., which is distributed in the Northern Hemisphere, and relapsing fevers are caused by Borrelia spp., which are found in temperate and tropical countries and are an emerging but neglected pathogens. In some departments of Colombia, there are records of the presence of Borrelia sp. in humans and bats. However, little is known about the impact and circulation of Borrelia spp. in the country, especially in wildlife, which can act as a reservoir and/or amplifying host. In this context, the objective of our research was to detect and identify the Borrelia species present in wild mammals in the departments of Caldas and Risaralda in Colombia. For morphological detection, blood smears and organ imprints were performed, and molecular identification was carried out through a nested PCR directed on the flagellin B (flaB) gene. A total of 105 mammals belonging to three orders (Chiroptera, Didelphimorphia and Rodentia) were analyzed, of which 15.24% (n = 16) were positive for Borrelia. Molecularly, the presence of Borrelia burgdorferi s.s. in lung tissues of Thomasomys aureus and blood of Mus musculus (Rodentia) was detected, with 99.64 and 100% identity, respectively. Borrelia sp. genospecies from a clade branch of a bat-associated LDG sister group were identified in seven individuals of bat species, such as Artibeus lituratus, Carollia brevicauda, Sturnira erythromos, and Glossophaga soricina. Furthermore, two Borrelia genospecies from the RFG in seven individuals of bats (A. lituratus, Artibeus jamaicensis, Platyrrhinus helleri, Mesophylla macconnelli, Rhynchonycteris naso) and rodents (Coendou rufescens, Microryzomys altissimus) were documented. Additionally, the presence of a spirochete was detected by microscopy in the liver of a Sturnira erythromos bat specimen. These results contain the first molecular evidence of the presence of B. burgdorferi s.s. in South America, which merits the need for comprehensive studies involving arthropods and vertebrates (including humans) in other departments of Colombia, as well as neighboring countries, to understand the current status of the circulation of Borrelia spp. in South America.

FtlA and FtlB Are Candidates for Inclusion in a Next-Generation Multiantigen Subunit Vaccine for Lyme Disease

Lyme disease (LD) is a tick-transmitted bacterial infection caused by Borreliella burgdorferi and other closely related species collectively referred to as the LD spirochetes. The LD spirochetes encode an uncharacterized family of proteins originally designated protein family twelve (PF12). In B. burgdorferi strain B31, PF12 consists of four plasmid-carried genes, encoding BBK01, BBG01, BBH37, and BBJ08. Henceforth, we designate the PF12 proteins family twelve lipoprotein (Ftl) A (FtlA) (BBK01), FtlB (BBG01), FtlC (BBH37), and FtlD (BBJ08). The goal of this study was to assess the potential utility of the Ftl proteins in subunit vaccine development. Immunoblot analyses of LD spirochete cell lysates demonstrated that one or more of the Ftl proteins are produced by most LD isolates during cultivation. The Ftl proteins were verified to be membrane associated, and nondenaturing PAGE revealed that FtlA, FtlB, and FtlD formed dimers, while FtlC formed hexamers. Analysis of serum samples from B. burgdorferi antibody (Ab)-positive client-owned dogs (n = 50) and horses (n = 90) revealed that a majority were anti-Ftl Ab positive. Abs to the Ftl proteins were detected in serum samples from laboratory-infected dogs out to 497 days postinfection. Anti-FtlA and FtlB antisera displayed potent complement-dependent Ab-mediated killing activity, and epitope localization revealed that the bactericidal epitopes reside within the N-terminal domain of the Ftl proteins. This study suggests that FtlA and FtlB are potential candidates for inclusion in a multivalent vaccine for LD.

Detection of 41-kDa bacterial flagellin protein by the lymphocyte transformation test-memory lymphocyte immunostimulation assay

BACKGROUND/OBJECTIVES

Diagnosis of human infection by various species of the bacterial genus Borrelia is mainly reliant on serological testing, polymerase chain reaction (PCR) or culture but such serological tests have been reported to have heterogeneous sensitivities, while Borrelia PCR and culture have been reported as being of modest diagnostic value. It has been suggested that the adjunctive use of the lymphocyte transformation test-memory lymphocyte immunostimulation assay (LTT-MELISA) may be helpful in this regard; however, the clinical usefulness of this assay has been questioned. The Borrelia immunodominant 41-kDa flagellin protein almost always gives rise to a marked human antibody response following infection. It was therefore decided to determine whether the LTT-MELISA detects the human antibody response to this antigen.

METHODS

Blood samples from consecutive patients with possible borreliosis attending a clinic were independently tested by both Western blots and LTT-MELISA.

RESULTS

After omitting cases with indeterminate Western blot results and equivocal LTT-MELISA results, multiple linear regression modelling demonstrated that the 41-kDa flagellin immunoglobulin (Ig) M level was predictable from two LTT-MELISA variables (F _2,51 = 5.981, P = 0.005). Similarly, the corresponding 41-kDa IgG model also contained two LTT-MELISA variables (F _2,57 = 3.700, P = 0.031).

CONCLUSION

It is concluded that the LTT-MELISA appears to be able to detect the response to this antigen.

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.

Prevalence of Tick-Borne Pathogens in Questing Ixodes ricinus and Dermacentor reticulatus Ticks Collected from Recreational Areas in Northeastern Poland with Analysis of Environmental Factors

Ticks, such as Ixodes ricinus and Dermacentor reticulatus, act as vectors for multiple pathogens posing a threat to both human and animal health. As the process of urbanization is progressing, those arachnids are being more commonly encountered in urban surroundings. In total, 1112 I. ricinus (n = 842) and D. reticulatus (n = 270) ticks were collected from several sites, including recreational urban parks, located in Augustów and Białystok, Poland. Afterwards, the specimens were examined for the presence of Borrelia spp., Babesia spp., Anaplasma phagocytophilum, Rickettsia spp., Bartonella spp., and Coxiella burnetii using the PCR method. Overall obtained infection rate reached 22.4% (249/1112). In total, 26.7% (225/842) of I. ricinus was infected, namely with Borrelia spp. (25.2%; 212/842), Babesia spp. (2.0%; 17/842), and A. phagocytophilum (1.2%; 10/842). Among D. reticulatus ticks, 8.9% (24/270) were infected, specifically with Babesia spp. (7.0%; 19/270), A. phagocytophilum (1.1%; 3/270), and Borrelia burgdorferi s.l. (0.7%; 2/270). No specimen tested positively for Rickettsia spp., Bartonella spp., or Coxiella burnetii. Co-infections were detected in 14 specimens. Results obtained in this study confirm that I. ricinus and D. reticulatus ticks found within the study sites of northeastern Poland are infected with at least three pathogens. Evaluation of the prevalence of pathogens in ticks collected from urban environments provides valuable information, especially in light of the growing number of tick-borne infections in humans and domesticated animals.

Overview of case definitions and contact tracing indications in the 2022 monkeypox outbreak

Background

In 2022, a new outbreak of the Mpox virus occurred outside of Africa, its usual endemic area. The virus was detected in European, American, Asian, and Oceanian countries where Mpox is uncommon or had not been reported previously and where the spread was rapid. The study aims to compare the case definition and the indications for contact tracing in case of Mpox infection among the World Health Organization (WHO), the European Centre for Disease Prevention and Control (ECDC), and four European Countries.

Methods

From August 2022 to November 2022, we conducted research, first on the WHO and ECDC official websites and then on the official websites of the Ministry of Health or National Health Agencies of four European Countries (Italy, France, Spain, and Portugal). All reports found were compared to enlighten the differences in the definition of the case and indications for contact tracing.

Results

The WHO divides the case definition into four categories: suspected, probable, confirmed, and discarded, while the ECDC divides cases into confirmed and probable. The ECDC defines contact as close and others, while the WHO divides it into high, medium, and minimal risk. The four countries analyzed show heterogeneity in both the case definitions and the indications for contact tracing.

Conclusions

Our analysis revealed heterogeneity in the case definition between the WHO and ECDC. Different countries followed different indications or have given their indications for both the case definition and contact tracing indications. Harmonization strengthens public health preparedness and response and creates unified communication.