Lyme borreliosis

Human-biting ticks and zoonotic tick-borne pathogens in North Africa: diversity, distribution, and trans-Mediterranean public health challenges

North Africa is home to more than 200 million people living across five developing economies (Egypt, Libya, Tunisia, Algeria, and Morocco) and two Spanish exclaves (Ceuta and Melilla), many of whom are impacted by ticks and tick-borne zoonoses. Populations in Europe are also increasingly vulnerable to North African ticks and tick-borne zoonoses due to a combination of climate change and the movement of ticks across the Mediterranean on migratory birds, human travellers, and trafficked wildlife. The human-biting ticks and tick-borne zoonoses in North Africa are reviewed along with their distribution in the region. We also assess present and future challenges associated with ticks and tick-borne zoonoses in North African and highlight opportunities for collaboration and coordination between governments in Europe and North Africa to address public health challenges posed by North African ticks and tick-borne zoonoses.

Antimicrobial resistance gene lack in tick-borne pathogenic bacteria

Tick-borne infections, including those of bacterial origin, are significant public health issues. Antimicrobial resistance (AMR), which is one of the most pressing health challenges of our time, is driven by specific genetic determinants, primarily by the antimicrobial resistance genes (ARGs) of bacteria. In our work, we investigated the occurrence of ARGs in the genomes of tick-borne bacterial species that can cause human infections. For this purpose, we processed short/long reads of 1550 bacterial isolates of the genera Anaplasma (n = 20), Bartonella (n = 131), Borrelia (n = 311), Coxiella (n = 73), Ehrlichia (n = 13), Francisella (n = 959) and Rickettsia (n = 43) generated by second/third generation sequencing that have been freely accessible at the NCBI SRA repository. From Francisella tularensis, 98.9% of the samples contained the FTU-1 beta-lactamase gene. However, it is part of the F. tularensis representative genome as well. Furthermore, 16.3% of them contained additional ARGs. Only 2.2% of isolates from other genera (Bartonella: 2, Coxiella: 8, Ehrlichia: 1, Rickettsia: 2) contained any ARG. We found that the odds of ARG occurrence in Coxiella samples were significantly higher in isolates related to farm animals than from other sources. Our results describe a surprising lack of ARGs in these bacteria and suggest that Coxiella species in farm animal settings could play a role in the spread of AMR.

A portable immunosensor provides sensitive and rapid detection of Borrelia burgdorferi antigen in spiked blood

There are no assays for detecting B. burgdorferi antigen in blood of infected Lyme disease individuals. Here, we provide proof-of-principle evidence that we can quantify B. burgdorferi antigen in spiked blood using a portable smartphone-based fluorescence microscope that measures immunoagglutination on a paper microfluidic chip. We targeted B. burgdorferi OspA to develop a working prototype and added examples of two antigens (OspC and VlsE) that have diagnostic value for discrimination of Lyme disease stage. Using an extensively validated monoclonal antibody to OspA (LA-2), detection of OspA antigen had a broad linear range up to 100 pg/mL in 1% blood and the limit of detection (LOD) was 100 fg/mL (= 10 pg/mL in undiluted blood), which was 1000 times lower than our target of 10 ng/mL. Analysis of the two other targets was done using polyclonal and monoclonal antibodies. OspC antigen was detected at LOD 100 pg/mL (= 10 ng/mL of undiluted blood) and VlsE antigen was detected at LOD 1-10 pg/mL (= 0.1-1 ng/mL of undiluted blood). The method is accurate and was performed in 20 min from sample to answer. When optimized for detecting several B. burgdorferi antigens, this assay may differentiate active from past infections and facilitate diagnosis of Lyme disease in the initial weeks of infection, when antibody presence is typically below the threshold to be detected by serologic methods.

Classical Borrelia Serology Does Not Aid in the Diagnosis of Persistent Symptoms Attributed to Lyme Borreliosis: A Retrospective Cohort Study

OBJECTIVE

The diagnosis of Lyme borreliosis is based on two-tier testing using an ELISA and Western blot. About 5-10% of patients report persistent symptoms of unknown etiology after treatment, resulting in substantial difficulties in further diagnostic workup. This paper presents a study aimed at determining whether serology can differentiate between patients with persistent symptoms attributed to Lyme and other patients with Lyme borreliosis.

METHODS

A retrospective cohort study included 162 samples from four subgroups: patients with persistent symptoms of Lyme (PSL), early Lyme borreliosis with erythema migrans (EM), patients tested in a general practitioner setting (GP), and healthy controls (HC). ELISA, Western blots, and multiplex assays from different manufacturers were used to determine inter-test variations in PSL and to compare reactivity against Borrelia-specific antigens among the groups.

RESULTS

In comparing the IgG and IgM reactivity by Western blot, IgG was more often positive in the PSL group than in the GP group. The individual antigen reactivity was similar between the PSL and EM or GP groups. Inter-test agreement among the manufacturers was variable, and agreement was higher for IgG testing compared to IgM.

CONCLUSIONS

Serological testing is unable to define the subgroup of patients with persistent symptoms attributed to Lyme borreliosis. Additionally, the current two-tier testing protocol shows a large variance among different manufacturers in these patients.

Detection of Borrelia burgdorferi sensu lato DNA in cerebrospinal fluid samples following pre-enrichment culture

Molecular methods for diagnosing Lyme neuroborreliosis (LNB) have shown suboptimal diagnostic sensitivities. The objective of this study was to improve the clinical sensitivity of PCR detection of Borrelia burgdorferi sensu lato spirochetes by inoculating cerebrospinal fluid (CSF) from patients suspected of LNB directly into culture medium at the time of lumbar puncture, with this pursuing enrichment of Borrelia spirochetes before PCR analysis. Adult patients with symptoms suggestive of LNB were prospectively enrolled at two hospitals in the Region of Southern Denmark. The CSF-culture samples were incubated for at least eight weeks. During this period, culture sample aliquots were analysed for the presence of Borrelia DNA by separate PCR protocols in two independent clinical laboratories. The included patients were diagnosed with definite (n=12) or possible (n=2) LNB, and non-LNB (n=171) based on clinical and paraclinical findings. Patients in the LNB and the non-LNB group had a median duration from symptom onset to lumbar puncture of 40 days (IQR [23-90] days) and 120 days (IQR [32-365] days), respectively. Pre-enrichment growth of Borrelia spirochetes was accomplished from three patients (21 %) in the LNB group. The positive culture samples were confirmed by both the digital droplet PCR and the real-time PCR methods employed. All CSF samples were PCR negative in the non-LNB group. The results of this study do not support the use of Borrelia-specific PCR as a general routine diagnostic tool in adults. Still, they suggest it may prove of additional value in selected patients with a limited time from symptom onset to sample collection.

Chemotaxis Coupling Protein CheW2 Is Not Required for the Chemotaxis but Contributes to the Full Pathogenicity of Borreliella burgdorferi

The bacterial chemotaxis regulatory circuit mainly consists of coupling protein CheW, sensor histidine kinase CheA, and response regulator CheY. Most bacteria, such as Escherichia coli, have a single gene encoding each of these proteins. Interestingly, the Lyme disease pathogen, Borreliella burgdorferi, has multiple chemotaxis proteins, e.g., two CheA, three CheW, and three CheY proteins. The genes encoding these proteins mainly reside in two operons: cheW2-cheA1-cheB2-cheY2 (A-I) and cheA2-cheW3-cheX-cheY3 (A-II). Previous studies demonstrate that all the genes in A-II are essential for the chemotaxis of B. burgdorferi; however, the role of those genes in A-I remains unknown. This study aimed to fill this gap using the CheW2 gene, the first gene in A-I, as a surrogate. We first mapped the transcription start site of A-I upstream of cheW2 and identified a σ70-like promoter (PW2) and two binding sites (BS1 and BS2) of BosR, an unorthodox Fur/Per homolog. We then demonstrated that BosR binds to PW2 via BS1 and BS2 and that deletion of bosR significantly represses the expression of cheW2 and other genes in A-I, implying that BosR is a positive regulator of A-I. Deletion of cheW2 has no impact on the chemotaxis of B. burgdorferi in vitro but abrogates its ability to evade host adaptive immunity, because the mutant can establish systemic infection only in SCID mice and not in immunocompetent BALB/c mice. This report substantiates the previous proposition that A-I is not implicated in chemotaxis; rather, it may function as a signaling transduction pathway to regulate B. burgdorferi virulence gene expression.

Prevalence of Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Rickettsia spp. and Babesia spp. in cattle serum and questing ticks from Belgium

BACKGROUND

Anaplasmosis, borreliosis, rickettsiosis and babesiosis are tick-borne diseases of medical, veterinary and economic importance. In Belgium, little is known on the prevalence of these diseases in animals and previous screenings relate only to targeted geographic regions, clinical cases or a limited number of tested samples. We therefore performed the first nationwide seroprevalence study of Anaplasma spp., A. phagocytophilum, Borrelia spp., Rickettsia spp. and Babesia spp. in Belgian cattle. We also screened questing ticks for the aforementioned pathogens.

METHODS

ELISAs and IFATs were performed on a representative sample set of cattle sera stratified proportionally to the number of cattle herds per province. Questing ticks were collected in areas where the highest prevalence for the forenamed pathogens in cattle serum were observed. Ticks were analyzed by quantitative PCR for A. phagocytophilum (n = 783), B. burgdorferi sensu lato (n = 783) and Rickettsia spp. (n = 715) and by PCR for Babesia spp. (n = 358).

RESULTS

The ELISA screening for antibodies to Anaplasma spp. and Borrelia spp. in cattle sera showed an overall seroprevalence of 15.6% (53/339) and 12.9% (52/402), respectively. The IFAT screening for antibodies against A. phagocytophilum, Rickettsia spp. and Babesia spp. resulted in an overall seroprevalence of 34.2% (116/339), 31.2% (99/317) and 3.4% (14/412), respectively. At the provincial level, the provinces of Liege and Walloon Brabant harboured the highest seroprevalence of Anaplasma spp. (44.4% and 42.7% respectively) and A. phagocytophilum (55.6% and 71.4%). East Flanders and Luxembourg exhibited the highest seroprevalence of Borrelia spp. (32.4%) and Rickettsia spp. (54.8%) respectively. The province of Antwerp showed the highest seroprevalence of Babesia spp. (11%). The screening of field-collected ticks resulted in a prevalence of 13.8% for B. burgdorferi s.l., with B. afzelii and B. garinii being the most common genospecies (65.7% and 17.1%, respectively). Rickettsia spp. was detected in 7.1% of the tested ticks and the only identified species was R. helvetica. A low prevalence was found for A. phagocytophilum (0.5%) and no Babesia positive tick was detected.

CONCLUSIONS

The seroprevalence data in cattle indicate hot spots for tick-borne pathogens in specific provinces and highlights the importance of veterinary surveillance in anticipating the emergence of diseases among humans. The detection of all pathogens, with the exception of Babesia spp. in questing ticks, underlines the need of raising awareness among public and professionals on other tick-borne diseases along with lyme borreliosis.

Detection, identification and genotyping of Borrelia spp. in ticks of Coastal-Karst and Littoral-Inner Carniola regions in Slovenia

The density and spread of tick vector species have increased throughout Europe in the last 30 years, leading to an increase of Lyme borreliosis cases, including in Slovenia. The aim of this study was to isolate Borrelia strains and determine the prevalence of B. burgdorferi sensu lato and B. miyamotoi in adults of Ixodes ricinus (Linnaeus) collected in 2019 in the two regions of the country (Coastal-Karst and Littoral-Inner Carniola) by cultivation and PCR. We isolated B. burgdorferi s.l. by culture method in 28/559 (5%) ticks from both regions. Culture-negative samples (531/559, i.e., 95%) were additionally tested by real-time PCR. In 155/531 (29.2%) PCR-positive samples, a fragment of flaB or glpQ was amplified and further sequenced to identify species of the Borrelia. Using both methods, cultivation and PCR, Borrelia spp. prevalence was 32.7% in the Coastal-Karst region and 33.0% in the Littoral-Inner Carniola region. Genotyping of the Borrelia spp. isolates revealed that 17/28 (60%) were B. garinii subtype Mlg2. Of all tick samples tested for B. miyamotoi 8/398 (2%) were PCR positive. Based on previous studies in these regions, we had expected more ticks to be infected with B. afzelii, but genotyping revealed that B. garinii was the most abundant.

Cerebrospinal fluid levels of the macrophage-specific biomarker sCD163 are diagnostic for Lyme neuroborreliosis: an observational cohort study

OBJECTIVES

We aimed to investigate levels of the macrophage-specific marker, sCD163, in cerebrospinal fluid and plasma in patients with Lyme neuroborreliosis. We tested the diagnostic value of CSF-sCD163 and ReaScan-CXCL13 and analyzed if plasma-sCD163 could monitor treatment response.

METHODS

An observational cohort study: Cohort 1-Cerebrospinal fluid from adults with neuroborreliosis (n=42), bacterial meningitis (n=16), enteroviral meningitis (n=29), and controls (n=33); Cohort 2-Plasma from 23 adults with neuroborreliosis collected at diagnosis, three, and six months. sCD163 was determined using an in-house sandwich ELISA. ReaScan-CXCL13 measured semiquantitative concentrations of CXCL13, cut-off ≥250 pg/ml diagnosed neuroborreliosis. Receiver Operating Characteristics analyzed the diagnostic strength. A linear mixed model including follow-up as categorical fixed effect analyzed differences in plasma-sCD163.

RESULTS

CSF-sCD163 was higher in neuroborreliosis (643 µg/l) than in enteroviral meningitis (106 µg/l, p<0.0001) and controls (87 µg/l, p<0.0001), but not bacterial meningitis (669 µg/l, p=0.9). The optimal cut-off was 210 µg/l, area under the curve (AUC) 0.85. Combining ReaScan-CXCL13 with CSF-sCD163 increased AUC to 0.89. Plasma-sCD163 showed little variation and was not elevated during the 6 months of follow-up. Conclusion CSF-sCD163 is diagnostic for neuroborreliosis with an optimal cut-off of 210 µg/l. Combining ReaScan-CXCL13 with CSF-sCD163 increases AUC. Plasma-sCD163 cannot monitor treatment response.

Clinical manifestations of Lyme neuroborreliosis in children: a review

Lyme neuroborreliosis (LNB) is a manifestation of Lyme disease involving the central and peripheral nervous system. It is caused by the spirochete Borrelia burgdorferi, transmitted by tick bites to a human host. Clinical signs of LNB develop after the dissemination of the pathogen to the nervous system. The infection occurs in children and adults, but the clinical manifestations differ. In adults, painful meningoradicultis is the most common manifestation of LNB, while children often present with facial nerve palsy and/or subacute meningitis. Subacute headache can be the only manifestation of LNB in children, especially during the summer months in Lyme disease-endemic regions. Non-specific symptoms, such as loss of appetite, fatigue or mood changes, may also occur, especially in young children. A high level of suspicion and early recognition of the various clinical manifestations presented by children with LNB is essential to minimize delay in diagnosis and optimize management. This review provides an overview of the spectrum of clinical manifestations, and discusses diagnosis, antibiotic treatment, and clinical outcome of LNB in children.

Lyme Borreliosis in Dogs: Background, Epidemiology, Diagnostics, Treatment and Prevention

Lyme borreliosis (LB) is a multisystemic tick-borne disease that can affect many organs and have various clinical manifestations in dogs. We attempted to summarise various aspects of Lyme disease: i. e., pathogenesis, epidemiology, benefits and risks of diagnostic approaches, treatment options, and prevention in dogs. Several diagnostic bottlenecks for LB in dogs and humans are compared. Because the occurrence of LB in both humans and dogs is closely related, monitoring its prevalence in dogs as sentinel animals is an excellent aid in assessing the risk of Lyme disease in a given geographic area. Although clinical symptoms in humans help clinicians diagnose LB, they are ineffective in dogs because canines rarely exhibit LB symptoms. Despite significant differences in sensitivity and specificity, sero-logical two-step detection of antibodies against Borrelia spp. (ELISA and Western blot) is the most commonly used method in humans and dogs. The limitations of the assay highlight the need for further research to develop new clinical markers and more accurate diagnostic tests. Due to the lack of a specific all-encompassing LB test, a definitive diagnosis of LB remains a difficult and time-consuming process in human and veterinary medicine. Understanding the disease prevalence and diagnostics, as well as preventing its spread with effective and timely treatment, are fundamental principles of good disease management.

Retrospective Study of Tick Bites Associated with Neurological Disease in a Level Three University Hospital in Switzerland

BACKGROUND

Ticks represent very important vectors of human and zoonotic pathogens, and tick-borne diseases (TBDs) are diagnosed with increasing frequency. Therefore, the aim of this retrospective study was to describe patients presenting with a complaint of tick bite in the emergency department (ED) of a large university hospital in Switzerland.

METHODS

Data were collected by searching for keywords in the routine clinic database to identify cases from 1 July 2012 to 30 June 2020. The patients' data were screened for preexisting diseases and demographic and clinical characteristics.

RESULTS

We included 415 patients collected over a period of 8 years, with highest admission frequencies from May to July. Of these, 82% were outpatients, 15.9% admitted to a hospital ward, and five to intensive care. The patients were allocated to three groups. The first group represented patients with erythema chronica migrans (ECM), which is pathognomonic for Lyme borreliosis (n = 45). Accordingly, 89% of cases in this group of patients were treated with antibiotics. The second group represented patients with other tick bite-associated erythema (n = 139). In this group, no particular clinical symptoms or laboratory findings were found. Finally, the largest group represented patients in which the tick bite was no longer visible (n = 201). This group of patients had significantly more evidence of neurological disorders (52%) and were treated at a higher rate with non-steroidal anti-inflammatory (29%) or antiviral (13%) drugs. Although the vaccination status for tick-borne encephalitis virus (TBEV) was not systematically evaluated, at least 10% of the latter group was vaccinated, indicating another source for neurological disease. Furthermore, only 14% of the tested patients were positive for IgM or IgG against TBEV.

CONCLUSION

This retrospective study indicates the presence of many undiagnosed neurological diseases following tick bites that could be caused by TBEV or an unknown infectious agent. Taken together, although tick bites were not very frequently seen in the present tertiary ED, the frequent presence of neurological symptoms demands a more systematic assessment of vaccination status and TBEV serology as well as further diagnostic evaluations in patients that report tick bites and neurological symptoms.

Tick maps on the virtual globe: First results using the example of Dermacentor reticulatus

Digital maps, particularly displayed on virtual globes, will represent the most important source of geographical knowledge in the future. The best known of these virtual globes is Google Earth, whose use in teaching at schools and universities is now common practice. As the first result of a series of forthcoming digital tick maps, the worldwide distribution of the marsh tick Dermacentor reticulatus is shown on Google Earth. For this purpose, various distribution maps of D. reticulatus were compiled, including digitized expert maps and a map of suitable habitats compiled with a species distribution model (SDM). A random forest model that estimates suitable habitats by combining information from tick observations, bioclimatic variables, altitude, and land cover was chosen for the latter. In the Google Earth application, the following maps can be selected: a historical expert map, a current expert map, a SDM predicted habitat suitability map, a combined expert-habitat suitability map (considered to be the best representation of the current distribution of D. reticulatus), and a map of rasterized tick locations. Users can overlay these maps according to their own requirements or combine it with other Google Earth content. For example, a comparison of the historical with the current expert map shows the spread of D. reticulatus over the past few decades. Additionally, high-resolution city maps of Bilbao (Spain), Grenoble (France), Berlin (Germany), Wrocław (Poland), Budapest (Hungary), Bucharest (Romania), and Tomsk (Russia) demonstrate the urban distribution of D. reticulatus in public parks, fallow land, and recreational areas. The Google Earth application, developed using the Keyhole Markup Language (KML), also contains fact sheets on biology, ecology, seasonal activity, and vector competence of D. reticulatus. This information has been prepared in a compact and easily understandable way for the target group, i.e. scientists from various disciplines, students, and lay people interested in the geographical distribution of ticks.

Physiotherapy and ecosystem services: improving the health of our patients, the population, and the environment

INTRODUCTION

The relevance of ecosystems to physiotherapy has traditionally been overlooked, despite its potential for health impacts relevant to conditions often managed by physiotherapists.

PURPOSE

The purpose of this article is to introduce the concept of ecosystem services to physiotherapists, and to discuss how understanding ecosystem services may improve patient care, and population and planetary health.

DISCUSSION AND CONCLUSION

Physiotherapists with an understanding of ecosystem services may improve patient care by value-adding to management through patient education, empathy, advocacy, and broader population health approaches. Physiotherapists are also well placed to promote the conservation and restoration of ecosystem through participation, advocacy, and the development of public health measures, to the benefit of global sustainability and population health. Further research is required into how physiotherapists currently use nature-based interventions, and the barriers and enablers to their use. To be adequately prepared to meet the challenges that climate change and environmental degradation pose to patient care, population health and health systems, both current and future physiotherapists need to take a broader view of their practice. By including consideration of the potential role of the environment and green space exposure in particular on their patient's health, physiotherapists can ultimately contribute more to population and planetary health.

Exploration of the induced cytokine responses in European Lyme neuroborreliosis: A longitudinal cohort study

Lyme neuroborreliosis (LNB) is a prevalent tick-borne disease in Europe caused by Borrelia burgdorferi sensu lato complex. Slightly suppressed induced Th1- and Th17-responses are seen at diagnosis. The induced immune response following antibiotic therapy is unknown. We hypothesized that the immune responses normalize after completing antibiotic treatment. An observational longitudinal cohort study investigating the induced immune response in adult patients with LNB at diagnosis, three and six months after treatment. Whole blood was added to three TruCulture® (Myriad RBM, Austin, USA) tubes each containing one stimulation. An additional TruCulture® tube was without stimulation representing the in vivo activation of blood immune cells. Nine cytokines were measured using Luminex (LX200, R&D Systems, BIO-Teche LTD). Changes in immune response were analyzed with linear mixed model including follow-up as categorical fixed effect. A total of 21 patients with 55 samples were included. All had clinical improvement, but 5/21 patients reported residual symptoms after six months. The non-induced release of IL-17A and IL-1β increased significantly from diagnosis to six month follow-up. Six months after treatment only IFN-α and TNF-α were below the reference range. Minor variations in the induced immune responses were seen during the study period. Th1- and Th17-responses continued to be low with low IFN-γ, IL-12p40, and IL-17A in multiple stimulations. Overall little dynamic was observed. The changes in the cytokine responses are most likely not linked to LNB pathogenesis and our results do not support the implementation of TruCulture® in the diagnostics or follow-up of LNB.

15-year Borrelia prevalence and species distribution monitoring in Ixodes ricinus/inopinatus populations in the city of Hanover, Germany

Lyme borreliosis, caused by Borrelia burgdorferi sensu lato (s.l.) spirochaetes, is the most common tick-borne disease (TBD) in the Northern Hemisphere. Rising incidences indicate that its epidemiology may be affected by global changes. Therefore, the current study aimed to assess changes in tick infection rates with Borrelia spp. over a 15-year monitoring period in the city of Hanover, Germany, as a follow-up to previous prevalence studies (years 2005, 2010 and 2015). To assess the epidemiological risk, ticks of the Ixodes ricinus/inopinatus-complex were sampled from April to October 2020 by the flagging method at 10 frequently visited recreation areas in Hanover. Analysis by quantitative real-time PCR of 2100 individual ticks revealed an overall Borrelia prevalence of 25.5% (535/2100). Regarding different tick developmental stages, nymphs showed a significantly lower Borrelia prevalence (18.4% [193/1050]) than adult ticks (32.6% [342/1050]). Comparison with previous years revealed a stable total Borrelia prevalence along with consistent infection rates in the different developmental stages over the 15-year monitoring period. Borrelia species differentiation by Reverse Line Blot was successful in 67.3% of positive ticks collected in 2020, with B. afzelii being the dominating species (59.2% of the differentiated infections), besides B. burgdorferi sensu stricto (s.s.), B. garinii, B. valaisiana, B. spielmanii, B. bavariensis and B. bissettiae and the relapsing fever spirochaete B. miyamotoi. Additionally, the proportion of infections attributed to B. afzelii showed a significant increase in 2020 compared to 2005 and 2015 (59.2% vs. 37.6% and 32.0% of successfully differentiated infections, respectively). Coinfections with Anaplasma phagocytophilum and Rickettsia spp. stayed stable comparing 2020 with previous years. Therefore, although changes in the Borrelia prevalence in questing ticks were not observed throughout the 15-year monitoring period, shifts in Borrelia species distribution may alter the epidemiological risk.

The Infection Rate of Bird-Feeding Ixodes ricinus Ticks with Borrelia garinii and B. valaisiana Varies with Host Haemosporidian Infection Status

BACKGROUND

Birds are known to maintain and spread human pathogenic borreliae, but they are common hosts of diverse parasite communities, notably haemosporidians. Only a few studies examined whether tick infestation and/or Borrelia prevalences vary with hosts' haemosporidian infection status.

METHODS

Here, we study whether Ixodes ricinus infestation rates and Borrelia infection rates in bird-feeding ticks vary according to haemosporidian infection status in a community of free-living avian tick hosts.

RESULTS

Birds of six avian species harbored the majority of ticks. Both the tick infestation prevalence and the intensity peaked during spring and summer, but while bird-feeding nymphs prevailed in spring, bird-feeding larvae dominated in summer. Almost half of the bird-feeding ticks were found to be positive for B. burgdorferi s.l. Although the majority of infections involved bird-associated B. garinii and B. valaisiana, B. garinii appears to be the dominant Borrelia strain circulating in locally breeding avian species. We detected a negative link between the hosts' haemosporidian infection status and the Borrelia infection rate of bird-feeding ticks, but the association was dependent on the host's age.

CONCLUSIONS

Our results on tick infestation intensity support the idea that more immunologically vulnerable hosts harbor more ticks but suggest that different mechanisms may be responsible for tick infestation rates among immunologically naïve and experienced avian hosts. The results on Borrelia infection rates in bird-feeding ticks are consistent with studies revealing that intracellular parasites, such as haemosporidians, can benefit from the host immune system prioritizing immune responses against extracellular parasites at the expense of immune responses against intracellular parasites. The findings of our study urge for a more robust design of parasitological studies to understand the ecology of interactions among hosts and their parasites.

Expounding the role of tick in Africa swine fever virus transmission and seeking effective prevention measures: A review

African swine fever (ASF), a highly contagious, deadly infectious disease, has caused huge economic losses to animal husbandry with a 100% mortality rate of the most acute and acute infection, which is listed as a legally reported animal disease by the World Organization for Animal Health (OIE). African swine fever virus (ASFV) is the causative agent of ASF, which is the only member of the Asfarviridae family. Ornithodoros soft ticks play an important role in ASFV transmission by active biological or mechanical transmission or by passive transport or ingestion, particularly in Africa, Europe, and the United States. First, this review summarized recent reports on (1) tick species capable of transmitting ASFV, (2) the importance of ticks in the transmission and epidemiological cycle of ASFV, and (3) the ASFV strains of tick transmission, to provide a detailed description of tick-borne ASFV. Second, the dynamics of tick infection with ASFV and the tick-induced immune suppression were further elaborated to explain how ticks spread ASFV. Third, the development of the anti-tick vaccine was summarized, and the prospect of the anti-tick vaccine was recapitulated. Then, the marked attenuated vaccine, ASFV-G-ΔI177L, was compared with those of the anti-tick vaccine to represent potential therapeutic or strategies to combat ASF.

Knowledge, Attitudes, and Behaviors Regarding Lyme Borreliosis Prevention in the Endemic Area of Northeastern Poland

(1) Background: The incidence of Lyme borreliosis (LB) is increasing in Europe. The new LB vaccine is still in clinical development, thus the dissemination of knowledge about the disease is essential. We assessed the knowledge, attitudes and preventive practices (KAP) against tick-borne diseases (TBDs) of people living in the endemic area in northeastern Poland. (2) Methods: We surveyed 406 adults using a 37-item anonymous paper survey. The data were analyzed with regression models. (3) Results: The two most popular knowledge sources were the Internet and doctors, selected by 77.8% and 53.4%, respectively. Respondents felt moderately knowledgeable about TBDs and tick bite prophylaxis (median scores 5/10, and 6/10, respectively), considered TBDs to be a significant health threat (median 8/10), attributed high risk to tick mouthparts remaining in the skin after tick removal (median 10/10), and shared multiple misconceptions regarding LB transmission, symptoms, and management. General knowledge scores (GKS) about TBDs and tick protection practices scores (TPS) were moderate (65.0%; IQR, 55.8−71.7%, 63.6%; 54.5−72.7%, respectively). Only 48.0% had a positive attitude towards TBE vaccination. A recent tick-bite was associated with higher GKS (OR, 2.55; 95% CI, 1.27−5.10; p = 0.008), higher TPS (OR 4.76, 95% CI, 2.0−11.1; p < 0.001), and a positive attitude towards TBE vaccine (OR 2.10, 1.07−4.10, p = 0.030). A positive vaccine attitude was also associated with obtaining TBD knowledge from doctors and other verified sources (OR, 2.654, 1.66−4.23; p < 0.001). Age, place of residence, and frequent exposure to ticks in green areas were not associated with GKS, TPS, nor vaccine attitude. (4) Conclusions: Increased risk perceptions are associated with adoption of behaviors preventing TBDs. Medical professionals play an important role in communicating knowledge about TBDs. There is a need to revise current communication strategies with respect to tick bites and prevention of LB and other TBDs.

Tick-borne diseases in Egypt: A one health perspective

Background

Ticks are important arthropod vectors that transmit pathogens to humans and animals. Owing to favourable climatic and environmental conditions, along with animal importation from neighbouring countries, ticks and tick-borne diseases (TBDs) are widespread in Egyptian localities. Here, we review the current knowledge on the epidemiology of TBDs in Egypt in light of the One Health paradigm.

Methods and results

Five scientific databases, including "Web of Science", "Scopus", "PubMed", "Science Direct", and "Google Scholar", were searched for articles describing TBDs in Egypt. A total of 18 TBDs have been reported in humans and animals, including three protozoal diseases (babesiosis, theileriosis, and hepatozoonosis), 12 bacterial diseases (anaplasmosis, ehrlichiosis, Lyme borreliosis, bovine borreliosis, tick-borne relapsing fever, Mediterranean spotted fever, African tick-borne fever, lymphangitis-associated rickettsiosis, bartonellosis, tularaemia, Q fever, and aegyptianellosis), and three viral diseases (Crimean-Congo haemorrhagic fever, Alkhurma haemorrhagic fever, and Lumpy skin disease).

Conclusions

Despite the circulation of zoonotic tick-borne pathogens among livestock and tick vectors, human infections have been overlooked and are potentially limited to infer the actual communicable disease burden. Therefore, facility-based surveillance of TBDs, combined with capacity building for laboratory diagnostics in healthcare facilities, is urgently required to improve diagnosis and inform policy-making in disease prevention. Additionally, collaboration between expert researchers from various disciplines (physicians, biologists, acarologists, and veterinarians) is required to develop advanced research projects to control ticks and TBDs. Considering that domestic livestock is integral to many Egyptian households, comprehensive epidemiological studies on TBDs should assess all disease contributors, including vertebrate hosts (animals, humans, and rodents) and ticks in the same ecological region, for better assessment of disease burden. Additionally, upscaling of border inspections of imported animals is required to stop crossover movements of ticks and TBDs.

Mapping the risk distribution of Borrelia burgdorferi sensu lato in China from 1986 to 2020: a geospatial modelling analysis

Lyme borreliosis, recognized as one of the most important tick-borne diseases worldwide, has been increasing in incidence and spatial extent. Currently, there are few geographic studies about the distribution of Lyme borreliosis risk across China. Here we established a nationwide database that involved Borrelia burgdorferi sensu lato (B. burgdorferi) detected in humans, vectors, and animals in China. The eco-environmental factors that shaped the spatial pattern of B. burgdorferi were identified by using a two-stage boosted regression tree model and the model-predicted risks were mapped. During 1986−2020, a total of 2,584 human confirmed cases were reported in 25 provinces. Borrelia burgdorferi was detected from 35 tick species with the highest positive rates in Ixodes granulatus, Hyalomma asiaticum, Ixodes persulcatus, and Haemaphysalis concinna ranging 20.1%−24.0%. Thirteen factors including woodland, NDVI, rainfed cropland, and livestock density were determined as important drivers for the probability of B. burgdorferi occurrence based on the stage 1 model. The stage 2 model identified ten factors including temperature seasonality, NDVI, and grasslands that were the main determinants used to distinguish areas at high or low-medium risk of B. burgdorferi, interpreted as potential occurrence areas within the area projected by the stage 1 model. The projected high-risk areas were not only concentrated in high latitude areas, but also were distributed in middle and low latitude areas. These high-resolution evidence-based risk maps of B. burgdorferi was first created in China and can help as a guide to future surveillance and control and help inform disease burden and infection risk estimates.

Lyme borreliosis in Belgium: a cost-of-illness analysis

BACKGROUND

Lyme borreliosis (LB) is the most common tick-borne disease in Europe and North America, yet its economic burden remains largely unknown. This study aimed to estimate the economic cost associated with the different clinical manifestations of LB in Belgium.

METHODS

An incidence approach and societal perspective were used to estimate the total cost-of-illness for LB in Belgium. Costs were calculated for patients with erythema migrans (EM) or disseminated/late LB, including patients who developed post-treatment Lyme disease syndrome (PTLDS). Direct medical, direct non-medical (transportation & paid help) and indirect non-medical costs (productivity losses) were included in the analysis. Ambulatory cost data were collected through a prospective cohort study from June 2016 to March 2020, in which patients with LB were followed up 6 to 12 months after diagnosis. Hospitalization costs were retrieved from the Minimal Clinical Data registry, a mandatory registry for all Belgian hospitals, linked to the Minimal Financial Data registry. Costs were expressed in 2019 euros.

RESULTS

The total annual cost associated with clinical manifestations of LB in Belgium was estimated at €5.59 million (95% UI 3.82-7.98). Of these, €3.44 million (95% UI 2.05-5.48) or 62% was related to disseminated/late LB diagnoses and €2.15 million (95% UI 1.30-3.26) to EM. In general, direct medical costs and productivity losses accounted for 49.8% and 46.4% of the total costs, respectively, while direct non-medical costs accounted for only 3.8%. The estimated mean costs were €193 per EM patient and €5,148 per disseminated/late LB patient. While patients with PTLDS seemed to have somewhat higher costs compared to patients without PTLDS, the number of patients was too small to have representative estimates.

CONCLUSIONS

We estimate the total annual direct medical costs, direct non-medical and indirect non-medical costs associated with LB to exceed €5.5 million per year, almost evenly distributed between EM (40%) and disseminated/late LB (60%). EM costs 26 times less per patient but occurs also 16 times more frequently than disseminated/late LB. The cost burden remains limited by comparison to other infectious diseases due to the relative lower incidence.

Incidence and associated factors of cetuximab-induced hypersensitivity infusion reactions in 1392 cancer patients treated in four French areas: a possible association with Lyme disease?

BACKGROUND

Previous studies have observed an increased incidence of Cetuximab-induced hypersensitivity infusion reactions (CI-IRs) in the southeastern states of the USA. Tick's bites were suspected of generating cross-reactions between cetuximab and alpha-gal. This study aims was to describe the incidence and associated risk factors of CI-IRs, in the French areas chosen according to their Lyme disease incidence.

PATIENTS AND METHODS

A retrospective chart review was conducted on patients that received cetuximab infusion from January 2010 to June 2019 in 4 French areas with different Lyme disease incidence rates.

RESULTS

Of 1392 patients, 117 (8.4%) experienced a CI-IR, including 68 severe (grade 3 or 4) reactions (4.9%). This CI-IR incidence was significantly higher in the Lyme disease high-risk area than in the other areas (13.2% versus 7.1%, 8.1% and 6.4%; P = 0.016). Sex (P = 0.53), premedication (P = 0.91), primary cancer location (P = 0.46) and chemotherapy regimen type (P = 0.78) had no impact on CI-IR incidence in the overall population. In the head and neck squamous cell carcinoma (HNSCC) patient subgroup, CI-IRs were significantly more frequent in the high-risk area (16.4% versus 6.7%, 7.1% and 7.0%; P = 0.0015).

CONCLUSION

This study suggests that patients treated in the French area with the highest incidence of Lyme disease are at a higher risk of CI-IRs.

An Overview of Anthropogenic Actions as Drivers for Emerging and Re-Emerging Zoonotic Diseases

Population growth and industrialization have led to a race for greater food and supply productivity. As a result, the occupation and population of forest areas, contact with wildlife and their respective parasites and vectors, the trafficking and consumption of wildlife, the pollution of water sources, and the accumulation of waste occur more frequently. Concurrently, the agricultural and livestock production for human consumption has accelerated, often in a disorderly way, leading to the deforestation of areas that are essential for the planet's climatic and ecological balance. The effects of human actions on other ecosystems such as the marine ecosystem cause equally serious damage, such as the pollution of this habitat, and the reduction of the supply of fish and other animals, causing the coastal population to move to the continent. The sum of these factors leads to an increase in the demands such as housing, basic sanitation, and medical assistance, making these populations underserved and vulnerable to the effects of global warming and to the emergence of emerging and re-emerging diseases. In this article, we discuss the anthropic actions such as climate changes, urbanization, deforestation, the trafficking and eating of wild animals, as well as unsustainable agricultural intensification which are drivers for emerging and re-emerging of zoonotic pathogens such as viral (Ebola virus, hantaviruses, Hendravirus, Nipah virus, rabies, and severe acute respiratory syndrome coronavirus disease-2), bacterial (leptospirosis, Lyme borreliosis, and tuberculosis), parasitic (leishmaniasis) and fungal pathogens, which pose a substantial threat to the global community. Finally, we shed light on the urgent demand for the implementation of the One Health concept as a collaborative global approach to raise awareness and educate people about the science behind and the battle against zoonotic pathogens to mitigate the threat for both humans and animals.

Borrelia multiplex: a bead-based multiplex assay for the simultaneous detection of Borrelia specific IgG/IgM class antibodies

Background

Lyme borreliosis (LB) is the most common tick-borne infectious disease in the northern hemisphere. The diagnosis of LB is usually made by clinical symptoms and subsequently supported by serology. In Europe, a two-step testing consisting of an enzyme-linked immunosorbent assay (ELISA) and an immunoblot is recommended. However, due to the low sensitivity of the currently available tests, antibody detection is sometimes inaccurate, especially in the early phase of infection, leading to underdiagnoses.

Methods

To improve upon Borrelia diagnostics, we developed a multiplex Borrelia immunoassay (Borrelia multiplex), which utilizes the new INTELLIFLEX platform, enabling the simultaneous dual detection of IgG and IgM antibodies, saving further time and reducing the biosample material requirement. In order to enable correct classification, the Borrelia multiplex contains eight antigens from the five human pathogenic Borrelia species known in Europe. Six antigens are known to mainly induce an IgG response and two antigens are predominant for an IgM response.

Results

To validate the assay, we compared the Borrelia multiplex to a commercial bead-based immunoassay resulting in an overall assay sensitivity of 93.7% (95% CI 84.8–97.5%) and a specificity of 96.5% (95%CI 93.5–98.1%). To confirm the calculated sensitivity and specificity, a comparison with a conventional 2-step diagnostics was performed. With this comparison, we obtained a sensitivity of 95.2% (95% CI 84.2–99.2%) and a specificity of 93.0% (95% CI 90.6–94.7%).

Conclusion

Borrelia multiplex is a highly reproducible cost- and time-effective assay that enables the profiling of antibodies against several individual antigens simultaneously.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07863-9.

What do we know about the microbiome of I. ricinus?

I. ricinus is an obligate hematophagous parasitic arthropod that is responsible for the transmission of a wide range of zoonotic pathogens including spirochetes of the genus Borrelia, Rickettsia spp., C. burnetii, Anaplasma phagocytophilum and Francisella tularensis, which are part the tick´s microbiome. Most of the studies focus on "pathogens" and only very few elucidate the role of "non-pathogenic" symbiotic microorganisms in I. ricinus. While most of the members of the microbiome are leading an intracellular lifestyle, they are able to complement tick´s nutrition and stress response having a great impact on tick´s survival and transmission of pathogens. The composition of the tick´s microbiome is not consistent and can be tied to the environment, tick species, developmental stage, or specific organ or tissue. Ovarian tissue harbors a stable microbiome consisting mainly but not exclusively of endosymbiotic bacteria, while the microbiome of the digestive system is rather unstable, and together with salivary glands, is mostly comprised of pathogens. The most prevalent endosymbionts found in ticks are Rickettsia spp., Ricketsiella spp., Coxiella-like and Francisella-like endosymbionts, Spiroplasma spp. and Candidatus Midichloria spp. Since microorganisms can modify ticks' behavior, such as mobility, feeding or saliva production, which results in increased survival rates, we aimed to elucidate the potential, tight relationship, and interaction between bacteria of the I. ricinus microbiome. Here we show that endosymbionts including Coxiella-like spp., can provide I. ricinus with different types of vitamin B (B2, B6, B7, B9) essential for eukaryotic organisms. Furthermore, we hypothesize that survival of Wolbachia spp., or the bacterial pathogen A. phagocytophilum can be supported by the tick itself since coinfection with symbiotic Spiroplasma ixodetis provides I. ricinus with complete metabolic pathway of folate biosynthesis necessary for DNA synthesis and cell division. Manipulation of tick´s endosymbiotic microbiome could present a perspective way of I. ricinus control and regulation of spread of emerging bacterial pathogens.

Antibiotic therapy of neuroborreliosis: A survey among infectious disease specialists and neurologists in Norway, Sweden, and Denmark

INTRODUCTION

Neuroborreliosis (NB) is a prevalent tick-borne neuroinfection in Europe. To delineate current practice in antimicrobial management of adults with NB and to prioritize future trials needed to optimize treatment recommendations, a questionnaire-based survey was performed.

METHODS

A self-administered Internet-based survey of NB treatment practices among specialists in infectious diseases and neurology based in Norway, Sweden, and Denmark was carried out between October 2021 and February 2022. The participants were also asked to prioritize four pre-defined research questions for randomized controlled trials (RCTs) on therapy for NB.

RESULTS

In total, 290 physicians (45% female) from Norway (30%), Sweden (40%), and Denmark (30%) participated in the survey. Of the responders, 230 (79%) were infectious disease specialists and 56 (19%) were neurologists. The preferred antibiotic treatment for patients with early NB was oral doxycycline (n = 225, 78%). Intravenous (IV) penicillin, ceftriaxone, or cefotaxime for the full treatment course was favored by 12%. A preferred treatment duration of 10-14 days for patients with NB was reported by 245 respondents (85%), most common among participants from Sweden (97%). A total of 170 (59%) responders reported having local hospital guidelines on the treatment of NB, most often with recommendation of oral doxycycline (92%) for 10-14 days (90%) as first line treatment. The prioritization score for future RCTs was highest for adjunctive prednisone therapy in NB patients with facial palsy (median 5; IQR 4-6) and for placebo versus repeated antibiotics in patients with persistent symptoms after completed antibiotic therapy for NB (median 5, IQR 3-6).

CONCLUSION

In Sweden, all respondents preferred treating NB with oral doxycycline for 10-14 days, whereas 5% in Norway and 19% in Denmark still treat NB with IV antibiotics for the entire treatment course. RCTs to define the role of adjunctive prednisolone in NB patients with facial palsy and repeated antibiotics in patients with persistent symptoms are prioritized for future research.

The Microbiota of Ixodes ricinus and Dermacentor reticulatus Ticks Collected from a Highly Populated City of Eastern Europe

Recent investigations have examined, through sequencing the V6 region of 16S rRNA gene, the microbiota of questing Ixodes ricinus and Dermacentor reticulatus ticks collected from rural areas of Central (Dnipropetrovs'k (region D) and Poltava (region P)) and Northeastern (Kharkiv (region K)) Ukraine. In addition to defining the bacterial microbiota of both tick species, the previous investigations also revealed a high degree of inter-sex and inter-regional variations in the tick microbiota. As a continuation of the two studies, the present investigation has analyzed individual microbiota of questing I. ricinus (n = 50) and D. reticulatus (n = 50) ticks originating from Kyiv, the largest city of Ukraine. The Kyiv tick microbiota were compared between males and females for each tick species. Additionally, a cross-regional analysis was performed to compare the microbiota of Kyiv ticks to those from regions D, K, and P. Numerous statistically significant inter-sex and inter-regional variations were detected when alpha diversity, beta diversity, the bacterial relative and differential abundances were assessed. The overall results demonstrated that the microbiota of Kyiv ticks were statistically different compared to the ticks of the other three regions. Besides existing climatic and geographical differences between the four regions, the authors hypothesize that various anthropogenic factors of the megapolis (e.g., animal species translocation, land management, ecology) could have contributed to the distinct microbiota of Kyiv ticks observed in this study.

Evolution of the vls Antigenic Variability Locus of the Lyme Disease Pathogen and Development of Recombinant Monoclonal Antibodies Targeting Conserved VlsE Epitopes

VlsE (variable major protein-like sequence, expressed) is an outer surface protein of the Lyme disease pathogen (Borreliella species) responsible for its within-host antigenic variation and a key diagnostic biomarker of Lyme disease. However, the high sequence variability of VlsE poses a challenge to the development of consistent VlsE-based diagnostics and therapeutics. In addition, the standard diagnostic protocols detect immunoglobins elicited by the Lyme pathogen, not the presence of the pathogen or its derived antigens. Here, we described the development of recombinant monoclonal antibodies (rMAbs) that bound specifically to conserved epitopes on VlsE. We first quantified amino-acid sequence variability encoded by the vls genes from 13 B. burgdorferi genomes by evolutionary analyses. We showed broad inconsistencies of the sequence phylogeny with the genome phylogeny, indicating rapid gene duplications, losses, and recombination at the vls locus. To identify conserved epitopes, we synthesized peptides representing five long conserved invariant regions (IRs) on VlsE. We tested the antigenicity of these five IR peptides using sera from three mammalian host species including human patients, the natural reservoir white-footed mouse (Peromyscus leucopus), and VlsE-immunized New Zealand rabbits (Oryctolagus cuniculus). The IR4 and IR6 peptides emerged as the most antigenic and reacted strongly with both the human and rabbit sera, while all IR peptides reacted poorly with sera from natural hosts. Four rMAbs binding specifically to the IR4 and IR6 peptides were identified, cloned, and purified. Given their specific recognition of the conserved epitopes on VlsE, these IR-specific rMAbs are potential novel diagnostic and research agents for direct detection of Lyme disease pathogens regardless of strain heterogeneity. IMPORTANCE Current diagnostic protocols of Lyme disease indirectly detect the presence of antibodies produced by the patient upon infection by the bacterial pathogen, not the pathogen itself. These diagnostic tests tend to underestimate early-stage bacterial infections before the patients develop robust immune responses. Further, the indirect tests do not distinguish between active or past infections by the Lyme disease bacteria in a patient sample. Here, we described novel monoclonal antibodies that have the potential to become the basis of direct and definitive diagnostic detection of the Lyme disease pathogen, regardless of its genetic heterogeneity.

Non-specific symptoms and post-treatment Lyme disease syndrome in patients with Lyme borreliosis: a prospective cohort study in Belgium (2016-2020)

Background

Patients with Lyme borreliosis (LB) may report persisting non-specific symptoms such as fatigue, widespread musculoskeletal pain or cognitive difficulties. When present for more than 6 months and causing a reduction in daily activities, this is often referred to as post-treatment Lyme disease syndrome (PTLDS). This study aimed to compare the occurrence of symptoms between LB patients and controls, to estimate the proportion of LB patients developing PTLDS and to identify risk factors.

Methods

A prospective cohort study was set up including three subpopulations: patients with an erythema migrans (EM) (i) or disseminated/late LB (ii) and a non-LB control group (iii). At 6- and 12-months follow-up, the occurrence of several symptoms, including six symptoms used to define PTLDS, i.e. muscle pain, joint pain, fatigue, memory problems, difficulties concentrating and problems finding words, and impact on daily activities, was compared between LB patients and controls. Finally, the proportion of LB patients developing PTLDS as defined by the Infectious Disease Society of America was estimated, including a time frame for symptoms to be present.

Results

Although the risk of presenting PTLDS-related symptoms was significantly higher in EM patients (n = 120) compared to controls (n = 128) at 6 months follow-up, the risk of presenting at least one of these symptoms combined with impact on daily activities was not significantly higher in EM patients, at either 6- or 12-months follow-up. A significant association was found between disseminated/late LB (n = 15) and the occurrence of any PTLDS-symptom with an impact on daily activities at both time points. The proportion of patients with PTLDS was estimated at 5.9% (95% CI 2.7–12.9) in EM patients and 20.9% (95% CI 6.8–64.4) in patients with disseminated/late LB (RR = 3.53, 95% CI 0.98–12.68, p = 0.053). No significant risk factors were identified, which may be explained by small sample sizes.

Conclusions

In our study, PTLDS was present in both LB cohorts, yet with a higher percentage in disseminated/late LB patients. Additional research is needed into risk factors for and causes of this syndrome. In addition, development and validation of standardized methods to assess the PTLDS case definition, easily applicable in practice, is of great importance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07686-8.

No correlation between symptom duration and intrathecal production of IgM and/or IgG antibodies in Lyme neuroborreliosis - a retrospective cohort study in Denmark

OBJECTIVES

In Europe, a definite diagnosis of Lyme neuroborreliosis (LNB) requires intrathecally produced Borrelia-specific antibodies. We aimed to examine if the time from symptom debut to lumbar puncture (LP) correlated with findings of intrathecal production of Borrelia-specific IgM and/or IgG antibodies in LNB METHODS: A retrospective study of 544 patients with a positive Borrelia burgdorferi antibody index (Bb-AI) analysed at the Department of Clinical Microbiology, Odense University Hospital, Denmark, between 01.01.1995 and 31.12.2020 RESULTS: The delay from symptom onset to LP for patients with positive Bb-AI IgM was 30 days (IQR 14-95 days), IgG 24 days (IQR 11-62), IgM+IgG 24 days (IQR 14-48), P = 0.098. Ninety-three patients had a second LP after median 125 days (IQR 28-432) and 25 had a third LP after median 282 days (IQR 64-539). Most patients (66.7%) did not convert from their initial intrathecal antibody finding. The prevalence of different clinical manifestations differed significantly between the three Bb-AI groups.

CONCLUSIONS

Intrathecal Borrelia-specific antibody production did not follow the typical immune response of initial IgM production followed by IgG production. Diagnosis of LNB stage should not be based on the type of antibodies found in the cerebrospinal fluid.

HIV and Mediterranean Zoonoses: A Review of the Literature

A zoonosis is an infectious disease that has jumped from a non-human animal to humans. Some zoonoses are very common in the Mediterranean area and endemic in specific regions, so they represent an important problem for public health. Human Immunodeficiency Virus (HIV) is a virus that has originated as a zoonosis and is now diffused globally, with the most significant numbers of infected people among the infectious diseases. Since the introduction of antiretroviral therapy (ART), the history for people living with HIV (PLWH) has changed drastically, and many diseases are now no different in epidemiology and prognosis as they are in not-HIV-infected people. Still, the underlying inflammatory state that is correlated with HIV and other alterations related to the infection itself can be a risk factor when infected with other bacteria, parasites or viruses. We reviewed the literature for infection by the most common Mediterranean zoonoses, such as Campylobacter, Salmonella, Brucella, Rickettsia, Borrelia, Listeria and Echinococcus, and a possible correlation with HIV. We included Monkeypox, since the outbreak of cases is becoming a concern lately. We found that HIV may be related with alterations of the microbiome, as for campylobacteriosis, and that there are some zoonoses with a significant prevalence in PLWH, as for salmonellosis.

A global dataset of microbial community in ticks from metagenome study

Ticks are important vectors of various zoonotic pathogens that can infect animals and humans, and most documented tick-borne pathogens have a strong bias towards microorganisms with strong disease phenotypes. The recent development of next-generation sequencing (NGS) has enabled the study of microbial communities, referred to as microbiome. Herein, we undertake a systematic review of published literature to build a comprehensive global dataset of microbiome determined by NGS in field-collected ticks. The dataset comprised 4418 records from 76 literature involving geo-referenced occurrences for 46 species of ticks and 219 microorganism families, revealing a total of 83 emerging viruses identified from 24 tick species belonging to 6 tick genera since 1980. The viral, bacterial and eukaryotic composition was compared regarding the tick species, their live stage and types of the specimens, or the geographic location. The data can assist the further investigation of ecological, biogeographical and epidemiological features of the tick-borne disease.

Measurement(s)	microbial community
Technology Type(s)	Next Generation Sequencing
Factor Type(s)	tick
Sample Characteristic - Organism	tick
Sample Characteristic - Environment	microbial community
Sample Characteristic - Location	Whole world

Large-Scale Sequencing of Borreliaceae for the Construction of Pan-Genomic-Based Diagnostics

The acceleration of climate change has been associated with an alarming increase in the prevalence and geographic range of tick-borne diseases (TBD), many of which have severe and long-lasting effects-particularly when treatment is delayed principally due to inadequate diagnostics and lack of physician suspicion. Moreover, there is a paucity of treatment options for many TBDs that are complicated by diagnostic limitations for correctly identifying the offending pathogens. This review will focus on the biology, disease pathology, and detection methodologies used for the Borreliaceae family which includes the Lyme disease agent Borreliella burgdorferi. Previous work revealed that Borreliaceae genomes differ from most bacteria in that they are composed of large numbers of replicons, both linear and circular, with the main chromosome being the linear with telomeric-like termini. While these findings are novel, additional gene-specific analyses of each class of these multiple replicons are needed to better understand their respective roles in metabolism and pathogenesis of these enigmatic spirochetes. Historically, such studies were challenging due to a dearth of both analytic tools and a sufficient number of high-fidelity genomes among the various taxa within this family as a whole to provide for discriminative and functional genomic studies. Recent advances in long-read whole-genome sequencing, comparative genomics, and machine-learning have provided the tools to better understand the fundamental biology and phylogeny of these genomically-complex pathogens while also providing the data for the development of improved diagnostics and therapeutics.

Comprehensive analyses of transcriptomes induced by Lyme spirochete infection to CNS model system

BACKGROUND

Lyme disease is a zoonotic disease caused by infection with Borrelia burgdorferi (Bb), the involvement of the nervous system in Lyme disease is usually referred to as Lyme neuroborreliosis (LNB). LNB has diverse clinical manifestations, most commonly including meningitis, Bell's palsy, and encephalitis. However, the molecular pathogenesis of neuroborreliosis is still poorly understood. Comprehensive transcriptomic analysis following Bb infection could provide new insights into the pathogenesis of LNB and may identify novel biomarkers or therapeutic targets for LNB diagnosis and treatment.

METHODS

In the present study, we pooled transcriptomic dataset of Macaca mulatta (rhesus) from our laboratory and the human astrocyte dataset GSE85143 from the Gene Expression Omnibus database to screen common differentially expressed genes (DEGs) in the Bb infection group and the control group. Functional and enrichment analyses were applied for the DEGs. Protein-Protein Interaction network, and hub genes were identified using the Search Tool for the Retrieval of Interaction Genes database and the CytoHubba plugin. Finally, mRNA expression of hub genes was validated in vitro and ex vivo from Bb infected models and normal controls by quantitative reverse transcription PCR (qRT-PCR).

RESULTS

A total of 80 upregulated DEGs and 32 downregulated DEGs were identified. Among them, 11 hub genes were selected. The pathway enrichment analyses on 11 hub genes revealed that the PI3K-Akt signaling pathway was significantly enriched. The mRNA levels of ANGPT1, TLR6, SREBF1, LDLR, TNC, and ITGA2 in U251 cells and/or rhesus brain explants by exposure to Bb were validated by qRT-PCR.

CONCLUSION

Our study suggested that TLR6, ANGPT1, LDLR, SREBF1, TNC, and ITGA may be candidate mammal biomarkers for LNB, and the TLR6/PI3K-Akt signaling pathway may play an important role in LNB pathogenesis.

Diagnostic Testing for Lyme Disease

Standard 2-tier testing (STTT), incorporating a screening enzyme immunoassay (EIA) or an immunofluorescence assay (IFA) that reflexes to IgM and IgG immunoblots, has been the primary diagnostic test for Lyme disease since 1995. In 2019, the Food and Drug Administration approved a modified 2-tier test strategy using 2 EIAs: offering a faster, less expensive, and more sensitive assay compared with STTT. New technologies examine early immune responses to Borrelia burgdorferi have the potential to diagnose Lyme disease in the first weeks of infection when existing serologic testing is not recommended due to low sensitivity.

Colocalization of Radicular Pain and Erythema Migrans in Patients With Bannwarth Syndrome Suggests a Direct Spread of Borrelia Into the Central Nervous System

BACKGROUND

There is a general assumption that after deposition into skin, Lyme borreliae disseminate hematogenously to other organs, resulting in extracutaneous manifestations of Lyme borreliosis, including Lyme neuroborreliosis. However, our experience over the past 40 years, along with several published case reports that observed colocalization of radicular pain and erythema migrans (EM) in patients with borrelial meningoradiculoneuritis (Bannwarth syndrome), argues against hematogenous dissemination in Lyme neuroborreliosis.

METHODS

We compared the location of EM in 112 patients with Bannwarth syndrome to 12315 EM patients without neurological involvement. Moreover, we assessed the colocalization of EM and radicular pain in patients with Bannwarth syndrome.

RESULTS

Compared to >12000 EM patients without neurological involvement, patients with Bannwarth syndrome had a significantly higher frequency of EM on head/neck (6% vs 1%; P=.0005) and trunk (47% vs 24%; P<.0001), similar frequency on arms (16% vs 16%; P=.91), but lower frequency on legs (30% vs 59%; P<.0001). Moreover, in 79% (89/112) of patients the site of EM matched the dermatomes of radicular pain. The odds for a congruent location of EM and radicular pain were highly significant with the highest odds ratios (OR) observed for head (OR=221), followed by neck (OR=159), legs (OR=69), arms (OR=48), and trunk (OR=33).

CONCLUSIONS

The greater frequency of EM on head/neck and trunk and the colocalization of EM with radicular pain in patients with Bannwarth syndrome suggest that central nervous system involvement in Lyme neuroborreliosis is due to a retrograde spread of borrelia from skin to the spinal cord via peripheral nerves.

Diversity of Tick-Borne Pathogens in Tick Larvae Feeding on Breeding Birds in France

Birds play a role in maintaining tick-borne diseases by contributing to the multiplication of ticks and pathogens on a local scale during the breeding season. In the present study, we describe the diversity of tick and pathogen species of medical and veterinary importance in Europe hosted by 1040 captured birds (56 species) during their breeding season in France. Of the 3114 ticks collected, Ixodes ricinus was the most prevalent species (89.5%), followed by I. frontalis (0.8%), I. arboricola (0.7%), Haemaphysalis concinna (0.5%), H. punctata (0.5%), Hyalomma spp. (0.2%), and Rhipicephalus spp. (0.06%). Because they may be representative of the bird infection status for some pathogen species, 1106 engorged tick larvae were screened for pathogens. Borrelia burgdorferi sensu lato was the most prevalent pathogen genus in bird-feeding larvae (11.7%), followed by Rickettsia spp. (7.4%), Anaplasma spp. (5.7%), Babesia spp. (2.3%), Ehrlichia spp. (1.4%), and B. miyamotoi (1%). Turdidae birds (Turdus merula and T. philomelos), Troglodytes troglodytes, and Anthus trivialis had a significantly higher prevalence of B. burgdorferi s.l.-infected larvae than other pathogen genera. This suggests that these bird species could act as reservoir hosts for B. burgdorferi s.l. during their breeding season, and thus play an important role in acarological risk.

Borrelial lymphocytoma

Borrelial lymphocytoma is a rare cutaneous manifestation of early localized European Lyme borreliosis. It manifests as a nodule or plaque with a diameter of up to a few centimeters. The lesion is, as a rule, solitary. It is more common in children than in adults and, in contrast to erythema migrans and acrodermatitis chronica atrophicans, has male predominance. A tick bite has been reported in approximately one half of patients; the tick bite is usually at the site or in the vicinity of the later borrelial lymphocytoma. The predilection site for the development of lesions is the breast in adults and the ear lobe in children. Borrelial lymphocytoma is frequently associated with erythema migrans, but rarely with other manifestations of Lyme borreliosis, and is predominantly caused by Borrelia afzelii. At presentation, approximately half of the patients with borrelial lymphocytoma have measurable serum borrelial antibodies and, in about one third, spirochetes can be cultivated from the skin lesion. A 14-day antibiotic therapy, as recommended for patients with erythema migrans, is highly successful. Posttreatment duration of a borrelial lymphocytoma is positively associated with the pretreatment duration of the lesion and with patient age, while treatment failure is associated with the clinical signs of disseminated Lyme borreliosis at presentation. Substantial improvements in knowledge on borrelial lymphocytoma and laboratory diagnostics in recent decades have contributed to earlier diagnosis and treatment. Consequently, borrelial lymphocytoma is usually a mild disease with a good prognosis.

Epidemiology of Lyme borreliosis based on outpatient claims data of all people with statutory health insurance, Germany, 2019

Introduction

Evidence of nationwide and regional morbidity of Lyme borreliosis (LB) in Germany is lacking.

Aims

We calculated the total number of incident LB cases in Germany in 2019, compared regional variations, investigated the extent of possible under-reporting in notification data and examined the association between high incidence areas and land cover composition.

Methods

We used outpatient claims data comprising information for people with statutory health insurance who visited a physician at least once between 2010 and 2019 in Germany (n = 71,411,504). The ICD-10 code A69.2 was used to identify incident LB patients. Spatial variations of LB were assessed by means of Global and Local Moran’s Index at district level. Notification data were obtained for nine federal states with mandatory notification from the Robert Koch Institute (RKI).

Results

Of all insured, 128,177 were diagnosed with LB in 2019, corresponding to an incidence of 179 per 100,000 insured. The incidence varied across districts by a factor of 16 (range: 40–646 per 100,000). We identified four spatial clusters with high incidences. These clusters were associated with a significantly larger proportion of forests and agricultural areas than low incidence clusters. In 2019, 12,264 LB cases were reported to the RKI from nine federal states, while 69,623 patients with LB were found in claims data for those states. This difference varied considerably across districts.

Conclusions

These findings serve as a solid basis for regionally tailored population-based intervention programmes and can support modelling studies assessing the development of LB epidemiology under various climate change scenarios.

Seroprevalence of vector-borne pathogens in outdoor workers from southern Italy and associated occupational risk factors

Background

Vector-borne diseases (VBDs) represent an emerging global threat to public health due to the geographical expansion of arthropod vectors. The study aims to assess the seroprevalence of selected vector-borne pathogens (VBPs) in different groups of outdoor workers and the occupational risk factors for exposure to arthropod bites.

Methods

A cross-sectional study was conducted on 170 workers recruited in two different regions of southern Italy, including farmers, forestry workers, veterinarians, geologists/agronomists and administrative employees, and tested for IgG antibodies against Bartonella henselae, Borrelia spp. Coxiella burnetii and Rickettsia conorii, using a chemiluminescent immunoassay (CLIA). The relationship among job characteristics, tick exposure and the prevalence of seropositive subjects for each pathogen was investigated by applying categorical principal component analysis (CATPCA).

Results

A high seroprevalence for C. burnetii (30.0%) and R. conorii (15.3%) was reported, mainly in farmers (67.7% and 54.8%, respectively) and forestry workers (29.0% and 16.1%, respectively), while a low prevalence was observed for B. henselae and Borrelia spp. (8.8% and 4.1%, respectively). The regression equation by CATPCA was significant for C. burnetii and R. conorii (P < 0.001), showing a positive association with job, tick bite exposure, working area and contact with animals.

Conclusions

These findings highlight the need of activating an appropriate occupational health response for minimizing the risk of arthropod vector exposure in workplaces, considering specific preventive measures in particular in high-risk job categories.

Graphical Abstract

Regional seropositivity for Borrelia burgdorferi and associated risk factors: findings from the Rhineland Study, Germany

Background

Lyme borreliosis is the most prevalent vector-borne disease in Europe, and numbers might increase due to climate change. However, borreliosis is not notifiable in North Rhine-Westphalia (NRW), Germany. Hence, little is known about the current human seroprevalence in NRW. However, the proportion of Borrelia burgdorferi sensu lato-infected ticks has increased in a NRW nature reserve. The literature suggests increasing age and male sex as risk factors for seropositivity, whereas the influence of socioeconomic status is controversial. Thus, we aimed to determine regional seropositivity for Borrelia burgdorferi sensu lato (B. burgdorferi s.l.) and its risk factors in the Rhineland Study population in Bonn, NRW, and to compare it with previous surveys to evaluate potential effects of climate change.

Methods

We assessed seropositivity in 2865 Rhineland Study participants by determining immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies for B. burgdorferi s.l. using a two-step algorithm combining enzyme-linked immunosorbent assay tests and line immunoblots. We calculated the odds of being classified as IgG or IgM positive as a function of age, sex, and educational level using binomial logistic regression models. We applied varying seropositivity classifications and weights considering age, sex and education to compensate for differences between the sample and regional population characteristics.

Results

IgG antibodies for B. burgdorferi s.l. were present in 2.4% and IgM antibodies in 0.6% of the participants (weighted: 2.2% [IgG], 0.6% [IgM]). The likelihood of IgG seropositivity increased by 3.0% (95% confidence interval [CI] 1.5–5.2%) per 1 year increase in age. Men had 1.65 times the odds for IgG seropositivity as women (95% CI 1.01–2.73), and highly educated participants had 1.83 times the odds (95% CI 1.10–3.14) as participants with an intermediate level of education. We found no statistically significant link between age, sex, or education and IgM seropositivity. Our weighted and age-standardized IgG seroprevalence was comparable to the preceding serosurvey German Health Interview and Examination Survey for Adults (DEGS) for NRW.

Conclusions

We confirmed that increasing age and male sex are associated with increased odds for IgG seropositivity and provide evidence for increased seropositivity in the highly educated group. B. burgdorferi s.l. seropositivity remained constant over the past decade in this regional German population.

Graphical abstract

Seasonal dynamics of tick burden and associated Borrelia burgdorferi s.l. and Borrelia miyamotoi infections in rodents in a Dutch forest ecosystem

Ixodes ricinus ticks transmit Borrelia burgdorferi sensu lato (s.l.) as well as Borrelia miyamotoi. Larvae become infected when feeding on infected rodents, with horizontal transmission of B. burgdorferi and horizontal and vertical transmission of B. miyamotoi. We studied seasonal dynamics of infection rates of I. ricinus and their rodent hosts, and hence transmission risk of these two distinctly different Borrelia species. Rodents were live-trapped and inspected for ticks from May to November in 2013 and 2014 in a forest in The Netherlands. Trapped rodents were temporarily housed in the laboratory and detached ticks were collected. Borrelia infections were determined from the trapped rodents and collected ticks. Borrelia burgdorferi s.l. and B. miyamotoi were found in ticks as well as in rodents. Rodent density was higher in 2014, whereas tick burden as well as the Borrelia infection rates in rodents were higher in 2013. The density of B. miyamotoi-infected nymphs did not differ between the years. Tick burdens were higher on Apodemus sylvaticus than on Myodes glareolus, and higher on males than on females. Borrelia-infection rate of rodents varied strongly seasonally, peaking in summer. As the larval tick burden also peaked in summer, the generation of infected nymphs was highest in summer. We conclude that the heterogeneity of environmental and host-specific factors affects the seasonal transmission of Borrelia spp., and that these effects act more strongly on horizontally transmitted B. burgdorferi spp. than on the vertically transmitted B. miyamotoi.

Long-term Outcome After Acute Peripheral Facial Palsy

PURPOSE

To analyze long-term outcomes in a large cohort of patients with acute peripheral facial palsy (APFP).

METHODS

Hospital-based, cross-sectional study. Data were abstracted from the electronic medical record. Time to recovery was assessed with Kaplan-Meier survival analyses. Binary logistic regression analysis was used to identify factors associated with outcome.

RESULTS

Three hundred seventy-two patients with APFP seen at a tertiary hospital between February 2015 and March 2021 were analyzed. Seasonal variation of APFP peaked in the early fall (September 29) and had a peak-to-low ratio of 1.36 (R 2 = 0.329, p < 0.001). Patients who tested positive for Lyme disease (10%) had an earlier peak (July 16) compared with those who were negative (October 15). Eighty-seven percent of patients had complete recovery (averaging 64 ± 61 days). Patients, with higher House-Brackmann (H-B) grades at presentation took longer to recover, were more likely to have aberrant regeneration and had lower final rates of recovery compared with those with lower H-B grades (χ 2 = 12.03, p < 0.001). Of the patients with residual palsies, 70% had evidence of aberrant regeneration, and nearly half of those had hemifacial spasm.

CONCLUSIONS

Most patients with APFP achieve complete recovery within 1 year, including those positive for Lyme. More severe palsy at presentation portends a worse outcome.

Retrospective Evaluation of Various Serological Assays and Multiple Parameters for Optimal Diagnosis of Lyme Neuroborreliosis in a Routine Clinical Setting

Laboratory diagnosis of Lyme neuroborreliosis (LNB) is challenging, and validated diagnostic algorithms are lacking. Therefore, this retrospective cross-sectional study aimed to compare the diagnostic performance of seven commercial antibody assays for LNB diagnosis. Random forest (RF) modeling was conducted to investigate whether the diagnostic performance using the antibody assays could be improved by including several routine cerebrospinal fluid (CSF) parameters (i.e., leukocyte count, total protein, blood-CSF barrier functionality, and intrathecal total antibody synthesis), two-tier serology on serum, the CSF level of the B-cell chemokine (C-X-C motif) ligand 13 (CXCL13), and a Borrelia species PCR on CSF. In total, 156 patients were included who were classified as definite LNB (n = 10), possible LNB (n = 7), or non-LNB patient (n = 139) according to the criteria of the European Federation of Neurological Societies using a consensus strategy for intrathecal Borrelia-specific antibody synthesis. The seven antibody assays showed sensitivities ranging from 47.1% to 100% and specificities ranging from 95.7% to 100%. RF modeling demonstrated that the sensitivities of most antibody assays could be improved by including other parameters to the diagnostic repertoire for diagnosing LNB (range: 94.1% to 100%), although with slightly lower specificities (range: 92.8% to 96.4%). The most important parameters for LNB diagnosis are the detection of intrathecally produced Borrelia-specific antibodies, two-tier serology on serum, CSF-CXCL13, Reibergram classification, and pleocytosis. In conclusion, this study shows that LNB diagnosis is best supported using multiparameter analysis. Furthermore, a collaborative prospective study is proposed to investigate if a standardized diagnostic algorithm can be developed for improved LNB diagnosis. IMPORTANCE The diagnosis of LNB is established by clinical symptoms, pleocytosis, and proof of intrathecal synthesis of Borrelia-specific antibodies. Laboratory diagnosis of LNB is challenging, and validated diagnostic algorithms are lacking. Therefore, this retrospective cross-sectional study aimed to compare the diagnostic performance of seven commercial antibody assays for LNB diagnosis. Multiparameter analysis was conducted to investigate whether the diagnostic performance using the antibody assays could be improved by including several routine (CSF) parameters. The results of this study show that LNB diagnosis is best supported using the detection of intrathecally produced Borrelia-specific antibodies, two-tier serology on serum, CSF-CXCL13, Reibergram classification, and pleocytosis. Furthermore, we propose a collaborative prospective study to investigate the potential role of constructing a diagnostic algorithm using multiparameter analysis for improved LNB diagnosis.

Abundance of Ixodes ricinus Ticks (Acari: Ixodidae) and the Diversity of Borrelia Species in Northeastern Poland

Monitoring the abundance of ticks and the prevalence of pathogens in ticks is an important activity in assessing the risk of tick-borne diseases and helps to develop preventive measures. This study aimed to estimate the density of Ixodes ricinus, the prevalence of Borrelia species, and their diversity in northeastern Poland. The overall mean I. ricinus density was 9.7 ticks/100 m². There were no differences between years, subregions, or habitats of study. The Borrelia infection rate was higher in females (22.6%) and males (14.3%) than in nymphs 5.5% (MIR). The most infected ticks came from the eastern subregion (10.1%) where the incidence of borreliosis among the inhabitants was over 20% higher than in the other subregions. In the infected ticks, B. afzelii (38.3%) and B. garinii (34.5%) were predominant. B. bavariensis was confirmed in I. ricinus in Poland for the first time. The most polymorphic was B. garinii. B. miyamotoi (belonged to the European type) was identified as a mono-infection in 0.9% of ticks and in 1.5% as a co-infection with B. afzelii and with B. garinii. Besides the risk of borreliosis and co-infections with different Borrelia species, physicians should also be aware of B. miyamotoi infections among patients.