Search Results (440)

Research increasingly identifies wild birds, particularly long-distance migratory species, as epidemiologically relevant hosts and vectors for tick-borne Borrelia species that pose risks to both avian and human health. This review contextualizes avian-associated Borrelia research historically and microbiologically, showing the role of avian hosts in the ecology of agents causing relapsing fever and Lyme borreliosis. We identify key publications that trace the evolution of Borrelia research—from early microscopic observations of spirochetes to the modern molecular and serological evidence. The review collects literature on the process by which Borrelia gained early scientific attention due to its characteristic morphology and elevated bloodstream concentrations during septicemic phases, which enabled early etiological links between the microbe and disease. It follows the recognition of avian spirochetosis caused by Borrelia anserina and charts the shift in focus after the discovery of Borrelia burgdorferi sensu lato (Subgen. novum recomm. Borreliella, Lyme-group Borrelia). Publications listed show that birds can transport infected human-parasitic ticks over long distances and, in certain bird species, selectively amplify Lyme-group Borrelia species, especially Borrelia garinii, which has the highest temperature tolerance and is thus potentially viable in avian hosts. The literature supports the role of birds in maintaining and disseminating Borrelia infections and infected ticks across continents. Full article

Background/Objectives: Lyme disease is a tick-borne zoonosis caused by Borrelia burgdorferi that can affect multiple organ systems. Although cardiovascular involvement is considered uncommon, it may lead to severe and potentially life-threatening complications, particularly conduction disturbances and inflammatory cardiac conditions. This review aims to describe the spectrum of cardiovascular manifestations documented in patients with Lyme disease, focusing on clinical presentation, diagnostic approaches, management strategies, and reported outcomes. Methods: A narrative literature review was performed using PubMed, MEDLINE, and Google Scholar. Articles published between January 2000 and July 2025 in English or Spanish were screened. Eligible studies included original research articles, systematic and narrative reviews, case series, and case reports describing confirmed Lyme disease with cardiovascular involvement. A total of 30 studies were included. The available evidence was predominantly based on case reports and small case series, with considerable heterogeneity in study design, patient populations, and reported outcomes. Data on clinical manifestations, diagnostic methods, treatment strategies, and outcomes were extracted and synthesized. Results: Atrioventricular conduction disturbances were the most frequently reported cardiovascular manifestation, ranging from first-degree block to complete heart block, often presenting abruptly with syncope or bradycardia. Other reported manifestations included atrial and ventricular arrhythmias, myocarditis, pericarditis, myopericarditis, valvular endocarditis, aortitis, and vasculitis. Diagnosis relied on a combination of clinical suspicion, epidemiologic exposure, serologic testing, electrocardiographic monitoring, and cardiac imaging. Most patients were treated with antimicrobial therapy, commonly intravenous ceftriaxone followed by oral doxycycline, with temporary pacemaker support required in selected cases. Overall, clinical outcomes were favorable when treatment was initiated promptly. Conclusions: Cardiovascular involvement in Lyme disease, although infrequent, encompasses a broad clinical spectrum with potentially serious consequences. Early recognition, appropriate diagnostic evaluation, and timely antimicrobial therapy are essential to ensure reversibility of cardiac manifestations and favorable outcomes. However, the available evidence is limited by heterogeneity and the predominance of low-level-evidence studies. Full article

Lyme disease is the most common reported vector-borne disease in North America and is also highly prevalent across Europe. Although tick-borne diseases are uncommon in Singapore, there remains a risk of imported tick-borne diseases among travelers from endemic regions. We present a case series of three pediatric patients with imported Lyme disease managed at a tertiary children’s hospital in Singapore, illustrating the varied clinical presentations of Lyme disease in children. One child developed meningitis following prior antibiotic therapy for Lyme disease, although causality cannot be definitively established. This series aims to highlight key diagnostic considerations and management principles relevant to clinicians practicing in non-endemic regions. Full article

Patients with Lyme disease often face uncertainty when navigating the healthcare system during pregnancy and when seeking healthcare for their children exposed to Lyme disease in utero. Little is known about these families’ experiences. This qualitative study explored the perspectives of 27 parents in the United States who had acute or chronic Lyme-related diagnoses while pregnant. Semi-structured interviews were coded and thematically analyzed. Six themes characterized positive patient–physician interactions: (1) validation of patient experiences, (2) transparency, (3) willingness to learn, (4) shared decision making, (5) empathy, and (6) continuity of care. These findings offer guidance for clinicians counseling patients facing prognostic uncertainty related to Lyme disease and similarly complex conditions. Full article

Lyme disease (LD) is classically defined as a tick-borne infection caused by Borrelia burgdorferi sensu lato (Bbsl). However, accumulating evidence indicates that, beyond microbial persistence, Bbsl infection can initiate sustained immune dysregulation and post-infectious inflammatory phenotypes in a subset of patients. This narrative review integrates open-access experimental, translational, and clinical data and discusses LD within the spectrum of infection-triggered, immune-mediated processes. We review key immunopathogenic mechanisms, including dysregulated innate immune activation, type I interferon (IFN-I) signaling, T helper 1 and T helper 17 (Th1/Th17) polarization with regulatory T-cell (Treg) insufficiency, antigen persistence (notably borrelial peptidoglycan), and pathways linking infection to autoimmunity such as molecular mimicry, epitope spreading, and human leukocyte antigen (HLA)-restricted susceptibility. These mechanisms are integrated with immune-mediated clinical manifestations affecting the central nervous system (CNS), peripheral nervous system (PNS), musculoskeletal system, heart, skin, and hematologic compartment. Finally, we discuss translational implications for diagnosis, biomarker-guided stratification, and emerging therapeutic strategies that extend beyond antimicrobial therapy, while addressing current controversies and limitations. This framework supports a mechanistic model in which Lyme disease-associated morbidity in selected patients reflects persistent immune activation and dysregulated host responses triggered by infection. Full article

Background and Aim: Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by immune dysregulation. Environmental factors, including infectious agents, have been proposed to influence disease activity in inflammatory bowel disease. Although Borrelia burgdorferi has been shown to exert complex immunomodulatory effects on host immune responses, its seroprevalence and potential association with disease activity in patients with ulcerative colitis have not been systematically investigated. This study aimed to evaluate the seroprevalence of Borrelia burgdorferi IgG antibodies in patients with ulcerative colitis and to assess the relationship between seropositivity and laboratory markers of disease activity. Methods: In this retrospective observational study, 100 patients with ulcerative colitis (59 males, 41 females; mean age 48.5 ± 17 years) who underwent Borrelia burgdorferi IgG serological testing due to musculoskeletal or neurological symptoms suggestive of possible Lyme disease between October 2020 and October 2024 were included. Demographic characteristics, hematological and biochemical parameters, and inflammatory markers were compared between seropositive and seronegative groups. Due to the retrospective design, validated clinical disease activity indices were not consistently available; therefore, disease activity was indirectly assessed using laboratory inflammatory markers. Results: Among patients with ulcerative colitis, 22% were seropositive for Borrelia burgdorferi IgG. Seropositive patients had significantly lower uric acid, alkaline phosphatase, and C-reactive protein levels compared to seronegative patients (p = 0.001, p = 0.023, and p = 0.020, respectively). Free T4 levels were significantly higher in the seropositive group (p = 0.049). In terms of erythrocyte indices, mean corpuscular volume and mean corpuscular hemoglobin were significantly higher, while RDW-CV values were significantly lower in seropositive patients (all p < 0.05). Conclusion:Borrelia burgdorferi IgG seropositivity in patients with ulcerative colitis was associated with lower laboratory markers of systemic inflammation and a more stable hematological profile. Although causality cannot be established, these findings may suggest a potential association between prior Borrelia exposure and a distinct inflammatory phenotype in UC; however, this relationship should be interpreted with caution. Further prospective and mechanistic studies are warranted to clarify the potential immunological interactions between environmental microbial exposure and inflammatory bowel disease activity. Full article

Lyme disease is the most common vector-borne disease in North America. Predicting Lyme disease incidence is a key component of public health preparedness. Previously, we demonstrated that the volume of data searches on Google Trends for terms related to Lyme disease, such as “Lyme” and “tick bite”, can be used as a tool to predict monthly human Lyme disease incidence at the state level. The objective of this project was to build upon our previous work by adding environmental and canine data to our predictive models for the prediction of state-level human and canine Lyme disease incidence. Human data were acquired from state health departments. Canine data were acquired from IDEXX Laboratories. We hypothesized that incorporating a One Health approach with human, animal, and environmental data would improve the predictive ability of the models. The One Health model performed significantly better (Mean Absolute Error [MAE] = 12.1) in predicting human disease incidence in 6 out of 16 states compared to the environmental data model (MAE = 16.5), human search terms model (MAE = 21.4), canine data (search terms + case count) model (MAE = 31.1), and the canine case data model (MAE = 32.0). For canine Lyme disease incidence, the One Health model performed worse (MAE = 330.5) compared to the canine search data model (MAE = 282.3), the human data (search terms + cases) model (MAE = 248.4), and the environmental data (MAE = 221.5) model. However, even the best-performing models had large prediction errors, which limit practical utility. Future studies should incorporate alternative data streams, such as electronic health records and insurance claims, to test predictive ability. Full article

To date, Lyme vaccine development has largely overlooked the vaccinee’s human leukocyte antigen (HLA) genetic makeup on which antibody production critically depends. Here, we evaluated in silico the predicted binding affinities of 192 HLA-II alleles with all 15-mer peptide sequences of five Borrelia burgdorferi proteins to identify peptides with strong binding affinity, as they would be the best candidates for antibody production in response to vaccination. We found the following: (a) 226 of the 1067 peptides tested (21.2%) were found to bind strongly to HLA-II molecules; (b) decorin-binding protein A had the greatest number of strongly binding peptides; and (c) 69 HLA-II alleles (primarily of the DRB1 gene) bound with strong affinity to peptides from Borrelia burgdorferi proteins. Finally, we tested for possible susceptibility to autoimmunity by any one of the 226 peptides above by searching for their occurrence in ~84,000 proteins of the human proteome and found overlap with only two 8-mer peptide sequences (embedded within the 226 15-mer peptides), neither of which was characterized by strong binding to HLA-I, suggesting a reduced likelihood of autoimmunity. These findings emphasize the importance of a personalized vaccine approach based on the vaccinee’s human leukocyte antigen genetic makeup and offer specific vaccine-candidate peptides that are predicted to maximize vaccine effectiveness and safety. The results of this computational study provide novel directions for future development of Lyme vaccines. Full article

The most common species of tick in Europe is the castor bean tick (Ixodes ricinus), which is found in forests, parks, and gardens and is active almost all year round. Ticks are among the most important arthropods and vectors of disease, transmitting a wide range of parasites that sometimes lead to the death of infected organisms. The peak incidence of tick-borne diseases occurs between May and September; however, due to global warming, people are increasingly exposed to tick-borne diseases throughout the year. In order to increase the possibility of preventing the transmission of diseases by ticks, it is necessary to become thoroughly familiar with the life cycle of ticks and the environment in which they live. Vaccines are available for some diseases, such as tick-borne encephalitis, while others require a highly specific diagnosis. Another major problem is the long period between the tick bite, which often goes unnoticed or is even ignored by the patient or the doctor, and the development of tick-borne diseases. Increasing attention is being paid to the prevention of tick-borne diseases through prevention of tick bites, quick tick removal, use of repellents, appropriate land management, vaccinations, and the use of plants as natural acaricides. Full article

Lyme borreliosis (LB), the most common European tick-borne disease, can manifest as an erythema migrans (EM) rash or as disseminated LB. The prospective Burden of Lyme Disease (BOLD) study evaluated the frequency of LB clinical manifestations, including signs, symptoms, and treatment patterns in 14 healthcare practices in endemic regions of six European countries: the Czech Republic, Germany, Poland, Slovakia, Slovenia, and Sweden. Between April 2021 and December 2022, patients with suspected LB were evaluated using predefined case definitions that were applied by investigators to identify medically attended LB cases. Enrolled cases were interviewed about their symptoms. Among the 797 LB cases, 615 (77.2%) had EM and 182 (22.8%) had disseminated disease; 154 of the disseminated cases had Lyme arthritis (LA), five had Lyme neuroborreliosis, and three had Lyme carditis. Geographically, the proportion of disseminated disease varied by country, from 1.1% in Slovenia to 78.0% in Slovakia. Overall, 76.3% of all LB cases in Slovakia were LA. Antibiotic use varied by country, although every country prescribed doxycycline. The frequency of LB manifestations varied substantially between countries. EM was the most common manifestation in all countries except Slovakia, where LA was most common. This study underscores the need for improved prevention strategies. Full article

Introduction: Ischemic stroke in young adults is uncommon and is frequently associated with rare etiologies, including autoimmune diseases and vasculitis. Takayasu arteritis (TA) is a chronic inflammatory large-vessel arteriopathy involving the aorta and its major branches and may result in cerebral ischemia due to arterial stenosis or thrombosis. Case Presentation: We report the case of a 26-year-old woman with a history of suspected rheumatoid arthritis and Lyme disease who presented with acute left-sided hemiparesis and dysarthria. At admission, large-vessel vasculitis had not yet been suspected, and the patient was treated according to standard acute stroke protocols. Computed tomography angiography (CTA) revealed occlusion of the right middle cerebral artery bifurcation and the right common carotid artery, with inflammatory changes involving the brachiocephalic trunk and subclavian arteries. Intravenous thrombolysis (iv rtPA) was followed by mechanical thrombectomy (MT), resulting in neurological improvement. Outcome: Further diagnostic work-up confirmed TA, and immunosuppressive therapy with cyclophosphamide and infliximab was initiated. Conclusion: This case underscores the importance of considering inflammatory large-vessel disease in young patients presenting with acute ischemic stroke and illustrates that endovascular reperfusion may be feasible in this clinical setting. Full article

The cause of chronic neurological effects associated with Lyme disease (LD) remains unclear. We propose that bacterial extracellular vesicles (BEVs) released by Borrelia burgdorferi, the causative agent of LD, exacerbate spirochete-induced damage and serve as a persistent source of antigenic stimulation. We showed that, over a 10-day period, in vitro cultures of B. burgdorferi B31 produced 38,000 BEVs per spirochete with a distinctive double-membrane structure and median diameter of 143.3 nm. BEVs contained known immunogenic and immunomodulatory molecules such as peptidoglycan, p66, flagellar filament protein (FlaB), basic membrane proteins A/B/D, BdrV, GroEL, CRASP-1, ErpA8, glycerophosphodiester phosphodiesterase, p37, OMS28, p13, OspA/B/C, VlsE, and outer membrane glycolipids (e.g., cholesteryl 6-O acyl beta D galactopyranoside). Chromosome-encoded 16S ribosomal RNA and cp32 plasmid-encoded OspE and terminase genes were also detected in the BEVs. Of the 45 Borrelia proteins identified in the urine of a C3H/HeJ murine model of Lyme disease, 14 were associated with BEVs. In human urine samples, 31 of 289 spirochete proteins detected in patients with either acute Lyme disease or persistent borreliosis post-treatment symptoms, including p66 and FlaB, were also BEV-associated. BEV treatment of HMC3 human microglial cells reduced phagocytic activity and triggered aberrant activation of inflammatory and immunometabolic pathways, including upregulation of interferon-alpha (IFN-α), aconitate decarboxylase 1 (Acod1), and Toll-like receptor 2 (TLR2) gene expression. BEVs also induced NRF2 nuclear translocation. In conclusion, these findings support that BEVs can amplify spirochete-induced damage and act as antigenic debris, driving dampened phagocytic activity and dysregulated inflammation, with implications for diagnostics and therapeutics targeting vesicle-mediated pathology. Full article

Lyme disease causes a significant financial and health burden. Recent advances in developing new Lyme disease vaccines have renewed optimism that vaccination may serve as an additional strategy to reduce this burden. Vaccination alone will not address the broader relevant public health challenges posed by ticks. Our experience with prior Lyme disease vaccines suggests that even an effective vaccine would not fully reduce the incidence of human disease. Importantly, vaccination against Borrelia genospecies would not affect tick abundance or exposure risk. It would also not mitigate the transmission of other tick-borne pathogens that are proliferating in human-biting ticks. Tick-borne disease risk is shaped by the biological features of ticks and tick-borne disease agents, which differ from those of mosquitoes and mosquito-borne disease agents. Unique tick characteristics create opportunities for exposure and complicate prevention and post-exposure case management. In addition to infectious diseases, ticks are associated with non-infectious conditions such as tick paralysis and alpha-gal syndrome that will not be affected by a Lyme disease vaccine. The introduction of a Lyme disease vaccine should be viewed as one part of a broader risk management strategy. Emphasis must remain on clinical awareness and education for at-risk individuals. Personal protective behaviours, surveillance, and integrated tick control will also be essential to managing tick-associated health risks in both vaccinated and unvaccinated populations. Full article

Background/Objectives: The 2020 Infectious Diseases Society of America (IDSA) guidelines recommend a single 200 mg dose of doxycycline within 72 h of tick removal after a high-risk bite for Lyme disease prophylaxis. However, limited data are available on prescribing practices related to this recommendation in highly endemic Lyme disease areas. Methods: We conducted a retrospective chart review on adult patients (aged ≥ 18 years) who received a single dose of oral doxycycline for Lyme disease prevention for the period 2022–2024 within a rural Wisconsin health system. Patient and provider prescribing characteristics were evaluated. Manual data abstraction was performed on a random sample of 155 prescribing events to assess adherence to IDSA guidelines. Results: A total of 2404 prophylaxis prescriptions were identified; 44% were prescribed to older adults between 65 and 79 years of age, 54% were prescribed to males, and 66% were prescribed to patients living in rural areas. Prescriptions peaked in spring and summer months, consistent with the known seasonal trends in tick activity. Prescribing was distributed relatively evenly across provider types, with the majority (77%) of cases occurring in outpatient and urgent care settings. Upon manual abstraction, doxycycline was indicated in 12% with the remainder either classified as possibly indicated or not indicated due to suboptimal documentation and nonadherence. Conclusions: Our study identified high rates of incomplete documentation and uncertainty in guideline concordance in a Lyme-endemic health system, highlighting the opportunities to support evidence-based prescribing and to improve documentation practices. Full article

Lyme disease is by far the most common arthropod-borne disease in the Northern Hemisphere. It is caused by certain Borrelia species that are primarily transmitted to hosts by Ixodid ticks; however, transplacental transmission of the spirochete in both animals and humans has been reported. Here, we report imaging of intact spirochetes in an archived placental tissue sample that is immunoreactive to Borrelia antibodies and from which Borrelia DNA was isolated. Both mother and child showed evidence of seroreactivity to Borrelia spp. in the years following the child’s birth, although neither individual tested positive by the conventional two-tiered serological algorithm. Cultivation of viable spirochetes from a vaginal swab of the mother and from the urine of the child some years later supports the possibility of vector-free transmission of Borrelia from mother to child. By amplifying several genomic loci from the DNA of cultured and non-cultured Borrelia from blood and body fluid samples of the mother and child, the Borrelia in both were identified as the same species, Borrelia burgdorferi sensu stricto, a strain specific to North America. Full article