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Objective: Borreliosis is a tickborne disease caused by several species of Borrelia spirochete. In Japan, autochthonous cases are increasing in Hokkaido, and in the central Honshu, where Niigata is located. This study aimed to reckon the presence of Borrelia spp. in ticks and its epidemiological significance in Niigata prefecture., Results: From 41 sites of Niigata, 1,939 DNA samples from ticks were tested for the presence of Borrelia spp. by PCR. The spirochete was detected in 55 samples, resulting in a prevalence of 2.83% (55/1,939) overall. The DNA sequencing analysis revealed 3 species of Borrelia in Niigata prefecture, B. japonica 76.4% (42/55), B. miyamotoi 3.6% (2/55) and an unidentified Borrelia sp. 20% (11/55). Borrelia japonica was detected from adults of Ixodes ovatus, predominantly in females. Higher prevalence of B. japonica was found in Joetsu area, border with Nagano and Toyama prefectures. B. miyamotoi was detected in Chuetsu region, the central area of Niigata in adult females of I. ovatus. One type of Borrelia, identified to genus level, was detected in larvae, nymph and adult stages of Haemaphysalis spp. ticks mainly in Kaetsu, the northern region of the prefecture., Competing Interests: Declarations. Ethics approval and consent to participate: No ethical permissions were necessary for this study. The ticks were collected from the environment of public places and no capture or handling of hosts were performed. Consent for publication: Not Applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Introduction: Ixodes ricinus, the castor bean tick, is the most prevalent tick species in Europe. It favours habitats such as shrubs, deciduous and mixed forests, but can also be found in urban environments. Due to its high vector competence, it is of enormous veterinary as well as medical importance, transmitting tick-borne encephalitis (TBE) virus, Borrelia burgdorferi s. l., the causative agent of lyme borreliosis, Rickettsia spp. and Anaplasma phagocytophilum amongst many other pathogens. In Kosovo, I. ricinus is the predominant species and a few studies, mostly based on human and animal seroprevalences, indicate the circulation of tick-borne pathogens. However, data on pathogens in I. ricinus are scarce in Kosovo, particularly in urban settings. This study aimed to provide first insights into the circulation of tic-kborne pathogens in I. ricinus from urban and peri-urban areas in Kosovo., Methods: Urban and peri-urban areas were sampled by flagging 150 m transects. In total, 197 ticks were morphologicaly identified as I. ricinus, and consequently DNA and RNA were isolated. All individuals were screened for the presence of tick-borne pathogens by using reverse line blotting (RLB) hybridisation., Results: DNA of nine different pathogens from four genera including Borrelia spp., Rickettsia spp., Anaplasma spp. and Babesia spp. was detected in 60 (33.5%) specimens. The most frequently detected pathogens were Rickettsia spp. (16.2%), followed by Borrelia spp. (11.7%). Altogether, 54 single infections, 11 double infections and 1 triple infection were observed., Conclusions: We provide first data on genotyping of B. burgdorferi sensu lato as well as the detection of Anaplasma, Babesia and Rickettsia from I. ricinus in this country. The data underline that particularly recreational (peri-)urban areas could facilitate the spillover of zoonotic tick-borne pathogens to humans in Kosovo and provide baseline data for future surveys., (© 2024 The Author(s). Zoonoses and Public Health published by Wiley‐VCH GmbH.)

The isolation of tick-borne relapsing fever (TBRF) spirochetes has proven to be a useful tool to understand their distribution in geographic areas where the tick vectors inhabit. However, their isolation and culture are not easy and in general an animal model is needed to achieve this task. Here, argasid ticks were collected from a neighborhood in Ciudad Caucel, and they were identified as Ornithodoros (Alectorobius) puertoricensis. To determine whether these were infected with TBRF bacteria they were fed with healthy mice but only a low burden of spirochetes was observed. An immunosuppressed mouse model was used to feed the ticks suspected to be infected with spirochetes. After tick feeding, a higher number of bacteria was observed in blood samples, and spirochetes were successfully cultivated in Barbour-Stoenner-Kelly (BSK)-IIB media. Molecular analyses indicated that the isolate was Borrelia puertoricensis, while whole genome sequencing confirmed the finding. In summary, the present report shows that A. puertoricensis is present in Ciudad Caucel, an urban neighborhood in the outskirts of Merida city, and these ticks are infected with B. puertoricensis. Despite the fact that this species has not been directly associated with TBRF it represents a potential medical and veterinary health risk., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2025 Vázquez-Guerrero et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Ixodes scapularis is a vector of several human pathogens in the United States, including Borrelia burgdorferi, the cause of Lyme disease, and Powassan virus (POWV), an emerging cause of severe encephalitis. Skin biopsies from tick bite sites are frequently collected and tested for the presence of spirochetes ( Borrelia spp.), which remain elusive. POWV testing is not performed despite the increasing incidence of POWV encephalitis. To determine the utility of staining skin biopsies for tick-borne pathogens, formalin-fixed paraffin-embedded specimens from 2010 to 2023 were examined by hematoxylin and eosin, Warthin-Starry stain, spirochete immunohistochemistry, and POWV in situ hybridization (ISH). These assays were optimized by staining histological sections from whole ticks, from which spirochetes were detected in two out of 14 patient-derived specimens, and POWV RNA was detected in multiple experimentally infected ticks. None of the 36 skin biopsies were positive for spirochetes, including 20 with retained tick mouth parts and six from patients with positive Lyme serology. POWV ISH was negative in all biopsies, including one laboratory confirmed case. Combining patients with skin biopsies and whole ticks ( n = 50), spirochetes were detected in specimens from only 1/5 (20%) patients with suspected erythema chronicum migrans (ECM). Although limited, our data suggest a poor correlation between ECM and the detection of spirochetes, findings in concordance with the published literature. Similarly, the absence of detectable POWV RNA in any of the tested skin biopsies or patient-derived ticks, including one laboratory confirmed case, suggest the limited utility of POWV ISH for clinical use without further analysis with a larger sample size.IMPORTANCETick-borne infections, including Lyme and Powassan encephalitis, cause significant morbidity and mortality and are challenging to diagnose and study in humans. We examined skin biopsies from patients with tick bites to look for direct evidence of microbes by histochemical, immunohistochemical, and in situ hybridization stains. To validate these assays, we also tested the same stains on histological sections from whole ticks infected with spirochetes or Powassan virus. Examination of skin biopsies using similar tools may prove valuable in studying the pathogenesis of diseases, such as southern tick-associated rash illness, for which a causative pathogen has not yet been identified., Competing Interests: The authors declare no conflict of interest.

A 58-year-old woman in Belgium with a history of follicular lymphoma treated with rituximab sought care for a rapid sensory-motor deficit. Seronegative neuroborreliosis caused by Borrelia spielmanii was diagnosed, likely related to humoral deficiency. High CXC motif chemokine ligand 13 levels and PCR confirmed the diagnosis. Ceftriaxone treatment led to full recovery.

Multicellular animals need to control the spread of invading pathogens. This is a particular challenge for blood-feeding vectors such as ticks, which ingest large amounts of blood potentially laden with harmful microorganisms. Ticks have a basic innate immune system and protect themselves from infection through innate immune responses involving pathways such as Janus kinase (JAK) or the signalling transducer activator of transcription (STAT). Direct antimicrobial defence occurs through the rapid synthesis of numerous antimicrobial agents including antimicrobial peptides (AMPs). The tick Ixodes ricinus is one of the main vectors of the Lyme disease pathogen, the spirochete Borrelia burgdorferi sensu lato. Data suggest that the JAK/STAT signalling pathway controls the expression of AMPs and regulates the infection of the pathogen in the tick body. The innate immune system during the off-host period keeps the level of spirochete infection in check. Spirochetes may influence the innate immune response in ticks. Therefore, the aim of this study was to analyse the expression of the genes related to the JAK/STAT pathway and selected AMPs in questing ticks in which B. burgorferi s.l. was detected. In the ticks infected with spirochetes, overexpression of genes related to the JAK/STAT signalling pathway was observed in the case of STAM and SOCS genes. AMPs genes such as def1, ric, lzs were overexpressed with different expression patterns. The results obtained suggest that AMPs may be involved in infection management in ticks., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical approval: The manuscript complies with the standards currently in force in Poland. The study does not contain any factors requiring ethics committee approval., (© 2025. The Author(s).)

Nymphal and larval Amblyomma cordiferum ticks, a relatively rare species, were collected from the Malaysian house rat (Rattus rattus diardii) in Peninsular Malaysia. Redescription and molecular analysis of nymphs and larvae, based on the 12S rRNA, 16S rRNA, and COI genes, revealed divergence from A. cordiferum in Taiwan, suggesting that the Taiwanese tick specimens may represent a different taxon. Molecular analysis of the pathogens in these specimens revealed three sequences of Rickettsia closely related or identical to Rickettsia raoultii (99.71-100%), two sequences of relapsing fever Borrelia identical to Borrelia theileri, and four sequences of Bartonella identical to Bartonella phoceensis. This study also identifies a new host record for A. cordiferum in R. r. diardii and reports the first detection of Rickettsia, Borrelia, and Bartonella in this tick species., Competing Interests: Declaration of competing interest All authors declare no competing interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Borrelia infection is caused by Borrelia burgdorferi sensu lato and transmitted by Ixodes ricinus ticks, a common tick-borne infection in Northern Europe. The establishment of Borrelia infection depends on transmission of the spirochetes, as well as the immune response generated in the skin after a bite. Here we aim to investigate the local immune response in the skin after a tick bite and assess the possible direct effects of Borrelia, by applying gene expression analysis of the immune response in skin exposed to Borrelia-infected and non-infected ticks, respectively., Methods: Skin biopsies from the study participants were taken 7-10 days after the tick-bite. The ticks and skin biopsies were analysed by real-time PCR for Borrelia spp. and other tick-borne pathogens. Dermal transcriptome profiles derived from RNA sequencing with focus on immune system regulation were created. In addition, we performed enrichment analysis of dermal transcriptome profiles with focus on immune system regulation., Results: Skin biopsies exposed to a Borrelia-positive tick induced an overall higher expression of immune-related genes. Cytokines involved in the regulation of T-cell and macrophage activation, pro-inflammatory regulators and Toll-like receptor 2, 3 and 7 involved in pathogen recognition were upregulated in skin exposed to Borrelia, although Borrelia DNA was not detected in the biopsies., Conclusion: The evidence of upregulation of genes in Borrelia exposed skin suggests an influence on the immune system of ticks and spirochetes. Characterization of Borrelia-associated gene expression signatures in the skin could contribute to future diagnostics and increase our understanding of the development of various manifestations of Borrelia infection., Competing Interests: Declarations. Ethics approval and consent to participate: The study was conducted in accordance with the Declaration of Helsinki, and the study protocol was approved by the local Ethics Committee of the Åland Islands Health Care, meeting number 2/2017 (21st of November 2017). All participants gave their written informed consent before study inclusion. Consent for publication: Not applicable. Competing interests: Per-Eric Lindgren has been a senior scientific external advisor to Pfizer Inc and Bavarian-Nordic A/S. The other authors declare no conflict of interest., (© 2024. The Author(s).)

Background: Borrelia miyamotoi and Borrelia burgdorferi sensu lato (s.l.) are important zoonotic agents transmitted by Ixodes ricinus ticks, which are widely distributed across Central Europe. Understanding the spatial distribution of these pathogens' prevalence will help identify areas with increased infection risk and facilitate the implementation of effective preventive measures., Methods: We analysed 12,955 I. ricinus ticks collected from 142 towns in the Czech Republic between 2016 and 2018. The ticks were pooled into 2591 groups of five and tested using duplex quantitative polymerase chain reaction (qPCR) for the presence of B. burgdorferi s.l. and B. miyamotoi. For each location, we estimated the overall prevalence of both agents using the EpiTools Epidemiological Calculator for pooled samples and calculated the minimum infection rate (MIR). To assess the potential risk of infection, we combined data on the abundance of nymphs and females with pathogen prevalence at each sampled site. Using a geographic information system (GIS), we mapped the MIR and infection risk of both Borrelia species across all 142 sampled locations and employed a geostatistical method (ordinary kriging) to predict MIR values and infection risk as continuous surfaces across the entire country., Results: We detected B. miyamotoi in 110 localities and B. burgdorferi s.l. in all 142 localities. The estimated prevalence of B. miyamotoi and B. burgdorferi s.l. in the collected ticks was 2.1% (95% confidence interval [CI] 1.8-2.3) and 27.1% (95% CI 26.0-28.3), respectively. For B. miyamotoi, we identified previously unknown, geographically distinct hotspots of MIR up to 8.3%, with MIR slightly higher in females (2.3%) than in males (1.9%) and nymphs (1.8%), though the difference was not statistically significant. In contrast, B. burgdorferi s.l. exhibited ubiquitous presence, with consistently high prevalence nationwide, showing similar MIRs in females (16.2%) and males (16.1%), and slightly lower in nymphs (15.6%). The highest infection risk for B. miyamotoi was 12.4 infected vectors per hour in southeastern Moravia, while the highest risk for B. burgdorferi s.l. reached 78.6 infected vectors per hour in the Bohemian-Moravian Highlands., Conclusions: Borrelia miyamotoi is widespread, forming distinct high-prevalence areas in certain regions. Borrelia burgdorferi s.l. demonstrates consistently high prevalence across most of the country, except for a few localized areas such as southwestern Czechia. Both pathogens exhibit natural nidality, forming regions with elevated prevalence and infection risk. Long-term time-series data are needed to confirm the spatio-temporal stability of these hotspots., Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Objectives: Crimean-Congo Hemorrhagic Fever (CCHF) is a tick-borne zoonotic viral disease that could be a public health concern. The overlapping of clinical symptoms of some acute bacterial febrile diseases with CCHF is of importance for clinical diagnosis. This study aimed to molecularly examination of Brucella, Coxiella burnetii, Borrelia, and Ehrlichia infections among individuals suspected of CCHF in Iran., Methods: In this study, 260 serum samples of suspected cases of CCHF with definitively negative laboratory test results for CCHF virus infection, were examined for Brucella spp., Coxiella burnetii, Borrelia spp., and Ehrlichia spp. by Real-time PCR., Results: According to the results, 3.46 % and 3.07 % of the patients were positive for brucellosis and Q fever, respectively. Notably, no cases of borreliosis or ehrlichiosis were detected. Among the positive cases for brucellosis (N = 9), three cases were identified as Brucella abortus infection. Individuals under the age of 43 displayed a significantly higher positivity rate for Q fever (p < 0.01). Furthermore, patients presenting with chills had a 5.81-fold increased likelihood of being infected with Q fever (95 % CI: 1.39-24.26) compared to those without chills. Notably, no other variables demonstrated a statistically significant association with Q fever infection., Discussion and Conclusions: The results of this study showed that bacterial infections such as Q fever and brucellosis should be considered as differential diagnoses of CCHF. It is recommended that other bacterial infections that can cause early clinical symptoms similar to CCHF should also be taken into consideration in future studies and serological and molecular investigations of these infections should be tested on a wide scale., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Bacteria of the genus Borrelia are agents of disease in both domestic animals and humans and pose a significant public health risk. Borrelia species have complex transmission cycles, often using rodents as vertebrate reservoir hosts. These bacteria are classified into three well-defined monophyletic groups: Borrelia burgdorferi sensu lato (Bbsl) complex, the relapsing fever (RF) group, and a third group associated with reptiles and echidnas. Moreover, a new group of Borrelia associated with rodents has recently been proposed, as these bacteria form a phylogenetic group separated from the previously mentioned groups. This study aimed to investigate the presence of DNA of Borrelia spirochetes in rodents in specific areas of the Colombian Caribbean., Methods: A total of 155 rodent spleen samples were selected from the tissue bank. These samples were obtained in the departments of La Guajira and Córdoba (Northern Colombia). DNA extraction and specific real-time polymerase chain reaction (PCR) targeting Borrelia 16S ribosomal RNA (rRNA) gene were performed, followed by nested PCR (nPCR) on positive samples to obtain larger fragments of the 16S rRNA gene and characterize the flaB gene. Alignments of generated sequences and ortholog sequences downloaded from Genbank were performed in Clustal Omega. A phylogenetic tree was built with the maximum likelihood method in IQTREE., Results: Spleen samples from rodents of the genera Heteromys, Mus, Necromys, Olygoryzomys, Proechymis, Rattus, Sigmodon, and Zygodontomys were processed. Overall, 6.5% (4/162) of the animals tested positive for Borrelia by real-time PCR. All quantitative PCR (qPCR)-positive samples were also positive for nPCR targeting the 16S rRNA gene, yielding fragments of 344-408 bp and 603-673 bp from two Sigmodon rodents and two Zygodontomys rodents from La Guajira and Córdoba. All samples were negative for the flaB gene. Only samples from Zygodontomys rodents presented good quality sequences. A BLASTn analysis showed a percentage of identity ranging between 98.16 and 96.06% with Borrelia sp. R57. Phylogenetic analysis revealed that sequences of the present study clustered with species of the recently proposed Borrelia "rodent group.", Conclusions: This is the first detection of borreliae of the "rodent group" in South America. Our results reaffirm the occurrence of a group of spirochetes associated with rodents, extending its geographic distribution to the Colombian Caribbean., Competing Interests: Declarations. Ethics approval and consent to participate: The rodents were captured under the permits of the National Authority of Environmental Licenses [ANLA], resolution no. 00914. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Borrelia miyamotoi spirochete is carried by Ixodidae ticks and causing Borrelia miyamotoi disease (BMD), a relapsing fever illness reported worldwide, often in the same geographic areas where Lyme disease is endemic. The purpose of this study was to examine the presence of B. miyamotoi infection in Dermacentor reticulatus and Ixodes ricinus ticks collected within the boundaries of the Chornobyl Exclusion Zone, Ukraine. A total of 1176 adult D. reticulatus ticks and 113 adult I. ricinus ticks sampled from five different habitats in the Chornobyl Exclusion Zone, Ukraine, were tested for Borrelia miyamotoi using a two-step nested PCR procedure. Borrelia miyamotoi was found in two (0.17%) out of the 1176 D. reticulatus ticks tested. The obtained sequences were submitted to GenBank (MZ365312-MZ365313). Phylogenetic analysis showed that the B. miyamotoi sequences detected cluster together with a strain originating from I. scapularis in the USA. The strain identified in the Chornobyl Exclusion Zone belongs to the group of strains found in Eastern Europe and Asia, north of the Himalayas. No I. ricinus ticks were found to be infected. This study presents the first detection of B. miyamotoi in D. reticulatus ticks in the Chornobyl Exclusion Zone, Ukraine., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

An undescribed relapsing fever group Borrelia species was detected in a male Haemaphysalis semermis tick infesting a rural cat in an indigenous population in Pahang National Park, Peninsular Malaysia. The 16 S rRNA gene sequence revealed close similarity of this variant to several undescribed Borrelia species and Borrelia theileri, with genetic distances ranging from 0.58 to 0.72%. Furthermore, the flaB, gyrB, and the concatenated 16 S rRNA + flaB + gyrB sequence analyses demonstrated that this variant is distinctly separated from multiple undescribed Borrelia species, Borrelia miyamotoi, and B. theileri, with genetic distances ranging from 3.41 to 7.00%. This study not only reports the first Borrelia found in H. semermis but also suggests that it forms a distinct clade within the relapsing fever group in Peninsular Malaysia., Competing Interests: Declarations Animal ethics approval No approval of research ethics committees was required for the purpose of this manuscript. Consent to participate Not applicable. Consent for publication Not applicable. Competing interests The authors declare no competing interests. Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Febrile illnesses contribute significantly to morbidity and mortality in sub-Saharan Africa, but the lack of diagnostic facilities and the broad spectrum of pathogens can lead to inadequate clinical management. The timely and reliable identification of the causative pathogens in febrile patients is the basis for the administration of optimal treatment. We aimed to evaluate the performance of a multiplex polymerase chain reaction (PCR) among blood culture-negative patients presenting with febrile diseases in Central Ethiopia. From April 2016 to June 2018, we collected blood samples from adults and children ≥1 year of age admitted with febrile diseases to the Asella Referral and Teaching Hospital, which is located at an altitude of 2,400 m. Total nucleic acids were extracted from frozen plasma samples using a MagNA Pure 96 instrument (Roche, Mannheim, Germany). The multiplex PCR assays were used in combination with LightCycler multiplex DNA master mix (Roche) on a LightCycler 480 instrument (Roche). We used the pathogen-specific assays targeted to Plasmodium spp., Borrelia spp., Rickettsia spp., Leptospira spp., Salmonella spp., and arboviruses. We tested plasma samples of 511 patients and found positive results for Plasmodium spp. (13, 2.5%), Borrelia spp. (12, 2.3%), and Rickettsia species (7, 1.3%); in total, pathogens were detected in 32 of the samples (6.3%). No pathogen was detected by multiplex PCR in 94% of blood culture-negative samples. Even if the pathogens identified by PCR were not necessarily causes of fever, molecular testing using a multiplex PCR can contribute to pathogen diagnosis in a proportion of febrile patients in the highland part of Ethiopia and help to improve the clinical management.

Introduction: The expanding geographical range of blacklegged ticks (BLTs), Ixodes scapularis, and its ability to transmit Borrelia burgdorferi, Anaplasma phagocytophilum, Babesia microti, and Borrelia miyamotoi poses an emerging public health risk. Our study determined the geographic distribution and the minimum infection rate (MIR) of B. burgdorferi-, A. phagocytophilum-, Ba. microti-, and B. miyamotoi-infected BLTs in Manitoba submitted to the Public Health Agency of Canada's passive tick surveillance programme from 1995 to 2017., Methods: Regression models were used to test the association of the MIR by year for each pathogen. Ticks were tested using PCR for B. burgdorferi since 1995, A. phagocytophilum since 2006, and Ba. microti and B. miyamotoi since 2013. The global positioning system coordinates of infected and uninfected ticks submitted during the surveillance period were plotted on a map of Manitoba using ArcGIS Pro version 3.1.2 to detect changes in the geographic distribution of ticks over time., Results: The overall MIR for B. burgdorferi was 139.7 (95% confidence interval [CI]: 129.0-150.5) per 1000 BLTs; however, it varied over time. After remaining stable from 1995 to 2005, the MIR increased by 12.1 per 1000 BLTs per year from 2005 to 2017 (95% CI: 7.0%-17.2%, p-value <0.01). The geographic distribution of B. burgdorferi-infected BLTs was centred around Winnipeg, Manitoba, and spread outward from this locality. The MIRs of A. phagocytophilum, Ba. microti, and B. miyamotoi were 44.8 per 1000 BLTs (95% CI: 38.1-51.6), 10.8 (95% CI: 6.6-15.0), and 5.2 (95% CI: 2.3-8.1) per 1000 BLTs, respectively, and showed no significant change over time., Conclusion: Passive surveillance revealed the presence of A. phagocytophilum-, Ba. microti-, and B. miyamotoi-infected BLTs in southern Manitoba and revealed an increased risk of exposure to B. burgdorferi-infected BLTs due to the increasing geographic range and MIR., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Tick-borne relapsing fever group borreliae (TBRFGB) are spirochetes that cause disease in humans and animals. Little is known about the prevalence of TBRFGB infections in ticks and humans in Kazakhstan. A total of 846 ticks belonging to ten species of the family Ixodidae and three species of the family Argasidae were collected from the vegetation, poultry shelters, domestic ruminants, bitten humans, pigeons, dogs and house walls in four oblasts of the southern and southeastern regions of Kazakhstan. The ticks were subjected to DNA extraction and identification of TBRFGB by conventional PCR using primers targeting flagella subunit B (flaB), glycerophosphodiester phosphodiesterase (glpQ) and P66 porin (P66) genes. The overall infection rate of TBRFGB in the ticks was 6.2 % (46/846). TBRFGB DNA was identified in Ixodes persulcatus (5.5 %; 26/477), Ornithodoros tartakovskyi (6 %; 2/36) and Argas persicus (13.4 %; 18/134) ticks. Partial sequencing of flaB, glpQ and P66 genes identified Borrelia miyamotoi in I. persulcatus and Borrelia anserina in A. persicus. To detect the presence of B. miyamotoi infection in people in the study region, we performed serological analysis of samples collected from 42 patients admitted to hospital with fever of unknown etiology or with a history of a tick bite. The analysis revealed IgM and IgG antibodies against one or several B. miyamotoi antigens in 10 % and 5 % of patients, respectively. The data obtained provide strong evidence of the presence of B. miyamotoi and B. anserina in the southern and southeastern regions of Kazakhstan, underscoring the need for increased awareness of potential infections caused by these borreliae in these regions., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Tick-borne pathogens are a worldwide threat to public health that can only be mitigated by knowledge on tick-host associations coupled with surveillance of their infection by pathogenic microorganisms. This information is not equally available throughout tick vector distribution range and is deficient in some geographical areas. In this study we did a molecular survey of tick-borne pathogens associated with different tick species in Morocco. We analyzed four different species of Hyalomma (Hyalomma aegyptium, Hyalomma anatolicum, Hyalomma dromedarii and Hyalomma impeltatum) and Rhipicephalus sanguineus sensu lato ticks from four vertebrate hosts and from the vegetation. The most common tick species collected was H. aegyptium feeding on Testudo graeca tortoises, followed by H. anatolicum from the vegetation. Hyalomma aegyptium feeding on T. graeca was found infected with Borrelia turcica, representing the first detection for Western North Africa, and Rickettsia sibirica mongolitimonae, also detected for the first time in Morocco. Rickettsia aeschlimannii was also detected in H. aegyptium feeding on T. graeca. Additionally, R. aeschlimannii was detected in H. anatolicum from the vegetation, and Rickettsia massiliae in R. sanguineus s.l. from an Algerian hedgehog Atelix algirus. Because H. aegyptium are common parasites of T. graeca tortoises, and these animals are subjected to pet trade, it is important to evaluate the associated human health risks through regular surveillance and perform awareness campaigns for prevention of the general public., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)

We performed nanopore-based metagenomic screening on 885 ticks collected from 6 locations in Mongolia and divided the results into 68 samples: 23 individual samples and 45 pools of 2-12 tick samples each. We detected bacterial and parasitic pathogens Anaplasma ovis, Babesia microti, Coxiella burnetii, Borrelia miyamotoi, Francisella tularensis subsp. holarctica and novicida, Spiroplasma ixodetis, Theileria equi, and Rickettsia spp., including R. raoultii, R. slovaca, and R. canadensis. We identified the viral pathogens Crimean-Congo hemorrhagic fever virus (2.9%), recently described Alongshan virus (ALSV) (2.9%), and Beiji nairovirus (5.8%). We assembled ALSV genomes, and maximum-likelihood analyses revealed clustering with viruses reported in humans and ticks from China. For ALSV, we identified surface glycoprotein markers associated with isolates from Asia viruses hosted by Ixodes persulcatus ticks. We also detected 20 virus species of unknown public health impact, including a near-complete Yanggou tick virus genome. Our findings demonstrate that nanopore sequencing can aid in detecting endemic and emerging tickborne pathogens.

To shed light on the importance of tick-borne diseases, especially in farm animals that often contact with farm workers, this study aimed to identify ticks and tick-borne pathogens in ruminants in Malaysia. Accordingly, specimen collection was conducted across Peninsular Malaysia yielded a total of 1241 ticks collected from 674 farm ruminants. Among these, four tick species were identified, with Rhipicephalus microplus being the most prevalent, constituting 99.03 % of the total tick population. Analysis of 130 tick pools revealed three positives for Borrelia. BLAST analyses of the flaB and 16S rRNA genes revealed high similarities to Borrelia theileri, ranging from 98.78 to 100 % for flaB and 99.23-99.45 % for 16S rRNA. These results align with the phylogenetic trees, where sequences from both genes clustered together with B. theileri, further supporting this identification. No Rickettsia and Bartonella bacteria were detected. This study represents the first occurrence of B. theileri in R. microplus in Malaysia., Competing Interests: Declaration of competing interest All authors declare no competing interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Ixodes ricinus ticks are ubiquitous in Europe, including in North-East Italy. These ticks are important vectors of several zoonotic pathogens of public health relevance. In this study, the habitat suitability range of I. ricinus ticks infected with zoonotic pathogens was predicted in North-East Italy, and relevant spatial predictors were identified. In 2015-2021, ticks were collected at 26 sampling sites in the study area. The collected ticks were screened for the presence of pathogens using PCR assays. For Borrelia , Rickettsia and Anaplasma/Ehrlichia species, data allowed for ecological niche modelling using Maxent. Environmental determinants potentially related to tick habitat suitability were used as model inputs. Predicted suitable habitat distributions revealed hotspots of the probability of pathogen presence in I. ricinus ticks mainly in the central and upper parts of the study area. Key environmental predictors were temperature, rainfall and altitude, and vegetation index for specific pathogens ( Rickettsia and Anaplasma / Ehrlichia species). Increased risk of exposure to tick-borne pathogens upon tick bites in the predicted hotspot areas can, therefore, be expected. This provides useful information for public health risk managers in this and other similar regions.

Lyme disease, caused by spirochetes in the Borrelia burgdorferi sensu lato clade within the Borrelia genus, is transmitted by Ixodes ticks and is currently the most prevalent and rapidly expanding tick-borne disease in Europe and North America. We report complete genome sequences of 47 isolates that encompass all established species in this clade while highlighting the diversity of the widespread human pathogenic species B. burgdorferi . A similar set of plasmids has been maintained throughout Borrelia divergence, indicating that they are a key adaptive feature of this genus. Phylogenetic reconstruction of all sequenced Borrelia genomes revealed the original divergence of Eurasian and North American lineages and subsequent dispersals that introduced B. garinii, B. bavariensis, B. lusitaniae, B. valaisiana, and B. afzelii from East Asia to Europe and B. burgdorferi and B. finlandensis from North America to Europe. Molecular phylogenies of the universally present core replicons (chromosome and cp26 and lp54 plasmids) are highly consistent, revealing a strong clonal structure. Nonetheless, numerous inconsistencies between the genome and gene phylogenies indicate species dispersal, genetic exchanges, and rapid sequence evolution at plasmid-borne loci, including key host-interacting lipoprotein genes. While localized recombination occurs uniformly on the main chromosome at a rate comparable to mutation, lipoprotein-encoding loci are recombination hotspots on the plasmids, suggesting adaptive maintenance of recombinant alleles at loci directly interacting with the host. We conclude that within- and between-species recombination facilitates adaptive sequence evolution of host-interacting lipoprotein loci and contributes to human virulence despite a genome-wide clonal structure of its natural populations., Importance: Lyme disease (also called Lyme borreliosis in Europe), a condition caused by spirochete bacteria of the genus Borrelia , transmitted by hard-bodied Ixodes ticks, is currently the most prevalent and rapidly expanding tick-borne disease in the United States and Europe. Borrelia interspecies and intraspecies genome comparisons of Lyme disease-related bacteria are essential to reconstruct their evolutionary origins, track epidemiological spread, identify molecular mechanisms of human pathogenicity, and design molecular and ecological approaches to disease prevention, diagnosis, and treatment. These Lyme disease-associated bacteria harbor complex genomes that encode many genes that do not have homologs in other organisms and are distributed across multiple linear and circular plasmids. The functional significance of most of the plasmid-borne genes and the multipartite genome organization itself remains unknown. Here we sequenced, assembled, and analyzed whole genomes of 47 Borrelia isolates from around the world, including multiple isolates of the human pathogenic species. Our analysis elucidates the evolutionary origins, historical migration, and sources of genomic variability of these clinically important pathogens. We have developed web-based software tools (BorreliaBase.org) to facilitate dissemination and continued comparative analysis of Borrelia genomes to identify determinants of human pathogenicity., Competing Interests: The authors declare no conflict of interest.

Background: Ticks carry a variety of microorganisms, some of which are pathogenic to humans. The human risk of tick-borne diseases depends on, among others, the prevalence of pathogens in ticks biting humans. To follow-up on this prevalence over time, a Belgian study from 2017 was repeated in 2021., Methods: During the tick season 2021, citizens were invited to have ticks removed from their skin, send them and fill in a short questionnaire on an existing citizen science platform for the notification of tick bites (TekenNet). Ticks were morphologically identified to species and life stage level and screened using multiplex qPCR targeting, among others, Borrelia burgdorferi (sensu lato), Anaplasma phagocytophilum, Borrelia miyamotoi, Neoehrlichia mikurensis, Babesia spp., Rickettsia helvetica and tick-borne encephalitis virus (TBEV). The same methodology as in 2017 was used., Results: In 2021, the same tick species as in 2017 were identified in similar proportions; of 1094 ticks, 98.7% were Ixodes ricinus, 0.8% Ixodes hexagonus and 0.5% Dermacentor reticulatus. A total of 928 nymphs and adults could be screened for the presence of pathogens. Borrelia burgdorferi (s.l.) was detected in 9.9% (95% CI 8.2-12.0%), which is significantly lower than the prevalence of 13.9% (95% CI 12.2-15.7%) in 2017 (P = 0.004). The prevalences of A. phagocytophilum (4.7%; 95% CI 3.5-6.3%) and R. helvetica (13.3%; 95% CI 11.2-15.6%) in 2021 were significantly higher compared to 2017 (1.8%; 95% CI 1.3-2.7% and 6.8%; 95% CI 5.6-8.2% respectively) (P < 0.001 for both). For the other pathogens tested, no statistical differences compared to 2017 were found, with prevalences ranging between 1.5 and 2.9% in 2021. Rickettsia raoultii was again found in D. reticulatus ticks (n = 3/5 in 2021). Similar to 2017, no TBEV was detected in the ticks. Co-infections were found in 5.1% of ticks. When combining co-infection occurrence in 2017 and 2021, a positive correlation was observed between B. burgdorferi (s.l.) and N. mikurensis and B. burgdorferi (s.l.) and B. miyamotoi (P < 0.001 for both)., Conclusions: Although the 2021 prevalences fell within expectations, differences were found compared to 2017. Further research to understand the explanations behind these differences is needed., (© 2024. The Author(s).)

The objective of this study was to investigate the presence and genetic attributes of Borrelia spp. in cats and dogs from the West Azerbaijan Province, located in the northwest of Iran. A total of 250 blood samples from cats and 300 blood samples from dogs were collected, and information regarding their age, sex, breed, ownership status, sampling time and region was recorded. The identification of positive samples was accomplished through nested-PCR and sequencing, with subsequent analysis of the gene sequences conducted using BioEdit software. The gene sequences for Borrelia spp. in this study showed 100% similarity to reference sequences in the GenBank® database. Phylogenetic trees were built using MEGA11. The outcomes indicated that among 250 blood samples from cats, 48 (19.2%) tested positive for Borrelia spp. gene, with a CI from 14.8 to 24.53% for cats. Similarly, out of 300 blood samples from dogs, 45 (15%) tested positive for the Borrelia spp. gene, with a CI from 11.4 to 19.48% for dogs., (© 2024. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

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

Environmental dimensions, such as temperature, precipitation, humidity, and vegetation type, influence the activity, survival, and geographic distribution of tick species. Ticks are vectors of various pathogens that cause disease in humans, and Ixodes scapularis and Amblyomma americanum are among the tick species that transmit pathogens to humans across the central and eastern United States. Although their potential geographic distributions have been assessed broadly via ecological niche modeling, no comprehensive study has compared ecological niche signals between ticks and tick-borne pathogens. We took advantage of National Ecological Observatory Network (NEON) data for these two tick species and associated bacteria pathogens across North America. We used two novel statistical tests that consider sampling and absence data explicitly to perform these explorations: a univariate analysis based on randomization and resampling, and a permutational multivariate analysis of variance. Based on univariate analyses, in Amblyomma americanum , three pathogens (Borrelia lonestari , Ehrlichia chaffeensis , and E. ewingii ) were tested; pathogens showed nonrandom distribution in at least one environmental dimension. Based on the PERMANOVA test, the null hypothesis that the environmental position and variation of pathogen-positive samples are equivalent to those of A. americanum could not be rejected for any of the pathogens, except for the pathogen E. ewingii in maximum and minimum vapor pressure and minimum temperature. For Ixodes scapularis, six pathogens ( A. phagocytophilum , Babesia microti , Borrelia burgdorferi sensu lato, B. mayonii , B. miyamotoi , and Ehrlichia muris -like) were tested; only B. miyamotoi was not distinct from null expectations in all environmental dimensions, based on univariate tests. In the PERMANOVA analyses, the pathogens departed from null expectations for B. microti and B. burgdorferi sensu lato, with smaller niches in B. microti , and larger niches in B. burgdorferi sensu lato, than the vector. More generally, this study shows the value of large-scale data resources with consistent sampling methods, and known absences of key pathogens in particular samples, for answering public health questions, such as the relationship of presence and absence of pathogens in their hosts respect to environmental conditions., Competing Interests: The authors declare there are no competing interests., (©2024 Alkishe et al.)

The family Borreliaceae contains arthropod-borne spirochetes that cause two widespread human diseases, Lyme disease and relapsing fever. Lyme disease is a subacute, progressive illness with variable stage and tissue manifestations. Relapsing fever is an acute febrile illness with prominent bacteremia that may recur and disseminate, particularly to the nervous system. Clinical heterogeneity is a hallmark of both diseases. While human clinical manifestations are influenced by a wide variety of factors, including immune status and host genetic susceptibility, there is evidence that Borreliaceae microbial factors influence the clinical manifestations of human disease caused by this family of spirochetes. Despite these associations, the spirochete genes that influence the severity and manifestations of human disease are, for the most part, unknown. Recent work has identified lineage-specific expansions of lipoproteome-rich accessory genome elements in virulent clones of Borrelia burgdorferi. Using publicly available genome assemblies, it is shown that all Borreliaceae lineages for which sufficient sequence data are available harbor a similar pattern of strongly structured, lineage-specific expansions in their accessory genomes, particularly among lipoproteins, and that this pattern holds across phylogenetic scales including genera, species, and genotypes. The relationships among pangenome elements suggest that infrequent episodes of marked genomic change followed by clonal expansion in geographically and enzootically structured populations may account for the unique lineage structure of Borreliaceae. This analysis informs future genotype-phenotype studies among Borreliaceae and lays a foundation for studies of individual gene function guided by phylogenetic patterns of conservation, diversification, gain, and/or loss., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Changing climates are allowing the geographic expansion of ticks and their animal hosts, increasing the risk of Borrelia -caused zoonoses in Canada. However, little is known about the genomic diversity of Borrelia from the west of the Canadian Rockies and from the tick vectors Ixodes pacificus , Ixodes auritulus and Ixodes angustus . Here, we report the whole-genome shotgun sequences of 51 Borrelia isolates from multiple tick species collected on a range of animal hosts between 1993 and 2016, located primarily in coastal British Columbia. The bacterial isolates represented three different species from the Lyme disease-causing Borrelia burgdorferi sensu lato genospecies complex [ Borrelia burgdorferi sensu stricto ( n =47), Borrelia americana ( n =3) and Borrelia bissettiae ( n =1)]. The traditional eight-gene multi-locus sequence typing (MLST) strategy was applied to facilitate comparisons across studies. This identified 13 known Borrelia sequence types (STs), established 6 new STs, and assigned 5 novel types to the nearest sequence types. B. burgdorferi s. s. isolates were further differentiated into ten ospC types, plus one novel ospC with less than 92 % nucleotide identity to all previously defined ospC types. The MLST types resampled over extended time periods belonged to previously described STs that are distributed across North America. The most geographically widespread ST, ST.12, was isolated from all three tick species. Conversely, new B. burgdorferi s. s. STs from Vancouver Island and the Vancouver region were only detected for short periods, revealing a surprising transience in space, time and host tick species, possibly due to displacement by longer-lived genotypes that expanded across North America.This article contains data hosted by Microreact.

Borrelia theileri is a tick-borne spirochete causative agent of fever, apathy and reduced food consumption in cattle. Molecular diagnosis has expanded the understanding of Borrelia theileri with new hosts and geographical locations being described. The present study aimed to describe the first molecular detection of B. theileri in wild tapirs (Tapirus terrestris) from South America. Blood DNA samples obtained from 99 tapirs sampled in Pantanal (n = 61) and Cerrado (n = 38) biomes were screened using a qPCR assay based on the 16 S rRNA gene of Borrelia sp. Positive samples in the qPCR assay were subjected to PCR assays to allow characterization of fragments from 16 S rRNA and flaB genes. Two (2/99; 2.0%) animals from Pantanal biome were positive in the qPCR and one sample presented bands of expected size for the flaB protocol. Amplicons from this sample were successfully cloned and sequenced. In the phylogenetic analysis, Borrelia sp. from T. terrestris grouped together with B. theileri sequences previously detected in Rhipicephalus microplus ticks and cattle from Minas Gerais State in Brazil, Rhipicephalus geigyi from Mali, and R. microplus and Haemaphysalis sulcata from Pakistan. This finding contributes to our knowledge regarding susceptible hosts species for B. theileri. More studies are necessary to understand the potential effects of B. theileri on tapir's health., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The aim of this study was to determine the level of infection of Ixodes ricinus ticks with pathogens (Borrelia spp., Rickettsia spp., and Anaplasma spp.) collected from Lacerta agilis and Zootoca vivipara lizards in the urban areas of Wrocław (SW Poland). The study was carried out in July-August 2020. Lizards were caught by a noose attached to a pole or by bare hands, identified by species, and examined for the presence of ticks. Each lizard was then released at the site of capture. Ticks were removed with tweezers, identified by species using keys, and molecular tests were performed for the presence of pathogens. From 28 lizards (17 specimens of Z. vivipara and 11 specimens of L. agilis) a total of 445 ticks, including 321 larvae and 124 nymphs, identified as I. ricinus were collected. A larger number of ticks were obtained from L. agilis compared to Z. vivipara. Molecular tests for the presence of pathogens were performed on 445 specimens of I. ricinus. The nested PCR method for the fla gene allowed the detection of Borrelia spp. in 9.4% of ticks, and it was higher in ticks from L. agilis (12.0%) than from Z. vivipara (1.0%). The RFLP method showed the presence of three species, including two belonging to the B. burgdorferi s.l. complex (B. lusitaniae and B. afzelii), and B. miyamotoi. The overall level of infection of Rickettsia spp. was 19.3%, including 27.2% in ticks collected from Z. vivipara and 17.0% from L. agilis. Sequencing of randomly selected samples confirmed the presence of R. helvetica. DNA of Anaplasma spp. was detected only in one pool of larvae collected from L. agilis, and sample sequencing confirmed the presence of (A) phagocytophilum. The research results indicate the important role of lizards as hosts of ticks and their role in maintaining pathogens in the environment including urban agglomeration as evidenced by the first recorded presence of (B) miyamotoi and (A) phagocytophilum in I. ricinus ticks collected from L. agilis. However, confirmation of the role of sand lizards in maintaining (B) miyamotoi and A. phagocytophilum requires more studies and sampling of lizard tissue., (© 2024. The Author(s).)

Background: Ticks are hematophagous arthropods acting as important vectors for several microorganisms. Ticks have an important role in the epidemiology of numerous diseases from a public health standpoint. In Algeria, knowledge of tick-borne associated microorganisms is limited. This paper aimed to investigate the presence of microorganisms in Ixodes ticks in Ain Kerma El Tarf region., Materials and Methods: Ticks were collected from the environment using the flagging method in El Hannachir, Ain kerma (El Tarf province), conserved in 70% ethanol, and morphologically identified. DNA was individually isolated from the ticks and screened for the presence of Piroplasmids and Hepatozoon spp., Borrelia spp., Spotted fever group Rickettsia, Bartonella spp., Mycoplasma spp., Anaplasmataceae, Anaplasma phagocytophilum, Francisella tularensis., Results: Adult ticks of the genus Ixodes (n = 51) were collected. Due to their pronounced morphological resemblance, the sampled ticks are referenced as: I. ricinus/ I.inopinatus (n = 51, 26 males, 25 females). The following pathogens were identified in the tested ticks: Borrelia lusitaniae (n = 17; 33.33%), Rickettsia monacensis (n = 10; 19.60%), and R. helvetica (n = 5; 9.80%). In addition, five ticks (9.80%) were found to be coinfected with Borrelia lusitaniae and R. monacensis/ heletica. All ticks were negative for Piroplasmids and Hepatozoon spp., Bartonella spp., Mycoplasma spp., Anaplasmataceae, Anaplasma phagocytophilum and Francisella tularensis., Conclusion: Questing Ixodes ticks from Algeria are carriers of various pathogens, with Borrelia lusitaniae posing a potential risk in the country., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Borrelia, spirochetes transmitted by ticks, are the etiological agents of numerous multisystemic diseases, such as Lyme borreliosis (LB) and tick-borne relapsing fever (TBRF). This study focuses on two surface proteins from two Borrelia subspecies involved in these diseases: CspZ, expressed by Borrelia burgdorferi sensu stricto (also named BbCRASP-2 for complement regulator-acquiring surface protein 2), and the factor H binding A (FhbA), expressed by Borrelia hermsii. Numerous subspecies of Borrelia, including these latter, are able to evade the immune defenses of a variety of potential vertebrate hosts in a number of ways. In this context, previous data suggested that both surface proteins play a role in the immune evasion of both Borrelia subspecies by interacting with key regulators of the alternative pathway of the human complement system, factor H (FH) and FH-like protein 1 (FHL-1). The recombinant proteins, CspZ and FhbA, were expressed in Escherichia coli and purified by one-step metal-affinity chromatography, with yields of 15 and 20 mg or pure protein for 1 L of cultured bacteria, respectively. The purity was evaluated by SDS-PAGE and HPLC and is close to about 95%. The mass of CspZ and FhbA was checked by mass spectrometry (MS). Proper folding of CspZ and FhbA was confirmed by circular dichroism (CD), and their biological activity, namely their interaction with purified FH from human serum (recombinant FH 15-20  and recombinant FHL-1), was characterized by SPR. Such a study provides the basis for the biochemical characterization of the studied proteins and their biomolecular interactions which is a necessary prerequisite for the development of new approaches to improve the current diagnosis of LB and TBRF. KEY POINTS: • DLS, CD, SEC-MALS, NMR, HPLC, and MS are tools for protein quality assessment • Borrelia spp. possesses immune evasion mechanisms, including human host complement • CspZ and FhbA interact with high affinity (pM to nM) to human FH and rFHL-1., (© 2024. The Author(s).)

Relapsing fever (RF), a vector-borne disease caused by Borrelia spp., is characterized by recurring febrile episodes due to repeated bouts of bacteremia. RF spirochetes can be geographically and phylogenetically divided into two distinct groups; Old World RF Borrelia (found in Africa, Asia, and Europe) and New World RF Borrelia (found in the Americas). While RF is a rarely reported disease in the Americas, RF is prevalent in endemic parts of Africa. Despite phylogenetic differences between Old World and New World RF Borrelia and higher incidence of disease associated with Old World RF spirochete infection, genetic manipulation has only been described in New World RF bacteria. Herein, we report the generation of genetic tools for use in the Old World RF spirochete, Borrelia duttonii. We describe methods for transformation and establish shuttle vector- and integration-based approaches for genetic complementation, creating green fluorescent protein (gfp)-expressing B. duttonii strains as a proof of principle. Allelic exchange mutagenesis was also used to inactivate a homolog of the Borrelia burgdorferi p66 gene, which encodes an important virulence factor, in B. duttonii and demonstrate that this mutant was attenuated in a murine model of RF. Finally, the B. duttonii p66 mutant was complemented using shuttle vector- and cis integration-based approaches. As expected, complemented p66 mutant strains were fully infectious, confirming that P66 is required for optimal mammalian infection. The genetic tools and techniques reported herein represent an important advancement in the study of RF Borrelia that allows for future characterization of virulence determinants and colonization factors important for the enzootic cycle of Old World RF spirochetes., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Jackson-Litteken et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Introduction: Tick-borne pathogens, such as Borreliella spp., Rickettsia spp., and Anaplasma spp., are frequently detected in Germany. They circulate between animals and tick vectors and can cause mild to severe diseases in humans. Knowledge about distribution and prevalence of these pathogens over time is important for risk assessment of human and animal health., Methods: Ixodes ricinus nymphs were collected at different locations in 2009/2010 and 2019 in Germany and analyzed for tick-borne pathogens by real-time PCR and sequencing., Results: Borreliella spp. were detected with a prevalence of 11.96% in 2009/2010 and 13.10% in 2019 with B. afzelii and B. garinii as dominant species. Borrelia miyamotoi was detected in seven ticks and in coinfection with B. afzelii or B. garinii . Rickettsia spp. showed a prevalence of 8.82% in 2009/2010 and 1.68% in 2019 with the exclusive detection of R. helvetica . The prevalence of Anaplasma spp. was 1.00% in 2009/2010 and 7.01% in 2019. A . phagocytophilum was detected in seven tick samples. None of the nymphs were positive for C. burnetii ., Discussion: Here, observed changes in prevalence were not significant after a decade but require longitudinal observations including parameters like host species and density, climatic factors to improve our understanding of tick-borne diseases., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Mertens-Scholz, Hoffmann, Gethmann, Brangsch, Pletz and Klaus.)

Borrelia miyamotoi is an emerging tickborne pathogen that has been associated with central nervous system infections in immunocompromised patients, albeit infrequently. We describe a case-patient in Minnesota, USA, who had meningeal symptoms of 1 month duration. B. miyamotoi infection was diagnosed by Gram staining on cerebrospinal fluid and confirmed by sequencing.

The Borrelia genus contains two major clades, the Lyme borreliosis group, which includes the causative agents of Lyme disease/borreliosis (B. burgdorferi sensu stricto and other related B. burgdorferi sensu lato genospecies), and the relapsing fever borreliosis group (B. hermsii, B. turicatae, and B. parkeri). Other unclassified reptile- and echidna-associated Borrelia spp. (i.e., B. turcica and 'Candidatus Borrelia tachyglossi', respectively) do not belong in either of these two groups. In North America, Borrelia spp. from both of the major clades are important pathogens of veterinary and public health concern. Lyme disease is of particular interest because the incidence in the northeastern United States continues to increase in both dogs and humans. Birds have a potentially important role in the ecology of Borrelia species because they are hosts for numerous tick vectors and competent hosts for various Borrelia spp. Our goal was to investigate the prevalence of Borrelia spp. in four free-living species of upland game birds in Pennsylvania, USA including wild turkey (Meleagris gallopavo), ruffed grouse (Bonasa umbellus), ring-necked pheasants (Phasianus colchicus), and American woodcock (Scolopax minor). We tested 205 tissue samples (bone marrow and/or spleen samples) from 169 individuals for Borrelia using a flagellin gene (flab) nested PCR, which amplifies all Borrelia species. We detected Borrelia DNA in 12% (24/205) of samples, the highest prevalence was in wild turkeys (16%; 5/31), followed by ruffed grouse (13%; 16/126) and American woodcock (3%; 1/35). All pheasants (n = 13) were negative. We sequenced amplicons from all positive game birds and all were B. burgdorferi sensu stricto. Our results support previous work indicating that certain species of upland game birds are commonly infected with Borrelia species, but unlike previous studies, we did not find any relapsing fever borreliae. [ABSTRACT FROM AUTHOR]

Lyme disease and the spotted fever group rickettsiosis, involve bacteria belonging to the genus Borrelia and Rickettsia, respectively. These infections are the most important tick-borne zoonotic diseases involving ticks as vectors. Descriptive and epidemiological studies are essential to determine the animal hosts involved in the maintenance of these diseases. In the present study, 94 tick pool samples from 15 different host species located in the Region of Murcia (southeastern, Spain) were analysed. Ticks were morphologically identified as: Dermacentor marginatus, Hyalomma lusitanicum, Ixodes Ricinus, and Rhipicephalus sanguineus. Our results showed that 5.3% of the tick pool samples carried Borrelia spp. DNA, and 20.2% carried SFG Rickettsia DNA. In every hard tick pool Spot Fever Group (SFG) Rickettsia spp. DNA were detected, except for H. lusitanicum. Likewise, D. marginatum was the only species in which Borrelia spp. DNA was not detected. Barbary sheep and wild boar were the host species in which tick pools showed DNA presence of both pathogens. This study increases the knowledge about the presence of Borrelia spp. DNA and SFG Rickettsia spp. DNA in different hard tick species from this geographical area., (© 2024. The Author(s).)

The prevalence of tick-borne pathogens (TBP), Orientia tsutsugamushi, Rickettsia and Borrelia spp. in wild small animals, namely wild rodents, is now widely investigated. This study is to present the prevalence and distribution of O. tsutsugamushi, Rickettsia and Borrelia spp. in wild small animals and ticks collected from Gyeonggi and Gangwon provinces, Republic of Korea (ROK) in 2014. A total of 131 wild small animals, rodents and shrews, and 2,954 ticks were collected from Gyeonggi and Gangwon provinces from May to November 2014. The wild small animals (KR1-9) and ticks (K1-17) were grouped in accordance with capture dates and locations. Among the wild small animals, a total of 393 tissues and blood samples were extracted from six selected small animal series (KR1-3, KR6-8). Also, each date and location-grouped ticks were identified for its species and pooled according to the stage of development. Molecular identification for Rickettsia, Orientia, and Borrelia species was performed using polymerase chain reaction (PCR). To detect TBPs among wild small animals and ticks, primer sets targeting the 56 kDa protein encoding gene of Orientia spp., outer membrane protein B gene (OmpB) of Rickettsia spp., and 5S-23S intergenic spacer region (IGS) gene of Borrelia spp. were used. Of the 393 wild small animals' blood and tissue samples, 199 (50.6%) were positive for Orientia spp., 158 (40.2%) were positive for Borrelia spp., and 55 (14.0%) were positive for Rickettsia spp. Moreover, a total of 14 tick pools (n = 377) was positive for Rickettsia spp. (n=128, 34.0%) and Borrelia spp. (n=33, 8.8%). High prevalence of Orientia spp. and Rickettsia spp. in rodents and shrews were observed. This study presents significant insights by presenting data collected in 2014 that the prevalence of TBP was already high in mid 2010s. This study highlights the sustainable routine surveillance model for TBP.

Ticks serve as vectors and reservoirs of various Borrelia species, potentially causing diseases in humans and animals. Mazandaran, a fertile green land in northern Iran, provides ample grazing grounds for livestock and harbors at least 26 hard tick species. This study investigated Borrelia infection in hard ticks from forest areas in this region and compared their genetic identity with the species data in the GenBank database. A total of 2,049 ticks were collected manually from mammalian hosts or using dragging and flagging methods. These ticks were then grouped into 190 pools and 41 individuals based on host, species, developmental stage, and gender. A real-time PCR (qPCR) detected Borrelia DNA in 26 pools from female, male, and nymph of Rhipicephalus annulatus (n = 17) and Ixodes ricinus (n = 9) ticks and one individual female Haemaphysalis punctata tick. The generated partial flaB and glpQ sequences from qPCR-positive Rh. annulatus ticks exhibited the highest identities of 98.1-100% and 98.2% with Borrelia theileri and closely related undefined isolates. Additionally, in phylogenetic analysis, these sequences clustered within well-supported clades with B. theileri and the closely related undefined isolates from various geographic regions, confirming the presence of B. theileri in the north of Iran. Divergence in B. theileri flaB and glpQ sequences across various geographical areas suggests potential subspeciation driven by adaptations to different tick species. This divergence in our flaB sequences implies the possible introduction of B. theileri-infected ticks from different geographical origins into Iran., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Hard ticks are known vectors of various pathogens, including the severe fever with thrombocytopenia syndrome virus, Rickettsia spp., Coxiella burnetii, Borrelia spp., Anaplasma phagocytophilum, and Ehrlichia spp. This study aims to investigate the distribution and prevalence of tick-borne pathogens in southwestern Korea from 2019 to 2022. A total of 13,280 ticks were collected during the study period, with H. longicornis accounting for 86.1% of the collected ticks. H. flava, I. nipponensis and A. testudinarium comprised 9.4%, 3.6%, and 0.8% of the ticks, respectively. Among 983 pools tested, Rickettsia spp. (216 pools, 1.6% MIR) were the most prevalent pathogens across all tick species, with R. japonica and R. monacensis frequently detected in I. nipponensis and Haemaphysalis spp., respectively. Borrelia spp. (28 pools, 0.2% MIR) were predominantly detected in I. nipponensis (27 pools, 13.8% MIR, P < 0.001). Co-infections, mainly involving Rickettsia monacensis and Borrelia afzelii, were detected in I. nipponensis. Notably, this study identified R. monacensis for the first time in A. testudinarium in South Korea. These findings offer valuable insights into the tick population and associated pathogens in the region, underscoring the importance of tick-borne disease surveillance and prevention measures., (© 2024. The Author(s).)

Ixodes ricinus ticks are vectors of a plethora of pathogens. The purpose of this study was to screen 398 I. ricinus ticks for a variety of pathogens. Following the pooling, homogenization, and extraction of total nucleic acids, a real-time PCR was applied for the detection of a panel of tick-borne pathogens, while additional conventional PCRs combined with Sanger sequencing were applied for the detection of viruses and typing of Rickettsia and Borrelia species. At least one pathogen was detected in 60 of the 80 (75%) tick pools. Rickettsia spp. predominated, as it was detected in 63.75% of the pools (51/80; MIR 12.81%), followed by Borrelia spp. (35 pools (45%); MIR 8.79%), while Anaplasma phagocytophilum was detected in 2 pools (2.5%, MIR 0.5%). The ticks of six Rickettsia -positive pools were tested individually (from stored half-ticks); all sequences were identical to those of R. monacensis . Similarly, the ticks of six Borrelia -positive pools were tested individually, and it was shown that four belonged to the genospecies Borrelia garinii and two to Borrelia valaisiana . Phleboviruses were detected in 3 pools (3.75%; MIR 0.75%), with sequences clustering in the Ixovirus genus, while nairoviruses were detected in 7 pools (8.75%; MIR 1.76%), with one sequence clustering in the Orthonairovirus genus, and six clustering in the Norwavirus genus. Although a small number of ticks from only one area in Greece were tested, a variety of pathogens together with recently identified viruses were detected, prompting further studies in ticks and surveillance studies in humans.

Dermacentor (D.) reticulatus ticks carry and transmit a wide range of pathogens to vertebrate hosts. Limited information is available about the existence of emerging tick-borne pathogens and the distribution of D. reticulatus in Bosnia and Herzegovina. The study aimed to investigate the occurrence and distribution of D. reticulatus and to detect the presence of Anaplasma spp., Borrelia (B.) burgdorferi s.l., Rickettsia spp., and Babesia spp. in samples originating from questing ticks and ticks collected from domestic animals in various regions of Bosnia and Herzegovina. A total of 402 collected D. reticulatus ticks were widely distributed throughout the country. Of the 41 pools consisting of 205 individual D. reticulatus ticks, 21 (51.2%) indicated the presence of Rickettsia spp., 17 (41.4%) of Babesia spp., 2 (4.8%) of Anaplasma spp., and 1 (2.4%) of B. burgdorferi s.l. after real-time PCR screening. Our study indicates that D. reticulatus has significantly expanded its distribution and host range in Bosnia and Herzegovina. Moreover, our results represent the first detection of Babesia spp. in D. reticulatus in Bosnia and Herzegovina. Given the demonstrated presence of emerging pathogens in questing and feeding ticks, there is an urge to establish a surveillance system for ticks and tick-borne pathogens in Bosnia and Herzegovina.

Background: The taxonomic status of the relapsing fever spirochete Borrelia hermsii in western North America was established in 1942 and based solely on its specific association with the soft tick vector Ornithodoros hermsi . Multilocus sequence typing (MLST) of the 16S rRNA , flaB , gyrB , glpQ , and 16S-23S rRNA intergenic spacer of B. hermsii isolates collected over many years from various geographic locations and biological sources identified two distinct clades designated previously as B. hermsii Genomic Group I (GGI) and Genomic Group II (GGII). To better assess the taxonomic relationship of these two genomic groups to each other and other species of Borrelia , DNA sequences of the entire linear chromosome were determined. Materials and Methods: Genomic DNA samples were prepared from 11 spirochete isolates grown in Barbour-Stoenner-Kelly-H medium. From these preparations, DNA sequences of the entire linear chromosome of two isolates of B. hermsii belonging to each genomic group and seven additional species were determined. Results: Chromosomal sequences of four isolates of B. hermsii contained 919,212 to 922,307 base pairs. DNA sequence identities between the two genomic groups of B. hermsii were 95.86-95.99%, which were more divergent than chromosomal sequences comparing Borrelia parkeri and Borrelia turicatae (97.13%), Borrelia recurrentis and Borrelia duttonii (97.07%), and Borrelia crocidurae and B. duttonii (97.09%). The 3' end of the chromosome of the two GGII isolates also contained a unique intact oppA gene absent from all other species examined. Conclusion: Previous MLST and the chromosomal sequences presented herein support the division of the B. hermsii species complex into two species, B. hermsii sensu stricto ( = GGI) and Borrelia nietonii sp. nov. ( = GGII). We name this unique relapsing fever spirochete in honor of our late friend and colleague Dr. Nathan Nieto for his outstanding contributions to our understanding of tick-borne relapsing fever.

Background: Despite abundance of small mammals in Serbia, there is no information on their role in the epidemiology of tick-borne diseases (TBDs). This retrospective study aimed to identify different tick-borne pathogens (TBPs) in small mammals in Serbia collected during 2011. Materials and Methods: A total of 179 small mammals were collected from seven different localities in Serbia. The five localities belong to the capital city of Serbia-Belgrade: recreational areas-Ada Ciganlija, Titov gaj, and Košutnjak as well as mountainous suburban areas used for hiking-Avala and Kosmaj. The locality Veliko Gradište is a tourist place in northeastern Serbia, whereas the locality Milošev Do is a remote area in western Serbia with minor human impact on the environment. Results: The results of the presented retrospective study are the first findings of Rickettsia helvetica , Rickettsia monacensis , Neoehrlichia mikurensis , Borrelia afzelii , Borrelia miyamotoi , Babesia microti , Hepatozoon canis, and Coxiella burnetii in small mammals in Serbia. The presence of R. helvetica was confirmed in two Apodemus flavicollis , the presence of one of the following pathogens, R. monacensis , B. afzelii , H. canis , Ba. microti , and N. mikurensis was confirmed in one A. flavicollis each, whereas the presence of B. miyamotoi was confirmed in one Apodemus agrarius . Coinfection with B. afzelii and Ba. microti was confirmed in one A. flavicollis . DNA of C. burnetii was detected in 3 of 18 pools. Conclusions: The results confirm that detected pathogens circulate in the sylvatic cycle in Serbia and point to small mammals as potential reservoir hosts for the detected TBPs. Further large-scale studies on contemporary samples are needed to clarify the exact role of particular small mammal species in the epidemiology of TBDs caused by the detected pathogens.

Background: Ixodes inopinatus was described from Spain on the basis of morphology and partial sequencing of 16S ribosomal DNA. However, several studies suggested that morphological differences between I. inopinatus and Ixodes ricinus are minimal and that 16S rDNA lacks the power to distinguish the two species. Furthermore, nuclear and mitochondrial markers indicated evidence of hybridization between I. inopinatus and I. ricinus. In this study, we tested our hypothesis on tick dispersal from North Africa to Southern Europe and determined the prevalence of selected tick-borne pathogens (TBPs) in I. inopinatus, I. ricinus, and their hybrids., Methods: Ticks were collected in Italy and Algeria by flagging, identified by sequencing of partial TROSPA and COI genes, and screened for Borrelia burgdorferi s.l., B. miyamotoi, Rickettsia spp., and Anaplasma phagocytophilum by polymerase chain reaction and sequencing of specific markers., Results: Out of the 380 ticks, in Italy, 92 were I. ricinus, 3 were I. inopinatus, and 136 were hybrids of the two species. All 149 ticks from Algeria were I. inopinatus. Overall, 60% of ticks were positive for at least one TBP. Borrelia burgdorferi s.l. was detected in 19.5% of ticks, and it was significantly more prevalent in Ixodes ticks from Algeria than in ticks from Italy. Prevalence of Rickettsia spotted fever group (SFG) was 51.1%, with significantly greater prevalence in ticks from Algeria than in ticks from Italy. Borrelia miyamotoi and A. phagocytophilum were detected in low prevalence (0.9% and 5.2%, respectively) and only in ticks from Italy., Conclusions: This study indicates that I. inopinatus is a dominant species in Algeria, while I. ricinus and hybrids were common in Italy. The higher prevalence of B. burgdorferi s.l. and Rickettsia SFG in I. inopinatus compared with that in I. ricinus might be due to geographical and ecological differences between these two tick species. The role of I. inopinatus in the epidemiology of TBPs needs further investigation in the Mediterranean Basin., (© 2024. The Author(s).)

Background: Trombiculid mites are globally distributed, highly diverse arachnids that largely lack molecular resources such as whole mitogenomes for the elucidation of taxonomic relationships. Trombiculid larvae (chiggers) parasitise vertebrates and can transmit bacteria (Orientia spp.) responsible for scrub typhus, a zoonotic febrile illness. Orientia tsutsugamushi causes most cases of scrub typhus and is endemic to the Asia-Pacific Region, where it is transmitted by Leptotrombidium spp. chiggers. However, in Dubai, Candidatus Orientia chuto was isolated from a case of scrub typhus and is also known to circulate among rodents in Saudi Arabia and Kenya, although its vectors remain poorly defined. In addition to Orientia, chiggers are often infected with other potential pathogens or arthropod-specific endosymbionts, but their significance for trombiculid biology and public health is unclear., Results: Ten chigger species were collected from rodents in southwestern Saudi Arabia. Chiggers were pooled according to species and screened for Orientia DNA by PCR. Two species (Microtrombicula muhaylensis and Pentidionis agamae) produced positive results for the htrA gene, although Ca. Orientia chuto DNA was confirmed by Sanger sequencing only in P. agamae. Metagenomic sequencing of three pools of P. agamae provided evidence for two other bacterial associates: a spirochaete and a Wolbachia symbiont. Phylogenetic analysis of 16S rRNA and multi-locus sequence typing genes placed the spirochaete in a clade of micromammal-associated Borrelia spp. that are widely-distributed globally with no known vector. For the Wolbachia symbiont, a genome assembly was obtained that allowed phylogenetic localisation in a novel, divergent clade. Cytochrome c oxidase I (COI) barcodes for Saudi Arabian chiggers enabled comparisons with global chigger diversity, revealing several cases of discordance with classical taxonomy. Complete mitogenome assemblies were obtained for the three P. agamae pools and almost 50 SNPs were identified, despite a common geographic origin., Conclusions: P. agamae was identified as a potential vector of Ca. Orientia chuto on the Arabian Peninsula. The detection of an unusual Borrelia sp. and a divergent Wolbachia symbiont in P. agamae indicated links with chigger microbiomes in other parts of the world, while COI barcoding and mitogenomic analyses greatly extended our understanding of inter- and intraspecific relationships in trombiculid mites., (© 2024. The Author(s).)

Tick-borne microorganisms in many tick species and many areas of China are still not thoroughly investigated. In this study, 224 ticks including two species (Haemaphysalis longicornis and Haemaphysalis qinghaiensis) were collected from four cities in Hebei, Shandong, and Qinghai provinces, China. Ticks were screened for the presence of tick-borne bacterial microorganisms including Rickettsia, Anaplasmataceae (Anaplasma, Ehrlichia, Neoehrlichia, etc.), Coxiella, Borrelia, and Bartonella. Two Anaplasma species (Anaplasma ovis and Anaplasma capra) were detected in H. longicornis from Xingtai City of Hebei Province, with a positive rate of 3 % and 8 %, respectively. A Coxiella species was detected in H. longicornis ticks from all three locations in Hebei and Shandong provinces, with the positive rate ranging from 30 to 75 %. All the 16S and rpoB sequences were very similar (99.77-100 % identity) to Coxiella endosymbiont of Haemaphysalis ticks. An Ehrlichia species was detected in H. qinghaiensis (6/66, 9 %) from Xining City, Qinghai Province. The 16S and groEL sequences had 100 % and 97.40-97.85 % nucleotide identities to "Candidatus Ehrlichia pampeana" strains, respectively, suggesting that it may be a variant of "Candidatus Ehrlichia pampeana". All the ticks were negative for Rickettsia, Borrelia, and Bartonella. Because all the ticks were removed from goats or humans and were partially or fully engorged, it is possible that the microorganisms were from the blood meal but not vectored by the ticks. Our results may provide some information on the diversity and distribution of tick-borne pathogens in China., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2023 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Ticks are obligate hematophagous parasites that can transmit to vertebrate hosts several pathogens, including viruses, bacteria, protozoa and helminths. Among these agents, some Borrelia species some Borrelia species cause disease in humans and other vertebrate hosts; therefore, they have medical and veterinary health importance. To gather additional information on Borrelia species in Brazil, the current study aimed to detect the presence of these species in Ornithodoros cavernicolous ticks collected in September 2019 from cement pipes that are used by bats as shelter in a farm located in the midwestern region of Brazil. DNA samples obtained from 18 specimens of O. cavernicolous were subjected of two polymerase chain reactions, targeting a segment of the Borrelia fla B gene. Of the samples tested, only one (6 %, 1/18) showed amplification. The nucleotide sequence of the amplified DNA showed more than 97 % (293/300) identity with a sequence of a Borrelia sp. detected in blood collected from a bat from Macaregua Cave, Colombia, and more than 97 % (292/300) detected in lungs from vampire bats from northeastern Brazil. The deduced amino acid sequences were identical to each other. Phylogenetic analysis indicated that these sequences formed a group of Borrelia species (putatively associated with bats) that is closely related to sequences of Borrelia species of the Lyme borreliosis group. Further investigations should be carried out in order to determine whether the sequence of the Borrelia sp. we found belongs to a new taxon. It will also be of great importance to determine which vertebrate hosts, besides bats, O. cavernicolous ticks can parasitize in order to investigate whether the Borrelia sp. we found may be transmitted and cause disease to the other vertebrate hosts., Competing Interests: Declaration of Competing Interest The authors have no relevant financial or non-financial interests to disclose., (Copyright © 2023. Published by Elsevier GmbH.)

Lyme disease caused by the Borrelia species is a growing health concern in many parts of the world. Current treatments for the disease may have side effects, and there is also a need for new therapies that can selectively target the bacteria. Pathogens responsible for Lyme disease include B. burgdorferi , B. afzelii , and B. garinii . In this study, we employed structural docking-based screening to identify potential lead-like inhibitors against the bacterium. We first identified the core essential genome fraction of the bacterium, using 37 strains. Later, we screened a library of lead-like marine microbial metabolites ( n = 4730) against the arginine deiminase (ADI) protein of Borrelia garinii . This protein plays a crucial role in the survival of the bacteria, and inhibiting it can kill the bacterium. The prioritized lead compounds demonstrating favorable binding energies and interactions with the active site of ADI were then evaluated for their drug-like and pharmacokinetic parameters to assess their suitability for development as drugs. Results from molecular dynamics simulation (100 ns) and other scoring parameters suggest that the compound CMNPD18759 (common name: aureobasidin; IUPAC name: 2-[(4 R ,6 R )-4,6-dihydroxydecanoyl]oxypropan-2-yl (3 S ,5 R )-3,5-dihydroxydecanoate) holds promise as a potential drug candidate for the treatment of Lyme disease, caused by B. garinii . However, further experimental studies are needed to validate the efficacy and safety of this compound in vivo ., Competing Interests: The authors declare that they have no conflict of interest., (Copyright © 2024 Zarrin Basharat et al.)

Background: Changing geographical and seasonal activity patterns of ticks may increase the risk of tick infestation and tick-borne pathogen (TBP) transmission for both humans and animals., Methods: To estimate TBP exposure of dogs and cats, 3000 female I. ricinus from these hosts were investigated for Anaplasma phagocytophilum and Borrelia species., Results: qPCR inhibition, which was observed for ticks of all engorgement stages but not questing ticks, was eliminated at a template volume of 2 µl. In ticks from dogs, A. phagocytophilum and Borrelia spp. prevalence amounted to 19.0% (285/1500) and 28.5% (427/1500), respectively, while ticks from cats showed significantly higher values of 30.9% (464/1500) and 55.1% (827/1500). Accordingly, the coinfection rate with both A. phagocytophilum and Borrelia spp. was significantly higher in ticks from cats (17.5%, 262/1500) than dogs (6.9%, 104/1500). Borrelia prevalence significantly decreased with increasing engorgement duration in ticks from both host species, whereas A. phagocytophilum prevalence decreased only in ticks from dogs. While A. phagocytophilum copy numbers in positive ticks did not change significantly over the time of engorgement, those of Borrelia decreased initially in dog ticks. In ticks from cats, copy numbers of neither A. phagocytophilum nor Borrelia spp. were affected by engorgement. Borrelia species differentiation was successful in 29.1% (365/1254) of qPCR-positive ticks. The most frequently detected species in ticks from dogs were B. afzelii (39.3% of successfully differentiated infections; 70/178), B. miyamotoi (16.3%; 29/178), and B. valaisiana (15.7%; 28/178), while B. afzelii (40.1%; 91/227), B. spielmanii (21.6%; 49/227), and B. miyamotoi (14.1%; 32/227) occurred most frequently in ticks from cats., Conclusions: The differences in pathogen prevalence and Borrelia species distribution between ticks collected from dogs and cats may result from differences in habitat overlap with TBP reservoir hosts. The declining prevalence of A. phagocytophilum with increasing engorgement duration, without a decrease in copy numbers, could indicate transmission to dogs over the time of attachment. The fact that this was not observed in ticks from cats may indicate less efficient transmission. In conclusion, the high prevalence of A. phagocytophilum and Borrelia spp. in ticks collected from dogs and cats underlines the need for effective acaricide tick control to protect both animals and humans from associated health risks., (© 2024. The Author(s).)

Glycerol utilization as a carbohydrate source by Borreliella burgdorferi , the Lyme disease spirochete, is critical for its successful colonization and persistence in the tick vector. The expression of the glpFKD ( glp ) operon, which encodes proteins for glycerol uptake/utilization, must be tightly regulated during the enzootic cycle of B. burgdorferi . Previous studies have established that the second messenger cyclic di-GMP (c-di-GMP) is required for the activation of glp expression, while an alternative sigma factor RpoS acts as a negative regulator for glp expression. In the present study, we report identification of a cis element within the 5´ untranslated region of glp that exerts negative regulation of glp expression. Further genetic screen of known and predicted DNA-binding proteins encoded in the genome of B. burgdorferi uncovered that overexpressing Borrelia host adaptation regulator (BadR), a known global regulator, dramatically reduced glp expression. Similarly, the badR mutant significantly increased glp expression. Subsequent electrophoretic mobility shift assay analyses demonstrated that BadR directly binds to this cis element, thereby repressing glp independent of RpoS-mediated repression. The efficiency of BadR binding was further assessed in the presence of c-di-GMP and various carbohydrates. This finding highlights multi-layered positive and negative regulatory mechanisms employed by B. burgdorferi to synchronize glp expression throughout its enzootic cycle.IMPORTANCE Borreliella burgdorferi , the Lyme disease pathogen, must modulate its gene expression differentially to adapt successfully to its two disparate hosts. Previous studies have demonstrated that the glycerol uptake and utilization operon, glpFKD , plays a crucial role in spirochetal survival within ticks. However, the glpFKD expression must be repressed when B. burgdorferi transitions to the mammalian host. In this study, we identified a specific cis element responsible for the repression of glpFKD . We further pinpointed Borrelia host adaptation regulator as the direct binding protein to this cis element, thereby repressing glpFKD expression. This discovery paves the way for a deeper exploration of how zoonotic pathogens sense distinct hosts and switch their carbon source utilization during transmission., Competing Interests: The authors declare no conflict of interest.