Search Results (18)

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

Ticks transmit diverse pathogens, posing significant public health threats in northeastern China; clarifying human-biting tick species and their carried pathogens is crucial for risk assessment and prevention. This study was designed as a pathogen detection and molecular epidemiological investigation. During the May-August period of each of 2023 and 2024, 232 ticks that had bitten humans were collected from a local sentinel hospital. Ticks were morphologically identified, followed by DNA extraction, semi-nested/nested PCR targeting specific genetic markers, and Sanger sequencing to detect bacterial pathogens. Four tick species were found, with Ixodes persulcatus dominant (87.9%), followed by Dermacentor silvarum (6.9%), Haemaphysalis concinna (3.5%), and Haemaphysalis japonica (1.7%). Seven bacterial pathogens were detected, including Candidatus Rickettsia tarasevichiae (35.3%) and Borreliella garinii (17.2%); 49.6% of ticks were pathogen-positive. The coinfection rate was 13.8%, most commonly Candidatus R. tarasevichiae plus B. garinii, and I. persulcatus carried all pathogens. These findings provide basic data on human-biting tick species and their bacterial pathogen spectrum in the region, serving as a reference for subsequent tick-borne disease research and targeted prevention. Full article

Monitoring the occurrence of Borreliaceae spirochetes in ticks may provide an indication of the risks of acquiring Lyme borreliosis (LB) and Borrelia miyamotoi disease (BMD). All ticks obtained in our study from humans in the years 2018–2022 (n = 1232) were identified morphologically for species, sex and developmental stage. The detection of Borreliaceae spirochetes and species identification were performed by nested PCR based on the flaB gene fragment and the region between the mag and trnI genes. Two species of ticks were identified: Ixodes ricinus (96.9%) and Dermacentor reticulatus (3.1%). The infection of I. ricinus ticks with Borreliaceae spirochetes was found to reach 18.3%, including B. miyamotoi (2.5%). Among Borreliella species, Bl. afzelii was the most frequent, followed by Bl. burgdorferi, Bl. spielmanii, Bl. valaisiana, Bl. garinii, Bl. bissettiae, Bl. californiensis and Bl. carolinensis. Borreliaceae spirochetes were also found in D. reticulatus ticks, of which Bl. afzelii and B. miyamotoi were the most common. In conclusion, ticks affecting humans in Poland represent a real risk of infection with Borreliaceae spirochetes, and knowledge of the prevalence and distribution of these bacteria is an important tool in assessing the risks of LB and BMD. Full article

Ticks from the Hyalomma genus have recently garnered public attention in countries in Northern and Central Europe, as they are transported by migratory birds and might have established stable populations due to climate warming. The main threat associated with Hyalomma ticks is their ability to transmit Crimean–Congo hemorrhagic fever virus (CCHFV), which can be fatal in up to 40% of cases. Here, we collected Hyalomma ticks from migratory birds during annual ringing actions in the spring seasons of 2023 and 2024. Four ticks were found on birds from the Acrocephalus genus and two on Hippolais icterina. The ticks were examined for the presence of Rickettsia spp., Babesia microti, Babesia divergens, Coxiella burnetii, Borreliella burgdorferi (s. l.), Anaplasma phagocytophilum, West Nile virus, and CCHF virus (CCHFV). The collected H. rufipes specimens were negative for tested pathogens, except for two ticks collected in 2024, which were positive for Rickettsia aeschlimannii. The data show that Hyalomma ticks are efficiently transported on birds preferring reedbeds or deciduous trees. The possibility of the occurrence of CCHF or rickettsiosis (induced by R. aeschlimannii) is currently assessed as low. Nevertheless, we have shown the transfer of Hyalomma ticks to Poland and indicated the need for careful future epidemiological monitoring of the presence of Hyalomma ticks. Full article

The increasing incidence of tick-borne diseases in Europe necessitates the development of accurate and high-throughput molecular tools for detecting pathogens in tick populations. In this study, we present a novel flaB gene-based profiling method for the detection and identification of Borrelia and Borreliella species in Ixodes ricinus ticks, combining newly designed primers with next-generation sequencing (NGS). The method was evaluated alongside conventional nested PCR targeting the flaB gene, as well as microbial profiling based on the V4 region of the rrs gene, using tick DNA extracted from 1088 specimens pooled into 94 samples. Our results demonstrate that the flaB gene-based profiling approach was the highest-performing out of the three methods, detecting Borreliaceae DNA in 83 DNA pools, compared to 58 and 56 pools using nested PCR and V4 rrs profiling, respectively. A total of 23 distinct flaB sequence variants were identified, corresponding to five Borreliaceae species: Borreliella afzelii, Bl. garinii, Bl. valaisiana, Bl. burgdorferi, and Borrelia miyamotoi. Additionally, the method enabled putative strain-level discrimination within species. Our results highlight the value of flaB gene-based profiling as a robust tool for ecological and epidemiological studies of Borreliaceae diversity in ticks. Full article

The microbial communities of Ixodes scapularis, the primary vector of Lyme disease in North America, exhibit regional variations that may affect pathogen transmission and vector competence. We analyzed bacterial communities in I. scapularis ticks collected from Broome County, New York, using 16S rRNA gene sequencing (18 ticks) as well as mass spectrometry-based proteomics (36 ticks). According to the 16S rRNA analysis, the endosymbiont Rickettsia buchneri was the most abundant species, with significantly higher (p = 0.0011) abundance in females (54.76%) compared to males (31.15%). We detected Borreliella burgdorferi in 44.44% of ticks and Anaplasma phagocytophilum in two nymphs but in high relative abundances (12.73% and 46.46%). Male ticks exhibited higher bacterial diversity, although the community composition showed no significant clustering by sex or life stage. Co-occurrence analysis revealed negative associations between R. buchneri and Pseudomonas (p = 0.0245), but no associations with B. burgdorferi. Proteomic analysis identified 12 R. buchneri-specific proteins, additionally detecting the protozoan pathogen Babesia microti in 18.18% of females. These findings provide the first comprehensive characterization of I. scapularis microbiomes in the Southern Tier region of New York and suggest broader distribution of R. buchneri across tick life stages than previously recognized, with potential implications for pathogen transmission dynamics. Full article

The western European hedgehog (Erinaceus europaeus) and the northern white-breasted hedgehog (E. roumanicus) are natural hosts of the tick Ixodes hexagonus, the vector of tick-borne pathogens such as the Borreliella bacteria responsible for Lyme disease. The aim of this study was to identify these pathogens in ticks collected from hedgehogs in northwestern Poland and to assess their genetic diversity by molecular analysis of the detected pathogens based on the flaB gene and the mag-trnI intergenic spacer. Among 101 hedgehogs examined, 737 ticks were found on 56 (55.45%) individuals, including 501 females of I. hexagonus. Borreliella spirochete infection was confirmed in 9 females of I. hexagonus (1.8%) obtained from 4 (3.96%) hedgehogs, detecting Borreliella (Bl.) afzelii (8/89%) and Bl. spielmanii (1/11%). Phylogenetic analysis based on the flaB gene and the mag-trnI intergenic spacer showed a lack of diversity in Bl. afzelii detected in I. hexagonus ticks collected from hedgehogs as well as little diversity against reference strains detected in small mammals and ticks collected from them. The results confirm that hedgehogs play an important role in the circulation of the detected spirochete species, at least as hosts of I. hexagonus ticks infected with them, indicating their potential to spread Borreliella spirochetes. Full article

Lyme disease is the most commonly reported vector-borne disease in the United States. Bartonella constitute an additional zoonotic pathogen whose public health impact and diversity continue to emerge. Rapid, sensitive, and specific detection of these and other vector-borne pathogens remains challenging, especially for patients with persistent infections. This report describes an approach for DNA extraction and PCR testing for the detection of Bartonella spp. and Borreliella spp. from dry blood spot (DBS) specimens from human patients. The present study included extraction of DNA and PCR testing of DBS samples from 105 patients with poorly defined, chronic symptoms labeled as Lyme-Like Syndromic Illness (LLSI). Bartonella spp. DNA was detected in 20/105 (19%) and Borreliella spp. DNA was detected in 41/105 (39%) patients with LLSI. Neither group of organisms was detected in DBS samples from 42 healthy control subjects. Bartonella spp. 16S–23S rRNA internal transcribed spacer sequences were highly similar to ones previously identified in yellow flies, lone star ticks, a human patient from Florida, mosquitoes in Europe, or B. apihabitans and choladocola strains from honeybees. These human strains may represent new genetic strains or groups of human pathogenic species of Bartonella. The 41 Borreliella spp. flaB gene sequences obtained from human patients suggested the presence of four different species, including B. burgdorferi, B. americana, B. andersonii, and B. bissettiae/carolinensis-like strains. These results suggest that specific aspects of the DBS DNA extraction and PCR approach enabled the detection of Bartonella spp. and Borreliella spp. DNA from very small amounts of human whole blood from some patients, including specimens stored on filter paper for 17 years. Full article

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

Raccoon dogs (Nyctereutes procyonoides) and raccoons (Procyon lotor) are invasive alien species originating from East Asia and North America, respectively. They are discussed as vectors and reservoirs for various infectious diseases, including vector-borne and zoonotic pathogens, and are therefore a potential threat to human and domestic animal health, as well as to biodiversity and conservation. In the years 2021 and 2022, 110 raccoon dogs (Nyctereutes procyonoides) and 30 raccoons (Procyon lotor) were screened via qPCR for the presence of Leptospira spp., Rickettsia spp. and Borreliella spp. in the German federal state of Schleswig-Holstein as part of a health and risk assessment study. Borreliella spp. were confirmed in one raccoon dog and one raccoon, identified as Borreliella afzelii in the raccoon. Leptospira spp. were found in 21 (19.44%) raccoon dogs and 2 (6.90%) raccoons. In five raccoon dogs, Leptospira spp. were identified as Leptospira borgpetersenii, Leptospira kirschneri and Leptospira interrogans. Full article

The abundant and widely distributed deermice Peromyscus leucopus and P. maniculatus are important reservoirs for several different zoonotic agents in North America. For the pathogens they persistently harbor, these species are also examples of the phenomenon of infection tolerance. In the present study a prior observation of absent expression of the high-affinity Fc immunoglobulin gamma receptor I (FcγRI), or CD64, in P. leucopus was confirmed in an experimental infection with Borreliella burgdorferi, a Lyme disease agent. We demonstrate that the null phenotype is attributable to a long-standing inactivation of the Fcgr1 gene in both species by a deletion of the promoter and coding sequence for the signal peptide for FcγRI. The Fcgr1 pseudogene was also documented in the related species P. polionotus. Six other Peromyscus species, including P. californicus, have coding sequences for a full-length FcγRI, including a consensus signal peptide. An inference from reported phenotypes for null Fcgr1 mutations engineered in Mus musculus is that one consequence of pseudogenization of Fcgr1 is comparatively less inflammation during infection than in animals, including humans, with undisrupted, fully active genes. Full article

In Europe, Ixodes ricinus tick is the vector of Lyme disease spirochetes and their relatives (Borreliella genus) and Borrelia miyamotoi. However, a newly described tick I. inopinatus with similar biological features and separated from I. ricinus may act as a vector for different Borrelia species. To date, eleven Borreliella species were detected in the natural populations of I. ricinus. Recently, two North American species have been detected in ticks parasitizing bats and red foxes in Europe, i.e., B. lanei and B. californiensis pointing to the necessity for searching for them in natural tick populations. In this study, using the coxI molecular marker only I. ricinus was identified in field-collected ticks with the exception of individual specimens of Haemaphysalis concinna. Using the flaB gene and mag-trnI intergenic spacer as molecular markers 14 Borreliaceae species have been detected with various frequencies in different parts of northern Poland. Among infected ticks, the most frequent were Borreliella (Bl.) afzelii (29.4%) and Bl. garinii (20.0%), followed by Bl. spielmanii, Bl. valaisiana, Bl. lanei, Bl. californiensis, B. miyamotoi, Bl. burgdorferi, Bl. carolinensis, Bl. americana, B. turcica, Bl. lusitaniae, Bl. bissettiae and Bl. finlandensis. Three of the above-mentioned species, i.e., Bl. lanei, Bl. californiensis and B. turcica were detected in this study for the first time in the natural ixodid tick population in Europe. The existence of the newly detected spirochetes increases their total diversity in Europe and points to the necessity of careful identification and establishment of the actual distribution of all Borreliaceae species transmitted by I. ricinus. Full article

Borreliella (syn. Borrelia) burgdorferi is a spirochete bacterium that causes tick-borne Lyme disease. Along its lifecycle B. burgdorferi develops several pleomorphic forms with unclear biological and medical relevance. Surprisingly, these morphotypes have never been compared at the global transcriptome level. To fill this void, we grew B. burgdorferi spirochete, round body, bleb, and biofilm-dominated cultures and recovered their transcriptomes by RNAseq profiling. We found that round bodies share similar expression profiles with spirochetes, despite their morphological differences. This sharply contrasts to blebs and biofilms that showed unique transcriptomes, profoundly distinct from spirochetes and round bodies. To better characterize differentially expressed genes in non-spirochete morphotypes, we performed functional, positional, and evolutionary enrichment analyses. Our results suggest that spirochete to round body transition relies on the delicate regulation of a relatively small number of highly conserved genes, which are located on the main chromosome and involved in translation. In contrast, spirochete to bleb or biofilm transition includes substantial reshaping of transcription profiles towards plasmids-residing and evolutionary young genes, which originated in the ancestor of Borreliaceae. Despite their abundance the function of these Borreliaceae-specific genes is largely unknown. However, many known Lyme disease virulence genes implicated in immune evasion and tissue adhesion originated in this evolutionary period. Taken together, these regularities point to the possibility that bleb and biofilm morphotypes might be important in the dissemination and persistence of B. burgdorferi inside the mammalian host. On the other hand, they prioritize the large pool of unstudied Borreliaceae-specific genes for functional characterization because this subset likely contains undiscovered Lyme disease pathogenesis genes. Full article

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

The black-legged tick (Ixodes scapularis) is the primary vector of Borrelia burgdorferi, the causative agent of Lyme disease in North America. However, the prevalence of Lyme borreliosis is clustered around the Northern States of the United States of America. This study utilized a metagenomic sequencing approach to compare the microbial communities residing within Ix. scapularis populations from northern and southern geographic locations in the USA. Using a SparCC network construction model, we performed potential interactions between members of the microbial communities from Borrelia burgdorferi–infected tissues of unfed and blood-fed ticks. A significant difference in bacterial composition and diversity was found between northern and southern tick populations. The network analysis predicted a potential antagonistic interaction between endosymbiont Rickettsia buchneri and Borrelia burgdorferi sensu lato. The network analysis, as expected, predicted significant positive and negative microbial interactions in ticks from these geographic regions, with the genus Rickettsia, Francisella, and Borreliella playing an essential role in the identified clusters. Interactions between Rickettsia buchneri and Borrelia burgdorferi sensu lato need more validation and understanding. Understanding the interplay between the microbiome and tick-borne pathogens within tick vectors may pave the way for new strategies to prevent tick-borne infections. Full article