Search Results (9)

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

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 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

Borrelia (Borreliella) burgdorferi, along with closely related species, is the etiologic agent of Lyme disease. The spirochete subsists in an enzootic cycle that encompasses acquisition from a vertebrate host to a tick vector and transmission from a tick vector to a vertebrate host. To adapt to its environment and persist in each phase of its enzootic cycle, B. burgdorferi wields three systems to regulate the expression of genes: the RpoN-RpoS alternative sigma (σ) factor cascade, the Hk1/Rrp1 two-component system and its product c-di-GMP, and the stringent response mediated by Rel_Bbu and DksA. These regulatory systems respond to enzootic phase-specific signals and are controlled or fine- tuned by transcription factors, including BosR and BadR, as well as small RNAs, including DsrABb and Bb6S RNA. In addition, several other DNA-binding and RNA-binding proteins have been identified, although their functions have not all been defined. Global changes in gene expression revealed by high-throughput transcriptomic studies have elucidated various regulons, albeit technical obstacles have mostly limited this experimental approach to cultivated spirochetes. Regardless, we know that the spirochete, which carries a relatively small genome, regulates the expression of a considerable number of genes required for the transitions between the tick vector and the vertebrate host as well as the adaptation to each. Full article