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PLoS Neglected Tropical Diseases Apr 2021Tick-borne relapsing fever (TBRF) is the most common vector-borne bacterial disease in humans in West Africa. It is frequently clinically confused with malaria. Our...
BACKGROUND
Tick-borne relapsing fever (TBRF) is the most common vector-borne bacterial disease in humans in West Africa. It is frequently clinically confused with malaria. Our study aims to determine, on a micro-geographic scale, the conditions for the maintenance and spread of TBRF in the Niakhar district of Senegal.
METHODOLOGY/PRINCIPAL FINDINGS
We conducted clinical, entomological and animal reservoir investigations. Field surveys were carried out in order to investigate the presence of Ornithodoros sonrai vector ticks and to detect Borrelia spp. by qPCR using the 16S rRNA and glpQ genes, respectively. Micromammal trapping series were carried out inside homes and Borrelia infection was detected using brain tissue qPCR. Capillary blood samples from febrile patients were also tested for Borrelia using qPCR. More than 97% (40/41) of the villages surveyed were infested with O. sonrai ticks. The prevalence of Borrelia spp. infections in ticks was 13% (116/910), and over 73% (85/116) were positively confirmed as being Borrelia crocidurae. Borreliosis cases accounted for 12% (94/800) of episodes of fever and all age groups were infected, with children and young people between the ages of 8-14 and 22-28 being the most infected by the disease (16% and 18.4%). TBRF cases occurred in all seasons, with a peak in August. In two species of small rodents that were found to be infected (Arvicanthis niloticus, Mus musculus), the proportion of Borrelia infection was 17.5% (10/57), and the highest prevalence of infection (40.9%, 9/22) was observed in A. niloticus.
CONCLUSION/SIGNIFICANCE
Our study indicates that TBRF is an endemic disease in the Niakhar district, where children and young people are the most infected. Arvicanthis niloticus and O. sonrai ticks are massively present and appear to be the main epidemiological reservoirs causing its extensive spread to humans.
Topics: Animals; Blood; Borrelia; Disease Vectors; Endemic Diseases; Humans; Ornithodoros; Public Health; RNA, Ribosomal, 16S; Relapsing Fever; Rodentia; Senegal
PubMed: 33886571
DOI: 10.1371/journal.pntd.0009184 -
Biomolecular NMR Assignments Oct 2021Decorin binding proteins (Dbps) mediate attachment of spirochetes in host organisms during the early stages of Lyme disease infection. Previously, different binding...
Decorin binding proteins (Dbps) mediate attachment of spirochetes in host organisms during the early stages of Lyme disease infection. Previously, different binding mechanisms of Dbps to glycosaminoglycans have been elucidated for the pathogenic species Borrelia burgdorferi sensu stricto and B. afzelii. We are investigating various European Borrelia spirochetes and their interactions at the atomic level using NMR. We report preparative scale recombinant expression of uniformly stable isotope enriched B. afzelii DbpA in Escherichia coli, its chromatographic purification, and solution NMR assignments of its backbone and sidechain H, C, and N atoms. This data was used to predict secondary structure propensity, which we compared to the North American B. burgdorferi sensu stricto and European B. garinii DbpA for which solution NMR structures had been determined previously. Backbone dynamics of DbpA from B. afzelii were elucidated from spin relaxation and heteronuclear NOE experiments. NMR-based secondary structure analysis together with the backbone dynamics characterization provided a first look into structural differences of B. afzelii DbpA compared to the North American species and will serve as the basis for further investigation of how these changes affect interactions with host components.
Topics: Borrelia burgdorferi Group
PubMed: 34357583
DOI: 10.1007/s12104-021-10039-2 -
MSystems Aug 2022Host association-the selective adaptation of pathogens to specific host species-evolves through constant interactions between host and pathogens, leaving a lot yet to be...
Host association-the selective adaptation of pathogens to specific host species-evolves through constant interactions between host and pathogens, leaving a lot yet to be discovered on immunological mechanisms and genomic determinants. The causative agents of Lyme disease (LD) are spirochete bacteria composed of multiple species of the Borrelia burgdorferi complex, including B. burgdorferi (), the main LD pathogen in North America-a useful model for the study of mechanisms underlying host-pathogen association. Host adaptation requires pathogens' ability to evade host immune responses, such as complement, the first-line innate immune defense mechanism. We tested the hypothesis that different host-adapted phenotypes among strains are linked to polymorphic loci that confer complement evasion traits in a host-specific manner. We first examined the survivability of 20 strains in sera and/or bloodstream and tissues from rodent and avian LD models. Three groups of complement-dependent host-association phenotypes emerged. We analyzed complement-evasion genes, identified among all strains and sequenced and compared genomes for individual strains representing each phenotype. The evolutionary history of loci is correlated with host-specific complement-evasion phenotypes, while comparative genomics suggests that several gene families and loci are potentially involved in host association. This multidisciplinary work provides novel insights into the functional evolution of host-adapted phenotypes, building a foundation for further investigation of the immunological and genomic determinants of host association. Host association is the phenotype that is commonly found in many pathogens that preferential survive in particular hosts. The Lyme disease (LD)-causing agent, B. burgdorferi (), is an ideal model to study host association, as is mainly maintained in nature through rodent and avian hosts. A widespread yet untested concept posits that host association in strains is linked to functional genetic variation conferring evasion to complement, an innate defense mechanism in vertebrate sera. Here, we tested this concept by grouping 20 strains into three complement-dependent host-association phenotypes based on their survivability in sera and/or bloodstream and distal tissues in rodent and avian LD models. Phylogenomic analysis of these strains further correlated several gene families and loci, including , with host-specific complement-evasion phenotypes. Such multifaceted studies thus pave the road to further identify the determinants of host association, providing mechanistic insights into host-pathogen interaction.
Topics: Humans; Borrelia; Phylogeny; Lyme Disease; Borrelia burgdorferi; Complement System Proteins
PubMed: 35938719
DOI: 10.1128/msystems.00488-22 -
PloS One 2017The isolation of B. burgdorferi sensu lato requires the use of complex cultivation media. The aim of the study was to compare the usefulness of BSK-H (a commercial...
The isolation of B. burgdorferi sensu lato requires the use of complex cultivation media. The aim of the study was to compare the usefulness of BSK-H (a commercial medium produced by HiMedia, India) and MKP medium. MKP and BSK-H media were prepared in accordance with the relevant protocols. Borrelia strains and skin culture biopsies were simultaneously inoculated into both media, incubated and checked for growth. Borrelial growth characteristics, isolation rates and characteristics of the isolated borreliae were analysed and compared. Initially, numbers of spirochaetes were higher in BSK-H than in MKP; however, in comparison with MKP, the strains subcultured in BSK-H medium were more frequently irregular, thin and non-motile, and rapidly died. In addition, the borrelial isolation rate from erythema migrans skin samples was higher in MKP than in BSK-H medium (108/171, 63.2% versus 70/171, 40.9%; p<0.0001). The far most frequently isolated species was Borrelia afzelii (92.9% and 97.2% strains isolated from BSK-H and MKP, respectively). Comparison of strains cultured from individual patients in both media showed differences in plasmid contents in 9/46 (19.6%) strain pairs, and protein profiles differed in 30/43 (69.8%) strain pairs, most often in the expression of OspC (in 27/28 patients OspC was expressed only in strains growing in MKP). BSK-H medium supports the growth of borrelial strains but MKP is superior with regard to the isolation rate, morphology and motility of strains. BSK-H medium supports fast initial growth of borreliae but this is followed by rapid deformation and death of the spirochaetes.
Topics: Borrelia burgdorferi; Culture Media; Erythema Chronicum Migrans; Humans
PubMed: 28170447
DOI: 10.1371/journal.pone.0171622 -
Euro Surveillance : Bulletin Europeen... May 2019Background clusters phylogenetically among relapsing fever borreliae, but is transmitted by hard ticks. Recent recognition as a human pathogen has intensified research... (Review)
Review
Background clusters phylogenetically among relapsing fever borreliae, but is transmitted by hard ticks. Recent recognition as a human pathogen has intensified research into its ecology and pathogenic potential.AimsWe aimed to provide a timely critical integrative evaluation of our knowledge on , to assess its public health relevance and guide future research.MethodsThis narrative review used peer-reviewed literature in English from January 1994 to December 2018.Results occurs in the world's northern hemisphere where it co-circulates with sensu lato, which causes Lyme disease. The two borreliae have overlapping vertebrate and tick hosts. While ticks serve as vectors for both species, they are also reservoirs for . Three genotypes are described, but further diversity is being recognised. The lack of sufficient cultivable isolates and vertebrate models compromise investigation of human infection and its consequences. Our understanding mainly originates from limited case series. In these, human infections mostly present as influenza-like illness, with relapsing fever in sporadic cases and neurological disease reported in immunocompromised patients. Unspecific clinical presentation, also occasionally resulting from Lyme- or other co-infections, complicates diagnosis, likely contributing to under-reporting. Diagnostics mainly employ PCR and serology. infections are treated with antimicrobials according to regimes used for Lyme disease.ConclusionsWith co-infection of tick-borne pathogens being commonplace, diagnostic improvements remain important. Developing in vivo models might allow more insight into human pathogenesis. Continued ecological and human case studies are key to better epidemiological understanding, guiding intervention strategies.
Topics: Amoxicillin; Animals; Anti-Bacterial Agents; Borrelia; Borrelia Infections; Borrelia burgdorferi; Disease Reservoirs; Disease Vectors; Humans; Ixodidae; Salivary Glands; Tick Bites; Ticks
PubMed: 31064634
DOI: 10.2807/1560-7917.ES.2019.24.18.1800170 -
The Journal of Biological Chemistry Jan 2020Lyme disease, also known as Lyme borreliosis, is the most common tick-transmitted disease in the Northern Hemisphere. The disease is caused by the bacterial spirochete... (Review)
Review
Lyme disease, also known as Lyme borreliosis, is the most common tick-transmitted disease in the Northern Hemisphere. The disease is caused by the bacterial spirochete and other related species. One of the many fascinating features of this unique pathogen is an elaborate system for antigenic variation, whereby the sequence of the surface-bound lipoprotein VlsE is continually modified through segmental gene conversion events. This perpetual changing of the guard allows the pathogen to remain one step ahead of the acquired immune response, enabling persistent infection. Accordingly, the locus is the most evolutionarily diverse genetic element in Lyme disease-causing borreliae. Small stretches of information are transferred from a series of silent cassettes in the locus to generate an expressed mosaic gene version that contains genetic information from several different silent cassettes, resulting in ∼10 possible sequences. Yet, despite its extreme evolutionary flexibility, the locus has rigidly conserved structural features. These include a telomeric location of the gene, an inverse orientation of and the silent cassettes, the presence of nearly perfect inverted repeats of ∼100 bp near the 5' end of , and an exceedingly high concentration of G runs in and the silent cassettes. We discuss the possible roles of these evolutionarily conserved features, highlight recent findings from several studies that have used next-generation DNA sequencing to unravel the switching process, and review advances in the development of a mini- system for genetic manipulation of the locus.
Topics: Animals; Antigenic Variation; Antigens, Bacterial; Bacterial Proteins; Borrelia burgdorferi; Genetic Loci; Host-Pathogen Interactions; Humans; Immunity; Lipoproteins; Lyme Disease; Models, Molecular; Mutation
PubMed: 31753921
DOI: 10.1074/jbc.REV119.008583 -
Parasites & Vectors Jan 2023The genus Borrelia is composed of two well-defined monophyletic groups, the Borrelia burgdorferi sensu lato complex (Bb) and the relapsing fever (RF) group borreliae....
BACKGROUND
The genus Borrelia is composed of two well-defined monophyletic groups, the Borrelia burgdorferi sensu lato complex (Bb) and the relapsing fever (RF) group borreliae. Recently, a third group, associated with reptiles and echidnas, has been described. In general, RF group borreliae use rodents as reservoir hosts; although neotropical bats may also be involved as important hosts, with scarce knowledge regarding this association. The objective of this study was to detect the presence of Borrelia spp. DNA in bats from the department of Córdoba in northwest Colombia.
METHODS
During September 2020 and June 2021, 205 bats were captured in six municipalities of Córdoba department, Colombia. Specimens were identified using taxonomic keys and DNA was extracted from spleen samples. A Borrelia-specific real-time PCR was performed for the 16S rRNA gene. Fragments of the 16S rRNA and flaB genes were amplified in the positive samples by conventional PCR. The detected amplicons were sequenced by the Sanger method. Phylogenetic reconstruction was performed in IQ-TREE with maximum likelihood based on the substitution model TPM3+F+I+G4 with bootstrap values deduced from 1000 replicates.
RESULTS
Overall, 10.2% (21/205) of the samples were found positive by qPCR; of these, 81% (17/21) and 66.6% (14/21) amplified 16S rRNA and flaB genes, respectively. qPCR-positive samples were then subjected to conventional nested and semi-nested PCR to amplify 16S rRNA and flaB gene fragments. Nine positive samples for both genes were sequenced, and seven and six sequences were of good quality for the 16S rRNA and flaB genes, respectively. The DNA of Borrelia spp. was detected in the insectivorous and fruit bats Artibeus lituratus, Carollia perspicillata, Glossophaga soricina, Phyllostomus discolor, and Uroderma sp. The 16S rRNA gene sequences showed 97.66-98.47% identity with "Borrelia sp. clone Omi3," "Borrelia sp. RT1S," and Borrelia sp. 2374; the closest identities for the flaB gene were 94.02-98.04% with "Borrelia sp. Macaregua." For the 16S rRNA gene, the phylogenetic analysis showed a grouping with "Candidatus Borrelia ivorensis" and "Ca. Borrelia africana," and for the flaB gene showed a grouping with Borrelia sp. Macaregua and Borrelia sp. Potiretama. The pathogenic role of the Borrelia detected in this study is unknown.
CONCLUSIONS
We describe the first molecular evidence of Borrelia spp. in the department of Córdoba, Colombia, highlighting that several bat species harbor Borrelia spirochetes.
Topics: Animals; Borrelia; Chiroptera; RNA, Ribosomal, 16S; Phylogeny; Colombia; Likelihood Functions; DNA, Bacterial
PubMed: 36604762
DOI: 10.1186/s13071-022-05614-y -
Emerging Infectious Diseases Sep 2020We report a human case of Borrelia miyamotoi infection diagnosed in Austria. Spirochetes were detected in Giemsa-stained blood smears. The presence of B. miyamotoi in...
We report a human case of Borrelia miyamotoi infection diagnosed in Austria. Spirochetes were detected in Giemsa-stained blood smears. The presence of B. miyamotoi in the patient's blood was confirmed by PCR, and phylogenetic analysis identified an infection with a strain from Europe.
Topics: Animals; Austria; Borrelia; Europe; Humans; Ixodes; Phylogeny
PubMed: 32818401
DOI: 10.3201/eid2609.191501 -
Ticks and Tick-borne Diseases Jul 2023Borrelia miyamotoi is an emerging human pathogen that causes a relapsing fever-like disease named B. miyamotoi disease. The bacterium belongs to the relapsing fever...
Borrelia miyamotoi is an emerging human pathogen that causes a relapsing fever-like disease named B. miyamotoi disease. The bacterium belongs to the relapsing fever borreliae, and similar to spirochetes of the Borrelia burgdorferi sensu lato group, it is transmitted only by hard ticks of the Ixodes ricinus complex. To date, B. miyamotoi has not been demonstrated to cause illness in dogs or cats, and is poorly documented in veterinary medicine. The aim of this study was to determine the B. miyamotoi presence in (i) host-seeking ticks and (ii) engorged Ixodes sp. ticks collected from dogs and cats during their inspection in veterinary clinics of the city of Poznań, west-central Poland. Host-seeking ticks were sampled in dog walking areas localized in urban forested recreational sites of the city. In this study, 1,059 host-seeking and 837 engorged I. ricinus ticks collected from 680 tick-infested animals (567 dogs and 113 cats) were screened. Additionally, 31 I. hexagonus ticks (one larva, 13 nymphs, and 17 females) were collected from three cats; one larva and one nymph were collected from two dogs; and one dog was infested with a single Dermacentor reticulatus female. Borrelia DNA was identified by the amplification and sequencing of the V4 hypervariable region of the 16S rRNA gene and flaB gene fragments. DNA of B. miyamotoi was detected in 22 (2.1%) of the host-seeking ticks (in all developmental tick stages and in all study areas). In addition, the engorged I. ricinus ticks exhibited a similar B. miyamotoi presence (1.8%). Fifteen I. ricinus ticks collected from animals tested positive for the presence of B. miyamotoi DNA, and the DNA of B. miyamotoi was observed in three (9.1%; one female and two nymphs) I. hexagonus ticks. The single D. reticulatus female collected from a dog tested PCR-negative for the bacterium. The results of this study demonstrated the establishment and broad presence of the bacterium in tick populations from different urban ecosystems of the city of Poznań. The lack of difference in the mean infection presence of animal-derived and host-seeking I. ricinus ticks suggests that the systematic surveillance of pets may be useful for the evaluation of human exposure to B. miyamotoi infected ticks in urban areas. Additional studies are required to further elucidate the role of domestic and wild carnivores in the epidemiology of B. miyamotoi, which remains unknown.
Topics: Humans; Dogs; Animals; Cats; Female; Ixodes; Ecosystem; Relapsing Fever; Poland; Cat Diseases; RNA, Ribosomal, 16S; Dog Diseases; Borrelia; Borrelia burgdorferi Group; Nymph
PubMed: 37172512
DOI: 10.1016/j.ttbdis.2023.102188 -
Journal of Applied Microbiology Dec 2015Little is known about the effects of phytochemicals against Borrelia sp. causing Lyme disease. Current therapeutic approach to this disease is limited to antibiotics....
AIMS
Little is known about the effects of phytochemicals against Borrelia sp. causing Lyme disease. Current therapeutic approach to this disease is limited to antibiotics. This study examined the anti-borreliae efficacy of several plant-derived compounds and micronutrients.
METHODS AND RESULTS
We tested the efficacy of 15 phytochemicals and micronutrients against three morphological forms of Borrelia burgdoferi and Borrelia garinii: spirochetes, latent rounded forms and biofilm. The results showed that the most potent substances against the spirochete and rounded forms of B. burgdorferi and B. garinii were cis-2-decenoic acid, baicalein, monolaurin and kelp (iodine); whereas, only baicalein and monolaurin revealed significant activity against the biofilm. Moreover, cis-2-decenoic acid, baicalein and monolaurin did not cause statistically significant cytotoxicity to human HepG2 cells up to 125 μg ml(-1) and kelp up to 20 μg ml(-1) .
CONCLUSIONS
The most effective antimicrobial compounds against all morphological forms of the two tested Borrelia sp. were baicalein and monolaurin. This might indicate that the presence of fatty acid and phenyl groups is important for comprehensive antibacterial activity.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study reveals the potential of phytochemicals as an important tool in the fight against the species of Borrelia causing Lyme disease.
Topics: Anti-Bacterial Agents; Biofilms; Borrelia burgdorferi; Borrelia burgdorferi Group; Hep G2 Cells; Humans; Micronutrients; Phytochemicals
PubMed: 26457476
DOI: 10.1111/jam.12970