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1.
Three strains of spirochetes (IKA1 to 3) were isolated from the midgut of Ixodes ovatus collected in the Ikawa region of the northern part of Shizuoka, Japan. These isolates had eight flagella, and their size and other morphological features were similar to Borrelia burgdorferi. They showed similar motility and reacted with monoclonal antibody (MAb) H9724 against borrelial flagella and with MAb H5332 against the outer surface protein A. These strains showed similar SDS-PAGE profiles to that of B. burgdorferi strain B31 and P/Bi isolated in the U.S.A. and Europe, respectively. Immunoblot with Lyme disease patient serum showed positive reactions with the flagella (41 Kilodalton, kDa), protein C (20 to 22 kDa), and outer surface protein A (29 kDa) of the isolates. Immunological properties, morphological characteristics, and epidemiological features revealed that these isolates were B. burgdorferi.  相似文献   

2.
Lyme disease risk is increasing in the United States due in part to the spread of blacklegged ticks Ixodes scapularis, the principal vector of the spirochetal pathogen Borrelia burgdorferi. A 5-year study was undertaken to investigate hypothesized coinvasion of I. scapularis and B. burgdorferi in Lower Michigan. We tracked the spatial and temporal dynamics of the tick and spirochete using mammal, bird, and vegetation drag sampling at eight field sites along coastal and inland transects originating in a zone of recent I. scapularis establishment. We document northward invasion of these ticks along Michigan’s west coast during the study period; this pattern was most evident in ticks removed from rodents. B. burgdorferi infection prevalences in I. scapularis sampled from vegetation in the invasion zone were 9.3% and 36.6% in nymphs and adults, respectively, with the majority of infection (95.1%) found at the most endemic site. There was no evidence of I. scapularis invasion along the inland transect; however, low-prevalence B. burgdorferi infection was detected in other tick species and in wildlife at inland sites, and at northern coastal sites in years before the arrival of I. scapularis. These infections suggest that cryptic B. burgdorferi transmission by other vector-competent tick species is occurring in the absence of I. scapularis. Other Borrelia spirochetes, including those that group with B. miyamotoi and B. andersonii, were present at a low prevalence within invading ticks and local wildlife. Reports of Lyme disease have increased significantly in the invasion zone in recent years. This rapid blacklegged tick invasion—measurable within 5 years—in combination with cryptic pathogen maintenance suggests a complex ecology of Lyme disease emergence in which wildlife sentinels can provide an early warning of disease emergence.  相似文献   

3.
Clinical characteristics associated with isolation of Borrelia burgdorferi sensu lato from skin have not been fully evaluated. To gain insight into predictors for a positive EM skin culture, we compared basic demographic, epidemiologic, and clinical data in 608 culture-proven and 501 culture-negative adult patients with solitary EM. A positive Borrelia spp. skin culture was associated with older age, a time interval of >2 days between tick bite and onset of the skin lesion, EM ≥5 cm in diameter, and location of the lesion on the extremities, whereas several other characteristics used as clinical case definition criteria for the diagnosis of EM (such as tick bite at the site of later EM, information on expansion of the skin lesion, central clearing) were not. A patient with a 15-cm EM lesion had almost 3-fold greater odds for a positive skin culture than patients with a 5-cm lesion. Patients with a free time interval between the tick bite and onset of EM had the same probability of a positive skin culture as those who did not recall a tick bite (OR=1.02); however, the two groups had >3-fold greater odds for EM positivity than patients who reported a tick bite with no interval between the bite and onset of the lesion. In conclusion, several yet not all clinical characteristics used in EM case definitions were associated with positive Borrelia spp. skin culture. The findings are limited to European patients with solitary EM caused predominantly by B. afzelii but may not be valid for other situations.  相似文献   

4.
Challenge of Dermacentor variabilis by hemocoel injection with Borrelia burgdorferi but not Bacillus subtilis or Escherichia coli provoked secretion of two low molecular weight peptides into the hemolymph plasma; the lower band co-migrated with a band previously identified as varisin (a tick defensin). These findings are consistent with reports that D. variabilis controls B. burgdorferi but not B. subtilis or E. coli by defensin-dependent bacteriolysis. Challenge of the tick midgut by capillary artificial feeding with bacteria also provoked expression of multiple low molecular weight peptides. In this case, however, all three bacteria elicited the response. Two bands, including the defensin-like peptide were expressed following challenge with B. subtilis and E. coli, but only the upper band following challenge with B. burgdorferi. Although they appeared intact, these spirochetes were no longer viable suggesting that borreliae in the midgut are controlled by a different method than the lytic response of the D. variabilis hemolymph. DD-RT-PCR revealed multiple mRNAs in the midgut of D. variabilis following challenge with B. burgdorferi, E. coli and Rickettsia montana. Although their identification remains to be determined, the large number of genes expressed in response to bacterial challenge presents intriguing possibilities for explaining the ability of the tick midgut to destroy invading microbes at the cellular level. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

5.
Lyme disease is a tick-borne infection caused by Borrelia burgdorferi sensu lato complex spirochetes. The spirochete is located in the gut of the tick; as the infected tick starts the blood meal, the spirochete must travel through the hemolymph to the salivary glands, where it can spread to and infect the new host organism. In this study, we determined the crystal structures of the key outer surface protein BBE31 from B. burgdorferi and its orthologous protein BSE31 (BSPA14S_RS05060 gene product) from B. spielmanii. BBE31 is known to be important for the transfer of B. burgdorferi from the gut to the hemolymph in the tick after a tick bite. While BBE31 exerts its function by interacting with the Ixodes scapularis tick gut protein TRE31, structural and mass spectrometry data revealed that BBE31 has a glutathione (GSH) covalently attached to Cys142 suggesting that the protein may have acquired some additional functions in contrast to its orthologous protein BSE31, which lacks any interactions with GSH. In the current study, in addition to analyzing the potential reasons for GSH binding, the three-dimensional structure of BBE31 provides new insights into the molecular details of the transmission process as the protein plays an important role in the initial phase before the spirochete is physically transferred to the new host. This knowledge will be potentially used for the development of new strategies to fight against Lyme disease.  相似文献   

6.
Ixodes scapularis is the specific arthropod vector for a number of globally prevalent infections, including Lyme disease caused by the bacterium Borrelia burgdorferi. A feeding-induced and acellular epithelial barrier, known as the peritrophic membrane (PM) is detectable in I. scapularis. However, whether or how the PM influences the persistence of major tick-borne pathogens, such as B. burgdorferi, remains largely unknown. Mass spectrometry-based proteome analyses of isolated PM from fed ticks revealed that the membrane contains a few detectable proteins, including a predominant and immunogenic 60 kDa protein with homology to arthropod chitin deacetylase (CDA), herein termed I. scapularis CDA-like protein or IsCDA. Although IsCDA is primarily expressed in the gut and induced early during tick feeding, its silencing via RNA interference failed to influence either the occurrence of the PM or spirochete persistence, suggesting a redundant role of IsCDA in tick biology and host-pathogen interaction. However, treatment of ticks with antibodies against IsCDA, one of the most predominant protein components of PM, affected B. burgdorferi survival, significantly augmenting pathogen levels within ticks but without influencing the levels of total gut bacteria. These studies suggested a preferential role of tick PM in limiting persistence of B. burgdorferi within the vector. Further understanding of the mechanisms by which vector components contribute to pathogen survival may help the development of new strategies to interfere with the infection.  相似文献   

7.

Background

For clinical development of a novel multivalent OspA vaccine against Lyme borreliosis, serological assays are required which can be used to establish immune correlates of protection against infection with Borrelia.

Methods

Four assays (an OspA IgG ELISA, a competitive inhibition (CI) ELISA, a Borrelia surface-binding (SB) assay and a Borrelia killing assay) were used to evaluate the correlation between immune responses induced by rOspA 1/2 (a chimeric immunogen containing protective epitopes from OspA serotypes 1 and 2), and protective immunity against infection by B. burgdorferi s.s. (OspA-1) and B. afzelii (OspA-2). Mice were immunized with OspA 1/2 doses ranging from 0.3 ng to 100 ng, to induce a range of OspA antibody titers, and exposed to needle challenge with B. burgdorferi s.s. or tick challenge with B. afzelii. Receiver operator characteristics (ROC) curves were constructed for each assay, and the area under the curve (AUC), sensitivity, specificity and Youden Index were calculated. Potential cutoff antibody titers which could be used as correlates of vaccine-induced protection were derived from the maximum Youden Index.

Results

Immunization with OspA-1/2 provided dose-dependent protection against infection with B. burgdorferi s.s. and B. afzelii. Antibody responses detected by all four assays were highly significantly correlated with protection from infection by either B. burgdorferi s.s. (p<0.0001 to 0.0062) or B. afzelii (p<0.0001). ROC analyses of the diagnostic effectiveness of each assay showed the AUC to range between 0.95 and 0.79, demonstrating that all assays distinguish well between infected and non-infected animals. Based on sensitivity, specificity and AUC, the OspA IgG ELISA and SB assays best discriminated between infected and non-infected animals.

Conclusions

All four assays differentiate well between Borrelia-infected and non-infected animals. The relatively simple, high throughput IgG ELISA would be suitable to establish immune correlates of protection for the novel OspA vaccine in clinical trials.  相似文献   

8.
More than 19,000 human cases of Lyme disease (LD) are reported each year in the United States. Lyme disease cases occur when humans are exposed to the bacterium Borrelia burgdorferi through the bite of an infected ixodid tick. The probability of human exposure to infected ticks results from a combination of human behaviors and entomological risk. Human behaviors include use of tick habitats, use of protective clothing, and grooming for tick removal. Entomological risks include the density of ticks in a habitat and the proportion of these that are infected with B. burgdorferi. Recent studies have suggested that humans are at higher risk of exposure to B. burgdorferi near edges between forests and herbaceous communities, including lawns and old fields, but whether this increased risk is a function of human behaviors, entomological risk, or both, is unknown. We assessed entomological risk across forest–old field edges in Dutchess County, NY. Densities of ticks and of infected ticks were considerably higher within forests than at forest–field edges, and were lowest within fields. Thus, edges between forests and fields do not pose a higher entomological risk than do the forests themselves, although risk at the edge is higher than in herbaceous habitat. Landscapes with abundant edges between forested and herbaceous habitat, and roughly even proportions of both, might attract both heavy human use and pose moderately high entomological risk, and thus could be targeted for mitigation. We suggest that determining appropriate methods for reducing human exposure to LD requires differentiating entomological risk from human behaviors.  相似文献   

9.
Lyme arthritis following infection with Borrelia burgdorferi (B. burgdorferi) is associated with the presence of bacteria in the joint, but the mechanism of persistent infection in the presence of specific antibodies and lymphocytes remains unknown. To investigate how an infection with B. burgdorferi might influence the local immune response in the joint, we examined the expression of cell adhesion molecules, human leucocyte antigens and inducible nitric oxide synthase (iNOS)-1 and -2 in human synovial cells after infection with B. burgdorferi in vitro. Synovial cells are known to influence the function of local immunologic effector cells and play a key role in the pannus formation of erosive arthritis. It has been shown previously that B. burgdorferi can persist in the cytosol of human synovial cells. The expression of the surface molecules ICAM-1, VCAM-1, HLA-class-I and -class-II and the cytosolic production of iNOS-1 and -2 in synovial cells was measured by flow cytometry for up to 5 days after infection with B. burgdorferi. A significant, lasting downregulation of surface ICAM-1 could be demonstrated on synovial cells, whereas no significant changes were seen in the expression of VCAM-1, HLA-class-I and -II, and of iNOS-1 and -2. To determine the biological significance of this downregulation an in vitro adhesion assay using peripheral blood mononuclear cells was developed. After infection with B. burgdorferi a significantly smaller number of mononuclear cells was adhering to the synovial cell monolayer. Adhesion of peripheral mononuclear cells was shown to be in part mediated by ICAM-1 by using a blocking mononuclear antibody against ICAM-1. Downregulation of ICAM-1 on synovial cells due to infection with B. burgdorferi might suppress the local immunosurveillance and might help the bacteria to persist in joint cells in vivo.  相似文献   

10.
Borrelia burgdorferi sensu lato (s.l.) is the causative agent of Lyme borreliosis, the most common tick‐borne zoonosis of humans in Europe and North America. Here, we assessed the relative importance of different passerine bird species as tick hosts and their contribution to the B. burgdorferi s.l. transmission cycle in a rural residential area in Scotland. We caught 1229 birds of 22 species during the tick‐questing season. On average, 29% carried larval ticks (0.8 larvae per individual) and 5% carried nymph ticks (0.06 nymphs per individual). All attached ticks tested were Ixodes ricinus. Using a nested‐PCR, we found that 20% of nymphs tested positive to B. burgdorferi s.l. and all these were of the genospecies Borrelia garinii. We identified two new bird species carrying infected nymphs: Eurasian Siskin Carduelis spinus and European Greenfinch Carduelis chloris. Ground‐foraging species were more important than arboreal species in hosting I. ricinus nymphs and B. burgdorferi s.l. Common Blackbirds Turdus merula were the most common hosts, with Song Thrushes Turdus philomelos, Dunnocks Prunella modularis, European Greenfinches and Chaffinches Fringilla coelebs also hosting high rates of infection.  相似文献   

11.
Borrelia burgdorferi and Anaplasma phagocytophilum are obligate intracellular parasites that maintain their life cycles in enzoonotic vector‐host cycles with Ixodes scapularis as a vector. In addition to ticks, the hosts are commonly infested with insects from the Hippoboscidae family. This study confirms the presence of B. burgdorferi and A. phagocytophilum in deer keds (Lipoptena cervi) removed from white‐tailed deer using PCR. Detection of these pathogens in deer ked represents a potential novel susceptibility of wildlife and also suggests the risk of transmission of these pathogens to humans and animals alike through the bite of an infected ectoparasite. This study represents the first instance in the U.S. of detection of tick‐borne pathogens in a member of the Hippoboscid family.  相似文献   

12.
13.
Borrelia burgdorferi sensu lato is the causative agent of Lyme borreliosis in humans. This inflammatory disease can affect the skin, the peripheral and central nervous system, the musculoskeletal and cardiovascular system and rarely the eyes. Early stages are directly associated with viable bacteria at the site of inflammation. The pathogen-host interaction is complex and has been elucidated only in part. B. burgdorferi is highly susceptible to antibiotic treatment and the majority of patients profit from this treatment. Some patients develop chronic persistent disease despite repeated antibiotics. Whether this is a sequel of pathogen persistence or a status of chronic auto-inflammation, auto-immunity or a form of fibromyalgia is highly debated. Since vaccination is not available, prevention of a tick bite or chemoprophylaxis is important. If the infection is manifest, then treatment strategies should target not only the pathogen by using antibiotics but also the chronic inflammation by using anti-inflammatory drugs.  相似文献   

14.
Oral vaccination strategies are of interest to prevent transmission of Lyme disease as they can be used to deliver vaccines to humans, pets, and to natural wildlife reservoir hosts of Borrelia burgdorferi. We developed a number of oral vaccines based in E. coli expressing recombinant OspC type K, OspB, BBK32 from B. burgdorferi, and Salp25, Salp15 from Ixodes scapularis. Of the five immunogenic candidates only OspC induced significant levels of antigen-specific IgG and IgA when administered to mice via the oral route. Antibodies to OspC did not prevent dissemination of B. burgdorferi as determined by the presence of spirochetes in ear, heart and bladder tissues four weeks after challenge. Next generation sequencing of genomic DNA from ticks identified multiple phyletic types of B. burgdorferi OspC (A, D, E, F, I, J, K, M, Q, T, X) in nymphs that engorged on vaccinated mice. PCR amplification of OspC types A and K from flat and engorged nymphal ticks, and from heart and bladder tissues collected after challenge confirmed sequencing analysis. Quantification of spirochete growth in a borreliacidal assay shows that both types of spirochetes (A and K) survived in the presence of OspC-K specific serum whereas the spirochetes were killed by OspA specific serum. We show that oral vaccination of C3H-HeN mice with OspC-K induced significant levels of antigen-specific IgG. However, these serologic antibodies did not protect mice from infection with B. burgdorferi expressing homologous or heterologous types of OspC after tick challenge.  相似文献   

15.
Borrelia burgdorferi, the agent of Lyme disease, spreads from the site of the tick bite to tissues such as heart, joints and the nervous tissues. Host glycosaminoglycans, highly modified repeating disaccharides that are present on cell surfaces and in extracellular matrix, are common targets of microbial pathogens during tissue colonization. While several dermatan sulfate‐binding B. burgdorferi adhesins have been identified, B. burgdorferi adhesins documented to promote spirochetal binding to heparan sulfate have not yet been identified. OspEF‐related proteins (Erps), a large family of plasmid‐encoded surface lipoproteins that are produced in the mammalian host, can be divided into the OspF‐related, OspEF‐leader peptide (Elp) and OspE‐related subfamilies. We show here that a member of the OspF‐related subfamily, ErpG, binds to heparan sulfate and when produced on the surface of an otherwise non‐adherent B. burgdorferi strain, ErpG promotes heparan sulfate‐mediated bacterial attachment to the glial but not the endothelial, synovial or respiratory epithelial cells. Six other OspF‐related proteins were capable of binding heparan sulfate, whereas representative OspE‐related and Elp proteins lacked this activity. These results indicate that OspF‐related proteins are heparan sulfate‐binding adhesins, at least one of which promotes bacterial attachment to glial cells.  相似文献   

16.
P66 is a Borrelia burgdorferi surface protein with β3 integrin binding and channel forming activities. In this study, the role of P66 in mammalian and tick infection was examined. B. burgdorferiΔp66 strains were not infectious in wild‐type, TLR2?/?‐ or MyD88?/?‐deficient mice. Strains with p66 restored to the chromosome restored near wild‐type infectivity, while complementation with p66 on a shuttle vector did not restore infectivity. Δp66 mutants are cleared quickly from the site of inoculation, but analyses of cytokine expression and cellular infiltrates at the site of inoculation did not reveal a specific mechanism of clearance. The defect in these mutants cannot be attributed to nutrient limitation or an inability to adapt to the host environment in vivo as Δp66 bacteria were able to survive as well as wild type in dialysis membrane chambers in the rat peritoneum. Δp66 bacteria were able to survive in ticks through the larva to nymph moult, but were non‐infectious in mice when delivered by tick bite. Independent lines of evidence do not support any increased susceptibility of the Δp66 strains to factors in mammalian blood. This study is the first to define a B. burgdorferi adhesin as essential for mammalian, but not tick infection.  相似文献   

17.

Background

Relapsing fever spirochetes are global yet neglected pathogens causing recurrent febrile episodes, chills, nausea, vomiting, and pregnancy complications. Given these nonspecific clinical manifestations, improving diagnostic assays for relapsing fever spirochetes will allow for identification of endemic foci and expedite proper treatment. Previously, an antigen designated the Borrelia immunogenic protein A (BipA) was identified in the North American species Borrelia hermsii. Thus far, BipA appears unique to relapsing fever spirochetes. The antigen remains unidentified outside of these pathogens, while interspecies amino acid identity for BipA in relapsing fever spirochetes is only 24–36%. The current study investigated the immunogenicity of BipA in Borrelia turicatae, a species distributed in the southern United States and Latin America.

Methodology/Principal Findings

bipA was amplified from six isolates of Borrelia turicatae, and sequence analysis demonstrated that the gene is conserved among isolates. A tick transmission system was developed for B. turicatae in mice and a canine, two likely vertebrate hosts, which enabled the evaluation of serological responses against recombinant BipA (rBipA). These studies indicated that BipA is antigenic in both animal systems after infection by tick bite, yet serum antibodies failed to bind to B. hermsii rBipA at a detectable level. Moreover, mice continued to generate an antibody response against BipA one year after the initial infection, further demonstrating the protein''s potential toward identifying endemic foci for B. turicatae.

Conclusions/Significance

These initial studies support the hypothesis that BipA is a spirochete antigen unique to a relapsing fever Borrelia species, and could be used to improve efforts for identifying B. turicatae endemic regions.  相似文献   

18.

Ixodes ricinus ticks transmit Borrelia burgdorferi sensu lato (s.l.) as well as Borrelia miyamotoi. Larvae become infected when feeding on infected rodents, with horizontal transmission of B. burgdorferi and horizontal and vertical transmission of B. miyamotoi. We studied seasonal dynamics of infection rates of I. ricinus and their rodent hosts, and hence transmission risk of these two distinctly different Borrelia species. Rodents were live-trapped and inspected for ticks from May to November in 2013 and 2014 in a forest in The Netherlands. Trapped rodents were temporarily housed in the laboratory and detached ticks were collected. Borrelia infections were determined from the trapped rodents and collected ticks. Borrelia burgdorferi s.l. and B. miyamotoi were found in ticks as well as in rodents. Rodent density was higher in 2014, whereas tick burden as well as the Borrelia infection rates in rodents were higher in 2013. The density of B. miyamotoi-infected nymphs did not differ between the years. Tick burdens were higher on Apodemus sylvaticus than on Myodes glareolus, and higher on males than on females. Borrelia-infection rate of rodents varied strongly seasonally, peaking in summer. As the larval tick burden also peaked in summer, the generation of infected nymphs was highest in summer. We conclude that the heterogeneity of environmental and host-specific factors affects the seasonal transmission of Borrelia spp., and that these effects act more strongly on horizontally transmitted B. burgdorferi spp. than on the vertically transmitted B. miyamotoi.

  相似文献   

19.
Studies were carried out in the Connemara area of County Galway in the west of Ireland in order to determine the abundance and distribution of the tick, Ixodes ricinus and the prevalence of its infection with Borrelia burgdorferi. The tick was very abundant locally, in particular when associated with cattle, sheep and enclosed red deer. Large numbers of ticks not only occurred on the pastures, but also on adjacent roadside verges. No infections with B. burgdorferi could be demonstrated when nymphal ticks were sampled from central areas of the pastures, suggesting that livestock and red deer are probably not significant reservoirs of the spirochaete. Small numbers of infected nymphal and adult ticks were associated with hedges, dry stone walls, the margins of woodland adjoining infested pastures and in woodland from which livestock were excluded. Woodmice (Apodemus sylvaticus) were most numerous in such habitats and the majority were infected with B. burgdorferi.  相似文献   

20.
Lyme disease is the most common tick‐borne infectious disease in Europe and North America. Previous studies discovered the immunogenic role of a surface‐exposed lipoprotein (VlsE) of Borreliella burgdorferi. We employed high density peptide arrays to investigate the antibody response to the VlsE protein in VlsE‐positive patients by mapping the protein as overlapping peptides and subsequent in‐depth epitope substitution analyses. These investigations led to the identification of antibody fingerprints represented by a number of key residues that are indispensable for the binding of the respective antibody. This approach allows us to compare the antibody specificities of different patients to the resolution of single amino acids. Our study revealed that the sera of VlsE‐positive patients recognize different epitopes on the protein. Remarkably, in those cases where the same epitope is targeted, the antibody fingerprint is almost identical. Furthermore, we could correlate two fingerprints with human autoantigens and an Epstein‐Barr virus epitope; yet, the link to autoimmune disorders seems unlikely and must be investigated in further studies. The other three fingerprints are much more specific for B. burgdorferi. Since antibody fingerprints of longer sequences have proven to be highly disease specific, our findings suggest that the fingerprints could function as diagnostic markers that can reduce false positive test results.  相似文献   

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