Immunodominant proteins of Borrelia burgdorferi,the etiological agent of lyme borreliosis

Lyme borreliosis, a multisystem disorder involving the skin, the nervous system, the heart, the joints and many other organs, is a worldwide infectious disease which is transmitted by ticks of the Ixodes complex. Most frequently diagnosis is accomplished by detection of antibodies because the Borrelia are difficult to cultivate. Present serodiagnostic methods, however, are impaired by low sensitivity and unspecific reactions. The selection of immunodominant antigens with low cross-reactivity to other bacteria should improve antibody detection. Borrelia burgdorferi proteins have been analysed for cross-reactivity with immune sera from unrelated bacteria, and sera from patients with different stages of the disease. Suitable antigens for improving serodiagnosis have been detected and are reported here. In view of the immunological heterogeneity of Borrelia proteins, sensitivity of antibody detection may possibly be increased by using recombinant antigens derived from different strains. Immunization with recombinant OspA (a flagellum-associated protein) from a North American isolate protected mice from the challenge with three North American isolates. However, for development of an effective vaccine (especially in Europe), the heterogeneity of OspA has to be considered.This paper was presented at the IUMS Symposium on New Developments in Diagnosis and Control of Infectious Diseases held in conjunction with the Eighth International Congress of Virology, Berlin, Germany, 24–31 August 1990.     

Evaluation of a genotyping method based on the ospA gene to detect Borrelia burgdorferi sensu lato in multiple samples of lyme borreliosis patients

In this study we have developed a new Restriction-Fragment-Length-Polymorphism (RFLP) genotyping method for rapid detection and identification of Borrelia genospecies present as unique species or as co-infection in multiple specimens obtained simultaneously from 29 individual patients affected by early or late Lyme borreliosis (LB). The target of the RFLP-genotyping was the heterogeneous plasmid located ospA gene, thus we developed a method able to detect and differentiate between six clinically relevant Borrelia genospecies circulating in Europe, B. burgdorferi sensu stricto, B. garinii, B. afzelii, B. valaisiana, B. bissettii and B. spielmanii. In this study Borrelia DNA could be detected by PCR in at least one specimen of each patient, except in one case of neuroborreliosis (NB); blood samples gave the highest sensitivity in all patient groups. The genotyping indicated that B. afzelii was present in 8 patients with skin involvement, B. garinii in 2 cases of NB and 4 cases with skin involvement, B. burgdorferi sensu stricto was detected in one patient with skin involvement and another with Lyme arthritis. Different Borrelia species in distinct specimens were identified in one patient with EM. The RFLP analysis of 11 patients revealed mixed patterns, which suggested pluri-infection with different Borrelia species.     

Lectin-binding characteristics of a lyme borreliosis spirocheteBorrelia burgdorferi sensu stricto

Borrelial glycoconjugates were localized by labeled lectins on ultrathin cryosections and on surfaces of intact negatively stained bacteria. Protein-saccharide complexes in these glycoconjugates were partially characterized by means of enzyme deglycosylation and mild alkali pretreatment of cryosections. The results of labeling were examined by transmission electron microscopy. Statistically evaluated results (relative labeling index, chi2 test) of gold labeling indicated that surfaces of Borrelia burgdorferi strain B31 and external (outer) membrane vesicles (MVs) were covered with glycoconjugates containing O-glycosidically linked N-acetyl-D-galactosamine (GalNAc) and N-glycosidically linked N-acetyl-D-glucosamine (GlcNAc). The presence of N-linked GalNAc, sialic acid, mannose and fucose on the surfaces of outer membranes and MVs was probably due to an adherence of BSK-H medium components, especially rabbit serum, to Borrelia surfaces.     

Diversity of Borrelia burgdorferi sensu lato in Russian Far East

Thirty strains of Borrelia burgdorferi sensu lato have been isolated from Ixodes persulcatus ticks and from skin lesions of Lyme disease patients in the Russian Far East from 1997 to 2003. We amplified full-length outer surface protein A (ospA) gene of all strains. BLAST search and following phylogenetic analysis showed that strains form four well-defined groups. Four strains belong to Borrelia afzelii species. Other strains distributed into tree major groups, identified as Borrelia garinii. Indeed, based on the ospA gene comparison, phylogenetic relationship of these groups among each other does not differ from relationship among other previously defined groups inside B. burgdorferi sensu lato genogroup, such as B. afzelii or Borrelia bissettii. Further investigations of genetic and serologic properties of the strains belonging to those groups are required in order to clarify their taxonomic status.     

Analysis of the bmp gene family in Borrelia burgdorferi sensu lato

BmpA, BmpB, BmpC, and BmpD are homologous Borrelia burgdorferi lipoproteins of unknown functions, encoded by the bmp genes of paralogous chromosomal gene family 36. At least some of the Bmp proteins are immunogens in infected vertebrate hosts. The genetic organization of the bmp region has been characterized for a variety of B. burgdorferi sensu lato strains by Southern hybridization, PCR amplification, and DNA sequencing. All four bmp genes were present in the same relative order in all B. burgdorferi sensu lato low- and high-passage-number isolates. While there were no differences in the relative orders of the bmp genes in these species, variations in DNA sequence in the bmpD-bmpC and bmpC-bmpA intergenic regions were significantly more common than in the corresponding 3' bmpD and bmpC coding regions. The genetic structure of the chromosomal region containing the bmp genes thus appears to be well conserved across different species of B. burgdorferi, but variations in DNA fine structure that prevent PCR primer annealing may occur in this region and make Southern hybridization much more reliable than PCR for detection of the presence of these genes. Our results also suggest that bmp gene products may be used as reagents in the preparation of vaccines and diagnostic assays to protect against and diagnose Lyme disease produced by B. burgdorferi sensu lato.     

Borrelia burgdorferi sensu lato infection in mosquitoes from Szczecin area

The aim of the study was to determine the level of infection in mosquitoes with spirochetes Borrelia burgdorferi sensu lato in the woody areas of Szczecin. The mosquitoes were collected from May to September 2003. The spirochetes, Borrelia burgdorferi s. l., present in mosquitoes were detected in mosquitoes with indirect immunofluorescence assay (IFA) using rabbit anti-Borrelia burgdorferi antibodies and goat anti-rabbit IgG marked with fluorescein isocyanate (FITC). A total of 1557 females and 58 males were collected. They represented the genera Aedes (63%) and Culex (37%). The infection level of the mosquitoes from the area studied amounted to 1.7%. The results of the present study confirm the potential of these arthropods to spread Lyme borreliosis.     

Evaluation of a modified culture medium for Borrelia burgdorferi sensu lato

The aim of the present study was to assess the possible use of a modified medium, prepared in the laboratory using the constituents of Barbour-Stonner-Kelly (BSK) medium and medium 199 as base, for the culture of Borrelia strains, comparing the growth of individual strains in this medium and in the BSK-H medium, and the protein profile and antigenic characteristics of Borrelia proteins expressed in these media. A qualitative evaluation of growth of Borrelia species was made with acceptable results (morphology and motility), but during a quantitative evaluation using the three main genospecies of Borrelia, the better results were obtained with a B. burgdorferi sensu stricto strain. The modified medium did not enable the growth of a B. afzelii strain. The protein profile and antigenic characteristic of the expressed proteins in the modified medium were studied with satisfactory results. These results suggest the modified medium as an alternative for the cultivation of Borrelia strains, with some limitations, in poorly-resourced laboratories.     

Whole genome sequence of an unusual Borrelia burgdorferi sensu lato isolate

Human Lyme disease is caused by a number of related Borrelia burgdorferi sensu lato species. We report here the complete genome sequence of Borrelia sp. isolate SV1 from Finland. This isolate is to date the closest known relative of B. burgdorferi sensu stricto, but it is sufficiently genetically distinct from that species that it and its close relatives warrant its candidacy for new-species status. We suggest that this isolate should be named "Borrelia finlandensis."     

Ixodes ricinus and Borrelia burgdorferi sensu lato in the Royal Parks of London,UK

Experimental and Applied Acarology - Assessing the risk of tick-borne disease in areas with high visitor numbers is important from a public health perspective. Evidence suggests that tick presence,...     

Loss of plasmids of Borrelia burgdorferi sensu lato during prolonged in vitro cultivation

In the present study we analyzed stability of plasmid content in 34 Borrelia strains of three different species (13 Borrelia afzelii, 10 Borrelia garinii and 11 Borrelia burgodorferi sensu stricto) using pulse field gel electrophoresis (PFGE). During long-term in vitro cultivation consisting of 50 passages, plasmid loss was established in 46% of B. afzelii, 40% of B. garinii and 36% of B. burgdorferi sensu stricto strains. Loss of plasmids occurred as early as between the 5th and 10th passage, affected only plasmids in the range 9-41 kb but not plasmids in the range 50-68 kb and manifested with the loss of one to up to three plasmids.     

Coinfection with Borrelia burgdorferi sensu stricto and Borrelia garinii alters the course of murine Lyme borreliosis

Ixodes ricinus ticks and mice can be infected with both Borrelia burgdorferi sensu stricto and Borrelia garinii. The effect of coinfection with these two Borrelia species on the development of murine Lyme borreliosis is unknown. Therefore, we investigated whether coinfection with the nonarthritogenic B. garinii strain PBi and the arthritogenic B. burgdorferi sensu stricto strain B31 alters murine Lyme borreliosis. Mice simultaneously infected with PBi and B31 showed significantly more paw swelling and arthritis, long-standing spirochetemia, and higher numbers of B31 spirochetes than did mice infected with B31 alone. However, the number of PBi spirochetes was significantly lower in coinfected mice than in mice infected with PBi alone. In conclusion, simultaneous infection with B. garinii and B. burgdorferi sensu stricto results in more severe Lyme borreliosis. Moreover, we suggest that competition of the two Borrelia species within the reservoir host could have led to preferential maintenance, and a rising prevalence, of B. burgdorferi sensu stricto in European I. ricinus populations.     

Prevalence of Borrelia burgdorferi sensu lato and Anaplasmataceae members in Ixodes ricinus ticks in Alsace, a focus of Lyme borreliosis endemicity in France

Due to the high Lyme borreliosis incidence in Alsace, in northeastern France, we investigated in 2003-2004 three cantons in this region in order to determine the density of Ixodes ricinus ticks infected by Borrelia burgdorferi sensu lato and Anaplasmataceae. The peak density of nymphs infected by B. burgdorferi sensu lato at Munster and Guebwiller, where the disease incidence was high, was among the highest reported in Europe (105 and 114 per 100 m(2), respectively). In contrast, the peak density of infected nymphs was low in the canton of Dannemarie (5/100 m(2)), where the disease incidence was low. The two main species detected in ticks were Borrelia afzelii, more frequent in nymphs, and Borrelia garinii, more frequent in adult ticks. The rates of tick infection by Anaplasma phagocytophilum were 0.4% and 1.2% in nymphs and adults, respectively.     

Acylated cholesteryl galactosides are ubiquitous glycolipid antigens among Borrelia burgdorferi sensu lato

Lyme disease (LD) is the most common tick-borne disease in the Northern hemisphere. It is caused by Borrelia burgdorferi sensu lato, in particular, B. burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii. However, other genospecies have been implicated as causative factors of LD as well. Borrelia burgdorferi exhibits numerous immunogenic lipoproteins, but due to strong heterogeneity, the use of these proteins for serodiagnosis and vaccination is hampered. We and others have identified acylated cholesteryl galactosides (ACGal) as a novel glycolipid present in B. burgdorferi sensu stricto, B. afzelii, and B. garinii. ACGal is a strong antigen and the majority of patients display anti-ACGal antibodies in the chronic stages of LD. However, it is unknown whether ACGal is present in other presumably pathogenic B. burgdorferi genospecies. Therefore, we performed an analysis of the total lipid extracts of a wide spectrum of genospecies of B. burgdorferi sensu lato using thin-layer chromatography as well as Western blot and dot-blot assays. We show that ACGal is present in substantial quantities in all B. burgdorferi genospecies tested. Therefore, this molecule might improve the serological detection of rarely pathogenic genospecies, and may be used as a protective vaccine regardless of the prevailing genospecies.     

Habitat-specific diversity of Borrelia burgdorferi sensu lato in Europe,exemplified by data from Latvia

The distribution of Borrelia burgdorferi sensu lato genospecies in questing Ixodes ricinus ticks from ecologically distinct habitats in Latvia was analyzed. A significant variation in the frequency of the genospecies across sites was observed, pointing to the importance of the host community in the ecology of Lyme borreliosis.     

Risk indicators for the tick Ixodes ricinus and Borrelia burgdorferi sensu lato in Sweden

The distributional area of the tick Ixodes ricinus (L.), the primary European vector to humans of Lyme borreliosis spirochaetes (Borrelia burgdorferi sensu lato) and tick‐borne encephalitis virus, appears to be increasing in Sweden. It is therefore important to determine which environmental factors are most useful to assess risk of human exposure to this tick and its associated pathogens. The geographical distribution of I. ricinus in Sweden was analysed with respect to vegetation zones and climate. The northern limit of I. ricinus and B. burgdorferi s.l. in Sweden corresponds roughly to the northern limit of the southern boreal vegetation zone, and is characterized climatically by snow cover for a mean duration of 150 days and a vegetation period averaging 170 days. The zoogeographical distribution of I. ricinus in Sweden can be classified as southerly–central, with the centre of the distribution south of the Limes Norrlandicus. Ixodes ricinus nymphs from 13 localities in different parts of Sweden were examined for the presence of B. burgdorferi s.l. and found to be infected with Borrelia afzelii and Borrelia garinii. Tick sampling localities were characterized on the basis of the density of Borrelia‐infected I. ricinus nymphs, presence of specific mammals, dominant vegetation and climate. Densities of I. ricinus nymphs and Borrelia‐infected nymphs were significantly correlated, and nymphal density can thus serve as a general indicator of risk for exposure to Lyme borreliosis spirochaetes. Analysis of data from this and other studies suggests that high densities of Borrelia‐infected nymphs typically occur in coastal, broadleaf vegetation and in mixed deciduous/spruce vegetation in southern Sweden. Ixodes ricinus populations consistently infected with B. burgdorferi s.l. can occur in: (a) biotopes with shrews, rodents, hares and birds; (b) biotopes with shrews, rodents, hares, deer and birds, and (c) island locations where the varying hare (Lepus timidus) is the only mammalian tick host.     

Erratum to: Seroprevalence of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum in Danish horses

Background  

Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum are able to infect horses. However, the extend to which Danish horses are infected and seroconvert due to these two bacteria is unknown. The aim of the present study was to evaluate the seroprevalence of B. burgdorferi sensu lato and A. phagocytophilum in Danish horses.     

Prevalence of Borrelia burgdorferi sensu lato in ticks collected from migratory birds in Switzerland

The prevalence of ticks infected by Borrelia burgdorferi sensu lato on birds during their migrations was studied in Switzerland. A total of 1,270 birds captured at two sites were examined for tick infestation. Ixodes ricinus was the dominant tick species. Prevalences of tick infestation were 6% and 18.2% for birds migrating northward and southward, respectively. Borrelia valaisiana was the species detected most frequently in ticks, followed by Borrelia garinii and Borrelia lusitaniae. Among birds infested by infected ticks, 23% (6/26) were infested by B. lusitaniae-infected larvae. Migratory birds appear to be reservoir hosts for B. lusitaniae.     

Prevalence of Borrelia burgdorferi sensu lato genospecies in Ixodes ricinus ticks in Europe: a metaanalysis

In Europe, Borrelia burgdorferi genospecies causing Lyme borreliosis are mainly transmitted by the tick Ixodes ricinus. Since its discovery, B. burgdorferi has been the subject of many epidemiological studies to determine its prevalence and the distribution of the different genospecies in ticks. In the current study we systematically reviewed the literature on epidemiological studies of I. ricinus ticks infected with B. burgdorferi sensu lato. A total of 1,186 abstracts in English published from 1984 to 2003 were identified by a PubMed keyword search and from the compiled article references. A multistep filter process was used to select relevant articles; 110 articles from 24 countries contained data on the rates of infection of I. ricinus with Borrelia in Europe (112,579 ticks), and 44 articles from 21 countries included species-specific analyses (3,273 positive ticks). These data were used to evaluate the overall rate of infection of I. ricinus with Borrelia genospecies, regional distributions within Europe, and changes over time, as well as the influence of different detection methods on the infection rate. While the infection rate was significantly higher in adults (18.6%) than in nymphs (10.1%), no effect of detection method, tick gender, or collection period (1986 to 1993 versus 1994 to 2002) was found. The highest rates of infection of I. ricinus were found in countries in central Europe. B. afzelii and B. garinii are the most common Borrelia species, but the distribution of genospecies seems to vary in different regions in Europe. The most frequent coinfection by Borrelia species was found for B. garinii and B. valaisiana.     

Molecular evidence of coinfection of Borrelia burgdorferi sensu lato,human granulocytic ehrlichiosis agent,and Babesia microti in ticks from northwestern Poland

To assess the potential risk for tick-borne agents, Ixodes ricinus were collected from 2 sites in northwestern Poland. The ticks were tested by polymerase chain reaction for coinfection with Borrelia burgdorferi sensu lato (s. l.), human granulocytic ehrlichiosis (HGE) agent, and Babesia microti. Of the 533 processed ticks, 16.7% were positive for B. burgdorferi s. l., 13.3% for B. microti, and 4.5% for the HGE agent. Twenty ticks were coinfected with 2 or 3 of the pathogens.