Isolation of Lyme disease Borrelia from puffins (Fratercula arctica) and seabird ticks (Ixodes uriae) on the Faeroe Islands.
This is the first report on the isolation of Lyme disease Borrelia from seabirds on the Faeroe Islands and the characteristics of its enzootic cycle. The major components of the Borrelia cycle include the puffin (Fratercula arctica) as the reservoir and Ixodes uriae as the vector. The importance of this cycle and its impact on the spread of human Lyme borreliosis have not yet been established. Borrelia spirochetes isolated from 2 of 102 sampled puffins were compared to the borreliae previously obtained from seabird ticks, I. uriae. The rrf-rrl intergenic spacer and the rrs and the ospC genes were sequenced and a series of phylogenetic trees were constructed. Sequence data and restriction fragment length polymorphism analysis grouped the strains together with Borrelia garinii. In a seroepidemiological survey performed with residents involved in puffin hunting on the Faeroe Islands, 3 of 81 serum samples were found to be positive by two commonly used clinical tests: a flagellin-based enzyme-linked immunosorbent assay (ELISA) and Western blotting. These three positive serum samples also had high optical density values in a whole-cell ELISA. The finding of seropositive Faeroe Islanders who are regularly exposed to I. uriae indicate that there may be a transfer of B. garinii by this tick species to humans. (+info)
Specific antibodies reactive with the 22-kilodalton major outer surface protein of Borrelia anserina Ni-NL protect chicks from infection.
An outer surface lipoprotein of 22 kDa was identified in the avian pathogen Borrelia anserina Ni-NL by using antibody preparations reactive with bacterial surface-exposed proteins. Amino acid sequence analysis of the 22-kDa protein demonstrated 90% identity with VmpA of B. turicatae, suggesting that the protein belongs to the family of 20-kDa outer surface proteins of the genus Borrelia. All of the 60 chicks intramuscularly treated with antibodies specifically reacting with the 22-kDa protein and infected with strain Ni-NL were completely protected from infection, since no spirochetemia was detected, and from death. Control chicks were treated with immune sera raised against apathogenic strain B. anserina Es, which expresses a prominent 20-kDa polypeptide that is also a member of the Vmp family but does not cross-react immunologically with the 22-kDa protein of the Ni-NL strain. These animals, infected with B. anserina Ni-NL, showed a high degree of spirochetemia 10 days after infection, and all died between 14 and 21 days after infection. The results showed that the 22-kDa surface protein of B. anserina Ni-NL is a determinant of the pathogenic potential of the strain and also confirmed that only strain-specific antibodies are protective against B. anserina infection. (+info)
Tick-borne relapsing fever imported from West Africa: diagnosis by quantitative buffy coat analysis and in vitro culture of Borrelia crocidurae.
West African tick-borne relapsing fever (TBRF) is difficult to diagnose due to the low number of spirochetes in the bloodstream of patients. Previously, the causative microorganism, Borrelia crocidurae, had never been cultured in vitro. TBRF was rapidly diagnosed for two patients returning from western Africa with fever of unknown origin by quantitative buffy coat (QBC) analysis. Diagnosis was confirmed by intraperitoneal inoculation of blood specimens from patients into laboratory mice. In vitro experiments showed that QBC analysis may be as much as 100-fold more sensitive than thick smear. Spirochetes were also cultured from blood samples from both patients in modified Kelly's medium and were identified as B. crocidurae by partial sequencing of the PCR-amplified rrs gene. (+info)
Short report: Diagnosis of tick-borne relapsing fever by the quantitative buffy coat fluorescence method.
The quantitative buffy coat (QBC) parasite detection method is a sensitive and specific tool for the diagnosis of malaria parasites. It is also useful for the diagnoses of other hemoparasites, including Trypanosoma, Babesia, and Leptospira. We report a case of relapsing fever diagnosed by this technique in a short-term traveler from Senegal. The diagnosis was confirmed by the standard Giemsa hemoscopy and by the identification of significant titers of antibodies to Borrelia spp. of tick-borne relapsing fevers by specific immunofluorescence and Western blot tests. The QBC technique seems to be useful in the diagnosis of tick-borne relapsing fever in blood samples and should be included in the management of fever in the traveler returning from tropical regions. (+info)
Comparative analysis and immunological characterization of the Borrelia Bdr protein family.
Multiple circular and linear plasmids of Lyme disease and relapsing fever Borrelia spirochetes carry genes for members of the Bdr (Borrelia direct repeat) protein family. To define their common and divergent attributes, we first comprehensively compared the known homologs. Bdr proteins with predicted sizes ranging from 10.7 to 30. 6 kDa formed five homology groups, based on variable numbers of short direct repeats in a central domain and diverse N- and C-terminal domains. In a further characterization, Western blots were probed with rabbit antisera raised against either of two purified recombinant Bdr proteins from Borrelia burgdorferi B31. The results showed that antibodies cross-react and several Bdr paralogs 19.5 to 30.5 kDa in size are expressed by cultured strain B31 in a temperature-independent manner. In situ proteolysis, immunofluorescence, and growth inhibition assays indicated that Bdr proteins are not surface exposed. Distinct patterns of cross-reacting proteins of 17.5 to 33 kDa were also detected in other B. burgdorferi, Borrelia garinii, and Borrelia afzelii strains as well as in relapsing fever spirochetes Borrelia hermsii and Borrelia turicatae. Last, we examined whether these proteins are antibody targets during Lyme disease. Analysis of 47 Lyme disease patient sera by immunoblotting and enzyme-linked immunosorbent assays showed that 24 (51%) and 20 (43%), respectively, had detectable antibodies to one or more of the Bdr proteins. Together, these data indicate that Bdr proteins constitute a family of cross-reactive Borrelia proteins which are expressed in the course of Lyme disease and in vitro. (+info)
Identification of a novel strain of Borrelia hermsii in a previously undescribed northern California focus.
An epizootiologic investigation testing for the presence of tick-borne relapsing fever spirochetes in rodent and tick hosts was conducted at Eagle Lake in Lassen County, California. Six of 211 O. hermsii ticks and none of 180 rodents were polymerase chain reaction (PCR)-positive for Borrelia spirochetes. Sequencing of the PCR-amplified flagellin gene fragment suggests that the spirochetes from Eagle Lake represent a previously undescribed strain of Borrelia hermsii. (+info)
Characterization of VspB of Borrelia turicatae, a major outer membrane protein expressed in blood and tissues of mice.
Serotypes A and B of the relapsing fever spirochete Borrelia turicatae produce different disease manifestations in infected mice. Whereas serotype B causes more severe arthritis and reaches higher densities in the blood of mice than serotype A, serotype A invades the central nervous system earlier than serotype B during infection. These differences between serotypes A and B in mice are associated with the expression of different surface proteins, VspA and VspB, respectively, in the culture medium. To determine whether these proteins, in particular, VspB, are also expressed in vivo, scid mice infected with B. turicatae were studied. The expression of VspB by spirochetes in the blood was demonstrated in Coomassie blue-stained polyacrylamide gels and Western blots with a specific monoclonal antibody. Indirect immunofluorescence and immunoperoxidase studies confirmed the expression of VspB in the blood and also demonstrated VspB expression in the joints and heart. The gene for VspB was next identified and cloned by using partial amino acid sequencing, reverse transcriptase PCR, and a specific monoclonal antibody. The vspB gene encodes a protein of 216 amino acids that is 68% identical to VspA of B. turicatae and 44 to 56% identical to representative Vsp and OspC lipoproteins of other Borrelia spp. The processed VspB protein was distinguished from 26 other Vsp and OspC proteins by a high predicted isoelectric point at 9.39. The promoter region for vspB was similar to the promoter region for the vsp33 gene of Borrelia hermsii and for the ospC gene of Borrelia burgdorferi, two genes known to be environmentally regulated. These studies established that the virulence-associated VspB protein is expressed by spirochetes in the mouse and that VspB is a novel member of the Vsp-OspC family of proteins. (+info)
Toward the development of antibacterial vaccines: report of a symposium and workshop. Organizing Committee.
On 26 and 27 October 1998, the Department of Medicine at the University of California, San Francisco (UCSF), hosted a symposium and workshop on bacterial vaccines. The symposium featured invited speakers who are internationally recognized authorities in their fields and who discussed selected topics related to specific pathogens or specific principles of bacterial vaccine development. The workshop, held on the day following the symposium, brought together the invited speakers and members of the organizing committee, who came from UCSF and the University of California, Berkeley, to discuss 4 specific topics and to define priorities for future vaccine development. Considerable knowledge has been gained from successful and unsuccessful vaccine development efforts, and large gains in knowledge relevant to vaccine development have resulted from studies of basic immunology and microbial pathogenesis. This report summarizes the presentations at the symposium and the discussions of the workshop sessions. (+info)