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1.
Lyme disease is a tick borne zoonotic infection, caused by Borrelia burgdorferi s.l. bacteria. For the transmission of the disease, the presence of ticks is a prerequisite. Lyme borreliosis mostly occurs in people and dogs, but it may occur in other animals. Ticks which carry B. burgdorferi s.l. in Serbia are of the Ixodes ricinus specis. In Serbia, Lyme disease was detected for the first time in the late '80-es. In dogs, clinical symptoms may occur even months after a tick bite, and include weakness, lymphadenopathy, fever, lameness, arthritis, etc. In our survey, we have observed tick and dog populations in the province of Vojvodina (northern part of Serbia). I. ricinus ticks were collected and examined for the presence of B. burgdorferi s.l. in several chosen locations. In addition, blood samples were collected from house dogs and pets from the same locations, and analyzed for the presence of antibodies specific for B. burgdorferi s.l. The results showed a mean infection of ticks of 22.12%, and a mean seroprevalence of Lyme disease in dogs of 25.81%. We conclude that in Vojvodina there is an actual risk of Lyme borreliosis for other animals and humans, because of the persistence of B. burgdorferi s.l. in both tick and dog populations.  相似文献   

2.
Review The ecology of ticks transmitting Lyme borreliosis   总被引:1,自引:1,他引:0  
The main vectors of Borrelia burgdorferi sensu lato, the cause of Lyme borreliosis, are ixodid ticks of the Ixodes persulcatus species complex. These ticks, which occur throughout the northern temperate zone, have very similar life cycles and ecological requirements. All are three-host ticks, with the immature stages mainly parasitizing small to medium-sized mammals and birds and the adult females parasitizing large mammals such as deer, cattle, sheep and hares. The host-seeking stages show a distinct seasonality, which is regulated by diapause mechanisms and there appear to be major differences in this respect between the Old World and New World species. Most cases of human borreliosis are transmitted in the summer by the nymphal stages, with the exception of the Eurasian species, I. persulcatus, in which the adult females are mainly responsible. The ticks acquire the spirochaetes from a wide variety of mammals and birds but large mammals do not seem to be infective, so that t icks that feed almost exclusively on large mammals, for example in some agricultural habitats, are rarely infected. The greatest tick infection prevalences occur in deciduous woodland harbouring a diverse mix of host species and the diversity of the different genospecies of B. burgdorferi s.l. is also greatest in such habitats. There is evidence that these genospecies have different host predilections but, apart from the fact that I. persulcatus does not seem to be infected by B. burgdorferi sensu stricto, they do not seem to be adapted to different tick strains or species. © Rapid Science Ltd. 1998  相似文献   

3.
4.
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.  相似文献   

5.
In order to evaluate the presence of specific IgG antibodies to Borrelia burgdorferi in patients with clinical manifestations associated with Lyme borreliosis in Cali, Colombia, 20 serum samples from patients with dermatologic signs, one cerebrospinal fluid (CSF) sample from a patient with chronic neurologic and arthritic manifestations, and twelve serum samples from individuals without clinical signs associated with Lyme borreliosis were analyzed by IgG Western blot. The results were interpreted following the recommendations of the Centers for Diseases Control and Prevention (CDC) for IgG Western blots. Four samples fulfilled the CDC criteria: two serum specimens from patients with morphea (localized scleroderma), the CSF from the patient with neurologic and arthritic manifestations, and one of the controls. Interpretation of positive serology for Lyme disease in non-endemic countries must be cautious. However these results suggest that the putative "Lyme-like" disease may correlate with positivity on Western blots, thus raising the possibility that a spirochete genospecies distinct from B. burgdorferi sensu stricto, or a Borrelia species other than B. burgdorferi sensu lato is the causative agent. Future work will focus on a survey of the local tick and rodent population for evidence of spirochete species that could be incriminated as the etiologic agent.  相似文献   

6.
The analysis of different multi-host systems suggests that even hosts that are not capable of transmitting Borrelia burgdorferi sensu lato (s.l.) to the tick vector, Ixodes ricinus, or that are secondary reservoirs for these agents contribute to the intensity of transmission and to the overall risk of Lyme borreliosis, through the process of vector augmentation and pathogen amplification. On the other hand, above certain threshold densities, or in the presence of competition with primary reservoir hosts or low attachment rate of ticks to reservoir hosts, incompetent or less competent hosts may reduce transmission through dilution. The transmission of B. burgdorferi s.l. is affected by molecular processes at the tick-host interface including mechanisms for the protection of spirochaetes against the host's immune response. Molecular biology also increasingly provides important identification tools for the study of tick-borne disease agents. Ixodes ricinus and B. burgdorferi s.l. are expanding their geographical range to northern latitudes and to higher altitudes through the effects of climate change on host populations and on tick development, survival and seasonal activity. The integration of quantitative ecology with molecular methodology is central to a better understanding of the factors that determine the main components of Lyme borreliosis eco-epidemiology and should result in more accurate predictions of the effects of climate change on the circulation of pathogens in nature.  相似文献   

7.
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.  相似文献   

8.
Thirty-five strains of the Lyme disease spirochete Borrelia burgdorferi sensu lato (B. burgdorferi s. l.) were isolated from the blacklegged tick vector Ixodes scapularis in South Carolina, Georgia, Florida, and Rhode Island. They were characterized by PCR-restriction fragment length polymorphism (RFLP) analysis of rrf (5S)-rrl (23S) intergenic spacer amplicons. PCR-RFLP analysis indicated that the strains represented at least 3 genospecies (including a possible novel genospecies) and 4 different restriction patterns. Thirty strains belonged to the genospecies B. burgdorferi sensu stricto (B. burgdorferi s. s.), 4 southern strains were identified as B. bissettii, and strain SCCH-5 from South Carolina exhibited MseI and DraI restriction patterns different from those of previously reported genospecies. Complete sequences of rrf-rrl intergenic spacers from 14 southeastern and northeastern strains were determined and the phylogenetic relationships of these strains were compared. The 14 strains clustered into 3 separate lineages on the basis of sequence analysis. These results were confirmed by phylogenetic analysis based on 16S rDNA sequence analysis.  相似文献   

9.
The efficacy of the mitochondrially encoded cytochrome b gene as a molecular marker for the discrimination of the reservoir host species of the Lyme borreliosis spirochete, Borrelia burgdorferi sensu lato (s.l.), in its European vector Ixodes ricinus (Acari: Ixodidae) was determined. Degenerate PCR primers were designed which amplified orthologous regions of the cytochrome b gene in several animal species which act as B. burgdorferi s.l. reservoirs and hosts for I. ricinus. PCR products were amplified and characterized by hybridization and restriction fragment length polymorphism analysis. Restriction fragment length polymorphism analysis of a 638-bp PCR product with HaeIII and DdeI revealed unique restriction fragment profiles, which allowed the taxonomic identification of animals to the genus level. A system was devised for the detection of the larval host blood meal from the remnants in unfed nymphal I. ricinus ticks by nested PCR amplification. An inverse correlation was demonstrated between amplicon size and successful PCR amplification of host DNA from the nymphal stage of the tick. The stability of the cytochrome b product as a marker for the identification of the larval host species in the nymphal instar was demonstrated up to 200 days after larval ingestion (approximately 165 days after molting) by reverse line blotting with a host-specific probe. This assay has the potential for the determination of the reservoir hosts of B. burgdorferi s.l. by using extracts from the same individual ticks for both the identification of the host species and the detection of the Lyme borreliosis spirochete.  相似文献   

10.
The tick Ixodes ricinus is responsible for the transmission and maintenance of a wide variety of pathogenic organisms in the Northern Hemisphere, among which Lyme disease represents a major threat to humans. Despite numerous studies, the epidemiology of the different bacterial species responsible for this disease remains unclear. Recent evidence for a sex-biased genetic structure of its European vector leads us to analyse the consequences of this pattern on Borrelia transmission. Here we show that male and female ticks are not equivalently infected by Borrelia burgdorferi, that Borrelia afzelii affects tick migration capabilities, especially for the most vagile sex (i.e., male) and that Lyme borreliosis agents are consequently vectorised in a much more complex way than usually thought. Such results change the epidemiological perception of Lyme borreliosis and suggest new co-evolutionary pathways between the ticks and the borrelia.  相似文献   

11.
Members of the Borrelia burgdorferi sensu lato (s.l.) species complex are known to cause human Lyme borreliosis. Because of longevity of some reservoir hosts and the Ixodes tick vectors' life cycle, long-term studies are required to better understand species and population dynamics of these bacteria in their natural habitats. Ticks were collected between 1999 and 2010 in three ecologically different habitats in Latvia. We used multilocus sequence typing utilizing eight chromosomally located housekeeping genes to obtain information about species and population fluctuations and/or stability of B. burgdorferi s.l. in these habitats. The average prevalence over all years was 18.9%. From initial high-infection prevalences of 25.5%, 33.1% and 31.8%, from 2002 onwards the infection rates steadily decreased to 7.3%. Borrelia afzelii and Borrelia garinii were the most commonly found genospecies but striking local differences were obvious. In one habitat, a significant shift from rodent-associated to bird-associated Borrelia species was noted whilst in the other habitats, Borrelia species composition was relatively stable over time. Sequence types (STs) showed a random spatial and temporal distribution. These results demonstrated that there are temporal regional changes and extrapolations from one habitat to the next are not possible.  相似文献   

12.
Decorin binding proteins DbpA and DbpB act as Borrelia burgdorferi (B. burgdorferi) adhesins to decorin, and are able to elicit a persistent antibody response in the mouse; accordingly DbpA protein would seem to be promising in immunoprofilaxis of Lyme borreliosis (LB). This study examines the distribution of Dbp epitopes in European strains of B. burgdorferi, of different genospecies and the presence of antibodies to Dbps in human sera from patients suffering from early and late LB, as revealed by immunoblotting. Different levels of expression of Dbp epitopes were found both among and within genospecies; data from human sera indicate that Dbps are expressed during infection though not as strongly as in the mouse infection.  相似文献   

13.
We studied 48 Borrelia isolates that were associated with Lyme borreliosis or were isolated from ticks and identified three DNA relatedness groups by using the S1 nuclease method. The three DNA groups (genospecies) were associated with specific rRNA gene restriction patterns, protein electrophoresis patterns, and patterns of reactivity with murine monoclonal antibodies. Genospecies I corresponded to Borrelia burgdorferi sensu stricto since it contained the type strain of this species (strain ATCC 35210); this genospecies included 28 isolates from Europe and the United States. Genospecies II was named Borrelia garinii sp. nov. and included 13 isolates from Europe and Japan. Genospecies III (group VS461) included seven isolates from Europe and Japan.  相似文献   

14.
Borrelia garinii is one of the three major Borreliae responsible for Lyme borreliosis in Europe. We have characterized a protein of B. garinii (VS102) and a genomic fragment from the gene encoding this protein was cloned. The DNA sequence of the fragment showed high homology with a known gene of B. burgdorferi sensu stricto. The protein encoded by this gene in B. burgdorferi sensu stricto is a phosphocarrier protein (histidine-containing protein). A mutation T to G polymorphism at codon 57 was found to be specific to B. garinii. A PCR-based approach that allows the rapid detection of this mutation made it possible to specifically discriminate B. garinii from other B. burgdorferi genospecies with high sensitivity and specificity.  相似文献   

15.
The distribution of Borrelia burgdorferi sensu lato , the Lyme borreliosis agent, was surveyed in British ticks in the collection of the Natural History Museum, London. Alcohol-preserved specimens of eight species of ticks known to attack humans were studied: Ixodes ricinus , I. hexagonus , I. uriae , I. trianguliceps , Dermacentor reticulatus , Haemaphysalis punctata , Rhipicephalus sanguineus and Argas vespertilionis. The sample comprised all life stages and originated from a wide range of host species, collection dates (1896–1994) and geographical localities in England, Scotland and Wales.
Borrelia burgdorferi s. l. DNA, detected by a polymerase chain reaction that targeted the outer surface protein A gene, was found in all eight species. The overall proportion of PCR-positive specimens ranged from 7.8% for I. hexagonus (mostly from mustelids and hedgehogs) to 98.3% for I. uriae (mostly from seabirds). Borrelia burgdorferi s. l. DNA was found for the first time in the bat parasite A. vespertilionis (85.3%). The spirochaete is newly recorded in British populations of I. trianguliceps (97.4%, mostly from voles, mice and shrews), D. reticulatus (12.5% from dog and man) and R. sanguineus (30% from dogs and human dwellings). Of the four tick species with larvae available for testing, examples of I. ricinus, I. uriae and A. vespertilionis were PCR positive, as were significantly more nymphs than adults of I. ricinus, I. hexagonus and A. vespertilionis. Analyses showed that B. burgdorferi s. l. has been consistently present in British tick populations since at least 1897. Ticks positive for B. burgdorferi s. l. DNA were collected in all months of the year, throughout Britain, and were found on a wide range of mammal and bird species. PCR positivity does not prove vector or reservoir competence, but the use of archived material has demonstrated an extensive range of host–tick relationships involving B. burgdorferi s.l. in Britain for >100 years.  相似文献   

16.
Lyme borreliosis caused by the spirochete Borrelia burgdorferi is now the most common vectorborne disease in North America, Europe and Asia. It is a multisystemic infection which may cause skin, neurological, cardiac or rheumatologic disorders. The aims of the present thesis were: (i) to develop a PCR assay for direct detection of B. burgdorferi DNA and to evaluate the diagnostic utility of PCR in clinical specimens from patients with Lyme borreliosis and (ii) to study the taxonomic classification of B. burgdorferi isolates and its implications for epidemiology and clinical presentation. Laboratory diagnosis of Lyme borreliosis by direct demonstration of B. burgdorferi in clinical specimens would compared to current serology allow (i) optimal specificity, (ii) increased sensitivity during the first weeks of infection, when the antibody response is not yet detectable and (iii) discrimination between ongoing and past infection. Due to the extreme paucity of spirochetes in clinical specimens neither in vitro culture nor antigen detection had yielded a sufficient diagnostic sensitivity. Thus the recently introduced highly sensitive PCR methodology could be a solution and was thus studied. Assays for PCR amplification and subsequent identification of B. burgdorferi specific sequences were established and used. For all assays the analytical sensitivity was a few genome copies using purified DNA as template. The efficacy of PCR was initially evaluated using tissue samples from experimentally infected gerbils in order to start with biological samples a priori known to contain B. burgdorferi. B. burgdorferi DNA was detectable in 88% of the specimens. Thus the diagnostic sensitivity of PCR was comparable to and even higher than in vitro culture. PCR was significantly more sensitive than a histological B. burgdorferi specific immunophosphatase-staining method. The utility of the PCR was then tested for identification of B. burgdorferi DNA in skin biopsies from 31 patients with erythema migrans. The sensitivity of PCR was 71%, which was superior to culture and serology. Based on own and otherwise published results there is clear evidence for PCR being the most sensitive and specific test for detection of B. burgdorferi in skin biopsies from patients with both early and late dermatoborreliosis. However, since the clinical diagnosis of dermatoborreliosis in most instances is easy, an invasive procedure as a skin biopsy, will only be justified in patients with an atypical clinical presentation. The most frequent and serious manifestation of disseminated Lyme borreliosis is neuroborreliosis. PCR was applied to 190 patients with untreated and confirmed neuroborreliosis. B. burgdorferi DNA was detectable in 17-21% of CSF samples from patients with neuroborreliosis. In patients with very early neuroborreliosis (< 2 weeks), still being negative for specific intrathecal antibody synthesis, a positive PCR was more frequent than in patients with longer disease duration. PCR can be used as a diagnostic aid in these patients. However, in general the measurement of specific intrathecal antibody production in patients with neuroborreliosis was superior to PCR. In urine samples from patients with Lyme borreliosis the diagnostic sensitivity varied, generally showing a low reproducibility. Urine is thus not regarded as a suitable sample source for B. burgdorferi PCR. The reason may be the variable presence of Taq polymerase inhibitors. Based on a semi-quantitative detection system for amplicons, reflecting the input amount of specific DNA and thus the density of spirochetes in the clinical samples high amounts of DNA were found in skin biopsies whereas especially in urine the amount of DNA was low. When the present study was initiated there was no accepted classification of B. burgdorferi. A heterogeneity among B. burgdorferi strains might have important implications for understanding the epidemiology and different clinical presentations (dermatoborreliosis versus neuroborreliosis) and courses (self-limiting versus chronic disease). Furthermore, strain differences were of importance for selection of suitable antigens for diagnostic assays and for vaccine development. Since then, B. burgdorferi isolates have been studied by phenotypic and genotypic traits and have been shown to be highly heterogeneous. Our first approach was to genotype a panel of human B. burgdorferi isolates by restriction fragment length polymorphism (RFLP) of three genes. Thereafter, sequencing and dideoxy fingerprinting of ospA was applied. By RFLP the strains could be differentiated into two to five groups. The RFLP classification was compared with four different phenotypic and genotypic methods including the rRNA typing. Results obtained with the different methods correlated highly and confirmed the meanwhile accepted taxonomic classification by Baranton et al., According to this the term B. burgdorferi sensu lato comprises three different human pathogenic genospecies B. burgdorferi sensu stricto, B. garinii and B. afzelii. All three genospecies have been isolated among Danish patients with Lyme borreliosis and are thus prevalent in Denmark. Since isolation of B. burgdorferi from patients with Lyme borreliosis is laborious and often unsuccessful molecular typing methods based on PCR are recommended obviating the need for isolation by prior culture. Of special interest was to study a possible association of neuroborreliosis to certain B. burgdorferi genospecies, indicating species depended organotropism. By RFLP all six CSF isolates tested belonged to B. garinii and that 6 out of 7 isolates from patients with acrodermatitis chronica atrophicans belonged to B. afzelii. Due to the low culture yield of B. burgdorferi from CSF, the association of B. garinii and neuroborreliosis was further studied by sequence analysis and dideoxyfingerprinting analysis of ospA PCR amplicons obtained from CSF samples from patients with neuroborreliosis. Phylogenetic analysis showed that in 11 out of 13 patients B. garinii DNA was found in CSF. These data strongly supports the hypothesis that B. garinii is the principal agent of Lyme neuroborreliosis in Europe. Similarly it was shown that B. afzelii is associated with acrodermatitis chronica atrophicans and thus dermatoborreliosis. Due to a strain dependent different selection pressure in culture only PCR based methods can be used to answer whether mixed infection in patients specimens occur. Our data indicate that mixed infections in humans if ever are rare.  相似文献   

17.
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.  相似文献   

18.
Invasive vertebrate species can act as hosts for endemic pathogens and may alter pathogen community composition and dynamics. For the zoonotic pathogen Borrelia burgdorferi sensu lato, the agent of Lyme borreliosis, recent work shows invasive rodent species can be of high epidemiological importance and may support host-specific strains. This study examined the role of gray squirrels (Sciurus carolinensis) (n = 679), an invasive species in the United Kingdom, as B. burgdorferi sensu lato hosts. We found that gray squirrels were frequently infested with Ixodes ricinus, the main vector of B. burgdorferi sensu lato in the United Kingdom, and 11.9% were infected with B. burgdorferi sensu lato. All four genospecies that occur in the United Kingdom were detected in gray squirrels, and unexpectedly, the bird-associated genospecies Borrelia garinii was most common. The second most frequent infection was with Borrelia afzelii. Genotyping of B. garinii and B. afzelii produced no evidence for strains associated with gray squirrels. Generalized linear mixed models (GLMM) identified tick infestation and date of capture as significant factors associated with B. burgdorferi sensu lato infection in gray squirrels, with infection elevated in early summer in squirrels infested with ticks. Invasive gray squirrels appear to become infected with locally circulating strains of B. burgdorferi sensu lato, and further studies are required to determine their role in community disease dynamics. Our findings highlight the fact that the role of introduced host species in B. burgdorferi sensu lato epidemiology can be highly variable and thus difficult to predict.  相似文献   

19.
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   

20.
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.  相似文献   

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