80 resultados para Borrelia


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The different associations of Borrelia burgdorferi sensu lato spirochaetes with their natural reservoir hosts and tick vectors are slowly being unravelled. This review discusses the interactions of different genospecies of Lyme borreliosis spirochaetes and their differing tick vectors, vertebrate reservoirs and 'accidental hosts'. Particular reference is made to spirochaete-host interactions and occurrence of pathological consequences. Attention is focused on the unique prevalence of enzoonotic cycles in operation within the UK. Risk factors for acquiring Lyme borreliosis in man are discussed. (C) 2001 Lippincott Williams & Wilkins.

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We have previously shown that pathogenic leptospiral strains are able to bind C4b binding protein (C4BP). Surface-bound C4BP retains its cofactor activity, indicating that acquisition of this complement regulator may contribute to leptospiral serum resistance. In the present study, the abilities of seven recombinant putative leptospiral outer membrane proteins to interact with C4BP were evaluated. The protein encoded by LIC11947 interacted with this human complement regulator in a dose-dependent manner. The cofactor activity of C4BP bound to immobilized recombinant LIC11947 (rLIC11947) was confirmed by detecting factor I-mediated cleavage of C4b. rLIC11947 was therefore named LcpA (for leptospiral complement regulator-acquiring protein A). LcpA was shown to be an outer membrane protein by using immunoelectron microscopy, cell surface proteolysis, and Triton X-114 fractionation. The gene coding for LcpA is conserved among pathogenic leptospiral strains. This is the first characterization of a Leptospira surface protein that binds to the human complement regulator C4BP in a manner that allows this important regulator to control complement system activation mediated either by the classical pathway or by the lectin pathway. This newly identified protein may play a role in immune evasion by Leptospira spp. and may therefore represent a target for the development of a human vaccine against leptospirosis.

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Leptospirosis is a spirochetal zoonotic disease of global distribution with a high incidence in tropical regions. In the last 15 years it has been recognized as an important emerging infectious disease due to the occurrence of large outbreaks in warm-climate countries and, occasionally, in temperate regions. Pathogenic leptospires efficiently colonize target organs after penetrating the host. Their invasiveness is attributed to the ability to multiply in blood, adhere to host cells, and penetrate into tissues. Therefore, they must be able to evade the innate host defense. The main purpose of the present study was to evaluate how several Leptospira strains evade the protective function of the complement system. The serum resistance of six Leptospira strains was analyzed. We demonstrate that the pathogenic strain isolated from infected hamsters avoids serum bactericidal activity more efficiently than the culture-attenuated or the nonpathogenic Leptospira strains. Moreover, both the alternative and the classical pathways of complement seem to be responsible for the killing of leptospires. Serum-resistant and serum-intermediate strains are able to bind C4BP, whereas the serum-sensitive strain Patoc I is not. Surface-bound C4BP promotes factor I-mediated cleavage of C4b. Accordingly, we found that pathogenic strains displayed reduced deposition of the late complement components C5 to C9 upon exposure to serum. We conclude that binding of C4BP contributes to leptospiral serum resistance against host complement.

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The cellular and molecular characteristics of a cell line (BME26) derived from embryos of the cattle tick Rhipicephalus (Boophilus) microplus were studied. The cells contained glycogen inclusions, numerous mitochondria, and vesicles with heterogeneous electron densities dispersed throughout the cytoplasm. Vesicles contained lipids and sequestered palladium meso-porphyrin (Pd-mP) and rhodamine-hemoglobin, suggesting their involvement in the autophagic and endocytic pathways. The cells phagocytosed yeast and expressed genes encoding the antimicrobial peptides (microplusin and defensin). A cDNA library was made and 898 unique mRNA sequences were obtained. Among them, 556 sequences were not significantly similar to any sequence found in public databases. Annotation using Gene Ontology revealed transcripts related to several different functional classes. We identified transcripts involved in immune response such as ferritin, serine proteases, protease inhibitors,. antimicrobial peptides, heat shock protein, glutathione S-transferase, peroxidase, and NADPH oxidase. BME26 cells transfected with a plasmid carrying a red fluorescent protein reporter gene (DsRed2) transiently expressed DsRed2 for up to 5 weeks. We conclude that BME26 can be used to experimentally analyze diverse biological processes that occur in R. (B.) microplus such as the innate immune response to tick-borne pathogens. (C) 2008 Elsevier Ltd. All rights reserved.

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Blood samples collected from 201 humans, 92 dogs, and 27 horses in the state of Espirito Santo, Brazil, were tested by polymerase chain reaction, indirect immunofluorescence assays, and indirect enzyme-linked immunosorbent assay for tick-borne diseases (rickettsiosis, ehrlichiosis, anaplasmosis, borreliosis, babesiosis). Our results indicated that the surveyed counties are endemic for spotted fever group rickettsiosis because sera from 70 (34.8%) humans, 7 (7.6%) dogs, and 7 (25.9%) horses were reactive to at least one of the six Rickettsia species tested. Although there was evidence of ehrlichiosis (Ehrlichia canis) and babesiosis (Babesia cams vogeli, Theileria equi) in domestic animals, no human was positive for babesiosis and only four individuals were serologically positive for E. canis. Borrelia burgdorferi-serologic reactive sera were rare among humans and horses, but encompassed 51% of the canine samples, suggesting that dogs and their ticks can be part of the epidemiological cycle of the causative agent of the Brazilian zoonosis, named Baggio-Yoshinari Syndrome.

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As borrelioses constituem um grupo de doenças infecciosas causadas por espiroquetas do gênero Borrelia. A borreliose de Lyme, também denominada doença de Lyme, é uma doença infecciosa, não contagiosa, causada por espiroquetas pertencentes ao complexo Borrelia burgdorferi Sensu Lato e transmitida, mais frequentemente, por picada de carrapatos do gênero Ixodes. A doença apresenta quadro clínico variado, podendo desencadear manifestações cutâneas, articulares, neurológicas e cardíacas.

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For many vector-borne organisms, dogs can be used as sentinels to estimate the risk of human infection. The objective of this study was to use dogs as sentinels for multiple vector-borne organisms in order to evaluate the potential for human infection with these agents in southeastern Brazil. Blood from 198 sick dogs with clinicopathological abnormalities consistent with tick-borne infections were selected at the São Paulo State University Veterinary Teaching Hospital in Botucatu and tested for DNA and/or antibodies against specific vector-borne pathogens. At least one organism was detected in 88% of the dogs, and Ehrlichia canis DNA was amplified from 78% of the blood samples. Bartonella spp. seroreactivity was found in 3.6%. Leishmania chagasi antibodies were detected in 1% of the dogs. There was no serological or polymerase chain reaction evidence of infection with Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia chaffeensis, Ehrlichia ewingii, and Rickettsia rickettsii. The full E. canis 16S rRNA gene sequence of one of the Brazilian strains obtained in this study was identical to the causative agent of human ehrlichiosis in Venezuela. Ehrlichia canis may pose a human health hazard and may be undiagnosed in southeastern Brazil, whereas exposure to the other organisms examined in this study is presumably infrequent.

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Ticks on 140 domestic dogs from both urban and rural areas of Franca region in São Paulo state were identified with 102 dogs from urban areas and 38 from rural areas. Of urban dogs, 27.5% were infested exclusively by Rhipicephalus sanguineus ticks. Of the rural dogs, 36.8% were infested with the following tick species: R. sanguineus, Boophilus microplus, Amblyomma ovale and A. cajennense. Mixed infestations included a dog hosting A. cajennense and A. ovale and another with B. microplus and R. sanguineus. The most intense infestations were detected on urban dogs. Hemolymph tests of these ticks performed to detect rickettsial or Borrelia bacteria yielded negative results.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Lyme disease (LD) is a systemic inflammatory changes resulting from the direct action of the spirochete Borrelia burgdorferi on the host or indirect damage produced by immune response to this microorganism. This pathogen is transmitted by inoculation in the bloodstream by the tick genus Ixodes and is most commonly found in North America, Europe and Asia. In these regions, the dental community is aware about its commonest clinical symptoms, collaborating with the establishment of a diagnosis. However, in Brazil, the frequent facial or peripheral neurological manifestations, among them the Bell's palsy, ocular disorders, disorders in the temporomandibular joint, as well as paresthesia of upper and lower alveolar nerves are observed. In our country, the diagnosis of Lyme disease is primarily based on clinical symptomatology, but most of cases remain without diagnosis and treatment. Then, the detection of the early manifestations of Lyme disease by health professionals is essential for the proper antibiotic treatment, preventing the progression of the disease, and allowing the establishment of favorable prognostic.

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Lyme disease (LD) is a systemic infl ammatory changes resulting from direct action and the immune response to the spirochete Borrelia burgdoferi transmitted by inoculation of the fl ow of the genus Ixodes tick and is most commonly found in North America, Europe and Asia. This disease can lead to facial and peripheral neurological manifestations, such as Bell’s palsy, eye changes, disorders in the temporo-mandibular joint in addition to paresthesia of superior and inferior alveolar nerves. In Brazil, the diagnosis of LD is primarily based on clinical presentation, the erythema migrans skin, and epidemiological information of the patient. Recognition of the onset of the DL by health professionals is essential for the correct antibiotic treatment preventing the progression of the disease, and also relevant preventive guidelines for those living or working in endemic areas.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Tick-borne relapsing fever in western North America is a zoonosis caused by spirochetes in the genus Borrelia that are transmitted by argasid ticks of the genus Ornithodoros (1). Human disease occurs in many focal areas and is associated with infections of Borrelia hermsii, B. turicatae, and possibly B. parkeri (2,3). Although the ecologic parameters that maintain B. hermsii and B. turicatae differ, human infections usually occur in rustic cabins (B. hermsii) and caves (B. turicatae) inhabited by ticks and their terrestrial vertebrate hosts (1). Recently, Gill et al. (4) provided evidence that the argasid bat tick, Carios kelleyi, feeds upon humans. Subsequently, Loftis et al. (5) used PCR analysis and DNA sequencing to detect in C. kelleyi an unidentifi ed Borrelia species that was closely related to B. turicatae and B. parkeri.

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National Veterinary Services Laboratories in Ames, Iowa, confirmed vesicular stomatitis (VS) in horses at one premises in Texas. As of July 21, 2004, infected animals were identified on a total of 45 premises in Colorado (11), New Mexico (21), and Texas (13). These are the first reports of VS in livestock in the United States since the 1998 epizootic. SCWDS VS Studies Chronic Wasting Disease Developments: nearly 118,000 wild white-tailed deer, mule deer, and elk were tested in the United States from October 2002 to September 2003, with 592 animals testing positive for the CWD prion. More than $38,000,000 was spent by federal and state wildlife and animal health agencies on CWD-related activities during this same period. The Second International Chronic Wasting Disease Symposium, hosted by the Wisconsin Department of Natural Resources, will be held in Madison, Wisconsin, July 12-14, 2005. Crow Decoys Used in West Nile Virus Study Although Lyme disease caused by a spirochete bacterium, Borrelia burgdorferi, is relatively rare in the southeastern United States, a Lyme disease-like infection referred to as Southern Tick-Associated Rash Illness (STARI) and thought to be caused by Borrelia lonestari, has been recognized in people in this region. The Ohio Division of Wildlife joined SCWDS as an associate member beginning July 1, 2004. The Final Report of the 2003 Hemorrhagic Disease (HD) Surveillance project has been completed and distributed to all cooperators. New of Caroline Duffie, Robbie Edalgo and wife Jen, Clay George, Darrell Kavanaugh, Lynn Lewis-Weiss’s husband, Dr. Kevin Weiss, and Nate Mechlin. New SCWDS staff include Brian Chandler, Jay Cumbee, Ginger Goekjian, Bill Hamrick, Sabrina McGraw, Kerri Pedersen, and Ben Wilcox. Recent SCWDS Publications Available

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LigB is an adhesin from pathogenic Leptospira that is able to bind to extracellular matrix and is considered a virulence factor. A shotgun phage display genomic library was constructed and used for panning against Heparan Sulfate Proteoglycan (HSPG). A phage clone encoding part of LigB protein was selected in panning experiments and showed specific binding to heparin. To validate the selected clone, fragments of LigB were produced as recombinant proteins and showed affinity to heparin and to mammalian cells. Heparin was also able to reduce the binding of rLB-Ct to mammalian cells. Our data suggests that the glycosaminoglycan moiety of the HSPG is responsible for its binding and could mediate the attachment of the recombinant protein rLB-Ct. Thus, heparin may act as a receptor for Leptospira to colonize and to invade the host tissue. (C) 2012 Elsevier Inc. All rights reserved.