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G Baranton

Publications and source records attributed to G Baranton.

85 records · Page 5Linked to original sources
PubMed1989

Cross-reaction with Borrelia burgdorferi antigen of sera from patients with human immunodeficiency virus infection, syphilis, and leptospirosis.

We have studied the cross-reaction with Borrelia burgdorferi of sera positive for leptospirosis, syphilis, or human immunodeficiency virus by using the microimmunofluorescence test (micro-IF). The percentage of sera reactive in the micro-IF before absorption varied from 7 to 37% and was reduced to 3 to 8% after absorption with a commercial Reiter treponemal antigen. The cross-reaction of sera positive for syphilis or human immunodeficiency virus was distinguished from the homologous reaction with sera from patients with Lyme disease in the immunoblot test results. However, the cross-reaction could not always be distinguished from the homologous reaction with sera from patients with leptospirosis whose sera scored positive in the micro-IF for B. burgdorferi.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Human leptospirosis in Reunion Island. A 3-year epidemiological study (1985-1987)].

During a three-year period (1985-1987), in Reunion Island, 252 cases of leptospirosis were clinically diagnosed in humans, and serologically confirmed. The epidemiological study showed a significant male predominance, presence during all ages of life; no month and no geographical zone are spared but maximal incidences are noted during periods of and in localities with the most important rainfall. Severe forms are frequent but mortality remains low.

Adolescent↗
PubMedDate not supplied

First isolation of bacteriophages for a spirochaete: potential genetic tools for Leptospira.

Three bacteriophages of the saprophytic aquicole bacterium Leptospira biflexa were isolated from sewage waters from the outskirts of Paris, France. These phages do not infect representative strains of the pathogenic species Leptospira interrogans, and their host range is restricted to serovar patoc of the saprophytic species. The phages were found to be lytic and no lysogenic state could be demonstrated. Electron micrographs showed that the phages were morphologically identical and had polyhedral heads and contractile tails. Their genomes were sensitive to restriction enzymes and consisted of double-stranded DNA. Pulsed-field agarose gel electrophoresis indicated that their genomes were linear: 60 kb for LE1 and 50 kb for LE3 and LE4.

Bacteriophages↗
PubMedDate not supplied

Polymerase chain reaction with the 30-kb circular plasmid of Borrelia burgdorferi B31 as a target for detection of the Lyme borreliosis agents in cerebrospinal fluid.

The polymerase chain reaction (PCR) was developed for use in the detection of Borrelia burgdorferi sensu lato, the Lyme disease agent. A 333-bp fragment of the 30-kbp circular plasmid from Borrelia burgdorferi B31 was amplified and PCR products were analysed by DNA-DNA hybridization. Sensitivity was enhanced by addition of a carrier to the samples before treatment and enabled detection of as few as 1 to 10 bacteria. Specific products were obtained only with the Lyme disease agents, but not with other spirochetes or unrelated bacteria. B. burgdorferi sensu lato was detected in cerebrospinal fluid (CSF) from 11 out of 45 patients with confirmed Lyme neuroborreliosis. In a prospective study, 20 out of 315 CSF samples from potential patients were PCR-positive. Forty uninfected patients were PCR-negative.

Base Sequence↗
PubMedDate not supplied

A new genomic species in Borrelia burgdorferi sensu lato isolated from Japanese ticks.

Five Borrelia strains (Ika2, HO14, Cow611C, 0612 and F63B) isolated from Ixodes ovatus ticks in Japan were analysed by DNA-DNA hybridization experiments, ribotyping, pulsed-field gel electrophoresis and protein electrophoresis. DNA relatedness set these strains in a new genomic species within the Borrelia burgdorferi complex; this species appears to be restricted to Japan and could be non-pathogenic for humans. The ribotype and pulsotype of strain Ika2 were atypical of the new genomic species.

Animals↗
PubMedDate not supplied

Human leptospirosis in the Mekong delta, Viet Nam.

To estimate the seroprevalence of human leptospirosis in the Mekong delta in Viet Nam, an epidemiological survey was conducted in the province of Tien Giang, which is representative of the socioeconomic activities of the region (rice growing and cattle breeding). A cross-sectional study included 35 clusters representing 1400 people randomly selected and aged 15-60 years. Sex, age, occupation, contact with animals, type of water supply, and individual habits were recorded. Leptospiral agglutinins were detected by the microagglutination test, with a battery of 22 live antigens representing the main pathogenic serogroups of Leptospira species and additional local strains. 263 sera (18.8%) gave positive results and 41 (2.9%) had a titre of agglutinins > or = 400, suggesting recent infection. No significant difference was found between females and males. The distribution of seroprevalence was homogeneous throughout the population studied, with the exception of the 15-25 years age group, in which leptospiral antibodies were less frequent. Fifteen serogroups were found, the most prevalent being Bataviae (21.7%), Panama (15.2%), Icterohaemorrhagiae (13.7%) and Australis (8.7%). No significant link between leptospiral seropositivity and professional activities or contacts with animals was found, indicating that leptospirosis in the Mekong delta may be considered as an environmentally linked disease. Leptospirosis is known to be endemic in south-east Asia, and these data demonstrated the high level of circulation of leptospires and the potential importance of leptospiral infections among the rural population in this area.

Adolescent↗
PubMedDate not supplied

Antigenic variation of Borrelia turicatae Vsp surface lipoproteins occurs in vitro and generates novel serotypes.

As a means of avoiding the host immune response, the tick-borne relapsing fever spirochete Borrelia turicatae undergoes antigenic variation in its abundant surface lipoproteins. In this study, B. turicatae strain Oz1, serotype B, was subcultured in vitro and cloned by limited dilutions after 50 passages. Four different serotypes (serotypes A, B, E, and F) differing by their expressed Vsp lipoproteins were isolated. Using pulsed-field gel electrophoresis, we showed that the variability in surface-exposed proteins is correlated with rearrangement between different linear plasmids, defining serotype-specific plasmid profiles. Moreover, we determined the nucleotide sequence of genes encoding the VspE and VspF lipoproteins, corresponding to the two novel serotypes E and F, respectively. Our results showed that antigenic variation in B. turicatae occurs spontaneously in vitro, in the absence of immune selection.

Antigenic Variation↗
PubMedDate not supplied

[The isolation of Borrelia from the tick Ixodes trianguliceps (Ixodidae) and the possible significance of this species in the epizootiology of ixodid tick-borne borrelioses].

Ixodes trianguliceps is a common tick species of the Eurasian forest zone. These ticks live probably in natural foci of ixodid tick-borne borrelioses (ITBB) from Western Europe to Transbaikalia, but their role in circulation of corresponding pathogens remains unclear. This study was performed in a natural ITBB focus located in the Perm region of Russia (near the Urals), where Borrelia garinii and B. afzelii circulate and I. persulcatus serves as their main vector. In July-August of 1994, 296 small mammals (mostly Clethrionomys glareolus) were tested for tick infestation. From these mammals, 49 I. trianguliceps and 252 I. persulcatus ticks were collected (16.3 and 83.7%, respectively). I. trianguliceps ticks were found on 33 rodents of three species: Cl. glareolus, Cl. rutilus, and Microtus oeconomus. The abundance of I. trianguliceps (on average, less than 0.2 ticks per animal) was approximately five times lower than that of I. persulcatus. I. trianguliceps larvae, nymphs, and adults (22, 15, and 5 specimens, respectively) were analyzed for Borrelia infection by plating their internal organs on the BSK-2 medium. Spirochete isolates were obtained from four nymphs. Three infected nymphs were collected from different Cl. glareolus specimens, and one was found on Cl. rutilus. According to the results of RFLP analysis, all four isolates were classified as B. garinii. This experiment is the first successful attempt to isolate one of ITBB pathogens from I. trianguliceps ticks. These ticks do not attack people, and their role in ITBB foci should be analyzed only in terms of epizootiology. The results of previous zoological-parasitological and bacteriological studies performed in the Ural region suggest that I. trianguliceps and I. persulcatus populations are maintained there by the same species of small rodents and insectivores, which mostly belong to the genera. Clethrionomys and Sorex. Many of them were identified as the reservoir hosts of Borrelia. These data, in complex with the fact of B. garinii isolation from I. trianguliceps, suggest that I. trianguliceps ticks are involved in the maintenance of Borrelia circulation in natural ITBB foci. Taking into account the low abundance of these ticks in the Ural forests, they should be regarded as an important but not principal component of the epizootic process. It is suggested that such a conclusion about the significance of I. trianguliceps ticks also pertains to ITBB foci of other regions.

Animals↗
PubMedDate not supplied

[The reservoir hosts and vectors of Borrelia--the causative organisms of ixodid tick-borne borrelioses in Russia].

327 Borrelia isolates from ixodid ticks of 3 species from 12 major administrative territories of Russia (from Leningrad Province in the west to Sakhalin Province in the east), as well as from forest myomorph rodents of 6 species and from skin biopsies of borreliosis patents, were identified by the PRC and RFLP methods. B. afzelii, B. garinii and B. garinii NT29 were shown to be widespread in Russia. No other Borrelia genospecies were found. The main vectors of B. afzelii and B. garinii were ixodid ticks Ixodes persulcatus and I.ricinus and their main reservoir hosts were forest myomorph rodents. In natural foci Borrelia mixed infection was observed among reservoir hosts and vectors. This determines the possibility and considerable probability of human infection caused by several Borrelia genospecies simultaneously.

Animals↗