Molecular characterization of Coxiella burnetii isolates by infrequent restriction site-PCR and MLVA typing

BACKGROUND: Coxiella burnetii, the causative agent of Q fever, has a wide host range. Few epidemiological tools are available, and they are often expensive or not easily standardized across laboratories. In this work, C. burnetii isolates from livestock and ticks were typed using infrequent restriction site-PCR (IRS-PCR) and multiple loci variable number of tandem repeats (VNTR) analysis (MLVA). RESULTS: By applying IRS-PCR, 14 C. burnetii isolates could be divided into six groups containing up to five different isolates. Clustering as deduced from MLVA typing with 17 markers provided an increased resolution with an excellent agreement to IRS-PCR, and with the plasmid type of each strain. MLVA was then applied to 28 additional C. burnetii isolates of different origin and 36 different genotypes were identified among the 42 isolates investigated. The clustering obtained is in agreement with published Multiple Locus Sequence Typing (MLST) data. Two panels of markers are proposed, panel 1 which can be confidently typed on agarose gel at a lower cost and in any laboratory setting (10 minisatellite markers with a repeat unit larger than 9 bp), and panel 2 which comprises 7 microsatellites and provides a higher discriminatory power. CONCLUSION: Our analyses demonstrate that MLVA is a powerful and promising molecular typing tool with a high resolution and of low costs. The consistency of the results with independent methods suggests that MLVA can be applied for epidemiological studies. The resulting data can be queried on a dedicated MLVA genotyping Web service

Multimethod Characterization of the French-Pyrenean Valley of Bagnères-de-Bigorre for Seismic-Hazard Evaluation: Observations and Models

International audienceA narrow rectilinear valley in the French Pyrenees, affected in the past by damaging earthquakes, has been chosen as a test site for soil response characteriza- tion. The main purpose of this initiative was to compare experimental and numerical approaches. A temporary network of 10 stations has been deployed along and across the valley during two years; parallel various experiments have been conducted, in particular ambient noise recording, and seismic profiles with active sources for struc- ture determination at the 10 sites. Classical observables have been measured for site amplification evaluation, such as spectral ratios of horizontal or vertical motions between site and reference stations using direct S waves and S coda, and spectral ratios between horizontal and vertical (H/V) motions at single stations using noise and S-coda records. Vertical shear-velocity profiles at the stations have first been obtained from a joint inversion of Rayleigh wave dispersion curves and ellipticity. They have subsequently been used to model the H/V spectral ratios of noise data from synthetic seismograms, the H/V ratio of S-coda waves based on equipartition theory, and the 3D seismic response of the basin using the spectral element method. General good agreement is found between simulations and observations. The 3D simulation reveals that topography has a much lower contribution to site effects than sedimentary filling, except at the narrow ridge crests. We find clear evidence of a basin edge effect, with an increase of the amplitude of ground motion at some distance from the edge inside the basin and a decrease immediately at the slope foot

Le Noyau terrestre (étude sismologique de quelques structures majeures influençant la dynamique terrestre)

TOULOUSE3-BU Sciences (315552104) / SudocTOULOUSE-Observ. Midi Pyréné (315552299) / SudocSudocFranceF

Anisotropy beneath the Pyrenees Range from teleseismic shear wave splitting: Results from a test experiment

International audienceWe have investigated the seismic anisotropy from SKS and SKKS wave splitting along a N-S profile perpendicular to the Pyrenean mountain belt. The line crossed the North Pyrenean Fault (NPF), which probably represents the plate boundary between the European and the Iberian plates. We observed large delay times δt (1.3 to 1.5 s) and uniform fast polarization directions ϕ (N100E) at three stations located on the Iberian plate. On the other hand, δt are smaller (0.5–1.0 s) and the ϕ scattered at stations located north of the NPF. The small scale variability, the relation with surface geology and the correlation of the δt with lithospheric thickness suggest that the anisotropy could be predominantly of lithospheric origin. However, an asthenospheric contribution cannot be ruled out. In the North Pyrenean Zone, an important thermal event before the Pyrenean compression has likely erased the former mantle fabric. The observed anisotropy is then likely related to the Pyrenean orogeny. On the Iberian plate, our splitting parameters are similar to those obtained at two stations located on Hercynian structures in Central Spain. This suggests that two contributions are likely superposed to that of the Pyrenean built up: one related to the Hercynian orogeny and the other one related to the rotation of the Iberian plate

Carte macrosismique du séisme d'Arette (zone épicentrale)

This macroseismic map shows the different degrees of intensity of the 1967 Arette earthquake in and around the village. With an estimated magnitude of 5.3 on the Richter local scale, the Arette earthquake was the most significant in metropolitan France during the 20th century, after the 1909 earthquake in Provence, and the last one causing major damage and a human toll in the metropolitan area. With a maximum intensity of VIII on the MSK scale in the epicentral zone, it destroys a large part of the nearby village of Arette, and damages several surrounding villages. The tremors are felt throughout southwestern France, as well as in Spain. Despite the violence of the earthquake, the toll is relatively modest, with one dead and a few hundred injured.Cette carte macrosismique établit les différents degrés d'intensité du séisme d'Arette de 1967 dans le village et aux alentours. D'une magnitude estimée à 5,3 sur l'échelle locale de Richter, le séisme d'Arette est le plus important ressenti en France métropolitaine au cours du XXe siècle, après celui de 1909 en Provence, et du dernier séisme ayant occasionné des dégâts importants et un bilan humain sur le territoire métropolitain. D'une intensité maximale de VIII sur l'échelle MSK au niveau de la zone épicentrale, il détruit une grande partie du proche village d'Arette, et endommage plusieurs villages alentours. Les secousses sont ressenties dans tout le Sud-Ouest de la France, ainsi qu'en Espagne. Malgré la violence du séisme, le bilan est relativement modeste et fait état d'un mort et de quelques centaines de blessés