Evolutionary history of hepatitis C virus genotype 5a in France, a multicenter ANRS study

The epidemic history of HCV genotype 5a is poorly documented in France, where its prevalence is very low, except in a small central area, where it accounts for 14.2% of chronic hepatitis C cases. A Bayesian coalescent phylogenetic investigation based on the E1 envelope gene and a non-structural genomic segment (NS3/4) was carried out to trace the origin of this epidemic using a large sample of genotype 5a isolates collected throughout France. The dates of documented transmissions by blood transfusion were used to calibrate five nodes in the phylogeny. The results of the E1 gene analysis showed that the best-fitting population dynamic model was the expansion growth model under a relaxed molecular clock. The rate of nucleotide substitutions and time to the most recent common ancestors (tMRCA) of genotype 5a isolates were estimated. The divergence of all the French HCV genotype 5a strains included in this study was dated to 1939 [95% HPD: 1921–1956], and the tMRCA of isolates from central France was dated to 1954 [1942–1967], which is in agreement with epidemiological data. NS3/4 analysis provided similar estimates with strongly overlapping HPD values. Phylodynamic analyses give a plausible reconstruction of the evolutionary history of HCV genotype 5a in France, suggesting the concomitant roles of transfusion, iatrogenic route and intra-familial transmission in viral diffusion

Autoantibodies against type I IFNs in patients with critical influenza pneumonia

In an international cohort of 279 patients with hypoxemic influenza pneumonia, we identified 13 patients (4.6%) with autoantibodies neutralizing IFN-alpha and/or -omega, which were previously reported to underlie 15% cases of life-threatening COVID-19 pneumonia and one third of severe adverse reactions to live-attenuated yellow fever vaccine. Autoantibodies neutralizing type I interferons (IFNs) can underlie critical COVID-19 pneumonia and yellow fever vaccine disease. We report here on 13 patients harboring autoantibodies neutralizing IFN-alpha 2 alone (five patients) or with IFN-omega (eight patients) from a cohort of 279 patients (4.7%) aged 6-73 yr with critical influenza pneumonia. Nine and four patients had antibodies neutralizing high and low concentrations, respectively, of IFN-alpha 2, and six and two patients had antibodies neutralizing high and low concentrations, respectively, of IFN-omega. The patients' autoantibodies increased influenza A virus replication in both A549 cells and reconstituted human airway epithelia. The prevalence of these antibodies was significantly higher than that in the general population for patients 70 yr of age (3.1 vs. 4.4%, P = 0.68). The risk of critical influenza was highest in patients with antibodies neutralizing high concentrations of both IFN-alpha 2 and IFN-omega (OR = 11.7, P = 1.3 x 10(-5)), especially those <70 yr old (OR = 139.9, P = 3.1 x 10(-10)). We also identified 10 patients in additional influenza patient cohorts. Autoantibodies neutralizing type I IFNs account for similar to 5% of cases of life-threatening influenza pneumonia in patients <70 yr old

ÉTUDE PAR MICROSCOPIE ÉLECTRONIQUE EN TRANSMISSION DE DÉFAUTS CRÉÉS PAR IMPLANTATION IONIQUE DANS DU SILICIUM < III >

Des échantillons de silicium ont subi soit une implantation phosphore (30 keV, 1016 at/cm2) soit des implantations arsenic (50 à 140 keV, dose de l'ordre de 1015 at/cm2). Dans le cas du phosphore, on observe en microscopie électronique une couche amorphe qui recristallise en épitaxie sur le substrat à 650 °C. Au cours de recuits à plus haute température, la formation et l'évolution de défauts tels que boucles de dislocations et dipôles ont été observées. Dans le cas de l'arsenic, la recristallisation de la couche amorphe s'accompagne d'une formation de micromacles et de défauts divers (boucles, défauts linéaires, ...).Silicon specimens have been implanted either with phosphorous ions (30 keV, 1016 at/cm2) or with arsenic ions (energies between 30 and 140 keV, doses in the order of 1015 at/cm2). In the case of phosphorous implantation, an amorphous layer has been observed using electron microscopy. The epitaxial recrystallization of this layer occurs at 650 °C. During annealing at higher temperatures, the formation and evolution of defects such as dislocation loops and dipoles have been observed. In the case of arsenic implantations, the formation of defects such as microtwins, loops, linear defects... takes place during the recrystallization of the amorphous layer

CARACTERISATION OPTIQUE DE DIFFERENTS TYPES DE NEIGE. EXTINCTION DE LA LUMIERE DANS LA NEIGE

La complexité des particules qui constituent le matériau neige ne permet pas un calcul rigoureux de ses paramètres optiques pour lesquels il est donc nécessaire de recourir à l'expérience. L'extinction de la lumière a été mesurée pour différents types de neige, dont le givre de profondeur, et pour des bandes spectrales allant du visible au proche infra-rouge. Les données expérimentales montrent une nette dépendance envers la taille des cristaux (D) en D-½ et révèlent l'effet de la pollution.The complex ice texture of the snow medium unables an exact calculation of its optical parameters, thus making measurements necessary. Flux extinction has been measured for various snow types, among which depth hoar, and for near infra-red and visible wavelengths. The data collected are strongly depending on grain size (D) as D-½ and on impurity content

Survey of delivery of prophylactic immunoglobulins following exposure to a measles case

In France, almost 23,000 cases of measles and 10 deaths have been reported between January 2008 and August 2012. French health authorities recommend delivery of human polyvalent immunoglobulins in the event of exposure to a measles case for some categories of unvaccinated persons (children under the age of 12 months, immunocompromised persons and pregnant women), within six days after exposure and following laboratory confirmation of the contact case. We carried out a postal survey among 368 French hospital pharmacies to evaluate the number of persons affected by this measure between 1 January 2010 and 31 August 2011, to describe the characteristics of these patients and to evaluate the application of the recommendations in terms of delay between exposure and immunoglobulin delivery, and confirmation of the contact case. The response rate to the survey was 73%. In total, 400 immunoglobulin deliveries were listed, most of them for children under the age of one year, and 84% of the 250 administrations with available information occurred within six days after exposure, as recommended. However, only 48% of the 209 treated contacts with available information were laboratory-confirmed when the immunoglobulins were delivered. This survey is the first evaluation of this recommendation since its introduction in 2005 and suggests that the recommendations may need to be updated. </jats:p