Hepatitis E Virus Seroprevalence among Blood Donors in Southwest Switzerland

Aim: The aim of this study was to determine the seroprevalence of Hepatitis E virus (HEV) among blood donors in southwest Switzerland.Background: HEV is recognized as a food-borne disease in industrialized countries, transmitted mainly through pork meat. Cases of transmission through blood transfusion have also been reported. Recent studies have revealed seroprevalence rates of 13.5%, 16.6% and 20.6% among blood donors in England, France and Denmark, respectively.Methods: We analyzed 550 consecutive blood donor samples collected in the region of Lausanne, canton of Vaud, Switzerland, for the presence of anti-HEV IgG, using the MP Diagnostics HEV ELISA kit. For each donor, we documented age, sex and alanine aminotransferase (ALT) value.Results: The study panel was composed of 332 men (60.4%) and 218 women (39.6%). Overall, anti-HEV IgG was found in 27 of 550 samples (4.9%). The seroprevalence was 5.4% (18/332) in men and 4.1% (9/218) in women. The presence of anti-HEV IgG was not correlated with age, gender or ALT values. However, we observed a peak in seroprevalence of 5.3% in individuals aged 51 to 70 years old.Conclusions: Compared with other European countries, HEV seroprevalence among blood donors in southwest Switzerland is low. The low seroprevalence may be explained by the sensitivity of commercial tests used and/or the strict regulation of animal and meat imports. Data regarding HEV prevalence in Swiss livestock are lacking and merit exploration

Long-Range Order in the Dipolar XY Antiferromagnet Er2Sn2O7

International audienceEr$_2$Sn$_2$O$_7$ remains a puzzling case among the extensively studied frustrated compounds of the rare-earthpyrochlore family. Indeed, while a first-order transition towards a long-range antiferromagnetic state withthe so-called Palmer-Chalker structure is theoretically predicted, it has not yet been observed, leaving theissue as to whether it is a spin-liquid candidate open. We report on neutron scattering and magnetizationmeasurements which evidence a second-order transition towards this Palmer-Chalker ordered state around108 mK. Extreme care was taken to ensure a proper thermalization of the sample, which has proved to becrucial to successfully observe the magnetic Bragg peaks. At the transition, a gap opens in the excitations,superimposed on a strong quasielastic signal. The exchange parameters, refined from a spin-waveanalysis in applied magnetic field, confirm that Er$_2$Sn$_2$O$_7$ is a realization of the dipolar $XY$ pyrochloreantiferromagnet. The proximity of competing phases and the strong $XY$ anisotropy of the Er$^{3+}$ magneticmoment might be at the origin of enhanced fluctuations, leading to the unexpected nature of the transition,the low ordering temperature, and the observed multiscale dynamics

Recherches épidémiologiques sur la maladie Maedi-Visna. Mise en évidence de foyers confirmés

A preliminary survey of Maedi-Visna disease has been undertaken by serological diagnosis in different flocks of sheeps and goats. Complement fixation, séroneutralisation immunofluorescence tests and eventually histological technics were used. The percentage of positive animals is the highest among flocks exhibiting clinical signs. The existence of Maedi-Visna disease focuses is thus confirmed and this show the practical importance of this affection.Une étude préliminaire destinée à apprécier l’importance de la maladie Maedi-Visna du mouton a été entreprise par dépistage sérologique parmi différents troupeaux ovins et caprins. Les méthodes suivantes ont été employées : fixation du complément, séroneutralisation, immunofluorescence, éventuellement complétées par des examens histologiques. Les résultats font apparaître un pourcentage d’animaux réagissants d'autant plus élevé qu'il existe des signes cliniques dans le troupeau. La mise en évidence de foyers de Maedi-Visna montre l'importance de cette affection.Russo Pierre, Remond Michèle, Sarrazin C., Lasserre Monique, Larenaudie Bertrand, Giauffret A., Marissal Ch., Boutrouille A. Recherches épidémiologiques sur la maladie Maedi-Visna. Mise en évidence de foyers confirmés. In: Bulletin de l'Académie Vétérinaire de France tome 133 n°1, 1980. pp. 129-138

Influence of sample quality on the magnetic properties of URu₂Si₂

The influence of the sample quality on the magnetic properties of the heavy-fermion superconductor URu2Si2 has been studied by neutron scattering, specific heat, electrical resistivity, and magnetic susceptibility measurements. Two single crystals prepared under identical conditions received different heat treatments. One crystal was annealed, the other was used as-grown. While the macroscopic properties and the magnetic excitations are essentially the same for the two crystals, the magnetic Bragg peak intensity have completely different temperature dependences. Despite this, the low-temperature magnetic moment is identical for the two samples, showing that the small moment of 0.023(3) μB is intrinsic. The finite correlation length (∼ 500 Å) appears to be related to defects. We discuss the relevance of itinerant versus localized behavior of the 5f electrons responsible for the magnetism, and the possibility of two successive phase transitions