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We report on the photon energy dependence of the K-shell double photoionization (DPI) of Mg, Al, and Si. The DPI cross sections were derived from high-resolution measurements of x-ray spectra following the radiative decay of the K-shell double vacancy states. Our data evince the relative importance of the final-state electron-electron interaction to the DPI. By comparing the double-to-single K-shell photoionization cross-section ratios for neutral atoms with convergent close-coupling calculations for He-like ions, the effect of outer shell electrons on the K-shell DPI process is assessed. Universal scaling of the DPI cross sections with the effective nuclear charge for neutral atoms is revealed.

The Camargue area of southern France experienced the re-emergence of West Nile Virus (WNV) in the late summer of 2000 and 2004. Immediately preceding the 2004 outbreak, samples were collected from 432 birds of 32 different species captured in mist nets and from 201 Cattle Egret (Bubulcus ibis) nestlings sampled in their nests between 1 April and 12 June 2004. West Nile virus neutralizing titers of >/=40 were detected in 4.8% (95% confidence limit, 2.9-7.5%) of the adult birds and in 1.6% (0.3-4.6%) of the egret nestlings. Migratory passerines had a higher prevalence of WNV neutralizing antibodies (7.0%) than did resident and short-distance migratory passerines (0.8%), suggesting exposure to WNV or a related flavivirus during overwintering in Africa.

Wild aquatic birds are considered to be the natural reservoir for influenza A viruses, and previous studies have focused mainly on species in the orders Anseriformes and Charadriiformes. In this study, we surveyed a larger spectrum of potential hosts belonging to 10 avian orders. Cloacal swabs (n=1,044) from 72 free-living bird species, were analysed by reverse transcription-polymerase chain reaction for the presence of avian influenza virus. Only two Mediterranean Gulls (Larus melanocephalus) tested positive; one of these viruses was identified as an H9N2 subtype. The absence of infection among passerine birds supports the idea that the prevalence of avian influenza virus infection in terrestrial species is low.

During fall 2005, the rapid and wide spread of highly pathogenic (HP) H5N1 avian influenza viruses (AIV) outside Asia alerted European health authorities. Because of abnormal and recurrent field mortality, wild migratory birds were considered to be the main dispersing agent of the virus at an intercontinental scale. European wintering wetlands, such as the Camargue (Rhône delta, France), are identified as potential hot spots for the risk of introduction and transmission of bird-borne diseases. In this study, we investigated the role of migratory waterbirds (mainly ducks) in the spread of HP H5N1 viruses. We combined molecular analysis of living and freshly killed birds with population surveillance (aerial censuses and death surveillance). We sampled 1345 birds belonging to 17 waterbird species (3 orders) in the Camargue between September 2005 and March 2006. The prevalence of AIV was 1.8%. We did not detect HP H5N1 virus. Population censuses did not reveal any population decreases nor abnormal mortalities. We discuss, in the light of these results, the implication of wild migratory ducks in the arrival of HP H5N1 AIV in Europe.

An equine West Nile virus (WNV) outbreak occurred in 2004 in the Camargue, a wetland area in the south of France where the virus was first reported in 1962 and re-emerged in 2000. WNV neutralizing antibodies were detected in resident birds and two isolates from a House Sparrow (Passer domesticus) and a Common Magpie (Pica pica) were completely sequenced. Phylogenetic analyses revealed that these isolates are closely related to strains previously found in horses in southern Europe and North Africa. More extensive investigation is required to determine whether WNV has been re-introduced or has become endemic in the Camargue.

The purpose of this study was to determine the importance of the effects of local agricultural and industrial activities on the contamination of little egret eggs laid in the Camargue area, a protected wetland area in the Mediterranean region. Despite the fact that human activity is widespread in the Camargue, concentrations of lindane (0.01-0.7 microg/g wet wt) and of polycyclic aromatic hydrocarbons (<0.5 microg/g wet wt) do not seem to be deleterious-at least for herons. Residues of dichlorodiethyltrichlorethylene (DDE) were usually below 1 microg/g wet weight. The principal threat comes from high concentrations of polychlorinated biphenyls (PCBs; 0.1-12 microg/g wet wt), which are known to have teratogenic effects in other bird species at similar concentrations and are thought to originate locally (sediments of the delta and industrial complex of Fos/Mer). For this reason, particular interest should be focused on the water/sediment quality of the Rhĵne River (France), on industrial sewage, and on wildlife contamination. A significant but weak link between colony site and lindane concentration was detected in eggs and may be attributed to the fact that our egg collection from each sampled colony was not synchronized with pesticide spread. A stronger site effect was observed for PCBs. Eggs collected near the industrial complex of Fos/Mer (petroleum, power plants) displayed the highest median concentration and the most contaminated eggs. Such results warrant thorough monitoring of this colony.