Suchergebnisse

Drawing upon the misinformation stories debunked by the three accredited fact-checking platforms in Spain, a content analysis of all the hoaxes (N = 292) bound to the Covid-19 pandemic is performed, over the first month of the state of alarm decreed by the Spanish Government (March 14th, 2020 – April 13th, 2020). The study shows that the hoaxes about the coronavirus were disseminated mainly on social networks and, among them, especially in closed ones, such as the WhatsApp mobile messaging application. It also detects the most frequent formal and content peculiarities of misinformation. The results reveal that the pandemic, in addition to generating a large number of hoaxes on health and science, also led to the dissemination of many political fake news. The formats, sources and territories of origin of the hoaxes are also explored. Beyond the empirical results, this study makes theoretical contributions in the framework of the emerging studies on information disorders. Specifically, it provides a definition of hoax, as well as a typology in which four main types are identified: joke, exaggeration, decontextualization and deception. Based on these four types, a 'hoax severity diagram' is proposed.

Brucella melitensis Rev 1 is the best vaccine available for the prophylaxis of small ruminant brucellosis and, indirectly, for reducing human brucellosis. However, Rev 1 shows anomalously high rates of spontaneous dissociation from smooth (S) to rough (R) bacteria, the latter being inefficacious as vaccines. This S-R instability results from the loss of the O-polysaccharide. To overcome this problem, we investigated whether some recently described mechanisms promoting mutations in O-polysaccharide genes were involved in Rev 1 S-R dissociation. We found that a proportion of Rev 1 R mutants result from genome rearrangements affecting the wbo O-polysaccharide loci of genomic island GI-2 and the wbkA O-polysaccharide glycosyltransferase gene of the wbk region. Accordingly, we mutated the GI-2 int gene and the wbk IS transposase involved in those arrangements, and found that these Rev 1 mutants maintained the S phenotype and showed lower dissociation levels. Combining these two mutations resulted in a strain (Rev 2) displaying a 95% decrease in dissociation with respect to parental Rev 1 under conditions promoting dissociation. Rev 2 did not differ from Rev 1 in the characteristics used in Rev 1 typing (growth rate, colonial size, reactivity with O-polysaccharide antibodies, phage, dye and antibiotic susceptibility). Moreover, Rev 2 and Rev 1 showed similar attenuation and afforded similar protection in the mouse model of brucellosis vaccines. We conclude that mutations targeting genes and DNA sequences involved in spontaneous O-polysaccharide loss enhance the stability of a critical vaccine phenotype and complement the empirical stabilization precautions taken during S Brucella vaccine production. © 2013 Mancilla et al.; licensee BioMed Central Ltd. ; This work was funded by MINECO (reference project AGL2011-30453-C04) of Spain, the FIMA foundation and the European Union's FP7/2007-2013 (grant agreement n° 221948, ICONZ - Integrated control of Neglected Zoonoses) and CSIC JAE-Doc program (FSE). ; We also acknowledge institutional support from the Unit of Information Resources for Research at the "Consejo Superior de Investigaciones Científicas" (CSIC) for the article-processing charges contribution. ; Peer Reviewed