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This dissertation is a theoretical study of the role of virality/virulence as a predominant technological term in the reproduction of social and cultural information in the digital age. I argue that viral media are not new phenomena, only the name is new. Media have always behaved as viruses; it is only when they become hyper-intensified in digital technology that their virulent function surfaces in language and culture. The project examines processes of self-replication and evolution undergone by various new media phenomena as they relate back to the global profusion of social networks, data centers, and cybernetic practices. Drawing from several contributions in media theory, political and social theory, and critical media studies, I argue that digital media have a hyper-intensifying effect on whatever objects, subjects, or realities they mediate or represent; thus networked societies are virulently swarmed by their own signs and images in information. Through an examination of three primary categories of digital proliferationlanguage, visuality, and sexualityI situate digital culture in a framework of virulence, arguing that the digital may be best understood as an effect of cultural hyper-saturation and implosion. I argue that virulent media networking processes come to constitute a powerful cybernetic system, which renders the human subject a mere function in its global operations. Lastly, I begin to develop a political critique of cybernetics, claiming that the proliferation of information, digital media, and communicative/representational technologies in the contemporary world emerges through an intensified ideological, economic, social, cultural, and metaphysical framework of productivism. This intensification engenders a system, or series of communicational circuits, whereby all techno-subjective activities are strategically stimulated, networked, recorded, and algorithmically appropriated to strengthen and reproduce 1) a global productivist system of cybernetics; 2) The material and ideological conditions for such a system to exist and thrive; 3) limitless virtual and digital production. ; Ph. D.

Parasite evolution is a major public health issue. The aim of this thesis is to understand micro-parasite virulence evolution through a theoretical approach based on within-host models linked to an epidemiological framework (also called embedded models). The host's immune response exerts a major selection pressure on parasite virulence. In parasitology, most within-host models incorporate the immune system as a dynamical system, but in these models, the outcome of the infection generally is an a priori assumption. Nevertheless, these models offer new perspectives to study virulence evolution. Most studies assume that a parasite cannot increase its transmission rate without causing more harm to its host. However, the existence of such a trade-off relationship between transmission and virulence has been challenged. Using an embedded model, we study how a trade-off can emerge and what its characteristics are. Applying this framework to the case of vector-borne parasites, we work out how specific aspects of the parasites and interaction with its host affect the trade-off. Finally, we investigate the consequences of multiple infections on virulence evolution. The results of our study have public health implications as our models allow to predict possible consequences of anti-parasite treatments on virulence evolution. We suggest it would be reasonable to take these effects into account when elaborating public health policies to avoid an "arms race" between hosts and parasites. ; L'évolution des parasites est un enjeu sanitaire majeur, qui a souvent été négligé. L'objet de cette thèse est de comprendre l'évolution de la virulence des micro-parasites grâce à une approche théorique basée sur des modèles intra-hôtes intégrés dans une dimension épidémiologique, aussi appelés modèles emboîtés. La réponse immunitaire de l'hôte exerce une pression de sélection majeure sur la virulence des parasites. En parasitologie, la plupart des modèles incluent le système immunitaire en tant que système dynamique mais dans ces modèles le résultat de l'infection est souvent une hypothèse a priori. Ces modèles ouvrent toutefois de nouvelles perspectives pour l'étude de l'évolution de la virulence.La plupart des études supposent qu'un parasite ne peut augmenter son taux de transmission sans nuire davantage à son hôte. Pourtant, l'existence d'une telle relation de compromis évolutif entre transmission et virulence est toujours remise en cause. Grâce à un modèle emboîté, nous étudions à quelles conditions un compromis évolutif peut émerger et quelles sont alors ses caractéristiques. En appliquant cette approche aux parasites à vecteur, nous montrons comment les aspects spécifiques du parasite et de son interaction avec l'hôte affectent le compromis. Finalement, nous étudions les conséquences des infections multiples sur l'évolution de la virulence.Les résultats de notre travail ont des implications sanitaires car nos modèles permettent de prévoir l'effet potentiel de traitements anti-parasitaires sur l'évolution de la virulence. Il serait judicieux de prendre en compte ces effets dans l'élaboration de politiques de santé afin d'éviter une « course aux armements » entre hôtes et parasites.

L'analyse ethnique du conflit du Darfour répandue en Occident n'exprime pas la réalité. Les diverses populations du Darfour ont depuis longtemps tissé les liens nécessaires à leur coexistence — même si le système de répartition de la terre pose problème. C'est la marginalisation politique, sociale et économique de la province, imputable à Khartoum, qui débouche sur l'explosion de 2003. La révolte provoque une réaction brutale du gouvernement de Khartoum, avec l'instrumentalisation des janjawid. La communauté internationale réagit lentement ; mais une solution n'est sans doute pas possible sans de profonds changements à Khartoum.

Fruit losses during postharvest storage and handling due to pathogen infections are one of the major problems in the global food chain supply. The application of chemical fungicides to control diseases is currently limited by legislation in some countries and also raises concerns about food and environmental safety. Exploring molecular aspects of pathogen-fruit interactions therefore has biological and economic significance as a means to help develop rational alternatives for disease control. In this review we present the current knowledge of molecular aspects in pathogen-fruit interactions, addressing the following topics: the application of new "omics" technologies for studying these interactions; the molecular mechanisms of fungal pathogen attack; the regulation of virulence by exogenous factors; and, finally, fruit defense mechanisms. ; Work in Tian's lab has been funded by the National Natural Science Foundation of China (31530057; 31371863). Work in the LGC lab has been funded by the Spanish Ministry of Economy and Competitiveness (AGL2011-30519-C03-01 and AGL2014-55802-R) and the Generalitat Valenciana (PrometeoII/2014/027). Work in the IRTA lab has been funded by the Spanish Ministry of Economy and Competitiveness by three national projects AGL2008-04828-C01/AGR, AGL2011-30519-C03/AGR and AGL2014-55287-C02. ; Peer reviewed

Salmonella is the second leading cause of human zoonoses in the European Union and represents a major challenge for the pork industry. Serovars S. Typhimurium, S. Derby and the monophasic variant of S. Typhimurium, implicated in human salmonellosis, are highly prevalent in pigs and also in human. The objectives of this research were to establish the infection dynamics in pigs by Salmonella under conventional and experimental rearing conditions, to evaluate pig colonization ability and pathogenicity in humans of the three serovars. In conventional farms, the serological monitoring of Salmonella antibodies allowed to evaluate the average age of seroconversion at 137 days and to identify a "farm effect" on the age of seroconversion. The first trial under experimental conditions revealed that pigs inoculated with the monophasic variant of S. Typhimurium excreted this serovar continuously in the feces. At autopsy dates 21, 49 or 84 days after inoculation, Salmonella were found in the different parts of the intestine, in the lymph nodes and at very high levels in the tonsils. After passage through the digestive tract, different MLVA profiles from that of the inoculated strain were identified suggesting that the genome of the strain has evolved. The second attempt to compare the colonizing ability in the pigs of the three serovars showed that the dynamics of excretion and colonization were similar regardless of the serovar. However, the amount excreted was significantly different: higher with the monophasic variant compared to S. Typhimurium. The pathogenicity in humans of 15 strains of porcine origin belonging to the 3 serovars was evaluated in vivo on an insect model Galleria mellonella, and in vitro on Caco-2 cells. The strains were found to be potentially virulent. On Caco-2, the monophasic variant had the highest cell adhesion percentage and Derby, the lowest. Different levels of virulence were observed between strains of the same serovar. This work brought new knowledge on the Salmonella issue in the pig sector. ; Salmonella est la deuxième cause de zoonoses humaines dans l'Union Européenne et représente un enjeu majeur pour la filière porcine. Les sérovars, S. Typhimurium, S. Derby et le variant monophasique de S. Typhimurium sont très prévalents chez le porc et également chez les humains. Les objectifs de ces travaux étaient d'établir la dynamique d'infection chez le porc par Salmonella en condition d'élevage conventionnel et expérimental, d'évaluer le pouvoir colonisateur chez le porc et le pouvoir pathogène chez les humains des trois sérovars. En élevage conventionnel, le suivi sérologique des anticorps anti-Salmonella a permis d'évaluer l'âge moyen de séroconversion à 137 jours et d'identifier un « effet ferme » sur l'âge de séroconversion. Le premier essai en condition expérimentale a mis en évidence que les porcs inoculés avec le variant monophasique de S. Typhimurium excrétaient ce sérovar de façon continue dans les fèces. Aux dates d'autopsies 21, 49 ou 84 jours après inoculation, les salmonelles ont été retrouvées dans les différentes parties de l'intestin, dans les nœuds lymphatiques et à des niveaux très élevés dans les amygdales. Après passage dans le tractus digestif, des profils MLVA différents de celui de la souche inoculée ont été identifiés suggérant que le génome de la souche a évolué. Le deuxième essai visant à comparer le pouvoir colonisateur chez le porc des trois sérovars a montré que la dynamique d'excrétion et de colonisation était similaire quel que soit le sérovar. Cependant, la quantité excrétée était significativement différente ; plus élevée avec le variant monophasique par rapport à S.Typhimurium. Le pouvoir pathogène chez l'homme de 15 souches d'origine porcine appartenant aux 3 sérovars a été évalué in vivo sur un modèle insecte Galleria mellonella, et in vitro sur cellules Caco-2. Les souches se sont révélées être potentiellement virulentes. Sur Caco-2, le variant monophasique avait un pourcentage d'adhésion aux cellules le plus élevé et Derby le plus bas. Différents niveaux de virulence ont été observés entre souches d'un même sérovar. Ce travail a apporté des nouvelles connaissances sur la problématique Salmonella en filière porcine.

Salmonella is the second leading cause of human zoonoses in the European Union and represents a major challenge for the pork industry. Serovars S. Typhimurium, S. Derby and the monophasic variant of S. Typhimurium, implicated in human salmonellosis, are highly prevalent in pigs and also in human. The objectives of this research were to establish the infection dynamics in pigs by Salmonella under conventional and experimental rearing conditions, to evaluate pig colonization ability and pathogenicity in humans of the three serovars. In conventional farms, the serological monitoring of Salmonella antibodies allowed to evaluate the average age of seroconversion at 137 days and to identify a "farm effect" on the age of seroconversion. The first trial under experimental conditions revealed that pigs inoculated with the monophasic variant of S. Typhimurium excreted this serovar continuously in the feces. At autopsy dates 21, 49 or 84 days after inoculation, Salmonella were found in the different parts of the intestine, in the lymph nodes and at very high levels in the tonsils. After passage through the digestive tract, different MLVA profiles from that of the inoculated strain were identified suggesting that the genome of the strain has evolved. The second attempt to compare the colonizing ability in the pigs of the three serovars showed that the dynamics of excretion and colonization were similar regardless of the serovar. However, the amount excreted was significantly different: higher with the monophasic variant compared to S. Typhimurium. The pathogenicity in humans of 15 strains of porcine origin belonging to the 3 serovars was evaluated in vivo on an insect model Galleria mellonella, and in vitro on Caco-2 cells. The strains were found to be potentially virulent. On Caco-2, the monophasic variant had the highest cell adhesion percentage and Derby, the lowest. Different levels of virulence were observed between strains of the same serovar. This work brought new knowledge on the Salmonella issue in the pig sector. ...

[EN] Staphylococcus aureus is a versatile pathogen able to cause disease in both humans and animals. In rabbits, this bacterium infects animals of different ages, producing several purulent lesions. The ability of S. aureus to cause disease depends on a combination of virulence factors. The aim of this study was therefore to investigate the distribution of bacterial virulence determinants in 69 S. aureus isolates from rabbits. Some virulence factors (7 adhesins, 1 toxin and 1 protease) were positive in all rabbit S. aureus isolates analysed, while others (1 adhesin and 10 toxins) were always negative. The remaining virulence factors were more variable among isolates. An association between genotype and the different profiles of virulence factors was observed, but not with the type of lesion (P 0.05). One strain of each genotype was further analysed by multilocus sequence typing, generating ST121, ST96 and ST2951, determining a greater number of enterotoxins in ST121 isolates compared to ST96 and ST2951 isolates, which could justify the different pathogenicity between strains. ; This study was supported by the Inter-ministerial Commission for Science and Technology (CICYT) of the Spanish Government (AGL2011-30170-C02-02 and AGL2014-53405-C2-2-P). The fellowship support for MP from Ministry of Education, Culture and Sports, Spain (AP2010-3907) is gratefully acknowledged. ; Viana Martín, D.; Selva, L.; Penadés, M.; Corpa, JM. (2015). Screening of virulence genes in Staphylococcus aureus isolates from rabbits. World Rabbit Science. 23(3):185-195. https://doi.org/10.4995/wrs.2015.3961 ; SWORD ; 185 ; 195 ; 23 ; 3

Hybridization between different species can result in the emergence of new lineages and adaptive phenotypes. Occasionally, hybridization in fungal organisms can drive the appearance of opportunistic lifestyles or shifts to new hosts, resulting in the emergence of novel pathogens. In recent years, an increasing number of studies have documented the existence of hybrids in diverse yeast clades, including some comprising human pathogens. Comparative and population genomics studies performed on these clades are enabling us to understand what roles hybridization may play in the evolution and emergence of a virulence potential towards humans. Here we survey recent genomic studies on several yeast pathogenic clades where hybrids have been identified, and discuss the broader implications of hybridization in the evolution and emergence of pathogenic lineages. © 2017 The Authors. Yeast published by John Wiley & Sons, Ltd. ; This work was supported in part by grants from the Spanish Ministry of Economy and Competitiveness, 'Centro de Excelencia Severo Ochoa 2013‐2017' SEV‐2012‐0208, and BFU2015‐67107 cofounded by European Regional Development Fund; from the CERCA programme / Generalitat de Catalunya; from the European Union and ERC Seventh Framework Programme (FP7/2007‐2013) under grant agreements FP7‐PEOPLE‐2013‐ITN‐606786 'ImResFun' and ERC‐2012‐StG‐310325; and a grant from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska–Curie grant agreement no. H2020‐MSCA‐ITN‐2014‐642095.

To initiate pathogenic development, pathogenic fungi respond to a set of inductive cues. Some of them are of an extracellular nature (environmental signals), while others are intracellular (developmental signals). These signals must be integrated into a single response whose major outcome is changes in the morphogenesis of the fungus. The regulation of the cell cycle is pivotal during these cellular differentiation steps; therefore, cell cycle regulation would likely provide control points for infectious development by fungal pathogens. Here, we provide clues to understanding how the control of the cell cycle is integrated with the morphogenesis program in pathogenic fungi, and we review current examples that support these connections. ; Research in the Pérez-Martín laboratory is supported by grants from the Spanish Government (BIO2014-55398-R) and ITNs from the EU (Ariadne and Fungibrain). ; Peer Reviewed

During the last years, Brazilian government control programs have detected an increase of Salmonella Heidelberg in poultry slaughterhouses a condition that poses a threat to human health However, the reasons remain unclear. Differences in genetic virulence profiles may be a possible justification. In addition, effective control of Salmonella is related to an efficient epidemiological surveillance system through genotyping techniques. In this context, the aim of this study was the detection of 24 virulence-associated genes in 126 S. Heidelberg isolates. We classified the isolates into 56 different genetic profiles. None of the isolates presented all the virulence genes. The prevalence of these genes was high in all tested samples as the lowest number of genes detected in one isolate was 10/24. The lpfA and csgA (fimbriae), invA and sivH (TTSS), and msgA and tolC (intracellular survival) genes were present in 100% of the isolates analyzed. Genes encoding effector proteins were detected in the majority of SH isolates. No single isolate had the sefA gene. The pefA gene was found in only four isolates. We have also performed a screening of genes associated with iron metabolism: 88.9% of isolates had the iroN geneand 79.4% the sitC gene. Although all the isolates belong to the same serotype, several genotypic profiles were observed. These findings suggest that there is a diversity of S. Heidelberg isolates in poultry products. The fact that a single predominant profile was not found in this study indicates the presence of variable sources of contamination caused by SH. The detection of genetic profiles of Salmonella strains can be used to determine the virulence patterns of SH isolates.

ABSTRACT During the last years, Brazilian government control programs have detected an increase of Salmonella Heidelberg in poultry slaughterhouses a condition that poses a threat to human health However, the reasons remain unclear. Differences in genetic virulence profiles may be a possible justification. In addition, effective control of Salmonella is related to an efficient epidemiological surveillance system through genotyping techniques. In this context, the aim of this study was the detection of 24 virulence-associated genes in 126 S. Heidelberg isolates. We classified the isolates into 56 different genetic profiles. None of the isolates presented all the virulence genes. The prevalence of these genes was high in all tested samples as the lowest number of genes detected in one isolate was 10/24. The lpfA and csgA (fimbriae), invA and sivH (TTSS), and msgA and tolC (intracellular survival) genes were present in 100% of the isolates analyzed. Genes encoding effector proteins were detected in the majority of SH isolates. No single isolate had the sefA gene. The pefA gene was found in only four isolates. We have also performed a screening of genes associated with iron metabolism: 88.9% of isolates had the iroN geneand 79.4% the sitC gene . Although all the isolates belong to the same serotype, several genotypic profiles were observed. These findings suggest that there is a diversity of S. Heidelberg isolates in poultry products. The fact that a single predominant profile was not found in this study indicates the presence of variable sources of contamination caused by SH. The detection of genetic profiles of Salmonella strains can be used to determine the virulence patterns of SH isolates.

During the last years, Brazilian government control programs have detected an increase of Salmonella Heidelberg in poultry slaughterhouses a condition that poses a threat to human health However, the reasons remain unclear. Differences in genetic virulence profiles may be a possible justification. In addition, effective control of Salmonella is related to an efficient epidemiological surveillance system through genotyping techniques. In this context, the aim of this study was the detection of 24 virulence-associated genes in 126 S. Heidelberg isolates. We classified the isolates into 56 different genetic profiles. None of the isolates presented all the virulence genes. The prevalence of these genes was high in all tested samples as the lowest number of genes detected in one isolate was 10/24. The lpfA and csgA (fimbriae), invA and sivH (TTSS), and msgA and tolC (intracellular survival) genes were present in 100% of the isolates analyzed. Genes encoding effector proteins were detected in the majority of SH isolates. No single isolate had the sefA gene. The pefA gene was found in only four isolates. We have also performed a screening of genes associated with iron metabolism: 88.9% of isolates had the iroN gene and 79.4% the sitC gene. Although all the isolates belong to the same serotype, several genotypic profiles were observed. These findings suggest that there is a diversity of S. Heidelberg isolates in poultry products. The fact that a single predominant profile was not found in this study indicates the presence of variable sources of contamination caused by SH. The detection of genetic profiles of Salmonella strains can be used to determine the virulence patterns of SH isolates.