39 research outputs found
Cameroonian blackflies (Diptera: Simuliidae) harbour a plethora of (RNA) viruses
No full textStrong epidemiological evidence suggests that onchocerciasis may be associated with epilepsy – hence the name onchocerciasis -associated epilepsy (OAE). However, the pathogenesis of OAE still needs to be elucidated, as recent studiesfailed to detect Onchocerca volvulus in the central nervous system of persons with OAE. Therefore, it was suggested that a potentially neurotropic virus transmitted by blackflies could play a role in triggering OAE. To investigate this hypothesis, adult blackflies were collected in an onchocerciasis endemic area with a high OAE prevalence in the Ntui Health District, Cameroon. A viral particle
-based shotgun sequencing approach was used to detect viral sequences in fifty
-five pools of ten blackflies. A very high abundance of viral reads was detected across multiple (novel) viral families, including viral families associated with human disease. Although, no genomes closely related to known neurotropic viruses were found in the blackfly virome, the plethora of novel viruses representing novel species, genera and even families, warrant further exploration for their potential to infect vertebrates. These results could serve as a first step for studying the viruses associated with the hematophagous blackfly, which also could be present in their nematode host O. volvulus. Exploring the diversity of viruses in blackflies should be included in the active surveillance of zoonotic diseases
Onchocerciasis (river blindness) also induces river epilepsy (onchocerciasis-associated epilepsy)
No full textAbstract: Onchocerciasis, commonly known as river blindness, has historically been identified as a skin and eye disease; however, recent epidemiological investigations suggest a potential direct or indirect association with epilepsy. Onchocerciasis-Associated Epilepsy (OAE) (river epilepsy) is a neglected public health problem in many remote onchocerciasis endemic areas in Africa with sub-optimal onchocerciasis elimination programs. OAE manifests in previously healthy children aged 3 to 18 years old in the absence of any obvious cause for epilepsy and is marked by a diverse range of convulsive and non-convulsive seizure types including head nodding seizures (nodding syndrome). Various pathophysiological mechanisms have been proposed to explain OAE, yet conclusive evidence supporting any particular hypothesis is currently lacking. Recent studies showed that strengthening onchocerciasis elimination programs significantly reduced the incidence of OAE. Treating epilepsy in onchocerciasis endemic regions is challenging. More advocacy is needed to provide uninterrupted free access to anti-seizure medication to persons with epilepsy in these remote impoverished areas
Sites where onchocerciasis interventions were associated with reduced epilepsy/NS burden.
No full textSites where onchocerciasis interventions were associated with reduced epilepsy/NS burden.</p
Methodological challenges for conducting case-control studies to investigate the association between onchocerciasis and epilepsy including nodding syndrome
No full textThe onchocerciasis hypothesis of nodding syndrome
No full textAbstract: Nodding syndrome (NS) is a phenotypic presentation of onchocerciasis-associated epilepsy (OAE). OAE is an important public health problem in areas with high ongoing Onchocerca volvulus transmission. OAE, including NS, is preventable by strengthening onchocerciasis elimination programs. The presence of tau in OAE postmortem brains could be the consequence of neuroinflammation directly or indirectly induced by O. volvulus. Omics research is needed to investigate whether O. volvulus worms contain a neurotropic virus
Beatrijs' biecht: stilistisch en semiotisch onderzoek
No full textL’objectif de la thèse est de rassembler des arguments permettant de déterminer si la seconde partie de la légende mariale moyen-néerlandaise Beatrijs (vv. 865-1038) est originale ou plutôt l’œuvre d’un continuateur. Dans la séquence narrative dont il est question, l’auteur développe le thème de la confession, préalable spirituel à la rémission des péchés.En premier lieu, l’analyse stylistique objective (c.-à-d. basée sur des paramètres quantitatifs) de l’ensemble du corpus-texte nous a permis de ne déceler aucune différence notable entre les deux parties de la légende.Ensuite, par l’étude de la structure diégétique, nous avons tenté d’expliquer le rôle du processus pénitentiel dans l’œuvre moyen-néerlandaise. Grâce aux principes d’analyse sémiotique de Propp, Greimas, Courtès et Dundes, nous avons pu remarquer que la légende présente une double articulation narrative reposant sur une double quête :le rejet du péché par le retour à l’espace hétérotopique initial (dans la première partie) et la quête de la pureté originale par la confession des péchés (dans la seconde partie). Cette dernière quête semble donc très logiquement faire partie intégrante de l’œuvre médiévale.The aim of this thesis is to determine whether the second part of the Middle-Dutch legend Beatrijs (vv. 865-1038) is original. In the final sequences, the author highlights the role of confession in the absolution of sins.In the first part of our work, we carried out a stylistic analysis of the whole legend that rested on quantifiable parameters. As no significant differences could be observed between the two parts, the stylistic homogeneity seemed obvious.In the second part of our research, the emphasis was laid on the narrative structural approach. On the basis of the theories of semioticians (Propp, Greimas, Courtès and Dundes), we could analyse the legend as a bimotifemic « complex tale » in which the success of the first quest in the first part (return to the heterotopic point of departure) must be considered the first stage in the expiation. The second quest in the second part (return to the original purity) can only be achieved through confession. This physical and spiritual movement ensures absolution and salvation :for that reason we can assert that the confession process is an integral part of the medieval legend as a whole.Doctorat en philosophie et lettres, Orientation langue et littératureinfo:eu-repo/semantics/nonPublishe
Genome diversity of Leishmania aethiopica
No full textLeishmania aethiopica is a zoonotic Old World parasite transmitted by Phlebotomine sand flies and causing cutaneous leishmaniasis in Ethiopia and Kenya. Despite a range of clinical manifestations and a high prevalence of treatment failure, L. aethiopica is one of the most neglected species of the Leishmania genus in terms of scientific attention. Here, we explored the genome diversity of L. aethiopica by analyzing the genomes of twenty isolates from Ethiopia. Phylogenomic analyses identified two strains as interspecific hybrids involving L. aethiopica as one parent and L. donovani and L. tropica respectively as the other parent. High levels of genome-wide heterozygosity suggest that these two hybrids are equivalent to F1 progeny that propagated mitotically since the initial hybridization event. Analyses of allelic read depths further revealed that the L. aethiopica - L. tropica hybrid was diploid and the L. aethiopica - L. donovani hybrid was triploid, as has been described for other interspecific Leishmania hybrids. When focusing on L. aethiopica, we show that this species is genetically highly diverse and consists of both asexually evolving strains and groups of recombining parasites. A remarkable observation is that some L. aethiopica strains showed an extensive loss of heterozygosity across large regions of the nuclear genome, which likely arose from gene conversion/mitotic recombination. Hence, our prospection of L. aethiopica genomics revealed new insights into the genomic consequences of both meiotic and mitotic recombination in Leishmania
