Jacques Paty, Philippe Deliac, Maxime Gioux, Bernard Claverie, Christian Gross
L'électroencéphalographie constitue le moyen le plus classique, et le plus aisé à réaliser, pour l'étude des activités électro-corticales. Les méthodes de traite- ment informatique du signal permettent d'affiner considérablement les rensei- gnements fournis, et l'électroencéphalographie quantitative, appliquée aux pro- blèmes de la sénéscence, se propose deux objectifs principaux : — évaluer les processus de vieillissement cérébral dans une perspective neurométrique; — faire la part d'une pathologie associée à l'âge.
SémiologieMaladies infectieuses et tropicalesMédecine interne (cardiologie, endocrinologie, néphrologie…)Licence : https://creativecommons.org/licenses/by/4.0/
Ouardia Bouayadi, Mohammed Bensalah, Nawal Rahmani, Said Assoufi, Mohammed Choukri
L'électrophorèse des protéines sériques (EPS) est une analyse de routine dans la pratique quotidienne d'un laboratoire de biologie médicale. Le but de notre étude est d’analyser les différents profils électrophorétiques rencontrés dans notre pratique courante. Nous avons mené une étude transversale portant sur 410 échantillons sériques qui ont été collectés dans le cadre de l’analyse de routine au sein du laboratoire de biochimie du Centre Hospitalier Universitaire (CHU) Mohammed VI d’Oujda. L’électrophorèse des protéines sériques a été réalisée sur automate Capilarys2 Flex piercing de Sebia. 241 sérums de femmes et 169 sérums d’hommes ont été collectés. Âgés de 1 à 91 ans avec une moyenne d’âge de 49 ans. 19,5% des EPS étaient normales, l’hypo-albuminémie a été noté chez 34% des cas, un syndrome inflammatoire chronique dans 19,5% des cas, un syndrome néphrotique chez 2% des cas, 5,8% de nos patients avaient un bloc béta-gamma, une hypogammaglobulinémie a été observée dans 8,5% des cas, et 29 pics monoclonaux ont été notés, une bis-albuminémie a été objectivée chez 2 patients. Sur les 410 prélèvements: 92 immunofixations ont été réalisées dont 23 étaient positives (objectivant une gammapathie monoclonale). Cette étude met en évidence la variabilité des motifs de prescription d’une électrophorèse des protéines sériques, ainsi que l’importance des données cliniques pour une interprétation meilleure.
ImmunologieLicence : The Pan African Medical Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Depuis 2022, une organisation académique proposant un Art du Soin en partenariat avec les patients et le public dans une dimension systémique (Enseignement, Soin, recherche et éducation populaire) accompagne de nouvelles pratiques de soin. Cet article propose d'éclairer un de ces nouveaux exercice en clinique, celui de tandems de partenariat médecin patient en milieu clinique. Cet éclairage de tandems de partenariat de soin développés tant en soins primaires qu'en établissement de santé permet selon les auteurs de deux pays différents, d'apporter des éléments de pertinence de ce nouveau type d'exercice et de poser une première hypothèse du contexte nécessaire à une mise à l'échelle de ces nouvelles figures impliqué dans le soin.
SémiologieMaladies infectieuses et tropicalesMédecine interne (cardiologie, endocrinologie, néphrologie…)Licence : https://creativecommons.org/licenses/by/4.0/
Différents concepts structurent le système d'information. Le principal concept structurant est le processus. À l'hôpital, le processus est le rétablissement du patient pour lequel de nombreux corps de métiers différents travaillent chaque jour. Dans notre orientation vers le système d'information, il s'agit de prendre en compte tous les processus en tant que porteurs d'informations; nous traiteront seulement le contenu informationnel des processus du secteur hospitalier.
Biostatistiques et épidémiologieSanté publiqueLicence : https://creativecommons.org/licenses/by/4.0/
Aimée Mudekereza Musimwa, Gray Wakamb Kanteng, Hermann Tamubango Kitoko, Oscar Numbi Luboya
IntroductionLa place des éléments traces métalliques essentiels en nutrition humaine ne peut plus être ignorée. Les déficits d'apports, les carences secondaires souvent sous – estimées, et les carences iatrogènes font le lit de pathologies telles que les infections et autres. D'où leurs dosages ont une importance particulière pour en évaluer la gravité et faciliter une prise en charge précoce ou améliorer le régime alimentaire. Cette étude a eu pour objectif de déterminer le profil sanguin en éléments traces (cuivre, sélénium, zinc, fer, chrome, cobalt, etc) chez les enfants malnutris et biens nourris dans un milieu minier à Lubumbashi.MéthodesTrois cents onze cas ont été colligés, 182 malnutris et 129 biens nourris, dans une étude descriptive transversale, effectuée de juillet 2013 à décembre 2014. Pour lequel un échantillonnage exhaustif a été réalisé. Le dosage des métaux dans le sérum s'est fait à l’ ICP-OES (spectrométrie de masse à plasma gon induit) au laboratoire de l'Office Congolais de Contrôle de Lubumbashi.RésultatsLes oligoéléments essentiels (cuivre, zinc, sélénium et fer) se retrouvent à des concentrations très basses chez les enfants malnutris comme chez les biens nourris. L'arsenic, le cadmium, le magnésium et le manganèse se présentent à des concentrations normales par rapport aux valeurs de références chez les enfants biens nourris. L'antimoine, le chrome, le plomb et le cobalt se retrouvent élevés chez les malnutris et biens nourris. Le nickel est normal chez les malnutris et les biens nourris. Le magnésium, manganèse se sont présentés à des taux très bas chez les enfants malnutris.ConclusionLes enfants malnutris et biens nourris présentent une malnutrition aux oligo-éléments essentiels associés aux éléments traces métalliques. Ce qui permet de supposer qu'une carence en micronutriments essentiel favorise l'absorption des métaux lourds.
PédiatrieLicence : The Pan African Medical Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Licence : The Pan African Medical Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Licence : The Pan African Medical Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
IntroductionElevated blood lead levels (BLL) and malaria carry an important burden of disease in West Africa. Both diseases might cause anemia and they might entail long-term consequences for the development and the health status of the child. Albeit the significant impact of malaria on lead levels described in Nigeria, no evaluation of the effect of elevated BLL on malaria risk has been investigated so far.Materials and MethodsBetween 2010 and 2012, blood lead levels of 203 Beninese infants from Allada, a semi-rural area 50km North from Cotonou, were assessed at 12 months of age. To assess lead levels, blood samples were analyzed by mass spectrometry. In parallel, clinical, microbiological and hematological data were collected. More precisely, hemoglobin, serum ferritin, CRP, vitamin B12, folate levels, and Plasmodium falciparum parasitemia were assessed and stool samples were also analyzed.ResultsAt 12 months, the mean BLL of infants was 7.41 μg/dL (CI: 65.2; 83), and 128 infants (63%) had elevated blood lead levels, defined by the CDC as BLL>5 μg/dL. Lead poisoning, defined as BLL>10 μg/dL, was found in 39 infants (19%). Twenty-five infants (12.5%) had a positive blood smear at 12 months and 144 infants were anemic (71%, hemoglobin<110 g/L). Elevated blood lead levels were significantly associated with reduced risk of a positive blood smear (AOR = 0.38, P-value = 0.048) and P. falciparum parasite density (beta-estimate = -1.42, P-value = 0.03) in logistic and negative binomial regression multivariate models, respectively, adjusted on clinical and environmental indicators.ConclusionOur study shows for the first time that BLL are negatively associated with malarial risk considering other risk factors. Malaria is one of the main causes of morbidity and mortality in infants under 5 years worldwide, and lead poisoning is the 6th most important contributor to the global burden of diseases measured in disability adjusted life years (DALYs) according to the Institute of
Biologie cellulaire et moléculaireGénétiqueBiostatistiques et épidémiologieLicence : Creative Commons Attribution License This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Malaria transmission relies on the differentiation of asexual parasites into gametocytes, a process initiated by sexual conversion (SC). Mutations in the host hemoglobin beta (HBB) gene are known to influence parasite growth and disease outcome, yet their impact on SC remains unclear. We investigated the effect of HBB mutant genotypes on Plasmodium falciparum (P. falciparum) SC and humoral immunity in individuals from Nanoro, Burkina Faso. To measure SC rates in natural human malaria infections, we developed a new ex vivo SC assay (evSCA). We found that in human natural P. falciparum infections, SC rates were higher in individuals with HbAS or HbAC than in individuals with wild-type HBB (HbAA). Consistently, using an in vitro SC assay (ivSCA) based on the NF54-gexp02-Tom reporter line we found that cultures grown in HbAS red blood cells (RBCs) had higher SC rates than those grown in HbAA RBCs. Furthermore, IgG and IgM responses against trophozoite- and stage I gametocyte-infected RBC antigens, quantified by flow cytometry, did not differ between plasma from individuals with different HBB genotypes. These results demonstrate that exposure to RBCs with HBB mutations enhances SC, highlighting a host-genetic factor that may influence malaria transmission potential. Author summaryTransmission of Plasmodium falciparum, a malaria causing parasite, depends on the parasite’s ability to produce gametocytes, the stage that infects mosquitoes. In many African regions where malaria is common, hemoglobin (Hb) variants such as hemoglobin S (the sickle-cell trait) and C are highly prevalent reflecting their role in protecting against severe disease. However, it remains unclear whether these variants also influence the parasite’s early shift toward gametocyte development (i.e., sexual conversion [SC]). In this study, we combined ex vivo and in vitro SC assays to measure SC in red blood cells with different hemoglobin genotypes. We found that SC was higher in parasites growing in red
Biologie cellulaire et moléculaireGénétiqueBiostatistiques et épidémiologieLicence : Creative Commons Attribution License This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Charles Antwi-Boasiako, Emmanuel Frimpong, Ben Gyan, Eric Kyei-Baafour, Fredericka Sey, Bartholomew Dzudzor, Mubarak Abdul-Rahman, Gifty B. Dankwah, Kate H. Otu, Tom A. Ndanu, Andrew D. Campbell, Ivy Ekem, Eric S. Donkor
Sickle cell disease (SCD) is an inherited blood disorder that can result in vasculopathy and end organ damage. Angiogenesis has been implicated as a key contributing factor to vascular mediated tissue injury in SCD. The relative plasma levels of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), and vascular endothelial growth factor (VEGF) greatly influence angiogenesis. Dysregulation of these growth factors, leading to a pro-angiogenic state in SCD patients, has been documented in the developed world but there is very little data in Africa. There is the need, therefore, for studies in Ghanaian SCD patients. The aim of this study was to assess plasma levels of Ang-1, Ang-2, and VEGF in homozygous (HbSS) SCD patients with or without complications and healthy controls (HbAA) in Ghana. The study was a case-control study involving 544 participants: 396 HbSS SCD patients and 148 HbAA healthy controls. The study was conducted at the Center for Clinical Genetics (Sickle Cell Clinic) and Accra Area Blood Centre for National Blood transfusion at the Korle-Bu Teaching Hospital, Accra, Ghana. The plasma levels of Ang-1, Ang-2, and VEGF of study participants were measured with a double sandwich enzyme-linked immunosorbent assay (ELISA) technique. Complete blood count (CBC) was measured with an autoanalyser. The mean plasma Ang-1, Ang-2, and VEGF were significantly higher in HbSS SCD patients with or without complications than healthy controls (p < 0.001). The Ang-2/Ang-1 ratio was significantly lower in the controls than the HbSS patients (p < 0.001). The Ang-2/Ang-1 ratio was higher in the HbSS patients with leg ulcers as compared with patients with other complications and healthy controls (p < 0.001). There were higher leucocyte counts in HbSS patients than healthy controls. Overall, there was elevated plasma levels of Ang-1, Ang-2, and VEGF in SCD patients. The higher Ang-2/Ang-1 plasma levels in patients with leg ulcers suggests a possible ongoing angiogenesis and response to
Biologie cellulaire et moléculaireGénétiqueImmunologieLicence : http://creativecommons.org/licenses/by/4.0/ Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ().
Mark R Alderson, F Marc LaForce, Ajoke Sobanjo-ter Meulen, Angela Hwang, Marie-Pierre Preziosi, Keith P Klugman
AbstractThe introduction and rollout of a meningococcal serogroup A conjugate vaccine, MenAfriVac, in the African meningitis belt has eliminated serogroup A meningococcal infections for >300 million Africans. However, serogroup C, W, and X meningococci continue to circulate and have been responsible for focal epidemics in meningitis belt countries. Affordable multivalent meningococcal conjugate vaccines are being developed to prevent these non-A epidemics. This article describes the current epidemiologic situation and status of vaccine development and highlights questions to be addressed to most efficiently use these new vaccines.
Biostatistiques et épidémiologieMicrobiologie (bactériologie, virologie)ImmunologieLicence : http://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Amadou Fall, André Fouda Bita, Clement Lingani, Mamoudou Djingarey, Carole Tevi-Benissan, Marie-Pierre Preziosi, Olivier Ronveaux, R. Mihigo, J. Okeibunor, Bartholomew Dicky Akanmori
BackgroundEpidemics of meningococcal disease constitute a major public health challenge in Africa, affecting mostly the 24 countries of the meningitis belt. These epidemics led to a call for a call for a safe, effective and affordable conjugate vaccine against the major serogroup responsible for recent epidemics by leaders of the region.ObjectiveThis paper documents experiences with efforts at eliminating epidemic meningitis in the African Region.MethodThe meningoccocal serogroup A conjugate vaccine was developed, licensed and offered to more than 235 million people through mass vaccination campaigns in 16 countries since 2010. Future plans include providing the vaccine to the remaining countries in the African Meningitis Belt and, to implement the vaccine into routine national infant immunization programme and to organise catch-up immunization campaigns every 5 years for unvaccinated <5 year-olds who had missed their routine vaccinations.ResultsThe success of the project is evidenced by the large declines in cases of group A meningococcal disease since 2010, with no cases reported in vaccinated persons across the 16 countries, reflecting the highly effective nature of the vaccine. The successful control of serogroup A meningococcal disease has highlighted the need to tackle other meningococcal serogroups through development of polyvalent conjugate vaccines with the aim of eliminating epidemics of meningococcal meningitis in the African region.
Microbiologie (bactériologie, virologie)ImmunologieMaladies infectieuses et tropicalesLicence : http://creativecommons.org/licenses/by/4.0/ This article is distributed under the terms of the Creative Commons Attribution 4.0 International License.
The W-Arly-Pendjari (WAP) ecosystem, shared among Benin, Burkina Faso and Niger, represents the last lion stronghold of West Africa. To assess the impact of trophy hunting on lion populations in hunting areas of the WAP, we analyzed trends in harvest rates from 1999 to 2014. We also investigated whether the hunting areas with higher initial hunting intensity experienced steeper declines in lion harvest between 1999 and 2014, and whether lion densities in hunting areas were lower than in national parks. Lion harvest rate remained overall constant in the WAP. At initial hunting intensities below 1.5 lions/1000km2, most hunting areas experienced an increase in lion harvest rate, although that increase was of lower magnitude for hunting areas with higher initial hunting intensity. The proportion of hunting areas that experienced a decline in lion harvest rate increased at initial hunting intensities above 1.5 lions/1000km2. In 2014, the lion population of the WAP was estimated with a spoor count at 418 (230–648) adults and sub-adult individuals, comparable to the 311 (123–498) individuals estimated in the previous 2012 spoor survey. We found no significant lion spoor density differences between national parks and hunting areas. Hunting areas with higher mean harvest rates did not have lower lion densities. The ratio of large adult males, females and sub-adults was similar between the national parks and the hunting areas. These results suggested that the lion population was not significantly affected by hunting in the WAP. We concluded that a quota of 1 lion/1000km2 would be sustainable for the WAP. Based on our results, an import embargo on lion trophies from the WAP would not be justified. It could ruin the incentive of local actors to conserve lions in hunting areas, and lead to a drastic reduction of lion range in West Africa.
Biostatistiques et épidémiologieSanté publiqueLicence : Creative Commons Attribution License This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Un grand nombre d'interventions neurochirurgicales nécessitent l'utilisation d'une têtière à broches pour immobiliser la tête du patient. Nous rapportons le cas d'une embarrure chez un adulte secondaire à l'utilisation de la têtière de Mayfeild. Le diagnostic a été posé en postopératoire d'une résection chirurgicale d'un médulloblastome par une tomodensitométrie cérébrale. Plusieurs facteurs semblent contribuer à augmenter le risque de complications dues à l'utilisation de la têtière de Mayfield. Les mesures de prévention sont discutées à travers une revue de littérature.
Médecine interne (cardiologie, endocrinologie, néphrologie…)Licence : The Pan African Medical Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
L’embolie de liquide amniotique (ELA) est une complication imprévisible de l’accouchement, souvent fatale, associant un collapsus cardiovasculaire sévère, un syndrome de détresse respiratoire aiguë et une hémorragie avec coagulation intra vasculaire disséminée (CIVD). Dès l’évocation du diagnostic, la prise en charge doit être multidisciplinaire et intensive. ELA est responsable d’une mortalité maternelle et néonatale importante, son incidence est extrêmement variable selon les études et le taux de mortalité maternelle varie entre 26 et 86 % selon les études. Ces dix dernières années, le pronostic materno-fœtal semble en amélioration grâce aux progrès de prise en charge standardisée multidisciplinaire sur les lieux d’accouchement. Nous rapportons deux cas d’embolie de liquide amniotique. Le premier cas s’est manifesté au cours du travail et le deuxième cas est survenu dans les suites immédiates de l’accouchement.
Médecine interne (cardiologie, endocrinologie, néphrologie…)Gynécologie-obstétriqueLicence : The Pan African Medical Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Licence : The Pan African Medical Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Introductionl´embolie pulmonaire constitue par sa morbi-mortalité demeurant élevée un véritable problème de santé publique. L´objectif de cette étude est d´évaluer l'impact de l'ISEP (indice de sévérité de l'embolie pulmonaire) score sur le pronostic de l´embolie pulmonaire.Méthodesétude rétrospective qui a colligé 146 cas d'embolies confirmées de façon formelle. A partir de l´ISEP score calculé pour l´ensemble de cette population, nous avons subdivisé nos patients en 2 groupes: un groupe à bas risque (BR) regroupant les classes I et II: 83 patients; un groupe à haut risque (HR) regroupant les classes III, IV et V: 63 patients. Le critère de jugement primaire de l´étude (MACE) regroupait la survenue d´un état de choc, la nécessité de ventilation mécanique, et la survenue d'un décès en intra-hospitalier.Résultatsla mortalité intra-hospitalière totale était de 15,1%, significativement plus importante dans le groupe à HR (25,4% contre 7,2%, p=0,001). En analyse de régression logistique, l'appartenance au groupe HR (OR=5,1; IC à 95%: [1,637 - 16,093]; p=0,005) et l'insuffisance rénale (OR=4,5; IC à 95%: [1,457 - 14,075]; p=0,009) étaient les facteurs indépendants de survenue de MACE. Au bout d´un suivi moyen de 18 ± 8 mois, on a noté plus de décès dans le groupe HR (68,4% contre 33%, p=0,004).Conclusionles résultats de notre étude démontrent que l´ISEP score est corrélé à la sévérité de l´EP ce qui devrait encourager la généralisation de l´utilisation de ce score de risque.English abstract
Licence : https://creativecommons.org/licenses/by/4.0/ The Pan African Medical Journal (ISSN: 1937-8688). This is an Open Access article distributed under the terms of the Creative Commons Attribution International 4.0 License (), which permits unrestricted use, distribution, and reproduction in any medium, p
Abdelmajid Bouzerda, Issam Serghini, Abdenassar El Kharass
La mortalité de l'embolie pulmonaire compliquée d'état de choc varie de 25 à plus de 50%. Les fibrinolytiques semblent donc justifiés dans cette situation, malgré la légère augmentation du risque hémorragique. Nous rapportons le cas d'une patiente admise pour une embolie pulmonaire à risque intermédiaire fort traitée avec succès par tenecteplase. A la lumière de cette observation et une revue de la littérature nous discutons l'indication des thrombolytique dans les embolies pulmonaire de gravité intermédiaire.Mortality rates from pulmonary embolism complicated by shock vary from 25 to more than 50%. Therefore, fibrinolytic therapy appears to be justified in this situation, despite a slight increased risk of bleeding. We here report the case of a patient admitted with intermediate-risk pulmonary embolism successfully treated with tenecteplase. This study and review of the literature aim to discuss the indication for thrombolysis in patients with intermediate-risk pulmonary embolism.
Licence : The Pan African Medical Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
La néphrolithotomie percutanée s’accompagne d’un risque de complications en particulier hémorragiques, qui en fait une technique potentiellement invasive. Nous rapportons le cas d’une patiente de 70 ans, traitée auparavant pour néphrolithotomie percutanée d’une lithiase sur un rein unique gauche. Une hématurie persistante de moyenne abondance est apparue il y a 2 mois et demi, et qui a motivé à la réalisation d’une tomodensitométrie découvrant un faux anévrisme intra rénal polaire inférieur, d’origine iatrogène. Il a nécessité une embolisation sélective efficace à la colle biologique.
Licence : The Pan African Medical Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Araceli Lamelas, Julia Hauser, Jean-Pierre Dangy, Abdul-Wahab M. Hamid, Katharina Röltgen, Mohamad R. Abdul Sater, Abraham Hodgson, Ali Sie, Thomas Junghanss, Simon R. Harris, Julian Parkhill, Stephen D. Bentley, Gerd Pluschke
Countries of the African ‘meningitis belt’ are susceptible to meningococcal meningitis outbreaks. While in the past major epidemics have been primarily caused by serogroup A meningococci, W strains are currently responsible for most of the cases. After an epidemic in Mecca in 2000, W:ST-11 strains have caused many outbreaks worldwide. An unrelated W:ST-2881 clone was described for the first time in 2002, with the first meningitis cases caused by these bacteria reported in 2003. Here we describe results of a comparative whole-genome analysis of 74 W:ST-2881 strains isolated within the framework of two longitudinal colonization and disease studies conducted in Ghana and Burkina Faso. Genomic data indicate that the W:ST-2881 clone has emerged from Y:ST-175(CC175) bacteria by capsule switching. The circulating W:ST-2881 populations were composed of a variety of closely related but distinct genomic variants with no systematic differences between colonization and disease isolates. Two distinct and geographically clustered phylogenetic clonal variants were identified in Burkina Faso and a third in Ghana. On the basis of the presence or absence of 17 recombination fragments, the Ghanaian variant could be differentiated into five clusters. All 25 Ghanaian disease isolates clustered together with 23 out of 40 Ghanaian isolates associated with carriage within one cluster, indicating that W:ST-2881 clusters differ in virulence. More than half of the genes affected by horizontal gene transfer encoded proteins of the ‘cell envelope’ and the ‘transport/binding protein’ categories, which indicates that exchange of non-capsular antigens plays an important role in immune evasion.
Biologie cellulaire et moléculaireGénétiqueMicrobiologie (bactériologie, virologie)Licence : Creative Commons Attribution 4.0 International License This is an open access article under the terms of the, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.
Araceli Lamelas, Simon R. Harris, Katharina Röltgen, Jean-Pierre Dangy, Julia Hauser, Robert A. Kingsley, Thomas R. Connor, Ali Sie, Abraham Hodgson, Gordon Dougan, Julian Parkhill, Stephen D. Bentley, Gerd Pluschke
ABSTRACTIn the African “meningitis belt,” outbreaks of meningococcal meningitis occur in cycles, representing a model for the role of host-pathogen interactions in epidemic processes. The periodicity of the epidemics is not well understood, nor is it currently possible to predict them. In our longitudinal colonization and disease surveys, we have observed waves of clonal replacement with the same serogroup, suggesting that immunity to noncapsular antigens plays a significant role in natural herd immunity. Here, through comparative genomic analysis of 100 meningococcal isolates, we provide a high-resolution view of the evolutionary changes that occurred during clonal replacement of a hypervirulent meningococcal clone (ST-7) by a descendant clone (ST-2859). We show that the majority of genetic changes are due to homologous recombination of laterally acquired DNA, with more than 20% of these events involving acquisition of DNA from other species. Signals of adaptation to evade herd immunity were indicated by genomic hot spots of recombination. Most striking is the high frequency of changes involving the pgl locus, which determines the glycosylation patterns of major protein antigens. High-frequency changes were also observed for genes involved in the regulation of pilus expression and the synthesis of Maf3 adhesins, highlighting the importance of these surface features in host-pathogen interaction and immune evasion. IMPORTANCEWhile established meningococcal capsule polysaccharide vaccines are protective through the induction of anticapsular antibodies, findings of our longitudinal studies in the African meningitis belt have indicated that immunity to noncapsular antigens plays a significant role in natural herd immunity. Our results show that meningococci evade herd immunity through the rapid homologous replacement of just a few key genomic loci that affect noncapsular cell surface components. Identification of recombination hot spots thus represents an eminent approa
Biologie cellulaire et moléculaireGénétiqueBiostatistiques et épidémiologieLicence : Creative Commons Attribution 3.0 Unported license This is an open-access article distributed under the terms of the.
Since 2006, the poultry population in Burkina Faso has been seriously hit by different waves of Highly Pathogenic Avian Influenza (HPAI) H5N1 epizootics. In December 2021, three distinct regions of Burkina Faso, namely, Gomboussougou, Bonyollo, and Koubri, detected HPAI H5N1 viruses in poultry. Whole genome characterization and statistical phylogenetic approaches were applied to shed light on the potential origin of these viruses and estimate the time of virus emergence. Our results revealed that the HPAI H5N1 viruses reported in the three affected regions of Burkina Faso cluster together within clade 2.3.4.4b, and are closely related to HPAI H5N1 viruses identified in Nigeria and Niger in the period 2021–2022, except for the PA gene, which clusters with H9N2 viruses of the zoonotic G1 lineage collected in West Africa between 2017 and 2020. These reassortant viruses possess several mutations that may be associated with an increased zoonotic potential. Although it is difficult to ascertain where and when the reassortment event occurred, the emergence of a H5N1/H9N2 reassortant virus in a vulnerable region, such as West Africa, raises concerns about its possible impact on animal and human health. These findings also highlight the risk that West Africa may become a new hotspot for the emergence of new genotypes of HPAI viruses.
Biologie cellulaire et moléculaireGénétiqueSanté publiqueLicence : https://creativecommons.org/licenses/by/4.0/ Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ().
Serogroup X meningococci (NmX) historically have caused sporadic and clustered meningitis cases in sub-Saharan Africa. To study recent NmX epidemiology, we analyzed data from population-based, sentinel and passive surveillance, and outbreak investigations of bacterial meningitis in Togo and Burkina Faso during 2006–2010. Cerebrospinal fluid specimens were analyzed by PCR. In Togo during 2006–2009, NmX accounted for 16% of the 702 confirmed bacterial meningitis cases. Kozah district experienced an NmX outbreak in March 2007 with an NmX seasonal cumulative incidence of 33/100,000. In Burkina Faso during 2007–2010, NmX accounted for 7% of the 778 confirmed bacterial meningitis cases, with an increase from 2009 to 2010 (4% to 35% of all confirmed cases, respectively). In 2010, NmX epidemics occurred in northern and central regions of Burkina Faso; the highest district cumulative incidence of NmX was estimated as 130/100,000 during March–April. Although limited to a few districts, we have documented NmX meningitis epidemics occurring with a seasonal incidence previously only reported in the meningitis belt for NmW135 and NmA, which argues for development of an NmX vaccine.
Biologie cellulaire et moléculaireGénétiqueBiostatistiques et épidémiologieLicence : This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.