Isolation of Angola-like Marburg virus from Egyptian rousette bats from West Africa.

Marburg virus (MARV) causes sporadic outbreaks of severe Marburg virus disease (MVD). Most MVD outbreaks originated in East Africa and field studies in East Africa, South Africa, Zambia, and Gabon identified the Egyptian rousette bat (ERB; Rousettus aegyptiacus) as a natural reservoir. However, the largest recorded MVD outbreak with the highest case-fatality ratio happened in 2005 in Angola, where direct spillover from bats was not  shown. Here, collaborative studies by the Centers for Disease Control and Prevention, Njala University, University of California, Davis USAID-PREDICT, and the University of Makeni identify MARV circulating in ERBs in Sierra Leone. PCR, antibody and virus isolation data from 1755 bats of 42 species shows active MARV infection in approximately 2.5% of ERBs. Phylogenetic analysis identifies MARVs that are similar to the Angola strain. These results provide evidence of MARV circulation in West Africa and demonstrate the value of pathogen surveillance to identify previously undetected threats

Prevalence and burden of HBV co-infection among people living with HIV:A global systematic review and meta-analysis

Globally, in 2017 35 million people were living with HIV (PLHIV) and 257 million had chronic HBV infection (HBsAg positive). The extent of HIV-HBsAg co-infection is unknown. We undertook a systematic review to estimate the global burden of HBsAg co-infection in PLHIV. We searched MEDLINE, Embase and other databases for published studies (2002-2018) measuring prevalence of HBsAg among PLHIV. The review was registered with PROSPERO (#CRD42019123388). Populations were categorized by HIV-exposure category. The global burden of co-infection was estimated by applying regional co-infection prevalence estimates to UNAIDS estimates of PLHIV. We conducted a meta-analysis to estimate the odds of HBsAg among PLHIV compared to HIV-negative individuals. We identified 506 estimates (475 studies) of HIV-HBsAg co-infection prevalence from 80/195 (41.0%) countries. Globally, the prevalence of HIV-HBsAg co-infection is 7.6% (IQR 5.6%-12.1%) in PLHIV, or 2.7 million HIV-HBsAg co-infections (IQR 2.0-4.2). The greatest burden (69% of cases; 1.9 million) is in sub-Saharan Africa. Globally, there was little difference in prevalence of HIV-HBsAg co-infection by population group (approximately 6%-7%), but it was slightly higher among people who inject drugs (11.8% IQR 6.0%-16.9%). Odds of HBsAg infection were 1.4 times higher among PLHIV compared to HIV-negative individuals. There is therefore, a high global burden of HIV-HBsAg co-infection, especially in sub-Saharan Africa. Key prevention strategies include infant HBV vaccination, including a timely birth-dose. Findings also highlight the importance of targeting PLHIV, especially high-risk groups for testing, catch-up HBV vaccination and other preventative interventions. The global scale-up of antiretroviral therapy (ART) for PLHIV using a tenofovir-based ART regimen provides an opportunity to simultaneously treat those with HBV co-infection, and in pregnant women to also reduce mother-to-child transmission of HBV alongside HIV

Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats

In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security

Functional study of TFIIH and the mechanisms of transcription and DNA repair

La régulation de l'expression des gènes et la réparation de l'ADN sont deux mécanismes essentiels à la survie de la cellule. La transcription des gènes de classe II codant pour les protéines est un mécanisme complexe faisant intervenir une myriade de protéines dont l'ARN polymérase II (ARNP II) et six facteurs généraux de la transcription (TFIIA, B, D, E, F et H). La réparation par excision de nucléotides (NER) permet l'élimination des lésions distordant l'ADN, c'est un mécanisme crucial pour le maintien de l'information génétique. Il fait également intervenir plus d'une vingtaine de protéines qui, pour certaines, se retrouvent mutées chez les patients atteints de maladies génétiques rares. Le facteur général de transcription TFIIH joue aussi un rôle dans l'étape d'ouverture de l'ADN autour de la lésion lors de la NER.Au cours de mon travail doctoral, j'ai entrepris dans un premier temps de détailler le rôle intrinsèque des différentes sous-unités du facteur TFIIH, et plus particulièrement de la sous-unité p44. J'ai ainsi pu montrer que la partie carboxy-terminale de cette protéine jouait un rôle dans la cohésion du complexe TFIIH mais aussi dans son activité d'échappée du promoteur lors de l'initiation de la transcription. Puis, dans un second temps, je me suis intéressé au mécanisme reliant la transcription à la réparation, nommé transcription couplée à la réparation. J'ai ainsi pu montrer qu'une ARNP II bloquée par une lésion cisplatine sur le brin transcrit de l'ADN se retrouve éjectée de l'ADN de façon ATP mais non réparation dépendante.Genes regulation and DNA repair are two processes vital to cell survival. Transcription of class II genes (mostly protein coding genes) is a complex process involving the functions of many proteins, among them the RNA polymerase II (RNAP II) and six general transcription factors (TFIIA, B, D, E, F and H). Nucleotide excision repair (NER) is a mechanism whereby DNA lesions are eliminated. It's a key mechanism for the maintenance of genetic information. More than twenty proteins participate in this reaction. Mutation in some of them give rise to DNA repair genetic disorders. The general transcription factor TFIIH plays also a role in DNA melting around the lesion during the NER reaction.During my PhD study, I first study the role of different TFIIH subunits, especially the p44 subunit. I was able to show that the carboxy-terminal domain of this protein is important for TFIIH cohesion but also promoter escape activity of TFIIH. Then I focused my attention on the mechanism that link transcription and DNA repair: transcription coupled repair. I was able to show that an RNAP II blocked by a cisplatin lesion on the transcribed DNA strand is ejected from the template in an ATP but not a repair dependent manner

Etude fonctionnelle de TFIIH et des mécanismes de transcription et de réparation de l’ADN

La régulation de l’expression des gènes et la réparation de l’ADN sont deux mécanismes essentiels à la survie de la cellule. La transcription des gènes de classe II codant pour les protéines est un mécanisme complexe faisant intervenir une myriade de protéines dont l’ARN polymérase II (ARNP II) et six facteurs généraux de la transcription (TFIIA, B, D, E, F et H). La réparation par excision de nucléotides (NER) permet l’élimination des lésions distordant l’ADN, c’est un mécanisme crucial pour le maintien de l’information génétique. Il fait également intervenir plus d’une vingtaine de protéines qui, pour certaines, se retrouvent mutées chez les patients atteints de maladies génétiques rares. Le facteur général de transcription TFIIH joue aussi un rôle dans l’étape d’ouverture de l’ADN autour de la lésion lors de la NER. Au cours de mon travail doctoral, j’ai entrepris dans un premier temps de détailler le rôle intrinsèque des différentes sous-unités du facteur TFIIH, et plus particulièrement de la sous-unité p.44. J’ai ainsi pu montrer que la partie carboxy-terminale de cette protéine jouait un rôle dans la cohésion du complexe TFIIH mais aussi dans son activité d’échappée du promoteur lors de l’initiation de la transcription. Puis, dans un second temps, je me suis intéressé au mécanisme reliant la transcription à la réparation, nommé transcription couplée à la réparation. J’ai ainsi pu montrer qu’une ARNP II bloquée par une lésion cisplatine sur le brin transcrit de l’ADN se retrouve éjectée de l’ADN de façon ATP mais non réparation dépendante

Functional study of TFIIH and the mechanisms of transcription and DNA repair

La régulation de l'expression des gènes et la réparation de l'ADN sont deux mécanismes essentiels à la survie de la cellule. La transcription des gènes de classe II codant pour les protéines est un mécanisme complexe faisant intervenir une myriade de protGenes regulation and DNA repair are two processes vital to cell survival. Transcription of class II genes (mostly protein coding genes) is a complex process involving the functions of many proteins, among them the RNA polymerase II (RNAP II) and six gene

Seroprevalence of hepatitis B and C infection among the HIV-positive population in Abuja, Nigeria

Background: In Nigeria, it is estimated that 3.6% of the population were living with Human immunodeficiency virus in 2009, and the country had the world’s second highest number of HIV/AIDS related deaths after South Africa. Viral hepatitis is also a major public health concern as hepatitis B virus (HBV) afflicts an estimated 350 million people, and hepatitis C virus (HCV) affects 150 million people worldwide. Objectives: We conducted a retrospective study of HBV and HCV seroprevalence among Nigerian population coming to our clinic in Abuja and receiving HIV/AIDS treatment. Methods: In this cohort study, we collected medical data from 443 HIV-positive patients between September 2010 and May 2011. Standard enzyme immunoassays were used to determine the serological prevalence of hepatitis B (HBsAg) and C (anti-HCV antibody) among HIV-positive individuals. Results: Among the HIV/AIDS positive individuals, we found that 35 patients were infected with hepatitis B virus (7.9%), 10 with hepatitis C virus (2.3%) and 3 with both hepatitis B and C viruses (0.7%). The overall hepatitis-HIV prevalence is 10.8%. The majority of the population infected was under 39 years of age (55%) and the same proportion of males and females was observed in all the studied categories (HIV, HIV + hepatitis B and/or C). Remarkably, an overall lower CD4 count was seen in the co-infected population (205 cells/μl versus 243 cells/μl), with the lowest seen for the triply infected individuals (97 cells/μl). Conclusions: Our findings underscore the importance of screening for hepatitis B and hepatitis C viruses in the HIVinfected population in developing countries, and particularly in sub-Saharan Africa, where the epidemics are still growing

Mutations in XPB and XPD helicases found in xeroderma pigmentosum patients impair the transcription function of TFIIH.

As part of TFIIH, XPB and XPD helicases have been shown to play a role in nucleotide excision repair (NER). Mutations in these subunits are associated with three genetic disorders: xeroderma pigmentosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD). The strong heterogeneous clinical features observed in these patients cannot be explained by defects in NER alone. We decided to look at the transcriptional activity of TFIIH from cell lines of XP individuals. We set up an immunopurification procedure to isolate purified TFIIH from patient cell extracts. We demonstrated that mutations in two XP-B/CS patients decrease the transcriptional activity of the corresponding TFIIH by preventing promoter opening. The defect of XPB in transcription can be circumvented by artificial opening of the promoter. Western blot analysis and enzymatic assays indicate that XPD mutations affect the stoichiometric composition of TFIIH due to a weakness in the interaction between XPD-CAK complex and the core TFIIH, resulting in a partial reduction of transcription activity. This work, in addition to clarifying the role of the various TFIIH subunits, supports the current hypothesis that XP-B/D patients are more likely to suffer from transcription repair syndromes rather than DNA repair disorders alone

Intracellular rate-limiting steps of gene transfer using glycosylated polylysines in cystic fibrosis airway epithelial cells

International audienceTo identify the intracellular barriers to efficient gene transfer, we studied the intracellular trafficking of biotinylated plasmid DNA complexed with either fluorescein-conjugated lactosylated or mannosylated polylysine by confocal microscopy. Both are known to be taken up by cystic fibrosis airway epithelial cells (SigmaCFTE29o- cells), but their gene transfer efficiencies differ markedly: lactosylated polylysine is the most efficient glycosylated polylysine while mannosylated polylysine is quite inefficient for gene transfer. Mannosylated complexes appeared to stay longer in endosomes labeled by anti-transferrin receptor antibody than lactosylated complexes (from 30 min to 3 h and from 10 min to 30 min, respectively). At 24 h, higher percentages of mannosylated than lactosylated complexes were localized inside lysosomes labeled by anti-LAMP-1 antibody (41.8 +/- 6.6% versus 19.8 +/- 5.2%, respectively, P < 0.05). Between 30 min and 8 h, complexes reached the nuclei labeled by anti-lamin A/C antibody and no difference was observed between the nuclear amounts of mannosylated and lactosylated complexes. However, as analyzed by a nuclease S1 transcription assay, initiation of transcription was prevented when plasmid DNA was complexed to mannosylated polylysine. Our results indicate that the major limiting steps for mannosylated versus lactosylated polylysine transfer of plasmid DNA are delayed exit from endosomes, high accumulation in lysosomes and limited transcription of the complexed plasmid DNA