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Résumé: Les maladies infectieuses émergentes sont récurrentes et représentent un enjeu de sécurité sanitaire planétaire. Le continent africain est particulièrement exposé aux risques infectieux épidémiques à cause du nombre d'agents infectieux qui y circulent, en particulier dans la faune, mais aussi de par des facteurs sociaux et environnementaux qui favorisent leur diffusion épidémique. Les épidémies à virus Ebola en Afrique de l'Ouest en 2014 et celles en République démocratique du Congo (RDC) ayant débuté en 2018 ont été l'occasion de mettre au point et de déployer de nouvelles techniques diagnostiques pour des laboratoires en Guinée et en RDC. Ces outils ont permis d'identifier rapidement l'agent infectieux, de retracer en temps réel les chaînes de contamination pour intervenir efficacement et développer un outil sérologique fiable permettant un diagnostic différentiel. Aujourd'hui, des structures équipées et fonctionnelles existent en Guinée et en RDC pour répondre aux risques d'émergence épidémique, pilotées par des chercheurs guinéens et congolais formés à des niveaux de compétence élevés et bénéficiant d'expérience et de connaissance de terrain uniques. Emerging infectious diseases appear recurrently and represent a threat to global health security. Africa is particularly exposed to the risks of infectious epidemics, due to both the number of circulating infectious agents, especially in wildlife, and the social and environmental factors that promote their epidemic spread. Ebola outbreaks in West Africa in 2014 and those in the DRC that began in 2018 were an opportunity to develop and deploy new diagnostic techniques in laboratories in Guinea and the Democratic Republic of the Congo (DRC). These tools made it possible to identify the infectious agent rapidly, to trace contamination chains in real time to enable effective interventions, and to develop a reliable serological tool for differential diagnoses. Today, equipped and functional facilities exist in both countries, led by Guinean and Congolese researchers trained to high levels of competence and benefiting from unique experience and field knowledge. [ABSTRACT FROM AUTHOR]

Background: Several variants of SARS-CoV-2 have a demonstrated impact on public health, including high and increased transmissibility, severity of infection, and immune escape. Therefore, this study aimed to determine the SARS-CoV-2 lineages and better characterize the dynamics of the pandemic during the different waves in Guinea., Methods: Whole genome sequencing of 363 samples with PCR cycle threshold (Ct) values under thirty was undertaken between May 2020 and May 2023. The Illumina iSeq 100 technology was used. The sequences were then analyzed using the GeVarli pipeline to generate consensus sequences and variant calling. All sequences isolated in Guinea and available on GISAID were included in the analysis for phylogenetic tree and phylodynamic determination. Nextstain tools were used for these analyses. Statistical analysis was done using GraphPad Prism version 10., Results: The circulation of SARS-CoV-2 in Guinea can be distributed in three different periods. The first, lasting from May to June 2020, was characterized by lineages B1 and B.1.1. The second period, from January 2021 to July 2021, was characterized by the lineages B.1.1.7 (Alpha), AY.122, B.1.1.318, R1, B.1.525 and B.1.629. The third period, between December 2021 and May 2023, was characterized by the Omicron variant, with nine subvariant majorities found. In addition, detecting variants in the period out of their circulation was documented. The importation and exportation investigation showed the strong movement viral association between Guinea and Senegal on the one hand and Guinea and Nigeria on the other., Conclusion: In summary, this study contributes to understanding the epidemic dynamics of the disease by describing the significant variants that circulated in Guinee and the distribution of this variant in the population. It also shows the importation and exportation of the virus during the pandemic. Sub-sampling and degradation of samples for sequences were observed. Organization and collaboration between laboratories are needed for a good sample-collecting and storage system for future direction., Competing Interests: Declarations. Ethics approval and consent to participate: Ethics approval for this study was obtained from the National Ethics Review Board (number 062/CNERS/22). The protection of confidentiality was promoted to all participants. All participants for whom nasopharyngeal samples were collected provided verbal informed consent to participate in the study. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Objectives: This study aimed to investigate the prevalence of orthoebolavirus antibodies in Madina Oula, a non-epidemic rural area in Guinea, in 2022., Methods: A cross-sectional study was conducted from March 14 to April 3, 2022 involving recording household and socio-demographic characteristics, lifestyle data, and collecting dried blood spots from 878 individuals in 235 households. Dried blood spots were tested using multiplex serology to detect antibodies to different orthoebolaviruses: Ebola virus, Bundibugyo virus, Sudan virus, Reston virus, and Bombali virus. Seroprevalence was estimated with a 95% confidence interval and a Z-test was performed to compare the seropositivity between children aged under 15 years and those over 15 years. Household and participant characteristics were analyzed using descriptive statistic, and socio-historical conditions were discussed., Results: The serological analysis conducted in 2022 on 878 participants revealed varying reactivity to orthoebolavirus antigens, notably, with glycoprotein antigens, particularly, glycoprotein Sudan virus (16%). A total of 21 samples exhibited reactivity with at least two antigens, with a median age of 27 years (interquartile range 10.00-35.00), ranging from 2 to 80 years. There is no significant difference between seropositivity in children aged under 15 (2.86%) years and those over 15 (2.14%) years. The antibody presence varied per village, with the highest prevalence observed in Ouassou and Dar-es-Salam., Conclusions: Serological data in a region unaffected by recent Ebola outbreaks indicate possible orthoebolavirus endemicity, emphasizing the need for preparedness against known or novel orthoebolaviruses with potential cross-reactivity., Competing Interests: Declarations of competing interest The authors have no competing interests to declare., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Emergence of mosquito-borne arboviruses has caused significant public health burden. The life cycle of arboviruses comprises sylvatic and urban cycles, including a wildlife reservoir, a human host, and an arthropod vector. However, many questions remain on the sylvatic cycles of arboviruses. In this study, we investigate the prevalence of IgG antibodies to arboviruses of public health importance in African bats. Material and Methods: We collected dried blood spots from bats in Cameroon, Guinea, and the Democratic Republic of the Congo (DRC). To detect IgG antibodies to 10 antigens of 6 arboviruses (Dengue, Zika, West Nile, Usutu, Chikungunya, and O'nyong nyong viruses), we adapted a previously validated multiplex detection assay based on the Luminex technology. Results: We tested samples from 2579 bats, representing 1917 frugivorous and 641 insectivorous bats distributed in 7 families and 21 species. Overall, 218/2579 (8.45%) bat samples reacted with at least 1 of the 10 antigens tested. The highest prevalence was observed against Usutu virus with 2.3% (59/2579), followed by 1.9% (49/2579) and 1.35% (35/2579) for the Dengue virus serotypes 4 and 3, respectively. The global seroprevalence varied by country and collection site: 11% (151/1376) in Cameroon, 3.5% (20/565) in DRC, and 7.3% (47/638) in Guinea. The highest rates were observed in Hypsignathus monstrosus (17.9%), Rousettus aegyptiacus (16.4%), and Eidolon helvum (10.7%), and in species from the insectivorous Molossidae family (7.8-8.9%). Finally, we observed changes in seroprevalence over the year in E. helvum and H. monstrosus colonies, which could be related to population structure. Conclusion: On more than 2500 bat samples tested, we showed variable IgG seroprevalences against multiple arboviruses. Overall, the prevalence of IgG antibodies of 8.45% against arboviruses found in bats suggest that they could play a role in arboviruses cycles in the wild, in addition to other animal species.

Background: Longitudinal analyses are needed to better understand long-term Ebola virus disease (EVD) sequelae. We aimed to estimate the prevalence, incidence, and duration of sequelae and to identify risk factors associated with symptom occurrence among EVD survivors in Guinea., Methods: We followed 802 EVD survivors over 48 months and recorded clinical symptoms with their start/end dates. Prevalence, incidence, and duration of sequelae were calculated. Risk factors associated with symptom occurrence were assessed using an extended Cox model for recurrent events., Results: Overall, the prevalence and incidence of all symptoms decreased significantly over time, but sequelae remained present 48 months after Ebola treatment center discharge with a prevalence of 30.68% (95% confidence interval [CI] 21.40-39.96) for abdominal, 30.55% (95% CI 20.68-40.41) for neurologic, 5.80% (95% CI 1.96-9.65) for musculoskeletal, and 4.24% (95% CI 2.26-6.23) for ocular sequelae. Half of all patients (50.70%; 95% CI 47.26-54.14) complained of general symptoms 2 years' postdischarge and 25.35% (95% CI 23.63-27.07) 4 years' post-discharge. Hemorrhage (hazard ratio [HR], 2.70; P = .007), neurologic (HR 2.63; P = .021), and general symptoms (HR 0.34; P = .003) in the EVD acute phase were significantly associated with the further occurrence of ocular sequelae, whereas hemorrhage (HR 1.91; P = .046) and abdominal (HR 2.21; P = .033) symptoms were significantly associated with musculoskeletal sequelae., Conclusions: Our findings provide new insight into the long-term clinical complications of EVD and their significant association with symptoms in the acute phase, thus reinforcing the importance of regular, long-term follow-up for EVD survivors., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: Insufficient long-term data are available on antibody kinetics in survivors of Ebola virus disease (EVD). Likewise, few studies, with very small sample sizes, have investigated cross-reactions between Ebolavirus spp. In this study, we aimed to assess the humoral antibody response and its determinants in survivors of EVD and assess cross-reactivity of antibodies between diverse Ebolavirus spp., Methods: In this observational, prospective cohort study, we collected blood samples from patients from three recruitment sites in Guinea included in the Postebogui study, and we assessed IgG antibody binding to recombinant glycoprotein, nucleoprotein, and 40-kDa viral protein (VP40) of Zaire (EBOV), Bundibugyo (BDBV), and Sudan (SUDV) Ebolaviruses. Participants from the PostEbogui study, from whom we had at least one blood sample that could be tested for the presence of antibodies, were eligible for this analysis. Patients in the PostEbogui study were assessed clinically at inclusion, 1 month and 3 months later, and subsequently every 6 months for up to 60 months after discharge from the Ebola treatment centre. We explored predictors of glycoprotein, nucleoprotein, and VP40 antibody concentrations through a linear mixed model. A logistic mixed model was done to estimate the probability of seropositivity and associated determinants. We assessed cross-reactivity by use of hierarchical cluster analysis., Findings: Of the 802 patients included in the Postebogui study, 687 were included in our analyses. 310 (45%) patients were men and 377 (55%) were women, with an overall median age at the time of the first blood sample of 27·3 years (IQR 19·5-38·2). We observed an overall significant decrease over time of EBOV antibodies, with antibodies against nucleoproteins decreasing more rapidly. At 60 months after discharge from the Ebola treatment centre, the probability of having antibodies against glycoproteins was 76·2% (95% CI 67·2-83·3), against nucleoproteins was 59·4% (46·3-71·3), and against VP40 was 60·9% (51·4-69·8). Persistence of EBOV RNA in semen was associated with higher concentrations of IgG antibodies against nucleoprotein EBOV antigens. Individually, we observed in some survivors an antibody wax-and-wane pattern. The proportion of cross-reactions was highest between glycoproteins from Kissidougou and Mayinga EBOV strains (94·5%, 95% CI 92·5-96·1), followed by EBOV VP40 and BDBV VP40 (88·3%, 85·7-90·6), and EBOV VP40 and SUDV VP40 (83·3%, 80·3-86·1)., Interpretation: The probability for survivors of EVD to have antibodies against one or more EBOV antigens remained high, although approximately 25% of survivors had undetectable antibodies, which could have implications, such as a possible decreasing population immunity, for future Ebola outbreaks in the same region., Funding: Reacting-Institut National de la Santé et de la Recherche Médicale, Institut de Recherche pour le Developpement, and Montpellier Université d'Excellence., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Seven years after the declaration of the first epidemic of Ebola virus disease in Guinea, the country faced a new outbreak-between 14 February and 19 June 2021-near the epicentre of the previous epidemic 1,2 . Here we use next-generation sequencing to generate complete or near-complete genomes of Zaire ebolavirus from samples obtained from 12 different patients. These genomes form a well-supported phylogenetic cluster with genomes from the previous outbreak, which indicates that the new outbreak was not the result of a new spillover event from an animal reservoir. The 2021 lineage shows considerably lower divergence than would be expected during sustained human-to-human transmission, which suggests a persistent infection with reduced replication or a period of latency. The resurgence of Zaire ebolavirus from humans five years after the end of the previous outbreak of Ebola virus disease reinforces the need for long-term medical and social care for patients who survive the disease, to reduce the risk of re-emergence and to prevent further stigmatization., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Zoonoses can constitute a threat for public health that can have a global importance, as seen with the current COVID-19 pandemic of severe acute respiratory syndrome coronavirus (SARS-CoV2). Bats have been recognized as an important reservoir of zoonotic coronaviruses (CoVs). In West Africa, where there is a high diversity of bat species, little is known on the circulation of CoVs in these hosts, especially at the interface with human populations. In this study, in Guinea, we tested a total of 319 bats belonging to 14 genera and six families of insectivorous and frugivorous bats across the country, for the presence of coronaviruses. We found CoVs in 35 (11%) of the tested bats-in three insectivorous bat species and five fruit bat species that were mostly captured close to human habitat. Positivity rates varied from 5.7% to 100%, depending on bat species. A wide diversity of alpha and beta coronaviruses was found across the country, including three sequences belonging to SarbeCoVs and MerbeCoVs subgenera known to harbor highly pathogenic human coronaviruses. Our findings suggest that CoVs are widely spread in West Africa and their circulation should be assessed to evaluate the risk of exposure of potential zoonotic CoVs to humans.

Emerging infectious diseases appear recurrently and represent a threat to global health security. Africa is particularly exposed to the risks of infectious epidemics, due to both the number of circulating infectious agents, especially in wildlife, and the social and environmental factors that promote their epidemic spread. Ebola outbreaks in West Africa in 2014 and those in the DRC that began in 2018 were an opportunity to develop and deploy new diagnostic techniques in laboratories in Guinea and the Democratic Republic of the Congo (DRC). These tools made it possible to identify the infectious agent rapidly, to trace contamination chains in real time to enable effective interventions, and to develop a reliable serological tool for differential diagnoses. Today, equipped and functional facilities exist in both countries, led by Guinean and Congolese researchers trained to high levels of competence and benefiting from unique experience and field knowledge.

Background: The prevalence of Ebola virus infection among people who have been in contact with patients with Ebola virus disease remains unclear, but is essential to understand the dynamics of transmission. This study aimed to identify risk factors for seropositivity and to estimate the prevalence of Ebola virus infection in unvaccinated contact persons., Methods: In this retrospective, cross-sectional observational study, we recruited individuals between May 12, 2016, and Sept 8, 2017, who had been in physical contact with a patient with Ebola virus disease, from four medical centres in Guinea (Conakry, Macenta, N'zérékoré, and Forécariah). Contact persons had to be 7 years or older and not diagnosed with Ebola virus disease. Participants were selected through the Postebogui survivors' cohort. We collected self-reported information on exposure and occurrence of symptoms after exposure using a questionnaire, and tested antibody response against glycoprotein, nucleoprotein, and 40-kDa viral protein of Zaire Ebola virus by taking a blood sample. The prevalence of Ebola virus infection was estimated with a latent class model., Findings: 1721 contact persons were interviewed and given blood tests, 331 of whom reported a history of vaccination so were excluded, resulting in a study population of 1390. Symptoms were reported by 216 (16%) contact persons. The median age of participants was 26 years (range 7-88) and 682 (49%) were male. Seropositivity was identified in 18 (8·33%, 95% CI 5·01-12·80) of 216 paucisymptomatic contact persons and 39 (3·32%, 5·01-12·80) of 1174 (2-4) asymptomatic individuals (p=0·0021). Seropositivity increased with participation in burial rituals (adjusted odds ratio [aOR] 2·30, 95% CI 1·21-4·17; p=0·0079) and exposure to blood or vomit (aOR 2·15, 1·23-3·91; p=0·0090). Frequency of Ebola virus infection varied from 3·06% (95% CI 1·84-5·05) in asymptomatic contact persons who did not participate in burial rituals to 5·98% (2·81-8·18) in those who did, and from 7·17% (3·94-9·09) in paucisymptomatic contact persons who did not participate in burial rituals to 17·16% (12·42-22·31) among those who did., Interpretation: This study provides a new assessment of the prevalence of Ebola virus infection among contact persons according to exposure, provides evidence for the occurrence of paucisymptomatic cases, and reinforces the importance of closely monitoring at-risk contact persons., Funding: Institut National de la Santé et de la Recherche Médicale, Reacting, the French Ebola Task Force, Institut de Recherche pour le Développement, and Montpellier University Of Excellence-University of Montpellier., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

To clarify the role of bats in the ecology of Ebola viruses, we assessed the prevalence of Ebola virus antibodies in a large-scale sample of bats collected during 2015-2017 from countries in Africa that have had previous Ebola outbreaks (Guinea, the Democratic Republic of the Congo) or are at high risk for outbreaks (Cameroon). We analyzed 4,022 blood samples of bats from >12 frugivorous and 27 insectivorous species; 2-37 (0.05%-0.92%) bats were seropositive for Zaire and 0-30 (0%-0.75%) bats for Sudan Ebola viruses. We observed Ebola virus antibodies in 1 insectivorous bat genus and 6 frugivorous bat species. Certain bat species widespread across Africa had serologic evidence of Zaire and Sudan Ebola viruses. No viral RNA was detected in the subset of samples tested (n = 665). Ongoing surveillance of bats and other potential animal reservoirs are required to predict and prepare for future outbreaks.

Questions remain as to whether an unnoticed Ebola outbreak occurred in Guinea before the 2014-2016 epidemic. To address this, we used a highly sensitive and specific Luminex-based assay for Ebola virus (EBOV) antibody detection to screen blood samples collected in the framework of the Demographic Health Survey performed in 2012 in Guinea. One sample (GF069) of 1,483 tested was positive at very high immunoglobulin G titer to Zaire EBOV in Guinée Forestière. Thus, at least 2 years before the 2014 EVD outbreak in Guinea, Zaire EBOV was circulating in rural areas of this country.

Introduction: Access to antiretroviral treatment (ART) becomes more and more effective in resource-limited settings (RLS). However, this global effort would be even more profitable if the access to laboratory services especially in decentralized settings was strengthened. We report the virological outcome and HIV-1 drug resistance in three West African countries using dried blood spots (DBS) samples., Methods: We included HIV-1-infected adults on ART ≥6 months and followed up in capital cities and decentralized sites in Senegal, Mali and Guinea-Conakry. Patients were consecutively enrolled and DBS were collected in field conditions and kept at ambient temperature before transfer to the reference laboratory. Viral load (VL) was quantified using the NucliSENS EasyQ HIV-1 v1.2. Genotyping of HIV-1 pol gene was performed using in-house protocol., Results: Of the 407 participants, 119, 152 and 136 were from Senegal, Mali and Guinea-Conakry, respectively. The median treatment duration was 36 months [IQR: 6-136]. Virological failure (VF) (VL≥3log10 copies/mL) was observed in 26% (95% confidence interval (CI), 18-35; n=31), 11% (95% CI, 6-17; n=16) and 24% (95% CI, 17-32; n=33) of patients in Senegal, Mali and Guinea-Conakry, respectively (p=0.001). Of samples presenting VL≥3log10 copies/mL (n=80), 70 were successfully genotyped. At least one drug resistance mutation (DRM) was detected in the following proportions: 70% (95% CI, 50-86; n=19), 93% (95% CI, 68-100; n=14) and 68% (95% CI, 48-84; n=19) in Senegal, Mali and Guinea-Conakry, respectively (p=0.22). Twenty-six per cent (26%; 95% CI, 16-38; n=18) of patients in VF harboured wild-type viruses, which is likely indicative of weak adherence. Phylogenetic analysis showed the predominance of CRF02_AG subtype (73%; 95% CI, 61-83; n=51)., Conclusions: We describe the ART outcome in capital and rural settings of Senegal, Mali and Guinea-Conakry. Our results in all of the three countries highlight the need to reinforce the ART adherence in order to minimize the occurrence of drug resistance. In addition, these findings provide additional evidence that the use of DBS as a sampling support could assist virological monitoring of patients on ART in remote areas.