SARS-CoV-2 infection in Africa: a systematic review and meta-analysis of standardised seroprevalence studies, from January 2020 to December 2021

IntroductionEstimating COVID-19 cumulative incidence in Africa remains problematic due to challenges in contact tracing, routine surveillance systems and laboratory testing capacities and strategies. We undertook a meta-analysis of population-based seroprevalence studies to estimate SARS-CoV-2 seroprevalence in Africa to inform evidence-based decision making on public health and social measures (PHSM) and vaccine strategy.MethodsWe searched for seroprevalence studies conducted in Africa published 1 January 2020-30 December 2021 in Medline, Embase, Web of Science and Europe PMC (preprints), grey literature, media releases and early results from WHO Unity studies. All studies were screened, extracted, assessed for risk of bias and evaluated for alignment with the WHO Unity seroprevalence protocol. We conducted descriptive analyses of seroprevalence and meta-analysed seroprevalence differences by demographic groups, place and time. We estimated the extent of undetected infections by comparing seroprevalence and cumulative incidence of confirmed cases reported to WHO.ProsperoCRD42020183634.ResultsWe identified 56 full texts or early results, reporting 153 distinct seroprevalence studies in Africa. Of these, 97 (63%) were low/moderate risk of bias studies. SARS-CoV-2 seroprevalence rose from 3.0% (95% CI 1.0% to 9.2%) in April-June 2020 to 65.1% (95% CI 56.3% to 73.0%) in July-September 2021. The ratios of seroprevalence from infection to cumulative incidence of confirmed cases was large (overall: 100:1, ranging from 18:1 to 954:1) and steady over time. Seroprevalence was highly heterogeneous both within countries-urban versus rural (lower seroprevalence for rural geographic areas), children versus adults (children aged 0-9 years had the lowest seroprevalence)-and between countries and African subregions.ConclusionWe report high seroprevalence in Africa suggesting greater population exposure to SARS-CoV-2 and potential protection against COVID-19 severe disease than indicated by surveillance data. As seroprevalence was heterogeneous, targeted PHSM and vaccination strategies need to be tailored to local epidemiological situations

SARS-CoV-2 variants of interest and concern naming scheme conducive for global discourse

A group convened and led by the Virus Evolution Working Group of the World Health Organization reports on its deliberations and announces a naming scheme that will enable clear communication about SARS-CoV-2 variants of interest and concern.Molecular basis of virus replication, viral pathogenesis and antiviral strategie

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

One severe acute respiratory syndrome coronavirus protein complex integrates processive RNA polymerase and exonuclease activities

In addition to members causing milder human infections, the Coronaviridae family includes potentially lethal zoonotic agents causing severe acute respiratory syndrome (SARS) and the recently emerged Middle East respiratory syndrome. The ∼30-kb positive-stranded RNA genome of coronaviruses encodes a replication/transcription machinery that is unusually complex and composed of 16 nonstructural proteins (nsps). SARS-CoV nsp12, the canonical RNA-dependent RNA polymerase (RdRp), exhibits poorly processive RNA synthesis in vitro, at odds with the efficient replication of a very large RNA genome in vivo. Here, we report that SARS-CoV nsp7 and nsp8 activate and confer processivity to the RNA-synthesizing activity of nsp12. Using biochemical assays and reverse genetics, the importance of conserved nsp7 and nsp8 residues was probed. Whereas several nsp7 mutations affected virus replication to a limited extent, the replacement of two nsp8 residues (P183 and R190) essential for interaction with nsp12 and a third (K58) critical for the interaction of the polymerase complex with RNA were all lethal to the virus. Without a loss of processivity, the nsp7/nsp8/nsp12 complex can associate with nsp14, a bifunctional enzyme bearing 3′-5′ exoribonuclease and RNA cap N7-guanine methyltransferase activities involved in replication fidelity and 5′-RNA capping, respectively. The identification of this tripartite polymerase complex that in turn associates with the nsp14 proofreading enzyme sheds light on how coronaviruses assemble an RNA-synthesizing machinery to replicate the largest known RNA genomes. This protein complex is a fascinating example of the functional integration of RNA polymerase, capping, and proofreading activities

Chikungunya fever in Africa. A systematic review

Since the identification of chikungunya virus (CHIKV), sporadic cases and outbreaks were reported in several African countries, on the Indian subcontinent, and in south-east Asia. In the last 20 years, there is a growing number of reports of CHIKV infections from African countries, but the overall picture of its circulation at the continent level remains ill-characterized because of under-diagnosis and under-reporting. Moreover, the public health impact of the infection in Africa is generally poorly understood, especially during outbreak situations. Our work has the aim to review available data on CHIKV circulation in Africa to facilitate the understanding of underlying reasons of its increased detection in the African continent

Nail penetration and predicted mycological efficacy of an innovative hydrosoluble ciclopirox nail lacquer vs. a standard amorolfine lacquer in healthy subjects.

Background  In a previous study a new hydrosoluble nail lacquer (P-3051) containing 8% ciclopirox (CPX) showed higher nail penetration compared to a water-insoluble 5% amorolfine (MRF) lacquer. To our knowledge, in vivo human data on a similar topic are not available. Objectives  To compare fingernail penetration of P-3051 with that of MRF reference in humans and to evaluate their predicted efficacy against Trichophyton rubrum and Candida parapsilosis. Methods  Single centre, randomized, multiple dose, open label, within subjects study. Test and reference were self-applied to all fingernails of either hand for 28 days. At baseline and after 15 and 25 days, the nail free edge was collected for analysis. Efficiency coefficients were calculated for T. rubrum and C. parapsilosis as ratios of nail concentration/minimum inhibitory concentration. The coefficients were classified as very high, high or poor. Results  Nail concentrations after 15 days were 2.82 ± 0.58 μg/mg for CPX and 0.64 ± 0.11 μg/mg for MRF. At day 25 there was a non-significant decline (1.85 ± 0.31 μg/mg, P = 0.077) for CPX and a highly significant (0.13  ± 0.03 μg/mg, P = 0.0002) 80% decline for MRF. Efficiency coefficients were very high/high in all subjects treated with P-3051 against both T. rubrum and C. parapsilosis; they were significantly lower for MRF reference against both pathogens at both observation points. Conclusions  P-3051 exhibited better penetration and higher predicted efficacy after in vivo multiple application to human fingernails when compared to MRF reference. These in vivo data are in good agreement with our previous in vitro study

N-ALKYL-NOR-TROPINE ESTERS OF 2-PHENYL-CYCLOHEXENIC ACIDS AS NEW BRONCHODILATOR AGENTS - EFFECT OF STRUCTURAL AND CONFORMATIONAL MODIFICATIONS ON AFFINITY FOR MUSCARINIC RECEPTORS

A series of N-alkyl-nor-tropine esters of 2-phenyl-2-cyclohexene-1-carboxylic, 2-phenyl-cyclohexanecarboxylic, and 2-phenyl-1-cyclohexene-1-acetic acids and their quaternary ammonium salts were synthesized and evaluated for bronchodilator activity by binding assays and pharmacological tests. The in vitro and in vivo functional activity results showed that some quaternary derivatives are potent anticholinergic bronchodilator agents, and 4 compounds (14-A, 16-A, 25-A and 28-A) were selected for pharmacotoxicological evaluation. The binding data also indicated that the affinity of these compounds for the tracheal membrane muscarinic receptors is markedly affected by structural modifications of both the cationic head and the acyl moiety of the molecule. In the series of N-alkyl-nor-tropine 2-phenyl-2-cyclohexene-1-carboxylate derivatives, a rather strict limitation of the bulk of the equatorial substituent of tropine nitrogen is required for very high affinity. Conformational analysis and molecular graphics techniques evidenced an influence of the acyl moiety conformation on the affinity of the different tropinic esters, suggesting that the carbonyl oxygen may participate in interaction with the binding site, eliciting a marked increase of potency when it is oriented in a proper conformation with respect to the tropinic nitrogen and the phenyl ring

In vitro antiviral activity of distamycin A against clinical isolates of herpes simplex virus 1 and 2 from transplanted patients

OBJECTIVE(S): Herpes simplex virus (HSV) infections in immunocompromised individuals may require prolonged antiviral therapy resulting in the emergence of viral strains resistant to the currently employed antiviral drugs. Distamycin A (DA), a basic antibiotic belonging to the lexitropsin DNA minor groove binding drugs, exhibits antiviral properties. In this study we evaluated the in vitro cytotoxicity and antiviral activity of DA against HSV type 1 and HSV type 2 clinical isolates from transplanted patients and compared them with those of acyclovir (ACV) in search of alternative antiviral drugs. METHODS: Viral detection and typing was performed by multiplex PCR and immunofluorescence assay; the in vitro cytotoxicity of DA and the antiviral activity of ACV and DA was evaluated respectively by neutral red uptake assay and plaque reduction assay for HSV2 isolates and fluorescence reduction assay for HSV1 isolates. RESULTS: Tissue culture 50% cytotoxic concentration of DA was 58 muM. Tissue culture 50% inhibitory concentration values ranged from 0.16 to 7.4 muM for the ACV-sensitive and from 5.4 to 32 muM for the ACV-resistant viral strains. CONCLUSIONS: In spite of the lower activity against ACV-resistant strains, DA may be used as an antiherpetic drug

Prudentia Iuris, 2000, n° 53. Apéndice (número completo)

Contenido: Exordio – Trabajos monográficos y de investigación realizados por profesores y alumnos de la carrera de grado y posgrado: Un aporte sobre la ignorancia y el error en materia penal / Alfredo Repetto – El hombre encarcelado y la pastoral penitenciaria / Ignacio Rodríguez Varela – Consideraciones preliminares sobre la culpabilidad y el error / Andrea Subissi – Agente encubierto / Ángel Daniel Rendo – Teorías de los fundamentos y los fines de la pena / Francisco A. Posada – Protección integral de la vida humana / Javier Anzoategui ; Analía Pastore ; Luis Velasc