Evidence of Sexual Transmission of Zika Virus D’Ortenzio, Eric; Matheron, Sophie; de Lamballerie, Xavier ...
The New England journal of medicine,
06/2016, Letnik:
374, Številka:
22
Journal Article
Recenzirano
Odprti dostop
To the Editor:
Zika virus (ZIKV), an emerging flavivirus, generally causes mild infection in humans but is associated with severe neurologic complications and adverse fetal outcomes. ZIKV is ...transmitted to humans primarily by aedes mosquitoes. However, there is some evidence of sexual transmission.
1
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Two studies have shown the presence of infectious ZIKV in semen.
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A recent article described detection of ZIKV RNA in semen 62 days after the onset of illness, but infectious virus was not cultured.
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We report a case of ZIKV infection in a previously healthy 24-year-old woman (Patient 1) who was living in Paris and in . . .
Abstract
Viral RNA genomes are modified by epitranscriptomic marks, including 2′-O-methylation that is added by cellular or viral methyltransferases. 2′-O-Methylation modulates RNA structure, ...function and discrimination between self- and non-self-RNA by innate immune sensors such as RIG-I-like receptors. This is illustrated by human immunodeficiency virus type-1 (HIV-1) that decorates its RNA genome through hijacking the cellular FTSJ3 2′-O-methyltransferase, thereby limiting immune sensing and interferon production. However, the impact of such an RNA modification during viral genome replication is poorly understood. Here we show by performing endogenous reverse transcription on methylated or hypomethylated HIV-1 particles, that 2′-O-methylation negatively affects HIV-1 reverse transcriptase activity. Biochemical assays confirm that RNA 2′-O-methylation impedes reverse transcriptase activity, especially at low dNTP concentrations reflecting those in quiescent cells, by reducing nucleotide incorporation efficiency and impairing translocation. Mutagenesis highlights K70 as a critical amino acid for the reverse transcriptase to bypass 2′-O-methylation. Hence, the observed antiviral effect due to viral RNA 2′-O-methylation antagonizes the FTSJ3-mediated proviral effects, suggesting the fine-tuning of RNA methylation during viral replication.
Graphical Abstract
Graphical Abstract
Zika virus is an arthropod-borne Flavivirus member of the Spondweni serocomplex, transmitted by Aedes mosquitoes. We report here the complete coding sequence of a Zika virus strain belonging to the ...Asian lineage, isolated from an infected patient returning from French Polynesia, an epidemic area in 2013/2014.
Despite no or limited pre-clinical evidence, repurposed drugs are massively evaluated in clinical trials to palliate the lack of antiviral molecules against SARS-CoV-2. Here we use a Syrian hamster ...model to assess the antiviral efficacy of favipiravir, understand its mechanism of action and determine its pharmacokinetics. When treatment is initiated before or simultaneously to infection, favipiravir has a strong dose effect, leading to reduction of infectious titers in lungs and clinical alleviation of the disease. Antiviral effect of favipiravir correlates with incorporation of a large number of mutations into viral genomes and decrease of viral infectivity. Antiviral efficacy is achieved with plasma drug exposure comparable with those previously found during human clinical trials. Notably, the highest dose of favipiravir tested is associated with signs of toxicity in animals. Thereby, pharmacokinetic and tolerance studies are required to determine whether similar effects can be safely achieved in humans.
Abstract
The ongoing Corona Virus Disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has emphasized the urgent need for antiviral therapeutics. ...The viral RNA-dependent-RNA-polymerase (RdRp) is a promising target with polymerase inhibitors successfully used for the treatment of several viral diseases. We demonstrate here that Favipiravir predominantly exerts an antiviral effect through lethal mutagenesis. The SARS-CoV RdRp complex is at least 10-fold more active than any other viral RdRp known. It possesses both unusually high nucleotide incorporation rates and high-error rates allowing facile insertion of Favipiravir into viral RNA, provoking C-to-U and G-to-A transitions in the already low cytosine content SARS-CoV-2 genome. The coronavirus RdRp complex represents an Achilles heel for SARS-CoV, supporting nucleoside analogues as promising candidates for the treatment of COVID-19.
•We report protocols for rapid full-genome characterisation of RNA viruses.•Technique is based on a specific amplification step followed by NGS-sequencing.•Primers designed amplify complete genomes ...in 3–8 overlapping PCR fragments.•We obtained full-genome sequences for 53 strains (33 DENV, 8 EV-A71, 12 RSV-A).•It provided characterisation of viral isolates in a single assay, and in just 4 days.
Accurate characterisation of viral strains constitutes a crucial objective for the management of modern virus collections. Next-generation sequencing (NGS) provides technical solution for fast and cost-effective full genome sequencing. Here, we report protocols for rapid full-genome characterisation of RNA viruses of medical importance: dengue virus, enterovirus A71 and respiratory syncytial virus A, based on a specific amplification step followed by NGS-sequencing. A subset of full-length genome sequences representing the genetic diversity of each virus type was selected in GenBank and used to design primer sets allowing the amplification of the complete genome in 3–8 overlapping PCR fragments. The technique was used for characterising 53 strains (33 DENV, 8 EV-A71, 12 RSV-A) from various genotypes and origins. In a single assay, and in just 4 days, it provided for all strains an excellent genomic coverage (∼99% including complete ORF for all strains) and accurate sequences with high number of reads per position (250–3500 on average). The elaboration of specific PCR-based full-genome sequencing protocols for diverse virus groups is likely to revolutionise the characterisation of viral isolates in modern collection, but also to contribute in the next future to the study of RNA viruses directly from biological samples.
Despite repeated outbreaks, in particular the devastating 2014-2016 epidemic, there is no effective treatment validated for patients with Ebola virus disease (EVD). Among the drug candidates is the ...broad-spectrum polymerase inhibitor favipiravir, which showed a good tolerance profile in patients with EVD (JIKI trial) but did not demonstrate a strong antiviral efficacy. In order to gain new insights into the antiviral efficacy of favipiravir and improve preparedness and public health management of future outbreaks, we assess the efficacy achieved by ascending doses of favipiravir in Ebola-virus-infected nonhuman primates (NHPs).
A total of 26 animals (Macaca fascicularis) were challenged intramuscularly at day 0 with 1,000 focus-forming units of Ebola virus Gabon 2001 strain and followed for 21 days (study termination). This included 13 animals left untreated and 13 treated with doses of 100, 150, and 180 mg/kg (N = 3, 5, and 5, respectively) favipiravir administered intravenously twice a day for 14 days, starting 2 days before infection. All animals left untreated or treated with 100 mg/kg died within 10 days post-infection, while animals receiving 150 and 180 mg/kg had extended survival (P < 0.001 and 0.001, respectively, compared to untreated animals), leading to a survival rate of 40% (2/5) and 60% (3/5), respectively, at day 21. Favipiravir inhibited viral replication (molecular and infectious viral loads) in a drug-concentration-dependent manner (P values < 0.001), and genomic deep sequencing analyses showed an increase in virus mutagenesis over time. These results allowed us to identify that plasma trough favipiravir concentrations greater than 70-80 μg/ml were associated with reduced viral loads, lower virus infectivity, and extended survival. These levels are higher than those found in the JIKI trial, where patients had median trough drug concentrations equal to 46 and 26 μg/ml at day 2 and day 4 post-treatment, respectively, and suggest that the dosing regimen in the JIKI trial was suboptimal. The environment of a biosafety level 4 laboratory introduces a number of limitations, in particular the difficulty of conducting blind studies and performing detailed pharmacological assessments. Further, the extrapolation of the results to patients with EVD is limited by the fact that the model is fully lethal and that treatment initiation in patients with EVD is most often initiated several days after infection, when symptoms and high levels of viral replication are already present.
Our results suggest that favipiravir may be an effective antiviral drug against Ebola virus that relies on RNA chain termination and possibly error catastrophe. These results, together with previous data collected on tolerance and pharmacokinetics in both NHPs and humans, support a potential role for high doses of favipiravir for future human interventions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Success in smallpox eradication was enabled by the absence of non-human reservoir for smallpox virus. However, other poxviruses with a wider host spectrum can infect humans and represent a potential ...health threat to humans, highlighted by a progressively increasing number of infections by (re)emerging poxviruses, requiring new improved diagnostic and epidemiological tools. We describe here a real-time PCR assay targeting a highly conserved region of the poxvirus genome, thus allowing a pan-Poxvirus detection (Chordopoxvirinae and Entomopoxvirinae). This system is specific (99.8% for vertebrate samples and 99.7% for arthropods samples), sensitive (100% for vertebrate samples and 86.3% for arthropods samples) and presents low limit of detection (< 1000 DNA copies/reaction). In addition, this system could be also valuable for virus discovery and epidemiological projects.
•We developed generic real-time PCR and RT-PCR for β-actin DNA and RNA sequences.•A unique primers/probe system detects β-actin sequences of many animal species.•Mammal, fish, batrachian and ...arthropod species were tested in this work.•Cellular nucleic acids that contaminate viral extracts can be quantified.•This assay is useful for virologists working with many cell lines or animal models.
As a member of the European Virus Archive (EVA) consortium, our laboratory is developing and maintaining a large collection of viruses. This collection implies the use of a panel of cell lines originating from various animal species.
In order to make easier the handling of such a large panel of cell lines, wide spectrum real-time PCR and RT-PCR assays were developed to allow the detection and the quantification of DNA and mRNA of β-actin, one of the most commonly used eukaryotic housekeeping genes. By using two degenerated primers and a unique probe, these two assays were shown to detect nucleic acids of a panel of vertebrate and invertebrate cell lines commonly used in animal virology. This panel included human, monkey, rodent, dog, pig, fish, batrachian, mosquito and tick cell lines. Additionally, the two assays amplified successfully β-actin-encoding sequences of sandflies. Sensitivity evaluation performed on synthetic DNA and RNA sequences showed that the two assays were very sensitive and suitable for accurate quantification.
The two assays constitute together a convenient method suitable for multiple purposes. They can be used for instance to estimate the amount of contaminating cellular genetic material prior to sequence-independent amplification of viral genomes achieved before high-throughput sequencing, to evaluate the efficiency of DNase and/or RNase treatments performed on cellular extract and to check nucleic acid extraction by using β-actin-encoding sequences as endogenous control. This assay will constitute a precious tool for virologists working with multiple cell lines or animal models.
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