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A distinct class of infectious agents, the virophages that infect giant viruses of the Mimiviridae family, has been recently described. Here we report the simultaneous discovery of a giant virus of Acanthamoeba polyphaga (Lentille virus) that contains an integrated genome of a virophage (Sputnik 2), and a member of a previously unknown class of mobile genetic elements, the transpovirons. The transpovirons are linear DNA elements of ∼7 kb that encompass six to eight protein-coding genes, two of which are homologous to virophage genes. Fluorescence in situ hybridization showed that the free form of the transpoviron replicates within the giant virus factory and accumulates in high copy numbers inside giant virus particles, Sputnik 2 particles, and amoeba cytoplasm. Analysis of deep-sequencing data showed that the virophage and the transpoviron can integrate in nearly any place in the chromosome of the giant virus host and that, although less frequently, the transpoviron can also be linked to the virophage chromosome. In addition, integrated fragments of transpoviron DNA were detected in several giant virus and Sputnik genomes. Analysis of 19 Mimivirus strains revealed three distinct transpovirons associated with three subgroups of Mimiviruses. The virophage, the transpoviron, and the previously identified self-splicing introns and inteins constitute the complex, interconnected mobilome of the giant viruses and are likely to substantially contribute to interviral gene transfer.

NEC was associated with C. butyricum strains and dysbiosis with an oxidized, acid, and poorly diversified gut microbiota. Our findings highlight the plausible toxigenic mechanism involved in the pathogenesis of NEC.

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In December 2019, a new severe acute respiratory syndrome coronavirus (SARS-CoV-2) causing coronavirus diseases 2019 (COVID-19) emerged in Wuhan, China. African countries see slower dynamic of COVID-19 cases and deaths. One of the assumptions that may explain this later emergence in Africa, and more particularly in malaria endemic areas, would be the use of antimalarial drugs. We investigated the in vitro antiviral activity against SARS-CoV-2 of several antimalarial drugs. Chloroquine (EC 50 = 2.1 μM and EC 90 = 3.8 μM), hydroxychloroquine (EC 50 = 1.5 μM and EC 90 = 3.0 μM), ferroquine (EC 50 = 1.5 μM and EC 90 = 2.4 μM), desethylamodiaquine (EC 50 = 0.52 μM and EC 90 = 1.9 μM), mefloquine (EC 50 = 1.8 μM and EC 90 = 8.1 μM), pyronaridine (EC 50 = 0.72 μM and EC 90 = 0.75 μM) and quinine (EC 50 = 10.7 μM and EC 90 = 38.8 μM) showed in vitro antiviral effective activity with IC 50 and IC 90 compatible with drug oral uptake at doses commonly administered in malaria treatment. The ratio C lung /EC 90 ranged from 5 to 59. Lumefantrine, piperaquine and dihydroartemisinin had IC 50 and IC 90 too high to be compatible with expected plasma concentrations (ratio C max /EC 90 < 0.05). Based on our results, we would expect that countries which commonly use artesunate-amodiaquine or artesunate-mefloquine report fewer cases and deaths than those using artemether-lumefantrine or dihydroartemisinin-piperaquine. It could be necessary now to compare the antimalarial use and the dynamics of COVID-19 country by country to confirm this hypothesis.

Objectives At the end of November 2019, a novel coronavirus responsible for respiratory tract infections (COVID-19) emerged in China. Despite drastic containment measures, this virus, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), spread in Asia and Europe. The pandemic is ongoing with a particular hotspot in Southern Europe and America; many studies predicted a similar epidemic in Africa, as is currently seen in Europe and the United States of America. However, reported data have not confirmed these predictions. One of the hypotheses that could explain the later emergence and spread of COVID-19 pandemic in African countries is the use of antimalarial drugs to treat malaria, and specifically, artemisinin-based combination therapy (ACT). Methods The antiviral activity of fixed concentrations of ACT at concentrations consistent with those observed in human plasma when ACT is administered at oral doses for uncomplicated malaria treatment was evaluated in vitro against a clinically isolated SARS-CoV-2 strain (IHUMI-3) in Vero E6 cells. Results Mefloquine-artesunate exerted the highest antiviral activity with % inhibition of 72.1 ± 18.3 % at expected maximum blood concentration (C max ) for each ACT drug at doses commonly administered in malaria treatment. All the other combinations, artesunate-amodiaquine, artemether-lumefantrine, artesunate-pyronaridine, or dihydroartemisinin-piperaquine, showed antiviral inhibition in the same ranges (27.1 to 34.1 %). Conclusions Antimalarial drugs for which concentration data in the lungs are available are concentrated from 10 to 160 fold more in the lungs than in blood. These in vitro results reinforce the hypothesis that antimalarial drugs could be effective as an anti-COVID-19 treatment.

In December 2019, a new severe acute respiratory syndrome coronavirus (SARS-CoV-2), causing coronavirus disease 2019 (COVID-19), emerged in Wuhan, China. Despite containment measures, SARS-CoV-2 spread in Asia, Southern Europe, then in America and currently in Africa. Identifying effective antiviral drugs is urgently needed. An efficient approach to drug discovery is to evaluate whether existing approved drugs can be efficient against SARS-CoV-2. Doxycycline, which is a second-generation tetracycline with broad-spectrum antimicrobial, antimalarial and anti-inflammatory activities, showed in vitro activity on Vero E6 cells infected with a clinically isolated SARS-CoV-2 strain (IHUMI-3) with median effective concentration (EC50) of 4.5 ± 2.9 µM, compatible with oral uptake and intravenous administrations. Doxycycline interacted both on SARS-CoV-2 entry and in replication after virus entry. Besides its in vitro antiviral activity against SARS-CoV-2, doxycycline has anti-inflammatory effects by decreasing the expression of various pro-inflammatory cytokines and could prevent co-infections and superinfections due to broad-spectrum antimicrobial activity. Therefore, doxycycline could be a potential partner of COVID-19 therapies. However, these results must be taken with caution regarding the potential use in SARS-CoV-2-infected patients: it is difficult to translate in vitro study results to actual clinical treatment in patients. In vivo evaluation in animal experimental models is required to confirm the antiviral effects of doxycycline on SARS-CoV-2 and more trials of high-risk patients with moderate to severe COVID-19 infections must be initiated.

Highlights Methylene blue 50% cytotoxicity concentration (CC 50 ) > 100 µM in Vero E6 cells. Methylene blue EC 50 of 0.3 ± 0.03 µM and EC 90 of 0.75 ± 0.21 µM at MOI of 0.25 against Vero E6 cells infected with SARS-CoV-2 strain (IHUMI-3). In comparison, EC 50 and EC 90 of 1.5 and 3.0 µM for hydroxychloroquine and 20.1 and 41.9 µM for azithromycin. C max /EC 50 and C max /EC 90 ratios in blood for methylene blue after oral administration were estimated at 10.1 and 4.0, respectively, and 33.3 and 13.3 after intravenous administration. Methylene blue EC 50 and EC 90 consistent with concentrations observed in human blood. Methylene blue inhibited SARS-CoV-2 replication in Vero E6 cells.