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Background Favipiravir is used to treat influenza, and studies demonstrate that it has antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods We performed a randomized, open-label, multicenter, phase 2 proof-of-concept trial of favipiravir in hospitalized adult patients with polymerase chain reaction (PCR)–positive coronavirus disease 2019 (COVID-19). Patients were randomized to standard of care (SOC) or favipiravir treatment (1800mg per os twice a day [b.i.d.] on day 1, followed by 1000mg b.i.d. for 13 days). The primary end point was time to viral clearance on day 29. Results Fifty patients were enrolled and stratified by disease severity (critical disease, severe disease, or mild to moderate disease). Nineteen patients were censored from the event of viral clearance based on being SARS-CoV-2 PCR-negative at the study outset, being PCR-positive at day 29, or because of loss to follow-up. Data from the 31 remaining patients who achieved viral clearance show enhanced viral clearance in the favipiravir group compared with the SOC group by day 29, with 72% of the favipiravir group and 52% of the SOC group being evaluable for viral clearance through day 29. The median time to viral clearance was 16.0 days (90% CI, 12.0 to 29.0) in the favipiravir group and 30.0 days (90% CI, 12.0 to 31.0) in the SOC group. A post hoc analysis revealed an effect in the subgroup of patients who were neutralizing antibody–negative at randomization. Treatment-emergent adverse events were equally distributed between the groups. Conclusions We demonstrate that favipiravir can be safely administered to hospitalized adults with COVID-19 and believe that further studies are warranted. ClinicalTrials.gov registration NCT04358549. [ABSTRACT FROM AUTHOR]

Influenza virus inflicts a heavy death toll annually and resistance to existing antiviral drugs has generated interest in the development of agents with novel mechanisms of action. Favipiravir is an antiviral drug that acts by increasing the genome-wide mutation rate of influenza A virus (IAV). Potential synergistic benefits of combining oseltamivir and favipiravir have been demonstrated in animal models of influenza, but the population-level effects of combining the drugs are unknown. In order to elucidate the underlying evolutionary processes at play, we performed genome-wide sequencing of IAV experimental populations subjected to serial pass-aging in vitro under a combined protocol of oseltamivir and favipiravir. We describe the interplay between mutation, selection, and genetic drift that ultimately culminates in population extinction. In particular, selective sweeps around oseltamivir resistance mutations reduce genome-wide variation while deleterious mutations hitchhike to fixation given the increased mutational load generated by favipiravir. This latter effect reduces viral fitness and accelerates extinction compared with IAV populations treated with favipiravir alone, but risks spreading both established and newly emerging mutations, including possible drug resistance mutations, if transmission occurs before the viral populations are eradicated. [ABSTRACT FROM AUTHOR]

The rapid evolution of drug resistance remains a critical public health concern. The treatment of influenza A virus (IAV) has proven particularly challenging, due to the ability of the virus to develop resistance against current antivirals and vaccines. Here, we evaluate a novel antiviral drug therapy, favipiravir, for which the mechanism of action in IAV involves an interaction with the viral RNA-dependent RNA polymerase resulting in an effective increase in the viral mutation rate. We used an experimental evolution framework, combined with novel population genetic method development for inference from time-sampled data, to evaluate the effectiveness of favipiravir against IAV. Evaluating whole genome polymorphism data across 15 time points under multiple drug concentrations and in controls, we present the first evidence for the ability of IAV populations to effectively adapt to low concentrations of favipiravir. In contrast, under high concentrations, we observe population extinction, indicative of mutational meltdown. We discuss the observed dynamics with respect to the evolutionary forces at play and emphasize the utility of evolutionary theory to inform drug development. [ABSTRACT FROM AUTHOR]

Influenza A virus (IAV) has a segmented genome that allows for the exchange of genome segments between different strains. This reassortment accelerates evolution by breaking linkage, helping IAV cross species barriers to potentially create highly virulent strains. Challenges associated with monitoring the process of reassortment in molecular detail have limited our understanding of its evolutionary implications. We applied a novel deep sequencing approach with quantitative analysis to assess the in vitro temporal evolution of genomic reassortment in IAV. The combination of H1N1 and H3N2 strains reproducibly generated a new H1N2 strain with the hemagglutinin and nucleoprotein segments originating from H1N1 and the remaining six segments from H3N2. By deep sequencing the entire viral genome, we monitored the evolution of reassortment, quantifying the relative abundance of all IAV genome segments from the two parent strains over time and measuring the selection coefficients of the reassorting segments. Additionally, we observed several mutations coemerging with reassortment that were not found during passaging of pure parental IAV strains. Our results demonstrate how reassortment of the segmented genome can accelerate viral evolution in IAV, potentially enabled by the emergence of a small number of individual mutations. [ABSTRACT FROM AUTHOR]

Background. Recent studies demonstrate that long palate, lung, and nasal epithelium clone 1 protein (LPLUNC1) is involved in immune responses to Vibrio cholerae, and that variations in the LPLUNC1 promoter influence susceptibility to severe cholera in humans. However, no functional role for LPLUNC1 has been identified Metods. We investigated the role of LPLUNC1 in immune responses to V. cholerae, assessing its affect on bacterial growth and killing and on innate inflammatory responses to bacterial outer membrane components, including purified lipopolysaccharide (LPS) and outer membrane vesicles. We performed immunostaining for LPLUNC1 in duodenal biopsies from cholera patients and uninfected controls. Results. LPLUNC1 decreased proinflammatory innate immune responses to V. cholerae and Escherichia coli LPS. The effect of LPLUNC1 was dose-dependent and occurred in a TLR4-dependent manner. LPLUNC1 did not affect lipoprotein-mediated TLR2 activation. Immunostaining demonstrated expression of LPLUNC1 in Paneth cells in cholera patients and controls Conclusions. Our results demonstrate that LPLUNC1 is expressed in Paneth cells and likely plays a role in modulating host inflammatory responses to V. cholerae infection. Attenuation of innate immune responses to LPS by LPLUNC1 may have implications for the maintenance of immune homeostasis in the intestine [ABSTRACT FROM AUTHOR]

Abstract: Immunostimulatory DNA sequences and their synthetic oligonucleotide analogs (CpG-ODN) activate innate immunity and can stimulate antibacterial effects against numerous intracellular pathogens. While it has been shown previously that CpG-ODN inhibit growth of Mycobacterium avium in murine and human macrophages, we now report that Mycobacterium tuberculosis growth can be inhibited by CpG-ODN treatment of human monocyte-derived macrophages (hMDM). This inhibitory effect was reversed by IFN-γ, which has been shown repeatedly to enhance the growth of virulent M. tuberculosis in cultured hMDM. The antibacterial effect of CpG-ODN in human macrophages was specific for M. tuberculosis when compared to other intracellular pathogens including Listeria monocytogenes and Salmonella enterica serovar Dublin. These data indicate that CpG-ODN can improve the ability of hMDM to contain growth of virulent M. tuberculosis. [Copyright &y& Elsevier]

High-density oligonucleotide microarrays allow simultaneous monitoring of the expression of a large number of cellular genes. Microarrays were used to screen the global human monocyte-derived macrophage transcriptional response to infection with the intracellular pathogen Mycobacterium tuberculosis. The microarray detected reproducible patterns of regulated gene expression. Analysis of the expression data showed induction of cytokines and chemokines, ribosomal proteins, and the interferon-response gene Stat1. Several changes were validated by quantitative reverse transcription polymerase chain reaction and immunoblot assays. Augmentation of the respiratory burst and preservation of the response to interferon-γ were also demonstrated. These data supplement existing knowledge on macrophage responses to tuberculosis infection. [Copyright &y& Elsevier]

Splenic infarction is a rare complication of infectious mononucleosis. We describe 3 cases of splenic infarction attributed to infectious mononucleosis that we encountered within a 2-month period. We underscore the awareness of this potential complication of infectious mononucleosis and discuss the differential diagnosis of splenic infarction, including infectious etiologies. While symptomatic management is usually sufficient for infectious mononucleosis-associated splenic infarction, close monitoring for other complications, including splenic rupture, is mandated. [ABSTRACT FROM AUTHOR]

Presents a case study on a patient whose pre-patellar bursa was infected with Sporothrix schenckii. Medical history of the patient; Treatment options conducted for the disease; Antimicrobial therapy for bursal sporotrichosis.