High prevalence of amantadine-resistant influenza A virus isolated in Gyeonggi Province, South Korea, during 2005–2010

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

Baicalin Downregulates RLRs Signaling Pathway to Control Influenza A Virus Infection and Improve the Prognosis

The objective of this study is to investigate the effects of baicalin on controlling the pulmonary infection and improving the prognosis in influenza A virus (IAV) infection. PCR and western blot were used to measure the changes of some key factors in RLRs signaling pathway. MSD electrochemiluminescence was used to measure the expression of pulmonary inflammatory cytokines including IFN-γ, TNF-α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, and KC/GRO. Flow cytometry was used to detect the proportion of Th1, Th2, Th17, and Treg. The results showed that IAV infection led to low body weight and high viral load and high expression of RIG-I, IRF3, IRF7, and NF-κB mRNA, as well as RIG-I and NF-κB p65 protein. However, baicalin reduced the rate of body weight loss, inhibited virus replication, and downregulated the key factors of the RLRs signaling pathway. Besides, baicalin reduced the high expression inflammatory cytokines in lung and decreased the ratios of Th1/Th2 and Th17/Treg to arouse a brief but not overviolent inflammatory response. Therefore, baicalin activated a balanced host inflammatory response to limit immunopathologic injury, which was helpful to the improvement of clinical and survival outcomes.

Antiviral treatment of influenza in South Korea

Antiviral therapy has an important role in the treatment and chemoprophylaxis of influenza. At present, two classes of antiviral agents, adamantanes and neuraminidase inhibitors, are available for the treatment and chemoprophylaxis of influenza in Korea. Because of the widespread resistance against adamantanes, neuraminidase inhibitors are mainly used. Because each country has a unique epidemiology of influenza, the proper use of antiviral agents should be determined based on local data. Decisions on the clinical practice in the treatment of influenza in South Korea are guided by the local surveillance data, practice guidelines, health insurance system and the resistance patterns of the circulating influenza viruses. This review highlights the role of antiviral agents in the treatment and outcome of influenza in Korea by providing comprehensive information of their clinical usage in Korea.

Synthesis and anti-influenza virus activity of 4-oxo- or thioxo-4,5-dihydrofuro[3,4-c]pyridin-3(1H)-ones

A target-free approach was applied to discover anti-influenza viral compounds, where influenza infected Madin-Darby canine kidney cells were treated 7500 different small organic chemicals individually and reduction of virus-induced cytopathic effect was measured. One of the hit compounds was (Z)-1-((5-fluoro-1H-indol-3-yl)methylene)-6-methyl-4-thioxo-4,5-dihydrofuro[3,4-c]pyridin-3(1H)-one (15a) with half-maximal effective concentrations of 17.4-21.1μM against influenza A/H1N1, A/H3N2 and B viruses without any cellular toxicity at 900μM. To investigate the structure-activity relationships, two dozens of the hit analogs were synthesized. Among them, 15g, 15j, 15q, 15s, 15t and 15x had anti-influenza viral activity comparable or superior to that of the initial hit. The anti-influenza viral compounds efficiently suppressed not only viral protein level of the infected cells but also production of viral progeny in the culture supernatants in a dose-dependent manner. Based on a mode-of-action study, they did not affect virus entry or RNA replication. Instead, they suppressed viral neuraminidase activity. This study is the first to demonstrate that dihydrofuropyridinones could serve as lead compounds for the discovery of alternative influenza virus inhibitors.

Baicalein, Ethyl Acetate, and Chloroform Extracts of Scutellaria baicalensis Inhibit the Neuraminidase Activity of Pandemic 2009 H1N1 and Seasonal Influenza A Viruses

This study rated antiviral activity of Scutellaria baicalensis Georgi (S. baicalensis) extracts against influenza A virus subtypes, for example, pandemic 2009 H1N1, seasonal H1N1 and H3N2. Ethyl acetate (EtOAc) and chloroform extracts inhibited in vitro neuraminidase (NA) enzymatic activity and viral replication more than methanol (MeOH) extract. EtOAc extract demonstrated NA inhibition IC50 values ranging from 73.16 to 487.40 μg/mL and plaque reduction IC50 values ranging from 23.7 to 27.4 μg/mL. Chloroform extract showed antiviral activities with plaque reduction IC50 values ranging from 14.16 to 41.49 μg/mL Time-of-addition assay indicated that EtOAc and chloroform extracts also significantly inhibited virus yields after infection. HPLC analysis demonstrated that baicalin was dominant in the MeOH extract; baicalein and chrysin were rich in the EtOAc and chloroform extracts. Molecular simulation revealed baicalein hydrogen bonding with Glu277 as well as hydrophobic and Van der Waals interactions with Ile222, Arg224, Ser246, and Tyr347 in NA1 active sites of NA1. Baicalein inhibited in vitro replication of influenza A viruses pandemic 2009 H1N1 (IC50 = 0.018 μM) and seasonal 2007 H1N1 using plaque reduction assays. A combination of low-dose baicalein with other anti-influenza agents could be applicable for development of alternative remedies treating influenza A virus infection.

Oseltamivir-resistant influenza viruses isolated in South Korea from 2005 to 2010

South Korean isolates of oseltamivir-resistant influenza viruses from 2005-2010 were investigated with a total 491 influenza viruses identified from 1702 specimens. Neuraminidase genes from 342 influenza viruses (71 A/H1N1, 74 pandemic A/H1N1 2009, 117 A/H3N2, and 80 B) were analyzed by RT-PCR with molecular markers for oseltamivir resistance. The H274Y mutation in the NA protein was identified in 100 % (n=40) of A/H1N1 viruses circulating in 2008-2009. Influenza A/H1N1 viruses harboring the H274Y substitution exhibited, on average, a 626-fold reduction in oseltamivir susceptibility and clustered with the A/Norway/1736/2007 strain. Close and timely monitoring for resistance to clinically available influenza antivirals should be consistently performed.