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Objectives: To investigate the susceptibility of epidemic influenza viruses to neuraminidase inhibitors (NAIs) and the emergence of resistant viruses after treatment, a prospective, observational study was done in the 2019-20 Japanese influenza season.Methods: Influenza viruses were isolated before and twice after treatment, the first at day 5 and the second at day 10. The 50% inhibitory concentrations (IC50s) to oseltamivir, zanamivir, peramivir, and laninamivir were measured and compared with those of 2010-11 to 2018-19 seasons. NA amino acid sequences were analyzed by next generation sequencing (NGS).Results: The IC50 geometric means of the NAIs for 128 A(H1N1)pdm09, 2 A(H3N2), and 33 B were comparable to those of the previous seasons. Only 2 (1.6%) A(H1N1)pdm09 with significantly high IC50 to oseltamivir were found pretreatment. No A(H3N2) or B had resistance. Treatment-emergent oseltamivir resistance was found in 2 among 33 oseltamivir-treated A(H1N1)pdm09, only at the second follow-up. The NGS indicated a rapid increase in the proportion of H275Y to wild type, from 0% to almost 100% between days 5 and 10.Conclusions: These results suggest the continued effectiveness of these NAIs for epidemic influenza in Japan. Treatment-emergent resistant H275Y A(H1N1)pdm09 viruses were detected after oseltamivir treatment, rapidly replacing the wild type. [ABSTRACT FROM AUTHOR]

Neuraminidase (NA) is one of the key surface proteins of the influenza virus, which is an important target for anti-influenza therapy. In the present study, bioassay-guided fractionation led to isolation of two new compounds, rhamnetin-3- O -β- d -glucuronide-6″-methyl ester ( 1 ) and rhamnazin-3- O -β- d -glucuronide-6″-methyl ester ( 2 ), along with seventeen known compounds ( 3 - 19 ), from the MeOH extract of Flos Caryophylli using in vitro NA inhibition assay. These isolated compounds exhibited significantly inhibitory effects on the NA with IC 50 values ranging from 8.4 to 94.1 μM and were found to protect MDCK cells from A (H1N1) influenza infections (EC 50 = 1.5–84.7 μM) with very low cytotoxicity to the host cells (CC 50 = 374.3–1266.9 μM)), with selective index (SI) ranging from 7 to 297. The primary structure-relationships of these isolates were also discussed. [ABSTRACT FROM AUTHOR]

Summary: Objective: There were many cases of pandemic influenza A (H1N1) 2009 (H1N1/09) in Japan during the 2009–2010 epidemic. They accounted for 16% of the total population (20.7 million/128 million), and 59% of the patients were children 15 years of age and under (12.2 million/20.7million). However, there were only 38 paediatric deaths. We analyzed the clinical manifestations and treatment of children hospitalized because of H1N1/09 infection in order to clarify the association between treatment with neuraminidase inhibitors and the low mortality rate. Methods: A retrospective chart review was performed on a total of 1000 paediatric inpatients. Results: The causes of the hospitalizations were respiratory complications in 651 cases (65.1%), neurological complications in 255 cases (25.5%) and other complications in 94 cases. Neuraminidase inhibitors, primarily oseltamivir, had been used to treat 984 (98.4%) of the 1000 patients, and in 88.9% of the patients, treatment with neuraminidase inhibitors was initiated within 48 h after the onset of illness. Only 12 (1.2%) of the 1000 patients underwent mechanical ventilation, and one patient died of H1N1/09 infection. Conclusions: Although a high proportion of the patients in this study had severe respiratory complications, the case fatality rate was only 0.1%. The low mortality rate of children due to the H1N1/09 epidemic in Japan was probably attributable to the universal implementation of early treatment with neuraminidase inhibitors. [Copyright &y& Elsevier]

Summary: Objective: To systematically review evidence relating to the clinical efficacy of oseltamivir, zanamivir and amantadine in the prevention of influenza. Methods: RCTs evaluating these interventions in seasonal prophylaxis and post-exposure prophylaxis were identified using electronic bibliographic databases and handsearching of retrieved articles. Results: Oseltamivir was effective in preventing symptomatic laboratory-confirmed influenza (SLCI) in seasonal prophylaxis in healthy adults and at-risk elderly subjects and in post-exposure prophylaxis within households of mixed composition. Post-exposure prophylaxis using oseltamivir for paediatric contacts was observed to prevent SLCI. Zanamivir prevented SLCI in seasonal prophylaxis in healthy adults, at-risk adults and adolescents and in post-exposure prophylaxis within mixed households, with a trend for seasonal and post-exposure preventative effects in elderly subjects. Evidence for amantadine prophylaxis across subgroups was very limited. However, amantadine prevented SLCI in seasonal prophylaxis in healthy adults and in outbreak control amongst adolescent subjects. Interventions were reported to be well tolerated by subjects, with a relatively low proportion of subjects experiencing drug-related adverse events and drug-related withdrawals. Conclusions: Evidence was identified for the efficacy of oseltamivir and zanamivir in preventing influenza in a range of population subgroups. The evidence base for amantadine was considerably more limited. [ABSTRACT FROM AUTHOR]

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• This is the first report on the antiviral activity of ethanolic extracts of L.strychnifolium stems and leaves against Influezna A subtype H5N1. • L.strychnifolium is a potential neuraminidase inhibitor. • Ethanolic and aqueous extracts of L.strychnifolium stems and leaves showed broad-antibacterial activity against both Gram negative and Gram positive bacteria. • Inositol; Olefins; Palmitic acid; Diterpene; Unsaturated fatty acid; Methyl-p-hydrozybenzoate and 1,2,3-Benzenetriol were identified by GC-MSD scan. The leaves and stems of Lysiphyllum strychnifolium (Craib) A. Schmitz (Fabaceae family) have been traditionally used in Thailand for detoxification and to treat pesticide poisoning in humans. To uncover novel uses of L.strychnifolium , the possible antiviral properties against avian influenza virus A, strain H5N1, were explored in this study. The ethanolic extracts of L.strychnifolium leaves and stems showed good inhibitory activities against H5N1 neuraminidase. Such activities have not been previously reported for this plant. Aqueous extracts did not show any inhibition. Thereafter, the anti-neuraminidase activities of ethanolic extracts were evaluated using fluorometric determination via a MUNANA-based enzyme inhibition assay. Ethanolic extracts of both stems and leaves showed good inhibitory activities against neuraminidase from Influenza A H5N1 with IC 50 values of 55.3 and 70.0 μg/mL, respectively. Moreover, anti-bacterial activities of aqueous and ethanolic extracts of L.strychnifolium leaves and stems were tested using the disc diffusion method. All extracts showed broad antibacterial activities against both Gram positive and Gram negative bacterial strains. Phytochemical constituents of all extracts were identified through Gas Chromatography - Mass Spectrometry (GC-MS) and revealed some compounds such as Methyl-p-hydrozybenzoate; Mome inositol; n-Hexadecanoic acid; Tetradecanamide; (Z)-9-Octadecanamide; 1,2,3,-Benzenetriol; Methylparaben; 4-(4-Hydroxyphenyl)-2-butanone; n-Hexadecanoic acid; Ethyl hexadecanoate; Phytol; (Z)-9-Octadecanoic acid, and Octadecanoic acid. This is the first report of neuraminidase inhibitor against Influenza A H5N1 and antibacterial activities derived from L.strychnifolium extracts. The authors suggest that this plant is an alternative source for treatment against influenza viruses and potential antibiotic agent. [ABSTRACT FROM AUTHOR]