Surveillance of antiviral resistance markers in Argentina: detection of E119V neuraminidase mutation in a post-treatment immunocompromised patient

Although vaccines are the best means of protection against influenza, neuraminidase inhibitors are currently the main antiviral treatment available to control severe influenza cases. One of the most frequent substitutions in the neuraminidase (NA) protein of influenza A(H3N2) viruses during or soon after oseltamivir administration is E119V mutation. We describe the emergence of a mixed viral population with the E119E/V mutation in the NA protein sequence in a post-treatment influenza sample collected from an immunocompromised patient in Argentina. This substitution was identified by a real-time reverse transcriptase polymerase chain reaction (RT-PCR) protocol and was confirmed by direct Sanger sequencing of the original sample. In 2014, out of 1140 influenza samples received at the National Influenza Centre, 888 samples (78%) were A(H3N2) strains, 244 (21.3%) were type B strains, and 8 (0.7%) were A(H1N1)pdm09 strains. Out of 888 A(H3N2) samples, 842 were tested for the E119V substitution by quantitative RT-PCR: 841 A(H3N2) samples had the wild-type E119 genotype and in one sample, a mixture of viral E119/ V119 subpopulations was detected. Influenza virus surveillance and antiviral resistance studies can lead to better decisions in health policies and help in medical treatment planning, especially for severe cases and immunocompromised patients.

Infl uenza a virus induced apoptosis: Inhibition of DNA laddering & caspase-3 activity by zinc supplementation in cultured HeLa cells.

Background & objectives: The pathogenesis of infl uenza virus infection involves virus replication in epithelial cells of the respiratory tract and the consequent degeneration of infected cells. Infl uenza virus induces cellular degeneration following infection of cultured cells in vitro, and the cytopathic effect (CPE) occurs principally through apoptotic cell death. This study was undertaken to fi nd out the effect of zinc on infl uenza virus induced apoptosis in cultured HeLa cells. Methods: The sub-confl uent monolayer HeLa cells were used to study the effect of zinc on infl uenza virus induced apoptosis. The apoptotic markers viz., caspase-3 activity, phagocytic index, morphological changes, and DNA fragmentation were assayed. Results: When HeLa cells were infected with a cell adapted pathogenic strain of infl uenza A (A/Udorn/ 317/72H3N2) virus, DNA fragmentation was observed in virus infected cells by 24 h post infection and caspase-3 activity was maximum at 4 h post infection after which it reached to plateau. Treatment of cells with 0.1 5mM concentration of zinc till 8 h post infection inhibited DNA fragmentation and also caspase 3 activity was decreased signifi cantly up to 2 h post infection. Interpretation & conclusions: When the infected HeLa cells were incubated with adherent macrophages, effi cient phagocytosis occurred and the release of virus into the culture medium was inhibited. These results suggested that inhibitory effect on infl uenza virus induced apoptotic death of cultured cells can be determined at an early stage of the infection by treatment of zinc.