Two cases of acute severe flaccid myelitis associated with enterovirus D68 infection in children, Norway, autumn 2014

Enterovirus D68 (EV-D68), phylogenetic clade B was identified in nasopharyngeal specimens of two cases of severe acute flaccid myelitis. The cases were six and five years-old and occurred in September and November 2014. EV-D68 is increasingly associated with acute flaccid myelitis in children, most cases being reported in the United States. Awareness of this possible neurological complication of enterovirus D68 infection is needed.

Burden and characteristics of influenza A and B in Danish intensive care units during the 2009/10 and 2010/11 influenza seasons

Influenza surveillance in Danish intensive care units (ICUs) was performed during the 2009/10 and 2010/11 influenza seasons to monitor the burden on ICUs. All 44 Danish ICUs reported aggregate data for incidence and point prevalence, and case-based demographical and clinical parameters. Additional data on microbiological testing, vaccination and death were obtained from national registers. Ninety-six patients with influenza A(H1N1)pdm09 were recorded in 2009/10; 106 with influenza A and 42 with influenza B in 2010/11. The mean age of influenza A patients was higher in 2010/11 than in 2009/10, 53 vs. 44 years (P = 0·004). No differences in other demographic and clinical parameters were detected between influenza A and B patients. In conclusion, the number of patients with severe influenza was higher in Denmark during the 2010/11 than the 2009/10 season with a shift towards older age groups in influenza A patients. Influenza B caused severe illness and needs consideration in clinical and public health policy.

Low vaccine effectiveness against influenza A(H3N2) virus among elderly people in Denmark in 2012/13 – a rapid epidemiological and virological assessment

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Low vaccine effectiveness against influenza A(H3N2) virus among elderly people in Denmark in 2012/13--a rapid epidemiological and virological assessment

In Denmark, the 2012/13 influenza season has been dominated by influenza A(H3N2). We estimated the vaccine effectiveness (VE) of the trivalent influenza vaccine by linking national registers in a test-negative case-control study of patients tested for influenza aged ≥65 years. The adjusted VE against laboratory-confirmed influenza A and B was -11% (95% CI: -41 to 14) and 69% (95% CI: 26 to 87), respectively. Genetic characterisation of the influenza A(H3N2) viruses indicated genetic drift, with seven substitutions at key antigenic sites.

Genome characterisation of the newly discovered avian influenza A H5N7 virus subtype combination

In Denmark, in 2003, a previously unknown subtype combination of avian influenza A virus, H5N7 (A/Mallard/Denmark/64650/03), was isolated from a flock of 12,000 mallards. The H5N7 subtype combination might be a reassortant between recent European avian influenza A H5, H7, and a third subtype, possibly an H6. The haemagglutinin and the acidic polymerase genes of the virus were closely related to a low-pathogenic Danish H5N2 virus A/Duck/Denmark/65041/04 (H5N2). The neuraminidase gene and the non-structural gene were most similar to the highly pathogenic A/Chicken/Netherlands/1/03 (H7N7) and the human-fatal A/Netherlands/219/03 (H7N7), respectively. The basic polymerase 1 and 2 genes were phylogenetically equidistant to both A/Duck/Denmark/65047/04 (H5N2) and A/Chicken/Netherlands/1/03 (H7N7). The nucleoprotein and matrix gene had highest nucleotide sequence similarity to the H6 subtypes A/Duck/Hong Kong/3096/99 (H6N2) and A/WDk/ST/1737/2000 (H6N8), respectively. All genes of the H5N7 strain were of avian origin, and no further evidence of pathogenicity to humans has been found.

An emerging avian influenza A virus H5N7 is a genetic reassortant of highly pathogenic genes

We full genome characterised the newly discovered avian influenza virus H5N7 subtype combination isolated from a stock of Danish game ducks to investigate the composition of the genome and possible features of high pathogenicity. It was found that the haemagglutinin and the acidic polymerase genes were closely related to a low pathogenic H5 strain (A/Duck/Denmark/65047/04 H5N2). The neuraminidase and the non-structural genes were closely related to the highly pathogenic H7N7 strains from The Netherlands 2003. The basic polymerase genes 1 and 2 were shared between the Danish H5N7 and H5N2 and the H7N7 from The Netherlands. The nucleoprotein and the matrix genes were closely related to H6 strains. Thus, the new H5N7 subtype share genes with H5, H7 and H6 subtypes and possesses internal genes originating from highly pathogenic strains. The findings emphasize the need for surveillance presumed low pathogenic avian influenza A viruses.

New avian influenza A virus subtype combination H5N7 identified in Danish mallard ducks

During the past years increasing incidences of influenza A zoonosis have made it of uppermost importance to possess methods for rapid and precise identification and characterisation of influenza A viruses. We present here a convenient one-step RT-PCR method that will amplify full-length haemagglutinin (HA) and neuraminidase (NA) directly from clinical samples and from all known subtypes of influenza A. We applied the method on samples collected in September 2003 from a Danish flock of mallards with general health problems and by this a previously undescribed influenza A subtype combination, H5N7, was identified. The HA gene showed great sequence similarity to the highly pathogenic avian influenza A virus (HPAIV) A/Chicken/Italy/312/97 (H5N2); however, the cleavage site sequence between HA1 and HA2 had a motif typical for low pathogenic avian influenza viruses (LPAIV). The full-length NA sequence was most closely related to the HPAIV A/Chicken/Netherlands/01/03 (H7N7) that infected chickens and humans in the Netherlands in 2003. Ten persons with direct or indirect contact with the Danish mallard ducks showed signs of influenza-like illness 2-3 days following the killing of the ducks, but no evidence of influence infections was detected. To our knowledge this is the first report of an H5N7 influenza A virus.