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ECDC Bi-weekly influenza surveillance overview - 10 September 2010: increasing ILI activity in Estonia, Hungary and Poland.

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  • ECDC Bi-weekly influenza surveillance overview - 10 September 2010: increasing ILI activity in Estonia, Hungary and Poland.

    Bi-weekly influenza surveillance overview - 10 September 2010 (ECDC, extracts, edited)


    [Source: European Centre for Disease Prevention and Control (ECDC), full PDF Document (LINK). Extracts, edited.]

    SURVEILLANCE REPORT

    Bi-weekly influenza surveillance overview - 10 September 2010


    Main surveillance developments in Weeks 34?35/2010 (23 Aug 2010 ? 05 Sep 2010)

    This first page contains the main developments this week and can be printed separately or together with the more detailed information following.

    During weeks 34 & 35/2010, low influenza activity was notified by all 16 reporting countries; sporadic activity was only reported by Cyprus and the UK (Wales).

    An increasing trend was observed by Estonia, Hungary and Poland.

    During weeks 34 & 35/2010, one influenza B virus was detected from sentinel specimens (the Netherlands) and three 2009 pandemic A(H1N1) viruses were isolated from non-sentinel specimens in Spain and in Poland. No SARI cases were reported during this period.


    Sentinel surveillance of influenza-like illness (ILI)/ acute respiratory infection (ARI):

    All notifying countries reported low influenza activity and sporadic activity was reported by Cyprus and UK (Wales).


    Virological surveillance:

    Sentinel physicians collected 39 respiratory specimens, of which one (2.5%) was influenza B virus. Three 2009 pandemic A(H1N1) viruses were detected from non-sentinel specimens.


    Hospital surveillance of severe acute respiratory infection (SARI):

    During weeks 34 & 35/2010, no SARI cases were reported.


    Sentinel surveillance (ILI/ARI)

    Weekly analysis ? epidemiology

    During weeks 34-35/2010, 16 of 29 countries reported the intensity indicator. For the 25th consecutive week, all reporting countries experienced low intensity (Map1, Table 1). The geographic spread was reported by 17 countries for these weeks: Cyprus and the UK (Wales) reported sporadic activity while no activity was reported by all 15 other countries. Only Estonia, Hungary and Poland reported an increasing trend.

    (...)

    Description of the system

    This surveillance is based on nationally organized sentinel networks of physicians, mostly general practitioners (GPs), covering at least 1?5% of the population in their countries. All EU/EEA Member States (except Liechtenstein) are participating. Depending on their country?s choice, each sentinel physician reports the weekly number of patients seen with influenza-like illness (ILI), acute respiratory infection (ARI) or both to a national focal point. From the national level, both numerator and denominator data are then reported to the European Surveillance System (TESSy) database. Additional semi-quantitative indicators of intensity, geographic spread and trend of influenza activity at the national level are also reported.


    Virological surveillance

    Weekly analysis ? virology

    During weeks 34 and 35/2010, 16 countries and the UK (England, Northern Ireland and Scotland) reported virological data. Table 2 shows the distribution of both sentinel and non-sentinel specimens by type and subtype.

    Sentinel physicians collected 39 specimens, one (2.5%) of which was positive for influenza B virus in the Netherlands.

    Four non-sentinel source specimens (e.g., specimens collected for diagnostic purposes in hospital settings) tested positive for influenza A, of which three were sub-typed as 2009 pandemic A(H1N1) viruses in Spain and Poland (Table 2).

    Cumulative data since week 40/2009 show that subtyping was performed on 16 203 type A influenza viruses detected in samples from sentinel practices. Of these, 99.6% (16 145) were identified as the 2009 pandemic A(H1N1) virus (Table 2).

    An update from CNRL on influenza virus characterisation can be found here: Surveillance report (August 2010).

    In summary, all 2009 pandemic A(H1N1) viruses received from EU countries have been antigenically similar and genetically closely related to the vaccine virus A/California/7/2009. In addition, most of the circulating influenza B viruses have been closely related to the current vaccine strain B/Brisbane/60/2008 (Victoria lineage; Table 3).

    For details on the current virus strains recommended by WHO for vaccine preparation click here.

    (...)


    Table 3: Results of antigenic characterisations of sentinel and non-sentinel influenza virus isolates, weeks 40/2009?35/2010

    [Strain name - Number of strains]
    • A(H1)v California/7/2009-like - 3353
    • A(H3) A/Brisbane/10/2007 (H3N2)-like - 9
    • A(H3) A/Perth/16/2009 (H3N2)-like - 35
    • B/Brisbane/60/2008-like (B/Victoria/2/87 lineage) - 19
    • B/Florida/4/2006-like (B/Yamagata/16/88 lineage) - 5


    Description of the system

    According to the nationally defined sampling strategy, sentinel physicians take nasal or pharyngeal swabs from patients with influenza-like illness (ILI), acute respiratory infection (ARI) or both and send the specimens to influenza-specific reference laboratories for virus detection, (sub-)typing, antigenic or genetic characterisation and antiviral susceptibility testing.


    Hospital surveillance ? severe acute respiratory infection (SARI)

    Weekly analysis ? SARI

    During weeks 34 and 35/2010, no SARI cases were reported to TESSy. Since the beginning of SARI surveillance, eleven countries reported 11 461 cases and 576 related fatalities (Table 4). In SARI cases where influenza virus was detected, 99.7% were 2009 pandemic A(H1N1) viruses (Table 5).


    Table 4: Cumulative number of SARI cases, weeks 40/2009?week 35/2010

    [Country - Number of cases - Incidence of SARI cases per 100,000 population - Number of fatal cases reported - Incidence of fatal cases per 100,000 population - Estimated population covered]
    • Austria - 2917 - ... - 41 - ... - ...
    • Belgium - 1749 - 16.39 - ... - ... - 10,668,666
    • Cyprus - 26 - ... - 9 - ... - ...
    • Finland - 1422 - 26.7 - 56 - 1.05 - 5,326,314
    • France - 1357 - ... - 302 - ... - ...
    • United Kingdom - 1639 - 4.15 - 65 - 0.16 - 39,503,332
    • Ireland - 903 - ... - 17 - ... - ...
    • Malta - 216 - 52.22 - 1 - 0.24 - 413,609
    • Netherlands - 652 - 3.95 - 29 - 0.18 - 16,521,505
    • Romania - 215 - 16.95 - 16 - 1.26 - 1,268,418
    • Slovakia - 365 - ... - 40 - ... - ...
    • Total - 11,461 - ... - 576 - ... - 73,701,844


    Table 5: Number of SARI cases by influenza type and subtype, weeks 34 & 35/2010

    [Virus type/subtype - Number of cases during current week - Cumulative number of cases since the start of the season]
    • Influenza A - 9184
      • A (pandemic H1N1) - ... - 9152
      • A(subtyping not performed) - ... - 25
      • A(H3) - ... - ...
      • A(H1) - ... - 7
      • A(H5) - ... - ...
    • Influenza B - ... - ...
    • Unknown - ... - 2277
    • Total - 0 - 11461


    The report text was written by an editorial team at the European Centre for Disease Prevention and Control (ECDC): Flaviu Plata, Phillip Zucs, Bruno Ciancio, Rene Snacken and Eeva Broberg. The bulletin text was reviewed by the Community Network of Reference Laboratories for Human Influenza in Europe (CNRL) coordination team: Adam Meijer, Rod Daniels, John McCauley and Maria Zambon. On behalf of the EISN members the bulletin text was reviewed by Joan O?Donnell (Health Protection Surveillance Centre, Ireland) and Katarina Prosenc (National Institute of Public Health, Slovenia).

    Maps and commentary used in this Weekly Influenza Surveillance Overview (WISO) do not imply any opinions whatsoever of ECDC or its partners on the legal status of the countries and territories shown or concerning their borders.

    All data published in the WISO are up-to-date on the day of publication. Past this date, however, published data should not be used for longitudinal comparisons as countries tend to retrospectively update their numbers in the database.

    ? European Centre for Disease Prevention and Control, Stockholm, 2010

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