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EuroFlu - Weekly Electronic Bulletin - Week 5 : 27/01/2014-02/02/2014 - 07 February 2014, Issue No. 516 (edited)

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  • EuroFlu - Weekly Electronic Bulletin - Week 5 : 27/01/2014-02/02/2014 - 07 February 2014, Issue No. 516 (edited)

    [Source: EuroFlu, full page: (LINK). Edited.]


    EuroFlu - Weekly Electronic Bulletin - Week 5 : 27/01/2014-02/02/2014 - 07 February 2014, Issue No. 516

    Variable influenza activity in Europe


    Summary, week 05/2014
    • Consultation rates for influenza-like illness (ILI) and acute respiratory infection (ARI) increased in most countries in the WHO European Region, but started to decrease in Bulgaria, Spain and Turkey, whose influenza seasons started earlier.
    • Nevertheless, the percentage of sentinel specimens testing positive for influenza decreased for the second consecutive week, although the number of countries with regional or widespread geographic influenza activity increased from the previous week.
    • Influenza A remained predominant in the Region.
    • The number of reported hospitalized laboratory-confirmed influenza cases increased over the last several weeks in southern and western European countries, with 80% of the cases during week 05/2014 being associated with A(H1N1)pdm09 infection.
    • At the same time, 54% of influenza positive cases of severe acute respiratory infection (SARI) in eastern European countries were associated with A(H3N2).

    The EuroFlu bulletin describes and comments on influenza activity in the 53 Member States in the WHO European Region to provide information to public health specialists, clinicians and the public on the timing of the influenza season, the spread of influenza, the prevalence and characteristics of circulating viruses (type, subtype and lineage) and severity.

    For a description of influenza surveillance in the WHO European Region see below.


    Virological surveillance for influenza

    For week 05/2014 a total of 12 647 specimens from sentinel and non-sentinel sources were tested for influenza, 2282 (18%) of which were positive: 2194 (96%) influenza A and 88 (4%) influenza B (Fig. 1 and 2).

    France, Norway, Portugal, Spain and Sweden reported more than half the influenza-positive cases.
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    Influenza A has remained dominant since week 40/2013. Of the 1403 influenza A viruses that were subtyped during week 05/2014, 909 (65%) were A(H1N1)pdm09 and 494 (35%) A(H3N2) (Fig. 2a).

    Since the beginning of weekly monitoring (week 40/2013), sentinel and non-sentinel sources have yielded 11 304 influenza detections, with an increasing proportion of influenza A viruses detected: 10 743 (95%) were influenza A and 561 (5%) influenza B viruses (Fig. 2b).

    The proportion of influenza A viruses subtyped as A(H1N1)pdm09 has increased: of the 7644 influenza A viruses subtyped, 4507 (59%) were A(H1N1)pdm09 and 3137 (41%) were A(H3N2).

    In addition, since week 40/2013, the lineage of 74 influenza B viruses has been determined: 69 (93%) belonged to the B/Yamagata lineage (the B lineage virus recommended by WHO for inclusion in trivalent seasonal influenza vaccines) and 5 (7%) to B/Victoria.
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    For week 05/2014, 23 countries reported influenza A as the dominant type (Map 1 and country table), an increase from the previous week.

    In countries providing data on dominant subtypes, influenza A(H3N2) was reported as dominant in Georgia, Italy, Slovenia and the former Yugoslav Republic of Macedonia, while Bulgaria, Greece, Hungary, Iceland, Latvia, Norway, Spain, Sweden and the United Kingdom (Scotland) reported A(H1N1)pdm09 as dominant.

    Albania, France, Ireland, the Russian Federation and Switzerland reported A(H1N1)pdm09 and A(H3N2) as co-dominant.


    Virus strain characterizations

    Circulating influenza viruses are assessed each season for their antigenic and genetic characteristics, to determine the extent of their antigenic similarity to the viruses included in the seasonal influenza vaccine, and determine the prevalence of mutations that affect pathogenicity or are associated with susceptibility to antiviral drugs.

    For the 2013/2014 northern hemisphere influenza season, WHO recommended inclusion of A/California/7/2009 (H1N1)pdm09-like, A/Texas/50/2012 (H3N2)-like and B/Massachusetts/2/2012-like (Yamagata lineage) viruses in vaccines (see the WHO headquarters web site).

    Since week 40/2013, 258 influenza viruses characterized antigenically by 10 countries (Denmark, Finland, Germany, Latvia, Norway, Portugal, Romania, the Russian Federation, Switzerland and the United Kingdom (England)) corresponded with the viruses recommended by WHO for inclusion in the current northern hemisphere seasonal influenza vaccine (Fig. 3).

    10 countries (Belgium, Denmark, Finland, Germany, the Netherlands, Norway, Portugal, the Russian Federation, Spain and Sweden) have characterized 318 influenza viruses genetically (Fig. 4).
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    (#) Included in the WHO-recommended composition of influenza virus vaccines for use in the 2013/2014 northern hemisphere influenza season.

    (*) Included in the WHO-recommended composition of influenza virus vaccines for use in the 2014 southern hemisphere influenza season.


    Monitoring of susceptibility to antiviral drugs

    Since week 40/2013, 7 countries (the Netherlands, Norway, Portugal, Spain, Sweden, the Russian Federation and the United Kingdom (England)) have screened 306 viruses for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir.

    Of the 220 A(H1N1)pdm09 viruses tested, 218 showed susceptibility to both drugs. 2 viruses carrying the neuraminidase H275Y amino acid substitution, causing resistance to oseltamivir, were detected in the United Kingdom in hospitalized patients.

    Of the 65 influenza A(H3N2) viruses tested, 64 showed susceptibility to both drugs. The remaining virus, detected in the United Kingdom in a hospitalized patient treated with oseltamivir, carried the neuraminidase E119V amino acid substitution and showed reduced inhibition by oseltamivir but normal inhibition by zanamivir.

    All 21 influenza B viruses tested showed susceptibility to oseltamivir and zanamivir.

    There is no indication of the spread of resistant viruses. All 60 influenza A(H1N1)pdm09 and 47 influenza A(H3N2) viruses screened for susceptibility to adamantanes were found to be resistant.


    Outpatient surveillance for influenza-like illness (ILI) and/or acute respiratory infection (ARI)

    During week 05/2014, most European countries continued to report low-intensity influenza activity (Map 2), with increasing trends (Map 4).

    Regarding geographic spread, influenza activity was predominantly sporadic (Map 3), but more countries than last week reported widespread activity.

    During week 5/2014, consultation rates increased in the majority of countries in the Region. Of 13 countries with established national thresholds, however, the rates were above the threshold only in Albania, Israel and Switzerland.

    In Bulgaria, Spain and Turkey, where the influenza season started earlier than in other countries, the consultation rates showed decreases.

    (…)

    During week 05/2014, 518 sentinel specimens tested positive for influenza, with 156 (30%) reported by Spain. The percentage of sentinel specimens testing positive for influenza decreased in the last two weeks, probably owing to the differences in influenza activity among countries in the Region: the influenza season has not progressed much in many countries and may have peaked in others.
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    During week 05/2014, 518 (26%) of the 1988 specimens collected from sentinel sources tested positive for influenza, the majority being influenza A(H3N2) (Fig. 6a). Click here for a detailed overview in a table format.
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    Hospital surveillance for SARI

    The number of SARI hospitalizations increased slightly from that in the previous week, with most cases occurring in the group aged 0–4 years (Fig. 7). At the same time, the number of cases in the group aged 5–14 increased, reported mainly by Armenia, Belarus and the Republic of Moldova.
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    During week 05/2014, 30 (18%) of the 171 SARI samples collected in Albania, Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, the Republic of Moldova, Romania, the Russian Federation, Serbia and Ukraine tested positive for influenza A, with majority being influenza A(H3N2) (Fig. 8a), correlating with the results of sentinel surveillance (Fig. 8a). Click here for a detailed overview in table format.
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    Since week 40/2013, 6 countries have reported 1605 hospitalized laboratory-confirmed influenza cases: 1588 (99%) were related to influenza type A and 17 (1%) to type B. Of 1078 subtyped influenza A viruses, 878 (81%) were A(H1)pdm09 and 200 (19%) were A(H3) viruses.

    5 countries reported a total of 124 fatal cases, all associated with influenza type A infection, of which 86 were subtyped: 70 (56%) as A(H1)pdm09 and 16 (13%) as A(H3).

    For more information on surveillance of confirmed hospitalized influenza, please see ECDC’s Weekly Influenza Surveillance Overview (WISO) at European Centre for Disease Prevention and Control web site.


    Respiratory syncytial virus (RSV)

    Based on the data presented by countries reporting on RSV, the positivity rate has been gradually increasing since week 40/2013 and peaked in week 50/2013 decreasing in all the reporting countries since than. This represents a slightly later start than in the previous season (see Country data and graphs for individual country data).


    EuroMOMO (European Mortality Monitoring Project)

    EuroMOMO is a project set up to develop and operate a routine public health mortality monitoring system to detect and measure, on a real-time basis, excess deaths related to influenza and other possible public health threats across 20 European Union (EU) countries.

    Pooled analysis of week data for 05/2014 showed that all-cause mortality was within the normal range for all reporting countries. Results of pooled analysis may vary, depending on which countries are included in the weekly analysis.

    For more information about the EUROMOMO mortality monitoring system please click here.

    (…)


    Country comments (where available)

    Republic of Moldova: This week were tested for Influenza A and B 28 samples: 9 of them were positive for RNA Influenza virus A(H3N2); 3 samples were positive for RNA hRSV, and 1 - for RNA Influenza A(H3N2) and RNA h RSV.

    (…)


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