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EuroFlu - Weekly Electronic Bulletin - Week 44 : 29/10/2012-04/11/2012 - 09 November 2012, Issue N? 461: Half type A influenza virus this week were H1N1pdm09
[Source: EuroFlu, full page: (LINK). Edited.]
EuroFlu - Weekly Electronic Bulletin - Week 44 : 29/10/2012-04/11/2012 - 09 November 2012, Issue N? 461
Sporadic Influenza detections in WHO European Region
Summary, week 44/2012
Levels of influenza activity in the Region remain low, with only a few countries reporting sporadic influenza detections.
The influenza positivity rate is stable; since the start of the season, A(H1N1)pdm09, A(H3N2) and type B viruses have circulated in approximately equal proportions, based on detections and subtyping of representative type A specimens from both sentinel and non-sentinel sources.
The number of hospitalizations due to severe acute respiratory infection (SARI) is stable, and none of the cases reported so far was associated with laboratory-confirmed influenza.
For a description of influenza surveillance in the WHO European Region, see below.
Virological surveillance for influenza
Overall, a total of 62 specimens tested positive for influenza in week 44/2012: 46 were type A and 16 were type B.
Of the influenza A viruses, 20 were subtyped: 8 as A(H3) and 12 as A(H1)pdm09 (Fig. 1).
Since week 40/2012, 200 influenza viruses from sentinel and non-sentinel sources have been typed: 138 (69%) were influenza A and 62 (31%) were influenza B.
Of the influenza A viruses 76 were subtyped: 43 (57%) as A(H3) and 33 (43%) as A(H1)pdm09.
This week, as in previous weeks this season, no country reported a dominant virus type, as illustrated on the map below.
(?)
Outpatient surveillance for influenza-like illness (ILI) and/or acute respiratory infection (ARI)
In general ILI and ARI consultation rates remain low and stable, without any significant geographic differences in terms of spread.
Only 9 countries out of 38 reported sporadic geographic spread, and 6 out of 37 reported increasing trends.
Only 1 country (Republic of Moldova) of the 18 that have established epidemic thresholds reported consultation rates for ILI/ARI above its national threshold.
(?)
The positivity rate among ILI and ARI cases from sentinel sources remains stable and low, which is quite usual for the beginning of an influenza season (see Fig. 2).
Out of the 486 specimens tested, 4 (0.8%) were positive for influenza viruses.
The number of specimens testing positive for influenza in weeks 40?44/2012 is still not sufficient for presentation, which requires at least 20 positive specimens per week.
Of 486 specimens, 4 tested positive for influenza A.
Click here for a detailed overview of cumulative influenza virus detections by type and subtype since week 40/2012.
58 specimens were reported positive for influenza: 42 were influenza A and 16 were influenza B.
Of the influenza A viruses, 16 were subtyped: 5 as A(H3N2) and 11 as A(H1)pdm09.
(?)
Hospital surveillance for SARI
This week, 9 countries (Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Republic of Moldova, Russian Federation, Serbia and Ukraine) out of 11 reported hospitalizations due to SARI, with most of the cases in the group aged 0?4 years (Fig. 3).
This week, as in previous weeks this season, none of the SARI cases was positive for influenza.
A total of 96 specimens was collected from hospitalized SARI cases in 8 countries (Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Russian Federation, Serbia and Ukraine).
Click here for a detailed overview of cumulative influenza virus detections by type and subtype since week 40/2012.
Monitoring of susceptibility to antiviral drugs
Since week 40/2012, 2 countries (the Netherlands and Sweden ) have screened 4 viruses for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir.
All of the 3 Influenza A(H3N2) and 1 influenza A(H1N1)pdm09 viruses that were screened showed susceptibility to oseltamivir and zanamivir.
All 3 influenza A(H3N2) viruses that were screened for susceptibility to adamantanes were found to be resistant.
Virus strain characterizations
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.
Since week 40/2012, 3 countries (Germany, Norway and Sweden) have characterized 5 influenza viruses genetically:
Description of influenza surveillance
The EuroFlu bulletin describes and comments on influenza activity in the 53 countries in the WHO European Region. Influenza activity is monitored through surveillance of ILI, ARI and/or hospital-based surveillance for severe disease. Primary care clinics conduct surveillance for ILI and/or ARI in most countries in the Region, although some countries routinely perform hospital-based surveillance. Surveillance data in the Region are collected from sentinel and non-sentinel systems. Sentinel data come from a network of designated clinicians who routinely and systematically collect respiratory specimens from ILI, ARI or SARI cases according to standard case definitions. Non-sentinel data come from a variety of other sources, including community outbreaks, general practitioners and hospitals that are not part of the sentinel surveillance system for influenza and may not use a standard case definition for ILI, ARI or SARI.
(?)
Country comments (where available)
Denmark: The two influenza A positive samples are A(H1N1)pdm09, although not confirmed at the NIC Denmark
Norway: Low but increasing number of influenza virus detections. A(H1)pdm09, A(H3) and B Yamagata lineage viruses appear to be circulating sporadically, in approximately equal numbers.
Republic of Moldova: None of Influenza viruses was detected in 14 sentinel specimens. 2 samples were positive for RNA Parainfluenza type 3 in 44th week.
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EuroFlu - Weekly Electronic Bulletin - Week 44 : 29/10/2012-04/11/2012 - 09 November 2012, Issue N? 461
Sporadic Influenza detections in WHO European Region
Summary, week 44/2012
Levels of influenza activity in the Region remain low, with only a few countries reporting sporadic influenza detections.
The influenza positivity rate is stable; since the start of the season, A(H1N1)pdm09, A(H3N2) and type B viruses have circulated in approximately equal proportions, based on detections and subtyping of representative type A specimens from both sentinel and non-sentinel sources.
The number of hospitalizations due to severe acute respiratory infection (SARI) is stable, and none of the cases reported so far was associated with laboratory-confirmed influenza.
For a description of influenza surveillance in the WHO European Region, see below.
Virological surveillance for influenza
Overall, a total of 62 specimens tested positive for influenza in week 44/2012: 46 were type A and 16 were type B.
Of the influenza A viruses, 20 were subtyped: 8 as A(H3) and 12 as A(H1)pdm09 (Fig. 1).
Since week 40/2012, 200 influenza viruses from sentinel and non-sentinel sources have been typed: 138 (69%) were influenza A and 62 (31%) were influenza B.
Of the influenza A viruses 76 were subtyped: 43 (57%) as A(H3) and 33 (43%) as A(H1)pdm09.
(?)
Outpatient surveillance for influenza-like illness (ILI) and/or acute respiratory infection (ARI)
In general ILI and ARI consultation rates remain low and stable, without any significant geographic differences in terms of spread.
Only 9 countries out of 38 reported sporadic geographic spread, and 6 out of 37 reported increasing trends.
Only 1 country (Republic of Moldova) of the 18 that have established epidemic thresholds reported consultation rates for ILI/ARI above its national threshold.
(?)
The positivity rate among ILI and ARI cases from sentinel sources remains stable and low, which is quite usual for the beginning of an influenza season (see Fig. 2).
Out of the 486 specimens tested, 4 (0.8%) were positive for influenza viruses.
The number of specimens testing positive for influenza in weeks 40?44/2012 is still not sufficient for presentation, which requires at least 20 positive specimens per week.
Click here for a detailed overview of cumulative influenza virus detections by type and subtype since week 40/2012.
58 specimens were reported positive for influenza: 42 were influenza A and 16 were influenza B.
Of the influenza A viruses, 16 were subtyped: 5 as A(H3N2) and 11 as A(H1)pdm09.
(?)
Hospital surveillance for SARI
This week, 9 countries (Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Republic of Moldova, Russian Federation, Serbia and Ukraine) out of 11 reported hospitalizations due to SARI, with most of the cases in the group aged 0?4 years (Fig. 3).
This week, as in previous weeks this season, none of the SARI cases was positive for influenza.
Click here for a detailed overview of cumulative influenza virus detections by type and subtype since week 40/2012.
Monitoring of susceptibility to antiviral drugs
Since week 40/2012, 2 countries (the Netherlands and Sweden ) have screened 4 viruses for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir.
All of the 3 Influenza A(H3N2) and 1 influenza A(H1N1)pdm09 viruses that were screened showed susceptibility to oseltamivir and zanamivir.
All 3 influenza A(H3N2) viruses that were screened for susceptibility to adamantanes were found to be resistant.
Virus strain characterizations
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.
Since week 40/2012, 3 countries (Germany, Norway and Sweden) have characterized 5 influenza viruses genetically:
- 3 belonged to the group (5) represented by A/Perth/10/2010 in the A/Victoria/208/2009, A(H3) clade;
- 1 belonged to the subgroup (3C) represented by A/Victoria/361/2011 in the A/Victoria/208/2009, A(H3) clade);
- 1 belonged to the group (6) represented by A/St Petersburg/27/2011 in the A(H1N1)pdm09 clade.
Description of influenza surveillance
The EuroFlu bulletin describes and comments on influenza activity in the 53 countries in the WHO European Region. Influenza activity is monitored through surveillance of ILI, ARI and/or hospital-based surveillance for severe disease. Primary care clinics conduct surveillance for ILI and/or ARI in most countries in the Region, although some countries routinely perform hospital-based surveillance. Surveillance data in the Region are collected from sentinel and non-sentinel systems. Sentinel data come from a network of designated clinicians who routinely and systematically collect respiratory specimens from ILI, ARI or SARI cases according to standard case definitions. Non-sentinel data come from a variety of other sources, including community outbreaks, general practitioners and hospitals that are not part of the sentinel surveillance system for influenza and may not use a standard case definition for ILI, ARI or SARI.
(?)
Country comments (where available)
Denmark: The two influenza A positive samples are A(H1N1)pdm09, although not confirmed at the NIC Denmark
Norway: Low but increasing number of influenza virus detections. A(H1)pdm09, A(H3) and B Yamagata lineage viruses appear to be circulating sporadically, in approximately equal numbers.
Republic of Moldova: None of Influenza viruses was detected in 14 sentinel specimens. 2 samples were positive for RNA Parainfluenza type 3 in 44th week.
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