FluWatch report: August 11 to August 24, 2013 (Weeks 33 & 34)
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Overall Summary
- Influenza activity in Canada remained at inter-seasonal levels during this 2-week period.
- The percentage of laboratory tests positive for all respiratory viruses decreased in weeks 33 and 34, with the number of tests low and similar to previous weeks.
- The ILI consultation rate was stable in recent weeks with a gradual downward trend, although it was above the average range in weeks 33 and 34.
Influenza Activity (geographic spread) and Outbreaks
The number of regions reporting influenza activity was at inter-seasonal levels in weeks 33 and 34. In weeks 33 and 34, four regions reported sporadic activity (Figure 1). Localized activity has not been reported since week 26 (Figure 2). No new influenza outbreaks were reported in weeks 33 or 34 (Figure 3).
Figure 1. Map of overall Influenza activity level by province and territory,
Canada, Week 34
Note: Influenza activity levels, as represented on this map, are assigned and reported by Provincial and Territorial Ministries of Health, based on laboratory confirmations, sentinel ILI rates (see graphs and tables) and reported outbreaks. Please refer to detailed definitions on the last page. For areas where no data is reported, late reports from these provinces and territories will appear on the FluWatch website.
Text equivalent for figure 1Map of overall Influenza activity level by province and territory, Canada
Figure 2. Number of influenza surveillance regions<SUP title="sub-regions within the province or territory as defined by the provincial/territorial epidemiologist. Graph may change as late returns come in">†</SUP> reporting widespread or localized influenza activity, Canada, by report week, 2012-2013 (N<SUP>*</SUP>=58)
†sub-regions within the province or territory as defined by the provincial/territorial epidemiologist. Graph may change as late returns come in.
* Total number of influenza surveillance regions in Canada
Text equivalent for figure 2Number of influenza surveillance regions reporting widespread or localized influenza activity, Canada, by report week, 2011-2012 (N=56)
Figure 3. Overall Number of Influenza Outbreaks, Canada, by Report Week, 2012-2013
Text equivalent for figure 3Overall Number of Influenza Outbreaks, Canada, by Report Week, 2011-2012
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Influenza and Other Respiratory Virus Detections
The overall percentage of positive influenza tests was low and stable, at 0.6% in week 33 and 0.3% in week 34. Among the nine influenza viruses detected in weeks 33 and 34, seven were influenza A (Table 1). Cumulative influenza virus detections by type/subtype to date are as follows: 85.1% influenza A [34.8% A(H3), 4.7% A(H1N1)pdm09 and 60.5% A(unsubtyped)] and 14.9% influenza B (Table 1).
Detailed information on age and type/subtype was complete for 26,123 cases (Table 2). The proportion of cases by age group is as follows: 14.8% <5 years; 10.4% between 5-19 years; 16.3% between 20-44 years; 17.0% between 45-64 years of age; 41.5% ≥65 years.
The percentage of positive tests for rhinovirus decreased during this 2-week period from 24.0% in week 32 to to 17.7% in week 34; although the number of positive tests was similar to previous weeks. The percentage of positive tests for parainfluenza declined slightly to 3.4% in week 34. The percentages of positive tests for other respiratory viruses were low in week 34: human metapneumovirus (hMPV) (0%), respiratory syncytial virus (RSV) (0.5%), coronavirus (0.6%) and adenovirus (2.1%) (Figure 5)<SUP>*</SUP>.
* For more details, see the weekly Respiratory Virus Detections in Canada Report.
<TABLE class=widthFull border=1 cellSpacing=0 cellPadding=2><CAPTION class=alignCenter>Table 1: Weekly & Cumulative numbers of positive influenza specimens
by Provincial Laboratories, Canada, 2012-2013</CAPTION><THEAD><TR class=bg-colour-yellow><TH id=ar1 rowSpan=3>Reporting provinces</TH><TH id=ac1 colSpan=6>Weekly
(August 11 to August 24, 2013)</TH><TH id=ac9 colSpan=6>Cumulative
(August 26, 2012 to August 24, 2013)</TH></TR><TR class=bg-colour-yellow><TH id=ac2 colSpan=5 headers=ac1>Influenza A</TH><TH id=ac8 headers=ac1>Influenza
B</TH><TH id=ac10 colSpan=5 headers=ac9>Influenza A</TH><TH id=ac16 headers=ac9>Influenza
B</TH></TR><TR class=bg-colour-yellow><TH id=ac3 headers=ac2>A Total</TH><TH id=ac4 headers=ac2>A(H1)</TH><TH id=ac5 headers=ac2>A(H3)</TH><TH id=ac6 headers=ac2>Pand H1N1</TH><TH id=ac7 class=noWrap headers=ac2>A
( <ABBR title=unsubtyped>Un S</ABBR>)Table 1 note*</TH><TH headers="ac1 ac8">Total</TH><TH id=ac11 headers=ac10>A Total</TH><TH id=ac12 headers=ac10>A(H1)</TH><TH id=ac13 headers=ac10>A(H3)</TH><TH id=ac14 headers=ac10>Pand H1N1</TH><TH id=ac15 class=noWrap headers=ac10>A
(Un S) Table 1 note*</TH><TH headers=ac16>Total</TH></TR></THEAD><TFOOT><TR><TD class=fontSize85 colSpan=13>* Unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Note: Weekly data is based on week of positive lab detection. Cumulative data includes updates to previous weeks; due to reporting delays, the sum of weekly report totals do not add up to cumulative totals. </TD></TR></TFOOT><TBODY><TR><TH id=ar2 class=bg-colour-yellow headers=ar1><ABBR title="British Columbia ">BC</ABBR></TH><TD class=alignRight headers="ar1 ar2 ac1 ac2 ac3">2</TD><TD class=alignRight headers="ar1 ar2 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar2 ac1 ac2 ac5">2</TD><TD class=alignRight headers="ar1 ar2 ac1 ac2 ac6">0</TD><TD class=alignRight headers="ar1 ar2 ac1 ac2 ac7">0</TD><TD class=alignRight headers="ar1 ar2 ac1 ac8">0</TD><TD class=alignRight headers="ar1 ar2 ac9 ac10 ac11">1938</TD><TD class=alignRight headers="ar1 ar2 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar2 ac9 ac10 ac13">1476</TD><TD class=alignRight headers="ar1 ar2 ac9 ac10 ac14">222</TD><TD class=alignRight headers="ar1 ar2 ac9 ac10 ac15">240</TD><TD class=alignRight headers="ar1 ar2 ac9 ac16">407</TD></TR><TR><TH id=ar3 class=bg-colour-yellow headers=ar1><ABBR title=Alberta>AB</ABBR></TH><TD class=alignRight headers="ar1 ar3 ac1 ac2 ac3">0</TD><TD class=alignRight headers="ar1 ar3 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar3 ac1 ac2 ac5">0</TD><TD class=alignRight headers="ar1 ar3 ac1 ac2 ac6">0</TD><TD class=alignRight headers="ar1 ar3 ac1 ac2 ac7">0</TD><TD class=alignRight headers="ar1 ar3 ac1 ac8">0</TD><TD class=alignRight headers="ar1 ar3 ac9 ac10 ac11">2363</TD><TD class=alignRight headers="ar1 ar3 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar3 ac9 ac10 ac13">1771</TD><TD class=alignRight headers="ar1 ar3 ac9 ac10 ac14">448</TD><TD class=alignRight headers="ar1 ar3 ac9 ac10 ac15">144</TD><TD class=alignRight headers="ar1 ar3 ac9 ac16">843</TD></TR><TR><TH id=ar4 class=bg-colour-yellow headers=ar1><ABBR title=Saskatchewan>SK</ABBR></TH><TD class=alignRight headers="ar1 ar4 ac1 ac2 ac3">1</TD><TD class=alignRight headers="ar1 ar4 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar4 ac1 ac2 ac5">0</TD><TD class=alignRight headers="ar1 ar4 ac1 ac2 ac6">0</TD><TD class=alignRight headers="ar1 ar4 ac1 ac2 ac7">1</TD><TD class=alignRight headers="ar1 ar4 ac1 ac8">0</TD><TD class=alignRight headers="ar1 ar4 ac9 ac10 ac11">844</TD><TD class=alignRight headers="ar1 ar4 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar4 ac9 ac10 ac13">476</TD><TD class=alignRight headers="ar1 ar4 ac9 ac10 ac14">74</TD><TD class=alignRight headers="ar1 ar4 ac9 ac10 ac15">294</TD><TD class=alignRight headers="ar1 ar4 ac9 ac16">325</TD></TR><TR><TH id=ar5 class=bg-colour-yellow headers=ar1><ABBR title=Manitoba>MB</ABBR></TH><TD class=alignRight headers="ar1 ar5 ac1 ac2 ac3">0</TD><TD class=alignRight headers="ar1 ar5 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar5 ac1 ac2 ac5">0</TD><TD class=alignRight headers="ar1 ar5 ac1 ac2 ac6">0</TD><TD class=alignRight headers="ar1 ar5 ac1 ac2 ac7">0</TD><TD class=alignRight headers="ar1 ar5 ac1 ac8">0</TD><TD class=alignRight headers="ar1 ar5 ac9 ac10 ac11">660</TD><TD class=alignRight headers="ar1 ar5 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar5 ac9 ac10 ac13">79</TD><TD class=alignRight headers="ar1 ar5 ac9 ac10 ac14">10</TD><TD class=alignRight headers="ar1 ar5 ac9 ac10 ac15">571</TD><TD class=alignRight headers="ar1 ar5 ac9 ac16">115</TD></TR><TR><TH id=ar6 class=bg-colour-yellow headers=ar1><ABBR title=Ontario>ON</ABBR></TH><TD class=alignRight headers="ar1 ar6 ac1 ac2 ac3">4</TD><TD class=alignRight headers="ar1 ar6 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar6 ac1 ac2 ac5">0</TD><TD class=alignRight headers="ar1 ar6 ac1 ac2 ac6">4</TD><TD class=alignRight headers="ar1 ar6 ac1 ac2 ac7">0</TD><TD class=alignRight headers="ar1 ar6 ac1 ac8">1</TD><TD class=alignRight headers="ar1 ar6 ac9 ac10 ac11">8297</TD><TD class=alignRight headers="ar1 ar6 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar6 ac9 ac10 ac13">3795</TD><TD class=alignRight headers="ar1 ar6 ac9 ac10 ac14">389</TD><TD class=alignRight headers="ar1 ar6 ac9 ac10 ac15">4113</TD><TD class=alignRight headers="ar1 ar6 ac9 ac16">954</TD></TR><TR><TH id=ar7 class=bg-colour-yellow headers=ar1><ABBR title=Quebec>QC</ABBR>
</TH><TD class=alignRight headers="ar1 ar7 ac1 ac2 ac3">0</TD><TD class=alignRight headers="ar1 ar7 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar7 ac1 ac2 ac5">0</TD><TD class=alignRight headers="ar1 ar7 ac1 ac2 ac6">0</TD><TD class=alignRight headers="ar1 ar7 ac1 ac2 ac7">0</TD><TD class=alignRight headers="ar1 ar7 ac1 ac8">1</TD><TD class=alignRight headers="ar1 ar7 ac9 ac10 ac11">9823</TD><TD class=alignRight headers="ar1 ar7 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar7 ac9 ac10 ac13">546</TD><TD class=alignRight headers="ar1 ar7 ac9 ac10 ac14">36</TD><TD class=alignRight headers="ar1 ar7 ac9 ac10 ac15">9241</TD><TD class=alignRight headers="ar1 ar7 ac9 ac16">1941</TD></TR><TR><TH id=ar8 class=bg-colour-yellow headers=ar1><ABBR title="New Brunswick">NB</ABBR>
</TH><TD class=alignRight headers="ar1 ar8 ac1 ac2 ac3">0</TD><TD class=alignRight headers="ar1 ar8 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar8 ac1 ac2 ac5">0</TD><TD class=alignRight headers="ar1 ar8 ac1 ac2 ac6">0</TD><TD class=alignRight headers="ar1 ar8 ac1 ac2 ac7">0</TD><TD class=alignRight headers="ar1 ar8 ac1 ac8">0</TD><TD class=alignRight headers="ar1 ar8 ac9 ac10 ac11">1872</TD><TD class=alignRight headers="ar1 ar8 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar8 ac9 ac10 ac13">771</TD><TD class=alignRight headers="ar1 ar8 ac9 ac10 ac14">75</TD><TD class=alignRight headers="ar1 ar8 ac9 ac10 ac15">1026</TD><TD class=alignRight headers="ar1 ar8 ac9 ac16">102</TD></TR><TR><TH id=ar9 class=bg-colour-yellow headers=ar1><ABBR title="Nova Scotia ">NS</ABBR>
</TH><TD class=alignRight headers="ar1 ar9 ac1 ac2 ac3">0</TD><TD class=alignRight headers="ar1 ar9 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar9 ac1 ac2 ac5">0</TD><TD class=alignRight headers="ar1 ar9 ac1 ac2 ac6">0</TD><TD class=alignRight headers="ar1 ar9 ac1 ac2 ac7">0</TD><TD class=alignRight headers="ar1 ar9 ac1 ac8">0</TD><TD class=alignRight headers="ar1 ar9 ac9 ac10 ac11">388</TD><TD class=alignRight headers="ar1 ar9 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar9 ac9 ac10 ac13">165</TD><TD class=alignRight headers="ar1 ar9 ac9 ac10 ac14">8</TD><TD class=alignRight headers="ar1 ar9 ac9 ac10 ac15">215</TD><TD class=alignRight headers="ar1 ar9 ac9 ac16">9</TD></TR><TR><TH id=ar10 class=bg-colour-yellow headers=ar1><ABBR title="Prince Edward Island ">PE</ABBR>
</TH><TD class=alignRight headers="ar1 ar10 ac1 ac2 ac3">0</TD><TD class=alignRight headers="ar1 ar10 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar10 ac1 ac2 ac5">0</TD><TD class=alignRight headers="ar1 ar10 ac1 ac2 ac6">0</TD><TD class=alignRight headers="ar1 ar10 ac1 ac2 ac7">0</TD><TD class=alignRight headers="ar1 ar10 ac1 ac8">0</TD><TD class=alignRight headers="ar1 ar10 ac9 ac10 ac11">117</TD><TD class=alignRight headers="ar1 ar10 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar10 ac9 ac10 ac13">76</TD><TD class=alignRight headers="ar1 ar10 ac9 ac10 ac14">10</TD><TD class=alignRight headers="ar1 ar10 ac9 ac10 ac15">31</TD><TD class=alignRight headers="ar1 ar10 ac9 ac16">1</TD></TR><TR><TH id=ar11 class=bg-colour-yellow headers=ar1><ABBR title="Newfoundland/Labrador ">NL</ABBR>
</TH><TD class=alignRight headers="ar1 ar11 ac1 ac2 ac3">0</TD><TD class=alignRight headers="ar1 ar11 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar11 ac1 ac2 ac5">0</TD><TD class=alignRight headers="ar1 ar11 ac1 ac2 ac6">0</TD><TD class=alignRight headers="ar1 ar11 ac1 ac2 ac7">0</TD><TD class=alignRight headers="ar1 ar11 ac1 ac8">0</TD><TD class=alignRight headers="ar1 ar11 ac9 ac10 ac11">718</TD><TD class=alignRight headers="ar1 ar11 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar11 ac9 ac10 ac13">240</TD><TD class=alignRight headers="ar1 ar11 ac9 ac10 ac14">2</TD><TD class=alignRight headers="ar1 ar11 ac9 ac10 ac15">476</TD><TD class=alignRight headers="ar1 ar11 ac9 ac16">20</TD></TR><TR><TH id=ar12 class=bg-colour-yellow headers=ar1>Canada</TH><TD class=alignRight headers="ar1 ar12 ac1 ac2 ac3">7</TD><TD class=alignRight headers="ar1 ar12 ac1 ac2 ac4">0</TD><TD class=alignRight headers="ar1 ar12 ac1 ac2 ac5">2</TD><TD class=alignRight headers="ar1 ar12 ac1 ac2 ac6">4</TD><TD class=alignRight headers="ar1 ar12 ac1 ac2 ac7">1</TD><TD class=alignRight headers="ar1 ar12 ac1 ac8">2</TD><TD class=alignRight headers="ar1 ar12 ac9 ac10 ac11">27020</TD><TD class=alignRight headers="ar1 ar12 ac9 ac10 ac12">0</TD><TD class=alignRight headers="ar1 ar12 ac9 ac10 ac13">9395</TD><TD class=alignRight headers="ar1 ar12 ac9 ac10 ac14">1274</TD><TD class=alignRight headers="ar1 ar12 ac9 ac10 ac15">16351</TD><TD class=alignRight headers="ar1 ar12 ac9 ac16">4717</TD></TR></TBODY></TABLE>
<TABLE class=widthFull border=1 cellSpacing=0 cellPadding=2><CAPTION>Table 2. Weekly & Cumulative numbers of positive influenza specimens by age groups
reported through case-based laboratory reporting, Canada, 2012-2013 Table 2 note*</CAPTION><THEAD><TR class=bg-colour-yellow><TH id=br1 rowSpan=3>Age groups</TH><TH id=bc1 colSpan=5>Weekly
(August 11 to August 24, 2013)</TH><TH id=bc8 colSpan=5>Cumulative
(August 26, 2012 to August 24, 2013)</TH></TR><TR class=bg-colour-yellow><TH id=bc2 colSpan=4 headers=bc1>Influenza A</TH><TH id=bc7 headers=bc1>B</TH><TH id=bc9 colSpan=4 headers=bc8>Influenza A</TH><TH id=bc14 headers=bc8>B</TH></TR><TR class=bg-colour-yellow><TH id=bc3 headers=bc2>A Total</TH><TH id=bc4 headers=bc2>Pandemic H1N1</TH><TH id=bc5 headers=bc2>A/H3N2</TH><TH id=bc6 headers=bc2>A unsubtyped</TH><TH headers="bc1 bc7">Total</TH><TH id=bc10 headers=bc9>A Total</TH><TH id=bc11 headers=bc9>Pandemic H1N1</TH><TH id=bc12 headers=bc9>A/H3N2</TH><TH id=bc13 headers=bc9>A unsubtyped</TH><TH headers=bc14>Total</TH></TR></THEAD><TFOOT><TR><TD class=fontSize85 colSpan=11>* Please note that this table reflects the number of specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported. Delays in the reporting of data may cause data to change retrospectively.</TD></TR></TFOOT><TBODY><TR><TH id=br2 headers=br1><5</TH><TD class=alignRight headers="br1 br2 bc1 bc2 bc3">0</TD><TD class=alignRight headers="br1 br2 bc1 bc2 bc4">0</TD><TD class=alignRight headers="br1 br2 bc1 bc2 bc5">0</TD><TD class=alignRight headers="br1 br2 bc1 bc2 bc6">0</TD><TD class=alignRight headers="br1 br2 bc1 bc7">0</TD><TD class=alignRight headers="br1 br2 bc8 bc9 bc10">3007</TD><TD class=alignRight headers="br1 br2 bc8 bc9 bc11">224</TD><TD class=alignRight headers="br1 br2 bc8 bc9 bc12">838</TD><TD class=alignRight headers="br1 br2 bc8 bc9 bc13">1945</TD><TD class=alignRight headers="br1 br2 bc8 bc14">853</TD></TR><TR><TH id=br3 headers=br1>5-19</TH><TD class=alignRight headers="br1 br3 bc1 bc2 bc3">0</TD><TD class=alignRight headers="br1 br3 bc1 bc2 bc4">0</TD><TD class=alignRight headers="br1 br3 bc1 bc2 bc5">0</TD><TD class=alignRight headers="br1 br3 bc1 bc2 bc6">0</TD><TD class=alignRight headers="br1 br3 bc1 bc7">0</TD><TD class=alignRight headers="br1 br3 bc8 bc9 bc10">1632</TD><TD class=alignRight headers="br1 br3 bc8 bc9 bc11">71</TD><TD class=alignRight headers="br1 br3 bc8 bc9 bc12">613</TD><TD class=alignRight headers="br1 br3 bc8 bc9 bc13">948</TD><TD class=alignRight headers="br1 br3 bc8 bc14">1080</TD></TR><TR><TH id=br4 headers=br1>20-44</TH><TD class=alignRight headers="br1 br4 bc1 bc2 bc3">0</TD><TD class=alignRight headers="br1 br4 bc1 bc2 bc4">0</TD><TD class=alignRight headers="br1 br4 bc1 bc2 bc5">0</TD><TD class=alignRight headers="br1 br4 bc1 bc2 bc6">0</TD><TD class=alignRight headers="br1 br4 bc1 bc7">1</TD><TD class=alignRight headers="br1 br4 bc8 bc9 bc10">3540</TD><TD class=alignRight headers="br1 br4 bc8 bc9 bc11">358</TD><TD class=alignRight headers="br1 br4 bc8 bc9 bc12">1223</TD><TD class=alignRight headers="br1 br4 bc8 bc9 bc13">1959</TD><TD class=alignRight headers="br1 br4 bc8 bc14">731</TD></TR><TR><TH id=br5 headers=br1>45-64</TH><TD class=alignRight headers="br1 br5 bc1 bc2 bc3">1</TD><TD class=alignRight headers="br1 br5 bc1 bc2 bc4">0</TD><TD class=alignRight headers="br1 br5 bc1 bc2 bc5">1</TD><TD class=alignRight headers="br1 br5 bc1 bc2 bc6">0</TD><TD class=alignRight headers="br1 br5 bc1 bc7">0</TD><TD class=alignRight headers="br1 br5 bc8 bc9 bc10">3734</TD><TD class=alignRight headers="br1 br5 bc8 bc9 bc11">330</TD><TD class=alignRight headers="br1 br5 bc8 bc9 bc12">1224</TD><TD class=alignRight headers="br1 br5 bc8 bc9 bc13">2180</TD><TD class=alignRight headers="br1 br5 bc8 bc14">702</TD></TR><TR><TH id=br6 headers=br1>65+</TH><TD class=alignRight headers="br1 br6 bc1 bc2 bc3">1</TD><TD class=alignRight headers="br1 br6 bc1 bc2 bc4">1</TD><TD class=alignRight headers="br1 br6 bc1 bc2 bc5">0</TD><TD class=alignRight headers="br1 br6 bc1 bc2 bc6">0</TD><TD class=alignRight headers="br1 br6 bc1 bc7">0</TD><TD class=alignRight headers="br1 br6 bc8 bc9 bc10">10002</TD><TD class=alignRight headers="br1 br6 bc8 bc9 bc11">138</TD><TD class=alignRight headers="br1 br6 bc8 bc9 bc12">3719</TD><TD class=alignRight headers="br1 br6 bc8 bc9 bc13">6145</TD><TD class=alignRight headers="br1 br6 bc8 bc14">842</TD></TR><TR><TH id=br7 headers=br1>Unknown</TH><TD class=alignRight headers="br1 br7 bc1 bc2 bc3">0</TD><TD class=alignRight headers="br1 br7 bc1 bc2 bc4">0</TD><TD class=alignRight headers="br1 br7 bc1 bc2 bc5">0</TD><TD class=alignRight headers="br1 br7 bc1 bc2 bc6">0</TD><TD class=alignRight headers="br1 br7 bc1 bc7">0</TD><TD class=alignRight headers="br1 br7 bc8 bc9 bc10">210</TD><TD class=alignRight headers="br1 br7 bc8 bc9 bc11">29</TD><TD class=alignRight headers="br1 br7 bc8 bc9 bc12">178</TD><TD class=alignRight headers="br1 br7 bc8 bc9 bc13">3</TD><TD class=alignRight headers="br1 br7 bc8 bc14">2</TD></TR><TR><TH id=br8 headers=br1>Total</TH><TD class=alignRight headers="br1 br8 bc1 bc2 bc3">2</TD><TD class=alignRight headers="br1 br8 bc1 bc2 bc4">1</TD><TD class=alignRight headers="br1 br8 bc1 bc2 bc5">1</TD><TD class=alignRight headers="br1 br8 bc1 bc2 bc6">0</TD><TD class=alignRight headers="br1 br8 bc1 bc7">1</TD><TD class=alignRight headers="br1 br8 bc8 bc9 bc10">22125</TD><TD class=alignRight headers="br1 br8 bc8 bc9 bc11">1150</TD><TD class=alignRight headers="br1 br8 bc8 bc9 bc12">7795</TD><TD class=alignRight headers="br1 br8 bc8 bc9 bc13">13180</TD><TD class=alignRight headers="br1 br8 bc8 bc14">4210</TD></TR></TBODY></TABLE>
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Figure 4. Influenza tests reported and percentage of tests positive, Canada,
by report week, 2012-2013
Text equivalent for figure 4Influenza tests reported and percentage of tests positive, Canada, by report week, 2011-2012
Figure 5. Percent positive influenza tests, compared to other respiratory viruses,
Canada, by reporting week, 2012-2013
Text equivalent for figure 5Percent positive influenza tests, compared to other respiratory viruses, Canada, by reporting week, 2011-2012
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Influenza Strain Characterizations
During the 2012-13 season, the National Microbiology Laboratory (NML) has antigenically characterized 1514 influenza viruses. The 662 influenza A(H3N2) viruses were antigenically similar to the vaccine strain A/Victoria/361/2011 and the 250 A(H1N1)pdm09 viruses were antigenically similar to the vaccine strain A/California/07/09. Among the influenza B viruses, 464 were antigenically similar to the vaccine strain B/Wisconsin/01/2010 (Yamagata lineage) and 138 were similar to B/Brisbane/60/2008 (Victoria lineage; component of the 2011-2012 seasonal influenza vaccine) (Figure 6).
Figure 6. Influenza strain characterizations, Canada, 2012-2013, N =1514
Note: The recommended components for the 2012-2013 Northern Hemisphere influenza vaccine include: an A/Victoria/361/2011 (H3N2)-like virus; an A/California/7/2009 (H1N1)pdm09-like virus; and a B/Wisconsin/1/2010-like virus.
Text equivalent for figure 6Influenza strain characterizations, Canada, 2011-2012
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Antiviral Resistance
During the 2012-13 season, NML has tested 1508 influenza viruses for resistance to oseltamivir, and 1505 influenza viruses for resistance to zanamivir. Among these, one A(H3N2) virus was resistant to oseltamivir and zanamivir, one A(H1N1)pdm09 virus was resistant to oseltamivir, and three influenza B virus samples were resistant to both oseltamivir and zanamivir. A total of 1344 influenza A viruses were tested for amantadine resistance and all but one A(H3N2) virus were resistant (Table 3).
<TABLE class=widthFull border=1 cellSpacing=0 cellPadding=2><CAPTION>Table 3. Antiviral resistance by influenza virus type and subtype, Canada, 2012-2013</CAPTION><THEAD><TR class=bg-colour-yellow><TH id=cr1 rowSpan=2>Virus type and subtype</TH><TH id=cc1 colSpan=2>Oseltamivir</TH><TH id=cc4 colSpan=2>Zanamivir</TH><TH id=cc7 colSpan=2>Amantadine</TH></TR><TR class=bg-colour-yellow><TH id=cc2 headers=cc1># tested</TH><TH id=cc3 headers=cc1># resistant (%)</TH><TH id=cc5 headers=cc4># tested</TH><TH id=cc6 headers=cc4># resistant (%)</TH><TH id=cc8 headers=cc7># tested</TH><TH id=cc9 headers=cc7># resistant (%)</TH></TR></THEAD><TFOOT><TR><TD class=fontSize85 colSpan=7><SUP>*</SUP> NA - not applicable</TD></TR></TFOOT><TBODY><TR><TH id=cr2 class="alignLeft bg-colour-blue" headers=cr1>A (H3N2)</TH><TD class=alignRight headers="cr2 cc2">653</TD><TD class=alignRight headers="cr2 cc3">1 (0.2%)</TD><TD class=alignRight headers="cr2 cc5">653</TD><TD class=alignRight headers="cr2 cc6">1 (0.2%)</TD><TD class=alignRight headers="cr2 cc8">1049</TD><TD class=alignRight headers="cr2 cc9">1048 (99.9%)</TD></TR><TR><TH id=cr3 class="alignLeft bg-colour-blue" headers=cr1>A (H1N1)</TH><TD class=alignRight headers="cr3 cc2">254</TD><TD class=alignRight headers="cr3 cc3">1 (0.4%)</TD><TD class=alignRight headers="cr3 cc5">251</TD><TD class=alignRight headers="cr3 cc6">0</TD><TD class=alignRight headers="cr3 cc8">295</TD><TD class=alignRight headers="cr3 cc9">295 (100%)</TD></TR><TR><TH id=cr4 class="alignLeft bg-colour-blue" headers=cr1>B</TH><TD class=alignRight headers="cr4 cc2">601</TD><TD class=alignRight headers="cr4 cc3">3 (0.5%)</TD><TD class=alignRight headers="cr4 cc5">601</TD><TD class=alignRight headers="cr4 cc6">3 (0.5%)</TD><TD class=alignRight headers="cr4 cc8">NA <SUP>*</SUP></TD><TD class=alignRight headers="cr4 cc9">NA <SUP>*</SUP></TD></TR><TR><TH id=cr5 class="alignLeft bg-colour-blue" headers=cr1>TOTAL</TH><TD class=alignRight headers="cr5 cc2">1508</TD><TD class=alignRight headers="cr5 cc3">5 (0.3%)</TD><TD class=alignRight headers="cr5 cc5">1505</TD><TD class=alignRight headers="cr5 cc6">4 (0.3%)</TD><TD class=alignRight headers="cr5 cc8">1344</TD><TD class=alignRight headers="cr5 cc9">1343 (99.9%)</TD></TR></TBODY></TABLE>
Influenza-like Illness (ILI) Consultation Rate
The national influenza-like-illness (ILI) consultation rate was similar between weeks 15 and 29, with an average of 16.2 ILI consultations per 1,000 patient visits (range 13.9 to 24.6). The rate continued a gradual downward trend in weeks 30-34, with an average of 12.3/1,000; and was 14.5/1,000 in week 34. The majority of weekly rates observed in weeks 18 to 34 were above the average range (Figure 7). The highest consultation rate was observed in children <5 years of age (41.7/1,000 visits) in week 33 and in children 5-19 years of age in week 34 (30.6/1,000 visits).
Figure 7. Influenza-like illness (ILI) consultation rates, Canada, by report week, 2012-2013 compared to 1996/97 through to 2011/12 seasons (with pandemic data suppressed)
Note: No data available for mean rate in previous years for weeks 19 to 39 (1996-1997 through 2002-2003 seasons). Delays in the reporting of data may cause data to change retrospectively.
Text equivalent for figure 7Influenza-like illness (ILI) consultation rates, Canada, by report week, 2011-2012 compared to 1996/97 through to 2010/11 seasons (with pandemic data suppressed)
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Severe Respiratory Illness Surveillance
Paediatric Influenza Hospitalizations and Deaths (IMPACT)
One new laboratory-confirmed influenza-associated paediatric (≤16 years of age) hospitalization was reported in week 34, a child <6 months of age with influenza A. No intensive care unit (ICU) admissions or deaths were reported by the Immunization Monitoring Program Active (IMPACT) network in weeks 33 and 34.
Since the start of the 2012-13 season, a total of 888 influenza-associated paediatric hospitalizations have been reported by the IMPACT network: 625 (70.4%) with influenza A [of which 124 (19.8%) were A(H3N2), 31 (5.0 %) were A(H1N1)pdm09 and the remaining 470 were A(unsubtyped); and 263 (29.6%) with influenza B. The distribution of cases by age group is as follows: 168 (18.9%) <6 months of age; 202 (22.7%) age 6-23 months; 254 (28.6 %) age 2-4 years; 189 (21.3%) age 5-9 years; and 75 (8.4%) age 10-16 years. Of the 888 cases, 110 (12.4%) were admitted to the ICU. Of the 92 ICU admissions with available data, 76 (82.6%) cases had at least one underlying condition. One death has been reported to date this season in a child 6-23 months of age with an underlying condition, with influenza B.
Note: The number of hospitalizations reported through IMPACT represents a subset of all influenza-associated paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
Adult Influenza Hospitalizations and Deaths (PCIRN)
Active surveillance of laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations reported by the PHAC/CIHR Influenza Research Network (PCIRN) Serious Outcomes Surveillance (SOS) network concluded for the 2012-13 influenza season on April 30th, 2013. However, the PCIRN-SOS network continues to report limited data on laboratory-confirmed cases of influenza identified through passive surveillance at 15 out of 17 hospital sites. No new hospitalizations, ICU admissions or deaths were reported in weeks 33 and 34.
The cumulative data for the season to date includes data from active surveillance from November 4, 2012 to April 30, 2013 and data from passive surveillance since May 1, 2013. The cumulative number of cases is 1,812: 1,627 (89.8%) with influenza A [of which 313 were A(H3N2), 22 were A(H1N1)pdm09, and 1,292 were A(unsubtyped)]; 139 (7.7%) with influenza B, and the type has not been reported for 46 cases. The age distribution of hospitalizations is as follows: 1,230 (67.9%) were ≥65 years of age, 375 (20.7%) were 45-64 years, 195 (10.8%) were 20-44 years, and 12 (0.7%) were <20 years of age. ICU admission was required for 216 hospitalizations; the majority of which were adults ≥65 years of age (126; 58.3%). A total of 116 deaths have been reported: 26 with influenza A(H3N2), one with A(H1N1)pdm09, 82 with A(unsubtyped), 6 with influenza B, and one untyped. More than 85% of the deaths (99/116) were in adults ≥65 years of age, 14 (12.1%) were adults 45-64 years of age, and 3 (2.6%) were 20-44 years of age.
Note: The number of hospitalizations reported through PCIRN represents a subset of all influenza-associated adult hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
Provincial/Territorial Influenza Hospitalizations and Deaths (Aggregate Surveillance System<SUP>*</SUP>)
In weeks 33 and 34, two new laboratory-confirmed influenza-associated hospitalization was reported from participating provinces and territories*, both cases of influenza A in adults ≥65 years of age. To date this season, 5,077 influenza-associated hospitalizations have been reported, of which 86.3% have been influenza A. Of those subtyped (49.3%), influenza A(H3) was the predominant influenza strain. Age information was available for 5,074 cases, and the age distribution is as follows: 2,665 (52.5%) were ≥65 years of age; 843 (16.6%) were 45-64 years of age; 454 (8.9%) were 20-44 years of age; 41 (0.8%) were 15-19 years of age; 278 (5.5%) were 5-14 years; and 793 (15.6%) were 0-4 years of age. Of the 1,401 cases with available data, there have been 222 hospitalisations for which admission to an ICU was required; the highest proportions have been in adults ≥65 years of age, followed by adults 45-64 years of age (36.0% and 33.8%, respectively). To date, 317 deaths have been reported: 258 adults ≥65 years of age, 37 adults 45-64 years; 13 adults 20-44 years, two children 5-14 years of age, and seven children 0-4 years of age. It is important to note that the cause of death does not have to be attributable to influenza, a positive laboratory test is sufficient for reporting. Detailed clinical information (e.g. underlying medical conditions) is not known for these cases.
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http://www.phac-aspc.gc.ca/fluwatch/.../index-eng.php
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