Canada: Widespread influenza activity reported in Ontario, Saskatchewan, parts of Alberta and Newfoundland. Localized activity reported in Quebec, parts of British Columbia, Nova Scotia and New Brunswick. The rest of the country reports either sporadic or no activity. During the week ending February 19, 2005 (week 07), sentinel physicians reported 33 cases of influenza-like illness (ILI) per 1000 patient visits, see ILI graph. Over the one week period, the Public Health Agency of Canada received 4788 reports of laboratory tests for influenza, including 722 (15.1%) influenza A detections and 70 (1.5%) influenza B detections (see table below). During this week, 104 new influenza outbreaks were reported. To date this season, there have been a total of 675 influenza outbreaks, of which 497 were reported in LTCF/ retirement lodges, 44 in hospitals and 134 in schools. The National Microbiology Laboratory (NML) has antigenically characterized 516 influenza viruses: 470 influenza A (H3N2) and 46 influenza B viruses. Of the 470 influenza A (H3N2), 427 (91%) were A/Fujian/411/02(H3N2)-like and 43 (9%) A/California/7/04-like viruses. Of the 46 influenza B, 45 were B/Shanghai/361/02-like and one B/HongKong/330/2001-like virus. Although the A/California/7/04 (H3N2)-like isolates have reduced titres to the A/Fujian/411/02-like antisera, the H3N2 component of the current vaccine is still expected to provide some level of protection against this new variant. The WHO has recommened that the vaccine for the 2005/06 northern hemisphere season contain the A/California/7/2004(H3N2)-like virus.

• WHO Recommendations for Influenza Vaccine Composition

During the one week period from February 13 to February 19, 29 reports of laboratory confirmed influenza-associated hospitalizations in 10 centres were reported through the IMPACT (Immunization Monitoring Program Active) network. One influenza-associated pediatric death has been reported this season. Since October 9th 2004, there have been a total of 246 reports, of which children aged 0 to 23 months accounted for the highest proportion (60%). Influenza A is the predominant virus type in these reports.

Avian Influenza: There have been no new human cases of avian influenza infection reported this week.

• WHO latest updates

United States: CDC: During the week ending February 12, 2005 (week 06), influenza activity continued to increase in the US. ILI accounted for 5.4% of patient visits to sentinel physicians, which is above the national baseline of 2.5%. Sentinel cities reported 8.0% of deaths as attributable to pneumonia and influenza, which is below the epidemic threshold of 8.2% for this week. Of the influenza A(H3N2) viruses characterized this season, 103 (45%) were most closely related to the recent reference strain, A/California/7/2004 and 125 (55%) were A/Fujian/411/2002-like. Six influenza-associated pediatric deaths have been reported this season.

• CDC Weekly Report

International: EISS: The north-eastern part of Europe is currently experiencing increasing influenza activity. The majority of viruses reported in Europe remains influenza A (H3), however in a number of countries the proportion of influenza B viruses is increasing or higher than that of influenza A viruses.

• EISS 

 

Total number of influenza tests performed and number of positive tests by province/territory of testing laboratory, Canada, 2004-2005

Province of reporting laboratories Report Period: February 13 to February 19, 2005 Season to Date: August 22, 2004 - February 19, 2005 Total # Influenza Tests # of Positive Tests Total # Influenza Tests # of Positive Tests Influenza A Influenza B Total Influenza A Influenza B Total NL 78 20 0 20 568 90 0 90 PE 2 1 0 1 55 18 0 18 NS 96 29 0 29 993 357 3 360 NB 225 89 0 89 1160 260 1 261 QC 1248 174 16 190 17567 3508 89 3597 ON 1735 275 49 324 17503 1805 151 1956 MB 155 12 0 12 1798 72 0 72 SK 433 62 0 62 3600 440 3 443 AB 648 28 3 31 8683 705 11 716 BC 168 32 2 34 2765 436 8 444 Canada 4788 722 70 792 54692 7691 266 7957

Specimens from NT, YT, and NU are sent to reference laboratories in other provinces.

Note: Cumulative data includes updates to previous weeks; due to reporting delays, the sum of weekly report totals do not add up to cumulative totals.

Abbreviations: Newfoundland/Labrador (NL), Prince Edward Island (PE), New Brunswick (NB), Nova Scotia (NS), Quebec (QC), Ontario (ON), Manitoba (MB), Saskatchewan (SK), Alberta (AB), British Columbia (BC), Yukon (YT), Northwest Territories (NT), Nunavut (NU)

Respiratory virus laboratory detections in Canada, by geographic regions, are available weekly on the following website:
<http://www.phac-aspc.gc.ca/bid-bmi/dsd-dsm/rvdi-divr/index-eng.php>

Number of influenza surveillance regions† reporting widespread or localized influenza activity, Canada, by report week, 2004-2005 (N=52)

† sub-regions within the province or territory as defined by the provincial/territorial epidemiologist. Graph may change as late returns come in.

Influenza Activity Level by Provincial and Territorial Influenza Surveillance Regions, Canada, February 13 to February 19, 2005 (Week 07)
	No Data No Activity Sporadic Activity Localized Activity Widespread Activity
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 outbreaks. Please refer to detailed definitions for the 2004-2005 season. For areas where no data is reported, late reports from these provinces and territories will appear on the FluWatch website. Select single maps by report week to get this updated information. <http://dsol-smed.phac-aspc.gc.ca/dsol-smed/fluwatch/fluwatch.phtml?lang=e> Click on the map to view provinces/territories and maps for other weeks.

Influenza tests reported and percentage of tests positive, Canada, by report week, 2004-2005

Percent positive influenza tests, compared to other respiratory viruses by reporting week, Canada, 2004-2005

Influenza strain characterization, Canada, cumulative, 2004-2005 influenza season by the Respiratory Viruses Section at the National Microbiology Laboratory
[N=516]

NACI recommends that the trivalent vaccine for the 2004-2005 season in Canada contain A/New Caledonia/20/99 (H1N1)-like, A/Fujian/411/2002 (H3N2)-like, and B/Shanghai/361/2002-like virus antigens.
Note: Vaccine producers may use antigenically equivalent strains because of their growth properties. A/Wyoming3/2003 and A/Kumamoto/102/2002 strains are antigenically equivalent to the A/Fujian/411/2002 (H3N2); B/Jilin/20/2003 and B/Jiangsu/10/2003 virus strains are antigenically equivalent to B/Shanghai/361/2002. The vaccines to be marketed in Canada for the 2004-2005 flu season contain A/New Caledonia/20/99 (H1N1), A/Wyoming/3/2003 (H3N2) and B/Jiangsu/10/2003 virus antigens.

Influenza-like illness (ILI) reporting rates, Canada, by report week, 2004-2005 compared to 1996/97 through 2003/2004 seasons

Note: No data available for mean rate in previous years for weeks 21 to 39 (1996-1997 through 2002-2003 seasons). During weeks 20-39, 2002-2003/2003-2004 seasons, ILI is reported once every two weeks, on even weeks only

Number of Outbreaks in Long Term Care Facilities by Report Week, Canada, 2004-2005

Please note that the above graphs may change as late returns come in.

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Definitions for the 2004-2005 season