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Low levels of influenza activity in Canada overall

During week 45, localized influenza activity was reported in the Central West region of Ontario and in Northern Alberta. Sporadic influenza activity was reported in regions of British Columbia, Alberta, Saskatchewan and Ontario while the rest of the country reported no activity (see map). In week 45, 12 (0.9%) of the 1,284 specimens tested for influenza virus were positive (see table). The majority (97%) of influenza detections so far this season were influenza A viruses. The ILI consultation rate remained low with a rate of 13 per 1,000 patient visits in week 45 (see ILI graph) and a sentinel response rate of 68%.

Antigenic Characterization:
The National Microbiology Laboratory (NML) has characterized seven influenza viruses for the 2006-2007 influenza season: one A/Wisconsin/67/2005(H3N2)-like virus (from Ontario) and six A/New Caledonia/20/99(H1N1)-like viruses (from Alberta) (see pie chart). Both strains are included in the composition of the 2006-2007 Canadian influenza vaccine.

Antiviral Resistance:
The NML has tested five influenza A isolates for amantadine resistance this season and found that the one influenza A(H3N2) isolate tested was resistant to amantadine. The other four isolates were influenza A/H1N1 which remain sensitive to amantadine. (see recommendation below)

Influenza-associated Pediatric Hospitalizations:
During week 45, no new laboratory-confirmed influenza-associated paediatric hospitalizations were reported through the Immunization Monitoring Program Active (IMPACT) network. One case has been reported to IMPACT since the start of this influenza season.

International:
WHO: During weeks 41-44, overall influenza activity remained low in both hemispheres. Localized influenza A(H3N2) activity was reported in Madagascar between weeks 41-43.

• WHO

EISS: In week 45, influenza activity in Europe remained low with only sporadic cases of influenza being reported since week 40. Consultation rates for ILI and/or acute respiratory infection (ARI) remained at baseline levels across the whole of Europe.

• EISS

Human Avian Influenza: Since 11 November, 2006, the WHO reported two additional cases of human infection with the H5N1 avian influenza virus in Indonesia. The first case is a 35-year-old female who developed symptoms on 7 November and was hospitalized on 10 November. Her source of exposure is currently under investigation. The second case is a 30-month-old boy who developed symptoms on 5 November, was hospitalized on 10 November, and died on 13 November. An initial investigation of his exposure source found reports of chicken deaths near his home in the days prior to symptom onset.

• WHO

Recommendation for the Use of Amantadine for Treatment and Prevention of Influenza
The Public Health Agency of Canada does not recommend the use of amantadine for treatment or prevention of influenza for the 2006-2007 season. This recommendation will be revisited if new information becomes available.

Total number of influenza tests performed and number of positive tests by province/territory of testing laboratory, Canada, 2006-2007

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.html>

Number of influenza surveillance regions† reporting widespread or localized influenza activity, Canada, by report week, 2006-2007 (N=76)

† 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, November 5, 2006 to November 11, 2006 (Week 45)
	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 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, 2006-2007

Percent positive influenza tests, compared to other respiratory viruses, Canada, by reporting week, 2006-2007

Influenza strain characterization, Canada, cumulative, 2006-2007 influenza season by the Respiratory Viruses Section at the National Microbiology Laboratory
[N=7]

{Strain characterization, number identified, per cent of total number}

NACI recommends that the trivalent vaccine for the 2006-2007 season in Canada contain A/New Caledonia/20/1999 (H1N1)-like, A/Wisconsin/67/2005 (H3N2)-like, and B/Malaysia/2506/2004-like virus antigens.

Influenza-like illness (ILI) consultation rates, Canada, by report week, 2006-2007 compared to 1996/97 through to 2005/06 seasons

Note: No data available for mean rate in previous years for weeks 19 to 39 (1996-1997 through 2002-2003 seasons).

Number of New Outbreaks in Long Term Care Facilities, Canada, by Report Week, 2006-2007

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

Definitions for the 2006-2007 season

[FluWatch]