Canada:
Influenza activity appears to have peaked in most parts of the country, with many regions now reporting localized activity, except for Quebec and southwestern Ontario where activity remains widespread (see map). Across Canada, during the week ending January 24 (week 04), sentinel physicians reported 18 cases of influenza-like illness (ILI) per 1,000 patient visits, which is below the expected range for this time of year (see ILI graph). Health Canada received 3,160 reports of laboratory tests for influenza, including 591 (19%) influenza A detections and 1 influenza B detection (see table below). The National Microbiology Laboratory has antigenically characterized 591 influenza viruses to date, 584/591 (99%) were influenza A viruses, including 557 (95%) A/Fujian/411/02(H3N2)-like, 25 (4.5%) A/Panama/2007/99(H3N2)-like, 1 (0.2%) A/NewCaledonia/20/99(H1N1)-like and 1 (0.2%) H1N2. Seven 7/551 (1%) were influenza B viruses, including 1 B/Hong Kong/330/2001-like and 6 B/Sichuan/379/99-like. Detections of other respiratory viruses are at or below the expected range for this time of year. To date, there have been a total of 657 outbreaks reported, including 388 influenza confirmed outbreaks in LTCF/retirement lodges (324) and hospitals (64) and 269 ILI outbreaks schools (181) and other (88).

United States:
CDC: During the week ending January 24, 2004, widespread activity was reported in 1 state while regional activity was reported by 20 states. ILI visits accounted for 2.0% of patient visits to sentinel physicians, which is below the national baseline of 2.5%. Sentinel cities reported 9.7% of deaths attributable to pneumonia and influenza, which is above the epidemic threshold of 8.2% for this week. A total of 565 influenza A(H3N2) isolates have been characterized to date; 106 (18.8%) were antigenically similar to the vaccine strain A/Panama/2007/99 and 459 (81.2%) were similar to the new drift variant A/Fujian/411/2002.
CDC: <http://www.cdc.gov/ncidod/diseases/flu/weekly.htm>

International:
WHO: Influenza activity associated with A/Fujian/411/2002-like viruses continues in some parts of Europe (Austria, Croatia, Denmark, Italy, and the Russian Federation) with marked increases reported in Latvia, Poland and Slovakia. Japan is reporting significant increases of influenza A (H3N2) in the north.
Avian Influenza: As of 30 January 2004, 11 cases of laboratory confirmed avian influenza (H5N1) have been reported, with: 8 cases in Viet Nam, including 6 deaths and 3 cases in Thailand, including two deaths. All cases have been in children with the exception of one adult case in Viet Nam. There remains no evidence of human-to-human spread in either country. In response to outbreaks of H5N1 in poultry in Asia, several countries are currently carrying out mass slaughter of millions of chickens to prevent spread to humans (see WHO H5N1 update).
SARS: As of 27 January 2004, WHO has reported two laboratory confirmed cases and one probable case of SARS-CoV infection in 3 unrelated residents of Guangzhou, Guangdong Province, China. All patients have recovered and no illness was seen in any of their contacts, including health care workers.
WHO SARS Update: <http://www.who.int/csr/sars/en/>
EISS: <http://www.eiss.org>
WHO H5N1 Update: <http://www.who.int/csr/don/en/>

Total number of influenza tests performed and number of positive tests by province/territory of testing laboratory, Canada, 2003-2004

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, 2003-2004 (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, January 18 to January 24, 2004 (Week 04)
	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 2003-2004 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, 2003-2004

Percent positive influenza tests, compared to other respiratory viruses by reporting week, Canada, 2003-2004

Influenza strain characterization, Canada, cumulative, 2003-2004 influenza season by the Respiratory Viruses Section at the National Microbiology Laboratory
[N=591]

NACI recommended components of the 2003-2004 Canadian vaccine: A/New Caledonia/20/99 (H1N1)–like virus, A/Panama/2007/99 (H3N2)-like virus and either B/Hong Kong/330/2001-like or B/Shangdong/7/97-like virus. Note: the influenza A(H1N2) virus strain is a reassortment virus derived from the influenza A (H1N1) and A(H3N2) virus strains. This H1N2 strain circulated widely during the 2001-2002 season and the current vaccine is expected to provide protection against this virus as well as providing good protection against A/Panama/2007/99(H3N2)-like viruses and some cross protection against the new A/Fujian/411/2002(H3N2)-like virus. However, the recently identified B/Sichuan/379/99-like viruses (B component of the 2001-2002 influenza vaccine) belong to a different lineage (B Yamagata lineage) than the B/Hong Kong/330/2001-like viruses included in this year’s vaccine.

Influenza-like illness (ILI) reporting rates, Canada, by report week, 2003-2004 compared to 1996/97 through 2002/2003 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, 2003-2004

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

Definitions for the 2003-2004 season

[FluWatch]