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Canada:
Influenza activity continues to decline across the
country with localized activity only being reported in Quebec,
while the rest of the country reports sporadic or no activity
(see map). Across
Canada, during the week ending March 20 (week 12), sentinel
physicians reported 18 cases of influenza-like illness (ILI)
per 1000 patient visits, which is below the expected range
for this time of year (see ILI graph). Health
Canada received 2,156 reports of laboratory tests for influenza,
including 58 (2.7%) influenza A detections and 12 influenza
B detections (see table below). The National
Microbiology Laboratory has antigenically characterized 746
influenza viruses to date, 732/746 (98.1%) were influenza
A viruses, including 705/732 (96.3%) A/Fujian/411/02(H3N2)-like,
25 (3.4%) A/Panama/2007/99(H3N2)-like, one A/NewCaledonia/20/99(H1N1)-like
and one H1N2. Fourteen (14/746) were influenza B viruses,
including three B/Hong Kong/330/2001-like and 11 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 has
been a total of 730 outbreaks reported, including 447 influenza
confirmed outbreaks in LTCF/retirement lodges (360) and hospitals
(87), and 283 ILI outbreaks in schools (188) and other (95).
Avian Situation in BC: The Canadian Food
Inspection Agency (CFIA) will depopulate all remaining chicken
flocks in the high-risk region of British Columbia's
Fraser Valley, in order to contain further spread of the
disease. The decision follows the detection of avian influenza
on two farms, bringing the total number of infected premises
in the high-risk region to five. Approximately 275,000 birds
will be destroyed and removed from 10 farms and 33 smaller
flocks.
See CFIA update: <http://www.inspection.gc.ca/english/anima/heasan/disemala/avflu/avflue.shtml> 
United
States:
CDC: During the week ending March 13, 2004,
no widespread or regional activity was reported in any state,
while one state reported local activity. ILI visits accounted
for 1.1% of patient visits to sentinel physicians, which
is below the national baseline of 2.5%. Sentinel cities reported
7.4% of deaths attributable to pneumonia and influenza, which
is below the epidemic threshold of 8.3% for this week. A
total of 727 influenza A(H3N2) isolates have been characterized
to date; 106 (14.6%) were antigenically similar to the vaccine
strain A/Panama/2007/99 and 621 (85.4%) were similar to the
new drift variant A/Fujian/411/2002.
CDC: <http://www.cdc.gov/flu/weekly/>
International:
WHO and EISS: Influenza activity remains
low in Europe. Influenza activity in Hong Kong continues
to increase with a number of outbreaks in schools reported.
Avian Influenza (WHO): As of 26th March
2004, the human H5N1 case count remains at 34 cases with
23 deaths in Viet Nam and Thailand. Investigation is underway
on a media report of a fatal case in Viet Nam. If confirmed,
it will be the first case in Viet Nam since February 20th
2004 (see WHO
H5N1 update).
EISS: <http://www.eiss.org>
WHO H5N1 Update: <http://www.who.int/csr/disease/avian_influenza/en/>
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Total number of influenza tests
performed and number of positive tests by province/territory of testing
laboratory, Canada, 2003-2004
Province
of
reporting
laboratories |
Report
Period:
March 14 to March 20, 2004 |
Season
to Date:
August 24, 2003 - March 20, 2004 |
Total #
Influenza
Tests |
# of
Positive Tests |
Total #
Influenza
Tests |
# of
Positive Tests |
| Influenza
A |
Influenza
B |
Total |
Influenza
A |
Influenza
B |
Total |
| NL |
5 |
1 |
0 |
1 |
913 |
152 |
0 |
152 |
| PE |
3 |
0 |
0 |
0 |
84 |
25 |
0 |
25 |
| NS |
0 |
0 |
0 |
0 |
1290 |
318 |
11 |
329 |
| NB |
20 |
0 |
0 |
0 |
1586 |
299 |
0 |
299 |
| QC |
693 |
52 |
9 |
61 |
16036 |
2694 |
48 |
2742 |
| ON |
797 |
1 |
3 |
4 |
28477 |
4465 |
25 |
4490 |
| MB |
99 |
1 |
0 |
1 |
2609 |
168 |
0 |
168 |
| SK |
116 |
0 |
0 |
0 |
5864 |
1069 |
1 |
1070 |
| AB |
345 |
3 |
0 |
3 |
12667 |
1187 |
0 |
1187 |
| BC |
78 |
0 |
0 |
0 |
3807 |
797 |
2 |
799 |
| Canada |
2156 |
58 |
12 |
70 |
73333 |
11174 |
87 |
11261 |
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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 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=746]
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
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