FluWatch report: February 22 to February 28, 2015 (Week 8)

Overall summary

In week 08, all influenza indicators except the influenza-like illness consultation rate remained similar to, or declined from the previous week.
Elevated influenza activity was mostly reported in the Central and Atlantic provinces and in a few regions in the Western provinces.
Influenza B detections continues to increase steadily, particularly in the Prairies and in Quebec. This increase in influenza B is expected as influenza B often shows up later in the flu season.
A(H3N2) continues to be the most common influenza virus this season and seniors continue to have the highest number of positive laboratory detections, hospitalizations and deaths.
Evidence from the National Microbiology Laboratory (NML) indicates that this year's vaccine will continue to provide protection against the circulating A(H1N1) and B strains.

Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2014-15 influenza season? Contact us at FluWatch@phac-aspc.gc.ca

Influenza/ILI Activity (geographic spread)
Influenza and Other Respiratory Virus Detections
Antiviral Resistance
Influenza Strain Characterizations
Influenza-like Illness (ILI) Consultation Rate
Influenza Outbreak Surveillance
Pharmacy surveillance
Sentinel Hospital Influenza Surveillance
Provincial/Territorial Influenza Hospitalizations and Deaths
Emerging Respiratory Pathogens
International Influenza Reports

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Organization: Public Health Agency of Canada

Date published: 2015-03-06

Influenza/ILI Activity (geographic spread)

In week 08, two regions in Quebec reported widespread activity. Twenty-three regions reported localized activity: BC(2), AB(2), MB, ON(7), QC(2), NB(4), NS(3), PE and NL. Twenty-five regions reported sporadic activity: in YK, NU, NT(2), BC(3), AB(3), SK(3), MB(3), QC(2), NB(3), NS(3), and NL. No activity was reported in seven regions: NU, MB, NS(3) and NL(2). Overall when compared to the previous week, there was a decrease in widespread activity. The majority of widespread and localized activity was reported in the Central and Atlantic provinces; however, more regions reported localised activity compared to the previous week.

Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, Week 08

Figure 1 Legend — Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, Week 08

Influenza and Other Respiratory Virus Detections

In week 08, the number of positive influenza tests (1,242) and the percentage positive for influenza A (11.1%) continued to decline from the previous week. The percentage of positive influenza B tests continued to increase and was 5.9% in week 08 (Figure 2). Influenza B detections were greater than influenza A detections in QC and AB; accounting for 57% and 63% of influenza detections respectively. To date, 93% of influenza detections have been influenza A, and 99.5% of those subtyped have been A(H3N2) (Table 1). To date this season, detailed information on age and type/subtype has been received for 30,350 cases. A significantly greater proportion of laboratory detections of influenza have been reported in adults ≥65 years of age (61%) this season (Table 2) compared to the 2013-14 season when only 16.3% of cases were in adults ≥65 years of age.

Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2014-15

In week 08, detections of all respiratory viruses except parainfluenza and human metapneumovirus (hMPV) decreased from the previous week (figure 3). Detections of respiratory syncytial virus (RSV) in week 08 were greater than the detections of influenza A with 867 detections (vs 818 detections of influenza A). In recent weeks, weekly detections of adenovirus, coronavirus, rhinovirus and parainfluenza have been greater than those reported in each of the past three seasons. Weekly detections of hMPV this season have been lower compared to the previous three seasons.

For more details, see the weekly Respiratory Virus Detections in Canada Report.

Figure 3. Number of positive laboratory tests for other respiratory viruses by report week, Canada, 2014-15

Table 1: Weekly and cumulative numbers of positive influenza specimens by type, subtype and province, Canada, 2014-15
Reporting provinces^{Footnote 1}	Weekly (February 22 to February 28, 2015)					Cumulative (August 24, 2014 to February 28, 2015)
	Influenza A				B	Influenza A				B
	A Total	A(H1)pdm09	A(H3)	A Footnote (Uns)	B Total	A Total	A(H1)pdm09	A(H3)	A(UnS)	B Total
BC	36	1	28	7	22	3408	24	2550	834	176
AB	23	0	15	8	39	3621	10	3455	156	446
SK	17	0	0	11	6	1293	0	0	1293	51
MB	12	0	3	9	5	1108	0	382	726	43
ON	341	7	113	221	48	10245	25	4357	5863	236
QC	200	0	0	200	260	10929	4	422	10503	1232
NB	145	0	26	119	25	864	0	128	736	43
NS	23	0	0	23	15	401	0	123	278	60
PE	6	0	6	15	0	111	0	53	526	4
NL	15	0	0	15	0	579	0	53	526	4
Canada	818	8	191	613	424	32559	64	11578	20917	2329
Percentage ^{Footnote 2}	65.9%	1.0%	23.3%	74.9%	34.1%	93.3%	0.2%	35.6%	64.2%	6.7%
Footnote 1 Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks. Return to footnote 1 referrer Footnote 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. Return to footnote 2 referrer : unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. Return to footnote Uns referrer

Table 2. Weekly and cumulative numbers of positive influenza specimens by type, subtype and age-group reported through case-based laboratory reporting^{Footnote 1,}^{Footnote 3}, Canada, 2014-15
Age groups (years)	Weekly February 22 to February 28, 2015					Cumulative (August 24, 2014 to February 28, 2015)
	Influenza A				B	Influenza A				B	Influenza A and B
	A Total	A(H1) pdm09	A(H3)	A Footnote (Uns)	Total	A Total	A(H1) pdm09	A(H3)	A (UnS)	Total	#	%
<5	28	2	3	23	21	1936	12	723	1201	162	2098	6.9%
5-19	13	4	4	5	35	1682	5	723	1782	269	1951	6.4%
20-44	26	0	5	21	60	3251	13	1460	1778	369	3620	11.9%
45-64	53	0	9	44	85	3609	13	1428	2168	512	4121	13.6%
65+	245	0	43	202	136	17677	10	6543	11124	766	18443	60.8%
Unknown	2	0	2	0	0	115	0	97	18	2	117	0.4%
Total	367	6	66	295	337	28270	53	11146	17071	2080	30350	100.0%
Percentage^{Footnote 2,}	52.1%	1.6%	18.0%	80.4%	47.9%	93.1%	0.2%	39.4%	60.4%	6.9%
Footnote 1 Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks. Return to footnote 1 referrer Footnote 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. Return to footnote 2 referrer Table 2 includes specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported.. Return to footnote 3 referrer : unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. Return to footnote UnS referrer

Antiviral Resistance

During the 2014-2015 influenza season, the NML has tested 764 influenza viruses for resistance to oseltamivir and 759 influenza viruses for resistance to zanamivir. All viruses were sensitive to zanamivir and one influenza A(H3N2) virus was resistant to oseltamivir. A total of 1042 influenza A viruses (99.9%) were resistant to amantadine (Table 3).

Table 3. Antiviral resistance by influenza virus type and subtype, Canada, 2014-15
Virus type and subtype	Oseltamivir		Zanamivir		Amantadine
Virus type and subtype	# tested	# resistant (%)	# tested	# resistant (%)	# tested	# resistant (%)
A (H3N2)	651	1	646	0	1038	1037 (99.9%)
A (H1N1)	3	0	3	0	4	4 (100%)
B	110	0	110	0	NA^{Table 3 - Footnote *}	NA ^{Table 3 - Footnote *}
TOTAL	764	1	759	0	1042	1041
Table 3 - Footnote * NA - not applicable Return to first Table 3 - Footnote * referrer

Influenza Strain Characterizations

During the 2014-2015 influenza season, the National Microbiology Laboratory (NML) has characterized 277 influenza viruses [125 A(H3N2), 3 A(H1N1) and 149 influenza B].

Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assay (n=125), one virus was antigenically similar to A/Texas/50/2012, five showed reduced titers to A/Texas/50/2012 and 119 were antigenically similar to A/Switzerland/9715293/2013, which is the influenza A(H3N2) component recommended for the 2015 Southern Hemisphere influenza vaccine. Additionally, 827 A(H3N2) viruses were unable to be tested by HI assay; however, sequence analysis showed that 825 belonged to a genetic group that typically shows reduced titers to A/Texas/50/2012.
Influenza A(H1N1): Three A(H1N1) viruses characterized were antigenically similar to A/California/7/2009.
Influenza B: Of the 149 influenza B viruses characterized, 142 viruses were antigenically similar to B/Massachusetts/2/2012, three viruses showed reduced titers against B/Massachusetts/2/2012, and four were B/Brisbane/60/2008-like (Figure 4).

Figure 4. Influenza strain characterizations, Canada, 2014-2015, N = 277

Strain	Number of specimens	Percentage
A/Texas/50/2012-like	1	0%
reduced titres to A/Texas/50/2012	5	2%
A/California/07/2009-like	3	1%
A/Switzerland/97 15293/2013-like	119	43%
B/Massachusetts/2/2012-like	142	51%
reduced titres to B/Massachusetts/2/2012	3	1%
B/Brisbane/60/2008-like	4	2%

Influenza-like Illness (ILI) Consultation Rate

The national influenza-like-illness (ILI) consultation rate increased to 52.0 consultations per 1,000, which is above expected levels for week 08 (Figure 5). The rate was highest among the 5 to 19 years of age group (67.7 consultations per 1,000) and lowest among the adults ≥65 years of age (34.6 consultations per 1,000).

Influenza Outbreak Surveillance

In week 08, 31 new outbreaks of influenza were reported, a decrease from the previous week. The majority of the outbreaks occurred in the Central and Atlantic provinces. Twenty-four outbreaks were reported in long-term care facilities (LTCF) and seven in institutional or community settings (Figure 6). Among the outbreaks in which the influenza subtype was known, two LTCF outbreaks were associated with A(H3N2). To date this season, 1,039 outbreaks in LTCFs have been reported and the majority of those with known subtypes were attributable to A(H3N2). There have been a higher number of reported influenza outbreaks to date this season compared to the same period in previous seasons.

Figure 6: Overall number of new laboratory-confirmed influenza outbreaks by report week, Canada, 2014-2015

**Figure 6: Overall number of new laboratory-confirmed influenza outbreaks by report week, Canada, 2014-2015**
Report week	Hospitals	Long Term Care Facilities	Other
35	0	0	0
36	0	0	0
37	0	0	0
38	0	1	0
39	0	5	1
40	0	0	0
41	0	2	0
42	0	3	0
43	0	2	0
44	0	1	0
45	0	2	0
46	0	3	0
47	0	16	1
48	3	17	1
49	2	32	3
50	2	57	13
51	9	94	22
52	8	114	21
53	9	122	35
1	12	152	31
2	8	118	19
3	6	54	14
4	13	64	16
5	7	51	13
6	4	60	10
7	2	45	9
8	0	24	7

Pharmacy surveillance

During week 08, the proportion of prescriptions for antivirals decreased to 157.8 antiviral prescriptions per 100,000 total prescriptions (from 221.8 per 100,000). The rate for antivirals since week 48 has been higher than the previous three seasons (Figure 7). The rate in all age groups decreased in week 08. The rate was highest among seniors at 260.3 per 100,000 total prescriptions and lowest among infants at 45.2 per 100,000 total prescriptions.

Figure 7. Proportion of prescription sales for influenza antivirals by age-group and week, Canada, 2014-15

Sentinel Hospital Influenza Surveillance

Paediatric Influenza Hospitalizations and Deaths (IMPACT)

In week 08, nine laboratory-confirmed influenza-associated paediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network: four cases of influenza A and five cases of influenza B (Figure 8a). A greater proportion of cases have been reported with influenza B in recent weeks, following the trend in laboratory detections. Among the reported cases, four (44%) were <2 years of age, three (44%) were 2 to 9 years of age and one (11%) was 10-16 years of age. One case was admitted to the ICU.

To date this season, 541 hospitalizations have been reported by the IMPACT network, 486 (90%) of which were cases of influenza A. Among cases for which the influenza A subtype was reported, 99% (157/159) were A(H3N2) (Table 4). To date, 66 cases were admitted to the ICU, of which 36 (55%) were 2 to 9 years of age (Figure 9a). A total of 38 ICU cases reported to have at least one underlying condition or comorbidity. Three deaths have been reported.

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 (CIRN)

In week 08, 67 laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations were reported by the PHAC/CIHR Influenza Research Network (PCIRN) Serious Outcomes Surveillance (SOS) network. Among the cases in week 08, 50 cases (75%) were in adults over the age of 65 and 53 cases (79%) had influenza A (Figure 8b).

To date this season, 1,810 cases have been reported; 1,741 (96%) with influenza A. The majority of cases (82%) were among adults ≥65 years of age (Table 5). One hundred and thirty-six ICU admissions have been reported and 103 cases were adults ≥65 years of age. A total of 97 ICU cases (71%) reported to have at least one underlying condition or comorbidity. Of the 94 ICU cases with known immunization status, 33 (35%) reported not having been vaccinated this season. Ninety-three deaths have been reported, 85 (91%) of the deaths were adults >65 years of age (Figure 9b).

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.

Table 4 - Cumulative numbers of paediatric hospitalizations with influenza reported by the IMPACT network, Canada, 2014-15
Age groups	Cumulative (Aug. 24, 2014 to February 28, 2015)
	Influenza A				B	Influenza A and B
	A Total	A(H1) pdm09	A(H3)	AFootnote (Uns)	Total	# (%)
0-5m	76	0	16	60	3	79 (14.6%)
6-23m	107	1	34	71	20	127 (23.5%)
2-4y	120	1	39	80	12	132 (24.4%)
5-9y	125	0	44	81	12	137 (25.3%)
10-16y	58	0	23	35	8	66 (12.2%)
Total	486	2	157	327	55	541
% ^{Footnote 1}	89.8%	0.4%	32.3%	67.3%	10.2%	100.0%
Footnote 1 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. Return to footnote 1 referrer Footnote 2 : unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. Return to footnote UnS referrer

Table 5 - Cumulative numbers of adult hospitalizations with influenza reported by the PCIRN-SOS network, Canada, 2014-15
Age groups	Cumulative (November 15, 2014 to February 28, 2015)
	Influenza A				B	Influenza A and B
	A Total	A(H1) pdm09	A(H3)	AFootnote (Uns)	Total	# (%)
16-20	5	0	1	4	0	5 (%)
20-44	97	1	40	56	4	101 (6%)
45-64	193	0	79	116	19	214 (12%)
65+	1444	3	576	865	46	1490 (82%)
Total	1741	4	696	1041	69	1810
% ^{Footnote 1}	96%	0%	40%	60%	4%	100%
Footnote 1 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. Return to footnote 1 referrer Footnote 2 : unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. Return to footnote UnS referrer

Figure 8A — Figure 8 - Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2014-15

**8A) Paediatric hospitalizations (≤16 years of age, IMPACT)**

Report week	Influenza A	Influenza B
35	0	0
36	0	0
37	2	0
38	1	0
39	1	0
40	1	0
41	2	0
42	1	0
43	3	1
44	4	0
45	4	0
46	9	3
47	9	1
48	14	4
49	30	2
50	44	2
51	55	1
52	65	2
53	49	2
1	53	5
2	41	2
3	34	2
4	25	1
5	13	4
6	8	7
7	12	12
8	5	4

Figure 8B - Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2014-15

**8B) Adult hospitalizations (≥16 year of age,** **PCIRN-SOS**)

Report week	Influenza A	Influenza B	Untyped
35	n/a	n/a	n/a
36	n/a	n/a	n/a
37	n/a	n/a	n/a
38	n/a	n/a	n/a
39	n/a	n/a	n/a
40	n/a	n/a	n/a
41	n/a	n/a	n/a
42	n/a	n/a	n/a
43	n/a	n/a	n/a
44	n/a	n/a	n/a
45	n/a	n/a	n/a
46	3	0	0
47	10	0	0
48	34	0	0
49	44	0	0
50	99	4	0
51	141	0	1
52	235	3	0
53	236	3	0
1	229	2	0
2	158	0	0
3	145	3	1
4	98	8	0
5	116	6	0
6	67	13	0
7	48	12	0
8	53	13	1

Figure 9a — Figure 9 - Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada, 2014-15

**9A) Paediatric hospitalizations (≤16 years of age, IMPACT)**

Age-group (years)	Hospitalizations(n=541)	ICU admissions(n=66)
0-5m	14.6%	3.0%
6-23m	23.5%	19.7%
2-4y	24.4%	33.3%
5-9y	25.3%	21.2%
10-16y	12.2%	22.7%

Figure 9b — Figure 9 - Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada, 2014-15

**9B) Adult hospitalizations (≥16 year of age,** **PCIRN-SOS**)

Age-group (years)	Hospitalizations (n=1806)	ICU admissions(n=136)	Deaths (n=93)
16-20	0.3%	0.0%	0.0%
20-44	5.5%	6.6%	3.2%
45-64	11.8%	17.6%	5.4%
65+	82.3%	75.7%	91.4%

Provincial/Territorial Influenza Hospitalizations and Deaths

In week 08, 213 laboratory-confirmed influenza-associated hospitalizations were reported from participating provinces and territories^{Footnote *}which is less than the number reported in week 07 (n=276).Of the 213 hospitalizations, all but 16 were due to influenza A, and 73% were in patients ≥65 years of age. Since the start of the 2014-15 season, 5,493 hospitalizations have been reported; 5,312 (97%) with influenza A. Among cases for which the subtype of influenza A was reported, 99.5% were A(H3N2). The majority of cases (71%) were ≥65 years of age (Table 6). A total of 274 ICU admissions have been reported to date: 54% (n=149) were in adults ≥65 years of age and 30% (n=83) were in adults 20-64 years. A total of 389 deaths have been reported since the start of the season: three children <5 years of age, one child 5-19 years, 32 adults 20-64 years, and 353 adults ≥65 years of age. Adults 65 years of age or older represent 91% of all deaths reported this season. Detailed clinical information (e.g. underlying medical conditions) is not known for these cases.

Footnote *

Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, and QC. Only hospitalizations that require intensive medical care are reported by Saskatchewan. ICU admissions are not distinguished among hospital admissions reported from Ontario. Data may also include cases reported by the IMPACT and CIRN networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from Ontario that occurred in previous weeks, as a result of retrospective updates to the cumulative total. It is important to note that the hospitalization or death does not have to be attributable to influenza, a positive laboratory test is sufficient for reporting.

Return to footnote * referrer

Return to footnote* referrer

Table 6. Cumulative number of hospitalizations with influenza reported by the participating provinces and territories, Canada, 2014-15
Age groups	Cumulative (24 August 2014 to February 21, 2015)
	Influenza A				B	Influenza A and B
	A Total	A(H1) pdm09	A(H3)	AFootnote (Uns)	Total	# (%)
0-4 years	363	2	132	229	8	371 (7%)
5-19 years	218	0	107	111	16	234 (4%)
20-44 years	263	3	133	127	18	281 (5%)
45-64 years	581	5	279	297	35	616 (11%)
65+ years	3832	1	1765	2066	94	3926 (71%)
Unknown	55	1	51	3	10	65 (1%)
Total	5312	12	2467	2833	181	5493
Percentage ^{Footnote 1}	96.7%	0.2%	46.6%	53.3%	3.3%	100.0%
Footnote 1 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. Return to footnote 1 referrer Footnote 2 unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. Return to footnote UnS referrer

See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2009-10 to 2014-15 on the Public Health Agency of Canada website.

Emerging Respiratory Pathogens

Human Avian Influenza
Influenza A(H7N9): Since the last FluWatch report, no new laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus were reported by the World Health Organization. Globally to March 6, 2015, the WHO reported a total of 572 laboratory-confirmed human cases with avian influenza A(H7N9) virus, including 204 deaths. Documents related to the public health risk of influenza A(H7N9), as well as guidance for health professionals and advice for the public is updated regularly on the following websites:

Influenza A(H5N6): Since the last FluWatch report, no new cases of human infection with avian influenza A (H5N6) virus from China has been reported by the World Health Organization. Globally to March 5, 2015, the WHO has been informed of a total of three cases of avian influenza A (H5N6) virus, including two deaths.

Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
Since the last FluWatch report, 10 new laboratory-confirmed cases of MERS-CoV have been reported by the World Health Organization. Globally, from September 2012 to March 6, 2015, the WHO has been informed of a total of 1,040 laboratory-confirmed cases of infection with MERS-CoV, including 383 deaths. All cases have either occurred in the Middle East or have had direct links to a primary case infected in the Middle East. The public health risk posed by MERS-CoV in Canada remains low (see the PHAC Assessment of Public Health Risk) and for the latest global risk assessment posted by the WHO on February 5, 2015: WHO MERS-CoV.

Documents related to the public health risk of MERS-CoV, as well as guidance for health professionals and advice for the public is updated regularly on the following websites:

Avian Influenza A(H5)
Since the last FluWatch report, no new information has been provided by the CFIA. Further information on the outbreak is provided on the following CFIA website.

CFIA - Notifiable Avian Influenza

For the latest Travel Health Notice on Avian Influenza (H5N1) visit the following webpage: PHAC - Travel Health Notice.

International Influenza Reports

FluWatch definitions for the 2014-2015 season

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).

Influenza-like-illness (ILI): Acute onset of respiratory illness with fever and cough and with one or more of the following - sore throat, arthralgia, myalgia, or prostration which is likely due to influenza. In children under 5, gastrointestinal symptoms may also be present. In patients under 5 or 65 and older, fever may not be prominent.

ILI/Influenza outbreaks

Schools:: Greater than 10% absenteeism (or absenteeism that is higher (e.g. >5-10%) than expected level as determined by school or public health authority) which is likely due to ILI.
Note: it is recommended that ILI school outbreaks be laboratory confirmed at the beginning of influenza season as it may be the first indication of community transmission in an area.
Hospitals and residential institutions:: two or more cases of ILI within a seven-day period, including at least one laboratory confirmed case. Institutional outbreaks should be reported within 24 hours of identification. Residential institutions include but not limited to long-term care facilities ( LTCF) and prisons.
Workplace:: Greater than 10% absenteeism on any day which is most likely due to ILI.
Other settings:: two or more cases of ILI within a seven-day period, including at least one laboratory confirmed case; i.e. closed communities.

Note that reporting of outbreaks of influenza/ILI from different types of facilities differs between jurisdictions.

Influenza/ILI activity level

1 = No activity: no laboratory-confirmed influenza detections in the reporting week, however, sporadically occurring ILI may be reported

2 = Sporadic: sporadically occurring ILI and lab confirmed influenza detection(s) with no outbreaks detected within the influenza surveillance region ^{Footnote †}

3 = Localized:

evidence of increased ILI^{Footnote **} and
lab confirmed influenza detection(s) together with
outbreaks in schools, hospitals, residential institutions and/or other types of facilities occurring in less than 50% of the influenza surveillance region^{Footnote †}

4 = Widespread:

evidence of increased ILI^{Footnote **} and
lab confirmed influenza detection(s) together with
outbreaks in schools, hospitals, residential institutions and/or other types of facilities occurring in greater than or equal to 50% of the influenza surveillance region^{Footnote †}

Note: ILI data may be reported through sentinel physicians, emergency room visits or health line telephone calls.

We would like to thank all the Fluwatch surveillance partners who are participating in this year's influenza surveillance program.

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Date modified:: 2015-03-06

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FluWatch report: February 22 to February 28, 2015 (Week 8)

Overall summary

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Influenza/ILI Activity (geographic spread)

Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, Week 08

Influenza and Other Respiratory Virus Detections

Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2014-15

Figure 3. Number of positive laboratory tests for other respiratory viruses by report week, Canada, 2014-15

Antiviral Resistance

Influenza Strain Characterizations

Figure 4. Influenza strain characterizations, Canada, 2014-2015, N = 277