FluWatch report: February 15 to February 21, 2015 (Week 7)

Overall summary

In week 07, all influenza indicators remained similar to, or declined, from the previous week.
Overall, elevated activity was mostly reported in the Central and Atlantic provinces.
For the past few weeks, influenza B detections have been increasing steadily, particularly in the Prairies and in Quebec. In week 07, influenza B detections were greater than influenza A detections in QC and AB. 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 type of influenza affecting Canadians. Seniors continue to have the highest number of positive laboratory detections, hospitalizations and deaths.
Detections of respiratory syncytial virus (RSV) continue to be the second most frequently detected virus after influenza.
Evidence from the National Microbiology Laboratory (NML) does indicate 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: 2015-02-27

Influenza/ILI Activity (geographic spread)

In week 07, six regions reported widespread activity: in ON(2). QC(2), PEI and NL. Twenty regions reported localized activity: in AB, ON(5), QC(2), NB(6), NS(5) and NL. Twenty-six regions reported sporadic activity: in YK, NU(2), BC(5), AB(4), SK(3), MB(4), QC(2), NB, NS(3), and NL. No activity was reported in four regions: NU, MB, NS and NF. No data was reported from NT. Overall, influenza activity in week 07 was similar to the previous week with elevated activity (widespread and localized) mostly reported in the Central and Atlantic provinces.

Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, Week 07

Figure 1 Legend — Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, Week 07

Influenza and Other Respiratory Virus Detections

In week 07, the number of positive influenza tests (1,279) and the percentage positive for influenza A (12.2%) continued to decline from the previous week The percentage of positive influenza B tests continued to increase and was 5.3% in week 07, the highest this season thus far (Figure 2). In week 07, influenza B detections were greater than influenza A detections in QC and AB; accounting for 53% and 60% of influenza detections respectively. When comparing by influenza type, the majority of the influenza A cases (62%) were in the elderly while the majority of the influenza B cases (61%) were >45 years of age. To date, 94% of influenza detections have been influenza A, and 99.6% of those subtyped have been A(H3N2) (Table 1). To date this season, detailed information on age and type/subtype has been received for 29,741 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 16.1% 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 07, detections of all respiratory viruses decreased from the previous week (figure 3). Respiratory syncytial virus (RSV) remains the second most frequently detected virus after influenza with 817 detections. Detections of RSV since week 38 have been higher than in the previous season. Weekly detections of human metapneumovirus this season have been lower compared to the previous season.

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 15 to February 21, 2015)					Cumulative (August 24, 2014 to February 21, 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	117	4	96	17	26	3163	16	2324	823	119
AB	23	1	16	6	35	3597	16	3436	152	406
SK	7	0	5	2	6	1279	0	821	458	41
MB	16	0	3	13	5	1096	0	379	717	38
ON	372	1	135	236	25	9850	18	4236	5596	183
QC	241	0	0	241	267	10758	4	422	10332	983
NB	54	0	0	54	15	719	0	102	617	50
NS	25	0	0	25	11	378	0	123	255	45
PE	7	0	7	0	0	105	1	102	2	2
NL	27	0	0	27	0	564	0	53	511	4
Canada	889	6	262	621	390	31509	48	11998	19463	1871
Percentage ^{Footnote 2}	69.5%	0.7%	29.5%	69.9%	30.5%	94.4%	0.2%	38.1%	61.8%	5.6%
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 15 to February 21, 2015					Cumulative (August 24, 2014 to February 21, 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	35	0	5	30	19	1928	10	776	1142	140	3068	7.0%
5-19	16	0	5	11	44	1687	1	919	767	249	1936	6.5%
20-44	51	0	7	44	65	3234	11	1579	1644	296	3530	11.9%
45-64	50	0	9	41	81	3580	14	1560	2006	414	3994	13.4%
65+	319	1	63	255	123	17473	9	6861	10603	625	18098	60.9%
Unknown	4	0	2	2	0	113	0	95	18	2	115	0.4%
Total	475	1	91	383	332	28015	45	11790	16180	1726	29741	100.0%
Percentage^{Footnote 2,}	58.9%	0.2%	19.2%	80.6%	41.1%	94.2%	0.2%	42.1%	57.8%	5.8%
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 659 influenza viruses for resistance to oseltamivir and 656 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 956 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)	565	1	562	0	954	953 (99.9%)
A (H1N1)	2	0	2	0	3	3 (100%)
B	92	0	92	0	NA^{Table 3 - Footnote *}	NA ^{Table 3 - Footnote *}
TOTAL	659	1	656	0	957	956
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 243 influenza viruses [110 A(H3N2), 2 A(H1N1) and 131 influenza B].

Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assay (n=110), one virus was antigenically similar to A/Texas/50/2012, five showed reduced titers to A/Texas/50/2012 and 104 were antigenically similar to A/Switzerland/9715293/2013, which is the influenza A(H3N2) component recommended for the 2015 Southern Hemisphere influenza vaccine. Additionally, 745 A(H3N2) viruses were unable to be tested by HI assay; however, sequence analysis showed that 743 belonged to a genetic group that typically shows reduced titers to A/Texas/50/2012.
Influenza A(H1N1): Two A(H1N1) viruses characterized were antigenically similar to A/California/7/2009.
Influenza B: Of the 131 influenza B viruses characterized, 124 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 = 243

**Figure 4: Influenza strain characterizations, Canada, 2014-15, N = 243**
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	2	1%
A/Switzerland/97 15293/2013-like	104	43%
B/Massachusetts/2/2012-like	124	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 decreased to 32.7 consultations per 1,000, which is within expected levels for week 07 (Figure 5). The rate was highest among the 5 to 19 years of age group (83.3 consultations per 1,000) and lowest among the adults ≥65 years of age (18.7 consultations per 1,000).

Influenza Outbreak Surveillance

In week 07, 56 new outbreaks of influenza were reported, a decrease from the previous week. The majority of the outbreaks occurred in the Central and Atlantic provinces. Forty-five outbreaks were reported in long-term care facilities (LTCF), two in hospitals and nine in institutional or community settings (Figure 6). An additional seven outbreaks of ILI were reported in schools. Among the outbreaks in which the influenza subtype was known, three LTCF outbreaks were associated with A(H3N2) and two outbreaks were associated with influenza B. To date this season, 1,015 outbreaks in LTCFs have been reported and the majority of those with known subtypes were attributable to A(H3N2). There has 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

Pharmacy surveillance

During week 07, the proportion of prescriptions for antivirals decreased to 226.4 antiviral prescriptions per 100,000 total prescriptions (from 299.6 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 07. The rate was highest among seniors at 407.0 per 100,000 total prescriptions and lowest among infants at 105.7 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 07, 24 laboratory-confirmed influenza-associated paediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network: 12 cases of influenza A and 12 cases of influenza B (Figure 8a). Among the reported cases, 11 (46%) were <2 years of age, five (46%) were 2 to 9 years of age and two (8%) was 10-16 years of age. Two cases were admitted to the ICU. To date this season, 530 hospitalizations have been reported by the IMPACT network, 480 (91%) 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, 65 cases were admitted to the ICU, of which 37 (57%) were 2 to 9 years of age (Figure 9a). 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 07, 60 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 07, 48 cases (80%) were in adults over the age of 65 and 48 cases (80%) had influenza A (Figure 8b). To date this season, 1,717 cases have been reported; 1,663 (97%) with influenza A. The majority of cases (83%) were among adults ≥65 years of age (Table 5). One hundred and twenty-nine ICU admissions have been reported and 97 cases were adults ≥65 years of age. A total of 94 ICU cases (73%) reported to have at least one underlying condition or comorbidity. Of the 91 ICU cases with known immunization status, 33 (36%) reported not having been vaccinated this season. Eighty deaths have been reported, 73 (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 21, 2015)
	Influenza A				B	Influenza A and B
	A Total	A(H1) pdm09	A(H3)	AFootnote (Uns)	Total	# (%)
0-5m	76	0	17	59	3	79 (14.9%)
6-23m	105	1	34	70	19	124 (23.4%)
2-4y	117	1	39	77	11	128 (24.2%)
5-9y	124	0	44	80	10	134 (25.3%)
10-16y	58	0	23	35	7	65 (12.3%)
Total	480	2	157	321	50	530
% ^{Footnote 1}	90.6%	0.4%	32.7%	66.9%	9.4%	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 21, 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	91	1	39	51	3	94 (5%)
45-64	183	0	75	108	15	198 (12%)
65+	1384	3	543	838	36	1420 (83%)
Total	1663	4	658	1001	54	1717
% ^{Footnote 1}	97%	0%	40%	60%	3%	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)**

**Figure 8 A) 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

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**)

**Figure 8 B) Adult hospitalizations (≥16 year of age, CIRN)**
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

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)**

Figure 9 A) Paediatric hospitalizations (≤16 years of age, IMPACT)
Age-group (years)	Hospitalizations(n=530)	ICU admissions(n=65)
0-5m	14.9%	3.1%
6-23m	23.4%	18.5%
2-4y	24.2%	32.3%
5-9y	25.3%	24.6%
10-16y	12.3%	21.5%

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**)

Figure 9 B) Adult hospitalizations (≥16 year of age, **PCIRN-SOS**)
Age-group (years)	Hospitalizations (n=1715)	ICU admissions(n=129)	Deaths (n=80)
16-20	0.3%	0.0%	0.0%
20-44	5.5%	6.2%	3.8%
45-64	11.5%	18.6%	5.0%
65+	82.7%	75.2%	91.3%

Provincial/Territorial Influenza Hospitalizations and Deaths

In week 07, 276 laboratory-confirmed influenza-associated hospitalizations were reported from participating provinces and territories^{Footnote *}which is slightly more than the number reported in week 06 (n=264).Of the 276 hospitalizations, all but 14 were due to influenza A, and 72% were in patients ≥65 years of age. Since the start of the 2014-15 season, 5,204 hospitalizations have been reported; 5,062 (97%) with influenza A. Among cases for which the subtype of influenza A was reported, 99.5% were A(H3N2). The majority of cases (72%) were ≥65 years of age (Table 6). A total of 254 ICU admissions have been reported to date: 55% (140) were in adults ≥65 years of age and 30% (75) were in adults 20-64 years. A total of 364 deaths have been reported since the start of the season: three children <5 years of age, one child 5-19 years, 24 adults 20-64 years, and 336 adults ≥65 years of age. Adults 65 years of age or older represent 93% 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

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	353	2	130	221	7	360 (7%)
5-19 years	213	0	105	108	10	223 (4%)
20-44 years	248	2	127	119	14	262 (5%)
45-64 years	549	5	262	282	27	576 (1%)
65+ years	3645	1	1686	1958	75	3720 (71%)
Unknown	54	1	50	3	9	63 (1%)
Total	5062	11	2360	2691	142	5204
Percentage ^{Footnote 1}	97.3%	0.2%	46.6%	53.2%	2.7%	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, one new laboratory-confirmed case of human infection with avian influenza A(H7N9) virus was reported by the World Health Organization. Globally to February 26, 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 February 26, 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, 47 new laboratory-confirmed cases of MERS-CoV have been reported by the World Health Organization. Globally, from September 2012 to February 26, 2015, the WHO has been informed of a total of 1,030 laboratory-confirmed cases of infection with MERS-CoV, including 381 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:: 2015-02-27

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FluWatch report: February 15 to February 21, 2015 (Week 7)

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 07

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 = 243