FluWatch report: March 29 to April 4, 2015 (Week 13)
Overall summary
- The majority of influenza activity continues to occur in the Central and Atlantic province however, less activity was reported this week from these regions.
- The number of influenza A and B detections decreased this week.
- Influenza B is having a greater impact on adults less than 65 years of age, compared to influenza A(H3N2), which circulated earlier in the season.
- 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
On this page
- 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: 2015-04-10
Related Topics
Influenza/ILI Activity (geographic spread)
In week 13, no regions reported widespread activity. Eighteen regions reported localized activity: AB, MB, ON(6), QC(3), NB(2), NS(3), PE and NL. Twenty-nine regions reported sporadic activity: in YK, NT(2), BC(3), AB(4), SK(3), MB(4), ON. QC(3), NB(5), and NS(3). Eleven regions reported no activity: NU(3), BC(2), NS(3), and NL(3).
Influenza and Other Respiratory Virus Detections
In week 13, the percentage positive for influenza A (3.4%) continued to decline from the previous week while the percentage of positive influenza B tests continued to increase (12.9%) (Figure 2). Influenza B detections were greater than influenza A in all provinces except NS. More influenza B has been observed to date this season (5,521) compared to the same time during the 2013-14 season (4,371). To date, 86% of influenza detections have been influenza A, and 99.3% of those subtyped have been A(H3N2) (Table 1). To date this season, detailed information on age and type/subtype has been received for 34,604 cases (Table 2). Adults ≥65 years of age have predominantly been affected by influenza A, accounting for 62% of influenza A detections. Influenza B, while much smaller in numbers, is mainly affecting individuals less than 65 years of age, they account for 60% of influenza B detections.
In week 13, detections for all other respiratory viruses remained similar to, or decreased from, the previous week (figure 3). Overall, the detections of other respiratory viruses have been declining since peaking in week 5.
For more details, see the weekly Respiratory Virus Detections in Canada Report.
Reporting provincesFootnote 1 | Weekly (March 29 to April 04, 2015) | Cumulative (August 24, 2014 to April 04, 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 | 7 | 0 | 0 | 7 | 24 | 3495 | 25 | 2603 | 867 | 321 |
AB | 14 | 0 | 11 | 3 | 45 | 3680 | 13 | 3513 | 154 | 712 |
SK | 1 | 0 | 0 | 1 | 10 | 1312 | 0 | 839 | 473 | 150 |
MB | 1 | 0 | 1 | 0 | 13 | 1121 | 0 | 390 | 731 | 103 |
ON | 60 | 1 | 25 | 34 | 104 | 11028 | 43 | 4633 | 6352 | 758 |
QC | 20 | 0 | 0 | 20 | 274 | 11352 | 4 | 422 | 10926 | 2848 |
NB | 30 | 0 | 5 | 25 | 62 | 1147 | 0 | 180 | 967 | 318 |
NS | 16 | 0 | 0 | 16 | 16 | 503 | 0 | 123 | 380 | 225 |
PE | 1 | 0 | 1 | 0 | 16 | 121 | 1 | 118 | 2 | 62 |
NL | 2 | 0 | 0 | 2 | 5 | 612 | 0 | 123 | 489 | 24 |
Canada | 152 | 1 | 43 | 108 | 569 | 34371 | 86 | 12944 | 21341 | 5521 |
Percentage Footnote 2 | 21.1% | 0.7% | 28.3% | 71.1% | 78.9% | 86.2% | 0.3% | 37.7% | 62.1% | 13.8% |
Age groups (years) | Weekly March 29 to April 04, 2015 | Cumulative (August 24, 2014 to April 04, 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 | 3 | 0 | 0 | 3 | 32 | 2073 | 18 | 805 | 1250 | 351 | 2424 | 7.0% |
5-19 | 4 | 0 | 0 | 4 | 35 | 1770 | 6 | 951 | 813 | 536 | 2306 | 6.7% |
20-44 | 6 | 0 | 0 | 6 | 54 | 3419 | 16 | 1652 | 1751 | 748 | 4167 | 12.0% |
45-64 | 7 | 0 | 1 | 6 | 98 | 3835 | 17 | 1639 | 2179 | 1247 | 5082 | 14.7% |
65+ | 46 | 0 | 17 | 29 | 168 | 18602 | 13 | 7215 | 11374 | 1897 | 20499 | 59.2% |
Unknown | 0 | 0 | 0 | 0 | 0 | 121 | 0 | 100 | 21 | 5 | 126 | 0.4% |
Total | 66 | 0 | 18 | 48 | 387 | 29820 | 70 | 12362 | 17388 | 4784 | 34604 | 100.0% |
PercentageFootnote 2, | 14.6% | 0.0% | 27.3% | 72.7% | 85.4% | 86.2% | 0.2% | 41.5% | 58.3% | 13.8% | ||
Antiviral Resistance
During the 2014-2015 influenza season, the NML has tested 1,121 influenza viruses for resistance to oseltamivir and zanamivir. All viruses were sensitive to zanamivir and one influenza A(H3N2) virus was resistant to oseltamivir. A total of 1,235 influenza A viruses (99.9%) were resistant to amantadine (Table 3).
Virus type and subtype | Oseltamivir | Zanamivir | Amantadine | |||
---|---|---|---|---|---|---|
# tested | # resistant (%) | # tested | # resistant (%) | # tested | # resistant (%) | |
A (H3N2) | 834 | 1 | 834 | 0 | 1230 | 1229 (99.9%) |
A (H1N1) | 6 | 0 | 6 | 0 | 6 | 6 (100%) |
B | 281 | 0 | 281 | 0 | NATable 3 - Footnote * | NA Table 3 - Footnote * |
TOTAL | 1121 | 1 | 1121 | 0 | 1236 | 1235 |
Influenza Strain Characterizations
During the 2014-2015 influenza season, the National Microbiology Laboratory (NML) has characterized 558 influenza viruses [179 A(H3N2), 9 A(H1N1) and 370 influenza B].
Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assay (n=179), one virus was antigenically similar to A/Texas/50/2012, five showed reduced titers to A/Texas/50/2012 and 173 were antigenically similar to A/Switzerland/9715293/2013, which is the influenza A(H3N2) component recommended for the 2015 Southern Hemisphere influenza vaccine. Additionally, 1,035 A(H3N2) viruses were unable to be tested by HI assay; however, sequence analysis showed that 1,033 belonged to a genetic group that typically shows reduced titers to A/Texas/50/2012.
Influenza A(H1N1): Nine A(H1N1) viruses characterized were antigenically similar to A/California/7/2009.
Influenza B: Of the 370 influenza B viruses characterized, 351 viruses were antigenically similar to B/Massachusetts/2/2012, three viruses showed reduced titers against B/Massachusetts/2/2012, and 16 were B/Brisbane/60/2008-like (Figure 4).
Figure 4. Influenza strain characterizations, Canada, 2014-2015, N = 558
The NML receives a proportion of the number of influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition (HAI) testing compared to the reference influenza strains recommended by WHO.
The recommended components for the 2014-2015 northern hemisphere trivalent influenza vaccine include: an A/California/7/2009(H1N1)pdm09-like virus, an A/Texas/50/2012 (H3N2)-like virus, and a B/Massachusetts/2/2012-like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus is recommended.
The WHO has released the recommended composition of the influenza vaccine for the northern hemisphere for the 2015-2016 season. Trivalent vaccines are recommended to contain 1) an A/California/7/2009 (H1N1)pdm09-like virus 2) an A/Switzerland/9715293/2013 (H3N2)-like virus, and 3) an B/Phuket/3073/2013-like virus(Yamagata lineage). Quadrivalent vaccines are recommended to additionally contain a B/Brisbane/60/2008-like virus (Victoria lineage).
Figure 4 - Text Description
Strain | Number of specimens | Percentage |
---|---|---|
A/Texas/50/2012-like | 1 | 1% |
reduced titres to A/Texas/50/2012 | 5 | 1% |
A/California/07/2009-like | 9 | 2% |
A/Switzerland/97 15293/2013-like | 173 | 31% |
B/Massachusetts/2/2012-like | 351 | 63% |
reduced titres to B/Massachusetts/2/2012 | 3 | 1% |
B/Brisbane/60/2008-like | 16 | 3% |
Influenza-like Illness (ILI) Consultation Rate
The national influenza-like-illness (ILI) consultation rate increased in week 13 to 31.2 consultations per 1,000, which is within expected levels (Figure 5).
Influenza Outbreak Surveillance
In week 13, 25 new outbreaks of influenza were reported. The majority of the outbreaks occurred in the Central and Atlantic provinces. Nineteen outbreaks were reported in long-term care facilities (LTCF), one in hospitals and five in institutional or community settings (Figure 6). Among the outbreaks in which the influenza type was known (n=9), seven outbreaks were associated with influenza B. To date this season, 1,192 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
1 All provinces and territories except NU report outbreaks in long-term care facilities. All provinces and territories with the exception of NU and QC report outbreaks in hospitals. Outbreaks of influenza or influenza-like-illness in other facilities are reported to FluWatch but reporting varies between jurisdictions. Outbreak definitions are included at the end of the report.
Figure 6 - Text Description
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 | 12 |
4 | 13 | 64 | 16 |
5 | 7 | 51 | 13 |
6 | 4 | 60 | 10 |
7 | 2 | 45 | 9 |
8 | 0 | 24 | 7 |
9 | 6 | 22 | 10 |
10 | 0 | 32 | 19 |
11 | 5 | 49 | 11 |
12 | 0 | 31 | 4 |
13 | 1 | 19 | 9 |
Pharmacy surveillance
Pharmacy surveillance for sales of influenza antivirals has ended for the 2014-2015 influenza season (Figure 7).
Sentinel Hospital Influenza Surveillance
Paediatric Influenza Hospitalizations and Deaths (IMPACT)
In week 13, 10 laboratory-confirmed influenza-associated paediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network. All 10 cases were 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, two (20%) were <2 years of age, five (50%) were 2 to 9 years of age and three (30%) were 10-16 years of age. Three ICU admissions were reported.
To date this season, 629 hospitalizations have been reported by the IMPACT network, 502 (80%) of which were cases of influenza A. Among cases for which the influenza A subtype was reported, 99% (162/164) were A(H3N2) (Table 4).To date, 82 cases were admitted to the ICU, of which 46 (56%) were 2 to 9 years of age (Figure 9a). A total of 54 ICU cases reported to have at least one underlying condition or comorbidity. Four 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 (PCIRN)
In week 13, 24 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 13, 20 cases (83%) were in adults over the age of 65 and 14 cases (58%) had influenza B (Figure 8b).
To date this season, 2,101 cases have been reported; 1,887 (90%) with influenza A. The majority of cases (82%) were among adults ≥65 years of age (Table 5). One hundred and fifty four ICU admissions have been reported and 116 cases were adults ≥65 years of age. Among the 154 ICU admissions, 12 were due to influenza B (six in adults 45 to 64 years of age and six in adults over the age of 65). A total of 110 ICU cases (73%) reported to have at least one underlying condition or comorbidity. Of the 112 ICU cases with known immunization status, 38 (34%) reported not having been vaccinated this season. One hundred and twenty three deaths have been reported, 113 (92%) 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.
Age groups | Cumulative (Aug. 24, 2014 to April 4, 2015) | |||||
---|---|---|---|---|---|---|
Influenza A | B | Influenza A and B | ||||
A Total | A(H1) pdm09 | A(H3) | AFootnote (Uns) | Total | # (%) | |
0-5m | 81 | 0 | 18 | 63 | 8 | 89 (14.1%) |
6-23m | 109 | 1 | 35 | 73 | 29 | 138 (21.9%) |
2-4y | 123 | 1 | 40 | 82 | 32 | 155 (24.6%) |
5-9y | 129 | 0 | 44 | 85 | 33 | 162 (25.8%) |
10-16y | 60 | 0 | 25 | 35 | 25 | 85 (13.5%) |
Total | 502 | 2 | 162 | 338 | 127 | 629 |
% Footnote 1 | 79.8% | 0.4% | 32.3% | 67.3% | 20.2% | 100.0% |
Age groups | Cumulative (November 15, 2014 to April 4, 2015) | |||||
---|---|---|---|---|---|---|
Influenza A | B | Influenza A and B | ||||
A Total | A(H1) pdm09 | A(H3) | AFootnote (Uns) | Total | # (%) | |
16-20 | 3 | 0 | 1 | 2 | 1 | 4 (%) |
20-44 | 105 | 1 | 54 | 50 | 10 | 115 (5%) |
45-64 | 215 | 1 | 92 | 122 | 52 | 267 (13%) |
65+ | 1564 | 3 | 734 | 827 | 151 | 1715 (82%) |
Total | 1887 | 5 | 881 | 1001 | 214 | 2101 |
% Footnote 1 | 90% | 0% | 47% | 53% | 10% | 100% |
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 8A - Text Description
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 | 8 | 1 |
48 | 15 | 4 |
49 | 30 | 2 |
50 | 41 | 2 |
51 | 58 | 1 |
52 | 64 | 2 |
53 | 48 | 2 |
1 | 53 | 5 |
2 | 41 | 2 |
3 | 33 | 1 |
4 | 25 | 1 |
5 | 12 | 4 |
6 | 9 | 8 |
7 | 14 | 11 |
8 | 5 | 6 |
9 | 5 | 12 |
10 | 6 | 14 |
11 | 7 | 11 |
12 | 0 | 24 |
13 | 0 | 10 |
8B) Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Figure 8B - Text Description
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 | 239 | 3 | 0 |
53 | 236 | 3 | 0 |
1 | 229 | 2 | 0 |
2 | 160 | 0 | 0 |
3 | 145 | 4 | 1 |
4 | 100 | 9 | 0 |
5 | 118 | 5 | 0 |
6 | 79 | 13 | 0 |
7 | 67 | 17 | 1 |
8 | 65 | 20 | 2 |
9 | 50 | 26 | 0 |
10 | 29 | 37 | 1 |
11 | 13 | 29 | 1 |
12 | 17 | 28 | 0 |
13 | 9 | 14 | 1 |
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 9A > - Text Description
Age-group (years) | Hospitalizations(n=629) | ICU admissions(n=82) |
---|---|---|
0-5m | 14.1% | 3.7% |
6-23m | 21.9% | 20.7% |
2-4y | 24.6% | 31.7% |
5-9y | 25.8% | 24.4% |
10-16y | 13.5% | 19.5% |
9B) Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Figure 9B - Text Description
Age-group (years) | Hospitalizations (n=2101) | ICU admissions(n=154) | Deaths (n=123) |
---|---|---|---|
16-20 | 0.2% | 0.0% | 0.0% |
20-44 | 5.5% | 5.8% | 2.4% |
45-64 | 12.7% | 18.8% | 5.7% |
65+ | 81.6% | 75.3% | 91.9% |
Provincial/Territorial Influenza Hospitalizations and Deaths
In week 13, 120 laboratory-confirmed influenza-associated hospitalizations were reported from participating provinces and territoriesFootnote *, which is less than the number reported the previous week. Of the 120 hospitalizations, 84 (70%) were due to influenza A and 82 (68%) were in patients ≥65 years of age.
Since the start of the 2014-15 season, 6,679 hospitalizations have been reported; 6,108 (91.5%) 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 352 ICU admissions have been reported to date: 53% (n=188) were in adults ≥65 years of age and 33% (n=116) were in adults 20-64 years. A total of 493 deaths have been reported since the start of the season: four children <5 years of age, three children 5-19 years, 40 adults 20-64 years, and 446 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.
Age groups | Cumulative (24 August 2014 to 4 April, 2015) | |||||
---|---|---|---|---|---|---|
Influenza A | B | Influenza A and B | ||||
A Total | A(H1) pdm09 | A(H3) | AFootnote (Uns) | Total | # (%) | |
0-4 years | 401 | 2 | 143 | 256 | 45 | 446 (7%) |
5-19 years | 267 | 2 | 130 | 135 | 65 | 332 (5%) |
20-44 years | 371 | 3 | 223 | 145 | 72 | 443 (7%) |
45-64 years | 572 | 5 | 239 | 328 | 73 | 645 (10%) |
65+ years | 4441 | 2 | 2066 | 2373 | 298 | 4739 (71%) |
Unknown | 56 | 1 | 52 | 3 | 18 | 74 (1%) |
Total | 6108 | 15 | 2853 | 3240 | 471 | 6679 |
Percentage Footnote 1 | 91.5% | 0.2% | 46.7% | 53.0% | 8.5% | 100.0% |
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 April 9, 2015, the WHO reported a total of 631 laboratory-confirmed human cases with avian influenza A(H7N9) virus, including 221 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 April 9, 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, 12 new laboratory-confirmed cases of MERS-CoV have been reported by the World Health Organization. Globally, from September 2012 to April 9, 2015, the WHO has reported a total of 1,102 laboratory-confirmed cases of infection with MERS-CoV, including 416 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)
The Canadian Food Inspection Agency (CFIA)'s testing at the National Centre for Foreign Animal Diseases has confirmed the strain causing a new avian influenza outbreak on one farm near Woodstock, as a highly-pathogenic H5N2 virus. No human cases have been reported. Avian influenza viruses do not pose risks to food safety when poultry and poultry products are properly handled and cooked. Avian influenza rarely affects humans that do not have consistent contact with infected birds. Further information on the outbreak is provided on the following CFIA website:
International Influenza Reports
- World Health Organization influenza update
- World Health Organization FluNet
- WHO Influenza at the human-animal interface
- Centers for Disease Control and Prevention seasonal influenza report
- European Centre for Disease Prevention and Control - epidemiological data
- South Africa Influenza surveillance report
- New Zealand Public Health Surveillance
- Australia Influenza Report
- Pan-American Health Organization Influenza Situation Report
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 ILIFootnote * 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 regionFootnote †
4 = Widespread:
- evidence of increased ILIFootnote * 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 regionFootnote †
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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