FluWatch report: September 7 to September 20, 2014 (Weeks 37 and 38)
- Several influenza indicators (activity levels, influenza detections, ILI and hospitalizations) increased in weeks 37 and 38 compared to recent weeks.
- Influenza A(H3N2) was the predominant circulating virus with some co-circulation of influenza B.
- In week 38, one influenza outbreak and three ILI outbreaks were reported.
- During these two weeks, both paediatric and adult hospitalizations with influenza were reported.
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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
Influenza/ILI Activity (geographic spread)
In weeks 37 and 38, the number of regions in Canada reporting influenza/ILI activity increased. In week 37, six regions (BC(2), ON(1) and QC(3)) reported sporadic activity. In week 38, one region in Alberta reported localized activity, and 11 regions (BC(3), AB(1), SK (1), ON(4) and QC(2)) reported sporadic activity (Figure 1). In week 37, ten regions did not report data, and in week 38, one region did not report.
Figure 1 Map of overall influenza/ILI activity level by province and territory, Canada, Week 30 - Text Description
Influenza and Other Respiratory Virus Detections
Although the number of positive influenza tests increased over the two week period, the percent positive for influenza detections remains low (<1%) (Figure 2). To date, 75% of influenza detections have been influenza A, and the majority of those subtyped have been A(H3) (Table 1). Among cases with reported age, the largest proportion was in those ≥65 years of age (42%) (Table 2).
In weeks 37 and 38, detections of other respiratory viruses were at inter-seasonal levels (RSV, coronavirus, and human metapneumovirus). Detections of parainfluenza and adenovirus were in keeping with their usual pattern of seasonal circulation. Detections of rhinovirus have increased 1-2 weeks earlier than seen in recent seasons, but are still in keeping with the usual pattern of seasonal circulation (figure 3).
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 - Text Description
|Reporting provincesFootnote 1||Two weeks (September 7 to September 20, 2014)||Cumulative (August 24 to September 20, 2014)|
|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|
|Percentage Footnote 2||80.0%||10.7%||50.0%||39.3%||20.0%||75.0%||9.1%||45.5%||45.5%||25.0%|
|Age groups (years)||Two weeks
(September 7 to September 20, 2014)
(August 24 to September 20, 2014)
|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||#||%|
Influenza Strain Characterizations
The National Microbiology Laboratory (NML) has not yet reported any influenza strain characterizations for the 2014-15 season (Figure 4).
|Virus type and subtype||Oseltamivir||Zanamivir||Amantadine|
|# tested||# resistant (%)||# tested||# resistant (%)||# tested||# resistant (%)|
|B||0||0||0||0||NATable 3 - Footnote *||NA Table 3 - Footnote *|
Influenza-like Illness (ILI) Consultation Rate
The national influenza-like-illness (ILI) consultation rate has been increasing steadily during the first four weeks of the 2014-15 season; and was 17.7 and 20.1 per 1,000 in weeks 37 and 38, respectively (Figure 5). The rates since mid-June have been above the expected range for this time of year.
Influenza Outbreak Surveillance
One new outbreak of influenza was reported in a long-term care facility in week 38 (Figure 6). Three outbreaks of influenza-like illness in schools were also reported in the same week.
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.
During this two-week period, the proportion of prescriptions for antivirals increased to 10.5 antiviral prescriptions per 100,000 total prescriptions in week 38 (Figure 7).
Sentinel Hospital Influenza Surveillance
Paediatric Influenza Hospitalizations and Deaths (IMPACT)
In weeks 37 and 38, four laboratory-confirmed influenza-associated paediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network (Figure 8a). These are the first hospitalizations reported through IMPACT this season. Three of the four were cases of influenza A and two were admitted to the ICU. The age distribution of cases ranged from <6 months to 16 years.
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)
Surveillance of laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations by the PHAC/CIHR Influenza Research Network (PCIRN) Serious Outcomes Surveillance (SOS) network has not yet begun for the 2014-15 season (Figure 8b).
Note: The number of hospitalizations reported through CIRN 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
Data suppressed for the 2014-15 season due to small values. Table 4 will be updated when additional data are received.
Table 5 - Cumulative numbers of adult hospitalizations with influenza reported by the PCIRN-SOS network, Canada, 2014-15
PCIRN-SOS surveillance for the 2014-15 season has not yet begun.
Figure 8 - Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2014-15
A) Paediatric hospitalizations (≤16 years of age, IMPACT)
Figure 8B - Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2014-15
B) Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Provincial/Territorial Influenza Hospitalizations and Deaths
Since the start of the 2014-15 season, four laboratory-confirmed influenza-associated hospitalizations have been reported from participating provinces and territoriesFootnote *; all with influenza A, and the majority were patients ≥65 years of age. No ICU admissions or deaths were reported.
Table 6. Cumulative number of hospitalizations with influenza reported by the participating provinces and territories, Canada, 2014-15
Data suppressed for the 2014-15 season due to small values. Table 6 will be updated when additional data are received.
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): No new cases of human infection with influenza A(H7N9) have been reported by the World Health Organization since the last FluWatch report. Globally to September 25, 2014, the WHO has been informed of a total of 453 laboratory-confirmed human cases with avian influenza A(H7N9) virus, including 175 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:
Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
Globally, from September 2012 to September 25, 2014, the WHO has been informed of a total of 846 laboratory-confirmed cases of infection with MERS-CoV, including 298 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).
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:
Enterovirus D68 (EV-D68)
As of September 26, 2014, confirmed cases of EV-D68 have been reported in Western and Central Canada. The EV-D68 strains detected in Canada match those associated with clusters of cases reported in the United States in recent months. Fall is the peak season for enterovirus circulation in both Canada and the US.
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.
- 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.
- 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.
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