Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
Issue #23 Page 1
INFLUENZA IN MANITOBA – 2010/2011 SEASON
Cases reported up to March 12, 2011
The public health disease surveillance system of Manitoba Health received its first laboratory-confirmed positive case of influenza for the 2010/2011 season (running from July 1, 2010 to June 30, 2011) during Week 39, September 26 – October 2, 2010. This season there have been 474 laboratory-confirmed cases of Influenza A and 1 lab-confirmed case of Influenza B in the province.
LABORATORY-CONFIRMED INFLUENZA
Reports from Cadham Provincial Laboratory (CPL) are forwarded to the public health disease surveillance system of Manitoba Health weekly. The number of positive cultures is an underestimate of the total number of cases, since not all persons with influenza seek medical attention, and of those that do, not all are cultured for the
virus.
Information contained within this update is based on positive lab reports confirmed on or before March 12, 2011. The date the laboratory specimen is taken is used to assign cases to the appropriate week/month.
INFLUENZA A
There have been 474 cases of Influenza A reported this season in Manitoba. Refer to Table 1 for a summary of cases by Regional Health Authority (RHA) and week of specimen collection and Table 3 for a summary of cases by age group. Refer to Figure 1 for an illustration of the number of laboratory-confirmed cases of Influenza A by
month in Manitoba, 2003/2004-2010/2011.
INFLUENZA B
There has been 1 case of Influenza B reported this season in Manitoba. Refer to Table 2 for a summary of cases by Regional Health Authority (RHA) and week of specimen collection and Table 3 for a summary of cases by age group. Refer to Figure 2 for an illustration of the number of laboratory-confirmed cases of Influenza B by
month in Manitoba, 2003/2004-2010/2011.
REPORTS OF INFLUENZA-LIKE ILLNESS OUTBREAKS
ILI outbreaks are defined as: 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. Hospitals and Residential institutions: two or more cases of ILI within a seven-day period, including at least one laboratory confirmed case. Other settings: two or more cases of ILI within a seven-day period, including at least one laboratory confirmed case; i.e. workplace, closed communities. These outbreaks of influenza must be accompanied by a positive influenza lab report to be
counted. The outbreak-related cases reflected on tables and figures within this report are labconfirmed. Most outbreak-related cases are not lab-confirmed.
Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
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As of March 12, 2011, there were 36 regional outbreaks of lab-confirmed Influenza A and no labconfirmed outbreaks of Influenza B reported to the public health disease surveillance system for the 2010-2011 season:
RHA: LTCF* Workplace
Acute Care Facility Community
Winnipeg 21 1 1
Brandon 2
Interlake 2
Central 2 1
Assiniboine 4
Parkland 1
Burntwood 1
* LTCF = long term care facility
NATIONAL FLUWATCH PROGRAM
Manitoba Health participates in the National FluWatch Program coordinated by the Public Health Agency of Canada and the College of Family Physicians of Canada. In addition to laboratoryconfirmation of influenza, this program relies on weekly reports of influenza-like illness (ILI) as reported by 23 current Manitoban sentinel physicians. These sentinels reflect cases found in eight regional health authorities.
Manitoba Health receives weekly reports from the Public Health Agency of Canada presenting the provincial ILI rate and the specific data for each of the participating sentinel physicians. Not all sentinel physicians participate in the program each week, and 8 of the 22 sentinels participate in swabbing for influenza with their ILI patients.
For the 2010/2011 season, ILI in the general population is defined as: 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.
Refer to Figure 3 for an illustration of the ILI rate and number of reporting sentinels as it relates to the number of laboratory-confirmed cases of influenza.
SUB-TYPING, STRAIN CHARACTERIZATION, AND ANTIVIRAL RESISTANCE
Sub-Typing: The following summarizes the breakdown of influenza by type and sub-type, as reported by CPL:
A/H1N1 A/H3N2 A unsubtyped A Total
1 57 416 474
Strain Characterization: Since September 1 st , 2010, National Microbiology Laboratory (NML)
reports that it has antigenically characterized 3 influenza viruses that were received from CPL. The Influenza A/H3N2 viruses characterized by NML were antigenically related to A/Perth/16/2009-like.
Antiviral Resistance: Since September 1 st , 2010, NML has tested for antiviral resistance on
Manitoba isolates with the following results:
Influenza A/H3N2:
Resistant Sensitive
Amantadine 4 0
Oseltamivir 0 3
Zanamivir 0 3
Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
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INFLUENZA-RELATED HOSPITALIZATIONS, ICU ADMISSIONS, AND DEATHS
Lab-confirmed report of influenza infection is required for a hospitalization, ICU admission, or death to be counted. Influenza-related death should be interpreted with caution as underlying cause of death may or may not be directly related to the lab-confirmed positive influenza diagnosis. See Figure 4 for an illustration of the number of severe events as it relates to the number of lab-
confirmed cases of Influenza.
Weekly Total Cumulative Total
Hospitalizations: 2 96
ICU Admissions: 0 16
Deaths: 0 6
Note: Cumulative data includes updates to previous weeks; due to reporting delays or amendments, the sum of weekly report totals may not add up to cumulative totals.
HEALTH LINKS – INFO SANTÉ (HL-IS)
HL-IS is a 24-hour, 7-days a week telephone information service staffed by registered nurses with the knowledge to provide answers over the phone to health care questions and guidance to appropriate care. From March 6-12, 2011, there were a total of 28 calls made to HL-IS Influenza Service. Of these
calls:
2 caller(s) selected to hear the Flu Appointment option 0 caller(s) selected the Influenza Program 21 caller(s) selected Flu Management 5 caller(s) selected the Free Flu Shot Program
See Figure 5 for an illustration of the number of calls as it relates to the number of lab-confirmed cases of influenza.
For other Epidemiology and Surveillance reports, please view the Manitoba Health Internet Website: http://www.gov.mb.ca/health/publichealth/surveillance/index.html
For national surveillance data, refer to: http://www.phac-aspc.gc.ca/fluwatch/index-eng.php
Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
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RHA 26/09 - 02/10 03/10 - 09/10 10/10 - 16/10 17/10 - 23/10 24/10 - 30/10 31/10 - 06/11 07/11 - 13/11 14/11 - 20/11 21/11 - 27/11 28/11 - 04/12 05/12 - 11/12 12/12 - 18/12 19/12 - 25/12 26/12 - 01/01 02/01 - 08/01 09/01 - 15/01 16/01 - 22/01 23/01 - 29/01 30/01 - 05/02 06/02 - 12/02 13/02 - 19/02 20/02 - 26/02 27/02 - 05/03 06/03 - 12/03 TOTAL
Winnipeg 0 0 0 0 0 1 0 4 6 7 20 28 31 30 12 3 3 7 2 1 5 2 5 1 168
Brandon 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 3 2 0 2 0 5 0 0 0 13
North Eastman 0 0 0 0 0 0 0 0 0 5 7 6 5 2 3 2 0 1 0 0 0 0 0 0 31
South Eastman 0 0 0 0 0 0 0 0 0 0 3 0 0 4 2 2 1 1 0 0 0 0 0 0 13
Interlake 0 0 0 0 0 0 0 0 0 0 6 9 5 4 0 1 1 0 0 1 0 0 1 0 28
Central 0 0 0 0 0 0 0 0 0 0 2 1 10 2 2 10 3 0 0 0 0 0 1 0 31
Assiniboine 0 0 0 0 0 0 0 0 0 0 1 0 1 5 5 3 7 5 5 0 1 0 0 0 33
Parkland 0 0 0 0 0 0 0 0 2 0 3 1 5 2 1 2 1 0 0 0 0 0 0 0 17
Norman 1 0 0 0 0 0 0 0 1 0 7 1 0 1 0 0 0 0 0 0 0 0 0 0 11
Burntwood 0 0 0 0 0 0 0 0 26 16 32 35 12 4 1 0 0 0 0 0 0 0 0 0 126
Churchill 0 0 0 0 0 0 0 0 0 2 0 0 0 1 0 0 0 0 0 0 0 0 0 0 3
MANITOBA 1 0 0 0 0 1 0 4 35 30 82 81 69 55 26 26 18 14 9 2 11 2 7 1 474
Table 1. Reported Cases of Influenza A by RHA and Week of Specimen Collection, Manitoba 2010-2011
RHA 26/09 - 02/10 03/10 - 09/10 10/10 - 16/10 17/10 - 23/10 24/10 - 30/10 31/10 - 06/11 07/11 - 13/11 14/11 - 20/11 21/11 - 27/11 28/11 - 04/12 05/12 - 11/12 12/12 - 18/12 19/12 - 25/12 26/12 - 01/01 02/01 - 08/01 09/01 - 15/01 16/01 - 22/01 23/01 - 29/01 30/01 - 05/02 06/02 - 12/02 13/02 - 19/02 20/02 - 26/02 27/02 - 05/03 06/03 - 12/03 TOTAL
Winnipeg 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1
Brandon 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
North Eastman 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
South Eastman 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Interlake 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Central 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Assiniboine 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Parkland 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Norman 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Burntwood 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Churchill 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
MANITOBA 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1
Table 2. Reported Cases of Influenza B by RHA and Week of Specimen Collection, Manitoba 2010-2011
Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
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# of cases % of total # of cases % of total
<1 yrs 30 6.3% 1 100.0%
1-4 yrs 46 9.7% 0 0.0%
5-9 yrs 27 5.7% 0 0.0%
10-14 yrs 32 6.8% 0 0.0%
15-19 yrs 13 2.7% 0 0.0%
20-24 yrs 18 3.8% 0 0.0%
25-29 yrs 23 4.9% 0 0.0%
30-39 yrs 52 11.0% 0 0.0%
40-49 yrs 42 8.9% 0 0.0%
50-59 yrs 40 8.4% 0 0.0%
60-69 yrs 18 3.8% 0 0.0%
70-79 yrs 33 7.0% 0 0.0%
>79 yrs 100 21.1% 0 0.0%
Missing 0 0.0% 0 0.0%
TOTAL 474 1
Table 3. Reported Cases of Influenza A and B by Age Group, in Manitoba 20102011
Age Group
Influenza A Influenza B
Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
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Figure 1. Laboratory-Confirmed Cases of Influenza A*, 2003/2004-2010/2011**
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
2003/2004 0 0 0 4 96 63 2 0 0 0 0 0
2004/2005 0 0 0 0 4 5 60 62 19 1 0 0
2005/2006 0 0 0 1 0 0 2 27 19 14 0 0
2006/2007 0 0 0 0 0 1 17 30 20 3 0 0
2007/2008 0 0 0 0 0 1 13 43 16 6 0 0
2008/2009 0 0 0 0 0 0 1 14 22 16 24 9
2009/2010 2 0 0 6 11 0 0 0 0 0 0 0
2010/2011 0 0 0 1 49 308 85 24 7
0
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
320
Number of Cases
* Excludes pandemic H1N1 cases reported during Wave 1 and 2 of the 2009/2010 pandemic. ** March 2011 monthly total up to March 12.
Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
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Figure 2. Laboratory-Confirmed Cases of Influenza B, 2003/2004-2010/2011*
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
2003/2004 0 0 0 0 0 0 0 0 0 0 0 0
2004/2005 0 0 0 0 0 0 0 14 38 10 4 0
2005/2006 0 0 0 0 0 0 5 9 10 1 0 0
2006/2007 0 0 0 0 0 0 1 0 0 0 0 0
2007/2008 0 0 0 0 0 1 5 14 9 10 1 0
2008/2009 0 0 0 0 0 1 1 10 20 4 2 0
2009/2010 0 0 0 0 0 0 0 0 0 0 0 0
2010/2011 0 0 0 0 0 1 0 0 0
0
10
20
30
40
50
Number of Cases
* March 2011 monthly total up to March 12.
Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
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Figure 3. Influenza-Like Illness (ILI) Rate, Number of Influenza A and B Cases by Week of Specimen Collection, and Number of Sentinels Participating in FluWatch, 2010-2011 Season by Week
0
10
20
30
40
50
60
70
80
90
0
10
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80
90
27/06
-03/07
04/07
-10/07
11/07
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18/07
-24/07
25/07
-31/07
01/08
-07/08
08/08
-14/08
15/08
-21/08
22/08
-28/08
29/08
-04/09
05/09
-11/09
12/09
-18/09
19/09
-25/09
26/09
-02/10
03/10
-09/10
10/10
-16/10
17/10
-23/10
24/10
-30/10
31/10
-06/11
07/11
-13/11
14/11
-20/11
21/11
-27/11
28/11
-04/12
05/12
-11/12
12/12
-18/12
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-25/12
26/12
-01/01
02/01
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09/01
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23/01
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30/01
-05/02
06/02
-12/02
13/02
-19/02
20/02
-26/02
27/02
-05/03
06/03
-12/03
ILI Rate/1000
Number of Cases
& Sentinels Reporting
Specimen Week
Influenza A Influenza B # Sentinels Reporting ILI Rate/1000 Patients
Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
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Figure 4. Number of Hospitalizations, ICU Admissions, and Number of Influenza A Cases by Week, Manitoba, 2010/2011 Influenza Season
0
10
20
30
40
50
60
70
80
90
Number of Cases/Events
Specimen Week
Influenza A Hospitalizations ICU Admissions Deaths
Influenza in Manitoba – 2010/2011 Season Source: CDC Unit, Manitoba Health
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Figure 5. Number of Calls to Health Links – Info Santé Influenza Service by Type of Enquiry* and Number of Influenza A and B Cases by Week, Manitoba, 2010/2011 Influenza Season
0
25
50
75
100
125
150
175
200
225
250
Number of Calls & Number of Cases
Specimen Week
Influenza A Influenza B Flu Clinic Influenza Program Flu Management Flu Criteria
* Influenza Program The number of calls where the caller selected the Influenza Program Flu Management The number of calls where the caller selected the Flu Management Flu Shot Criteria The number of calls where the caller selected the Free Flu Shot Program Flu Clinic The number of calls where the caller selected to hear the Flu Appointment option
** Number of calls to Health Links – Info Santé available for October 1-2 only (2010-2011 Health Links – Info Santé Seasonal Influenza Service was launched on October 1, 2010).