Manitoba Health Reports Influenza Activity In Manitoba

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Influenza

The following report details influenza activity in Manitoba from the start of the 2006/2007 flu season. The Communicable Diseases Control Unit of Manitoba Health received its first laboratory-confirmed positive case of influenza for the season during the week of January 8, 2007.

No new cases of influenza A have been reported in the province since last week. To date there have been 72 laboratory-confirmed cases of Influenza in the province. No additional Manitoba case have been strain characterized this week. To date in the province, 14 cases have been characterised, twelve of which were found to be A/Wisconsin/67/05-like (H3N2) and two of which has been identified as A/New Caladonia/20/99-like (H1N1). Typing of isolates from other provinces reveals that these two strains are generally circulating in the country. Both of these strains are included in the composition of the 2006/07 Canadian influenza vaccine.

LABORATORY-CONFIRMED INFLUENZA

! Reports of culture isolations and EIA detections from Cadham Provincial Laboratory (CPL) are forwarded to the Communicable Disease Control (CDC) Unit 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. While EIA detections and culture isolations comprise the largest number of reports from CPL, seroconversions are similarly forwarded to the CDC Unit weekly. Information contained within this update is based on positive lab reports received at the CDC Unit as of April 27, 2007.

! The specimen date (acute specimen date for seroconversions) is used to:

(a) extract cases; and,

(b) assign cases to the appropriate week/month

Influenza A

! There have been 71 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.

! Refer to Figure 1 for an illustration of the Epidemic Curve by specimen collection date.

! Refer to Table 2 and Figure 2 for a summary of cases by age group.

! Refer to Figure 3 for an illustration of the number of laboratory-confirmed cases by month and year in Manitoba, 2001/2002 to 2006/2007.

Influenza B

! There has been 1 case of Influenza B reported this season in Manitoba.

! Refer to Table 1 for a summary of cases by Regional Health Authority (RHA) and week of specimen collection.

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! Refer to Figure 1 for an illustration of the Epidemic Curve by specimen collection date.

! Refer to Table 2 for a summary of cases by age group.

! Refer to Figure 4 for an illustration of the number of laboratory-confirmed cases by month and year in Manitoba, 2001/2002 to 2006/2007.

SUSPECTED/CONFIRMED REPORTS OF INFLUENZA OUTBREAKS

! Reports of suspected/confirmed influenza outbreaks are directed to the CDC Unit by:

(a) a phone call/email from public health staff within a RHA;

(b) a phone call/email from CPL advising of the assignment of an outbreak code;

(c) completion and submission of an outbreak form

! As of April 27, 2007 there have been 18 outbreaks of respiratory illness reported to the CDC Unit since the beginning of the current flu season, eight of which have been lab confirmed. To date all confirmed outbreaks have occurred in Personal Care Homes. NATIONAL FLU WATCH PROGRAM

! Manitoba Health participates in the National Flu Watch Program co-ordinated 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 14 sentinel physicians reflecting 8 health authorities: South Eastman, Central, Brandon, Winnipeg, Assiniboine, Interlake, Norman and Burntwood. The CDC Unit 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.

! For the 2006/2007 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 could be due to influenza virus. 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 5 for an illustration of the ILI rate as it relates to the number of laboratory-confirmed cases of influenza.

INFLUENZA-RELATED DEATHS

! Reporting of influenza-related deaths is likely incomplete. Reports are based on notification by:

(a) Chief Medical Examiner;

(b) Medical Officers of Health in the Regional Health Authorities

(c) Infection Control Practitioners in long term care facilities

! There have been no suspected influenza-related deaths reported this season.

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