Saturday, December 12, 2009

Canada: FluWatch Week 48

 

 

# 4150

 

The Public Health Agency of Canada produces a weekly influenza summary called FluWatch, which is very similar to the US FluView report from the CDC. In it you will find maps, charts, and summaries of the previous week’s influenza surveillance.

 

As in the United States, Canada’s flu numbers this week are declining.

 

A few excerpts from this week’s report (ending Nov 21st), but follow the FluWatch link to read it in its entirety.

 

 

November 29, 2009 to December 5, 2009 (Week 48)

Summary of FluWatch Findings

  • At the national level, the overall influenza activity continued to decrease this week.
  • All FluWatch influenza indicators declined for at least the third consecutive week. The ILI consultation rate was even within the expected ranged for this time of the year.
  • The Pandemic (H1N1) 2009 strain accounted for nearly 100% of the positive influenza A subtyped specimens this week.
  • The intensity of Pandemic (H1N1) 2009 in the population was moderate. A decline has been experienced by all provinces and territories as indicated in the continued decreasing number of reported hospitalized cases (307 vs. 804), ICU admissions (83 vs. 139) and deaths (33 vs. 56) reported this week. Hospitalized cases occurred in all provinces and territories (PTs) that reported this week except YT while the deaths were from all PTs except NB, PE, NT and NU. From August 30 to December 5, 2009, a total of 6,621 hospitalized cases including 1,041 (15.7%) cases admitted to an intensive care unit (ICU) as well as 292 (4.4%) deaths had been reported.

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Canadian situation

Antigenic Characterization

Since September 1, 2009, the National Microbiology Laboratory (NML) has antigenically characterized 433 Pandemic (H1N1) 2009 viruses and eight seasonal influenza viruses (two influenza A/H1N1, five H3N2, and one B virus) that were received from Canadian laboratories.

 

 

Of the 433 pandemic influenza A (H1N1) viruses characterized, 430 (99.3%) were antigenically related to A/California/7/2009, which is the pandemic reference virus selected by WHO as the Pandemic (H1N1) 2009 vaccine. Three viruses (0.7%) tested showed reduced titer with antisera produced against A/California/7/09. Sequence analysis of the HA showed that the two viruses with reduced titer did not have the mutation at amino acid position 222 as reported by Norway.

 

Of the five seasonal influenza A (H3N2) viruses characterized, one was related to A/Brisbane/10/07, which is the influenza A/H3N2 component recommended for the 2009-10 influenza vaccine. Four viruses were antigenically related to A/Perth/16/09, which is the WHO recommended influenza A (H3N2) component for the 2010 Southern Hemisphere vaccine.

 

Antiviral Resistance

NML: Pandemic (H1N1) 2009 viruses tested so far have been sensitive to zanamivir (440 samples) but resistant to amantadine (441 samples).

Provinces: Seven cases of oseltamivir resistant Pandemic (H1N1) 2009 were reported to date in Canada; one in Alberta, four in Ontario and two in Quebec.