California 38-7 Over Fujian in Canadian H3N2 Influenza A Battle
Recombinomics Commentary
March 2, 2005
>> In recent weeks, experts have identified a new influenza strain dubbed A/California/7/2004(H3N2), so-called because of it was found in California's Santa Clara County.
Similar to the harsh A/Fujian strain that has been blamed for particularly severe flu outbreaks in recent years, A/California has been making a growing number of Canadians sick.
"We have identified it in six difference provinces," Health Canada's Dr. Theresa Tam told CTV, referring to B.C., Alberta, Manitoba, Ontario, Quebec and Newfoundland. "It appears to be moving across the country." <<
Weekly flu reports from the Public Health Agency in Canada show that like the US, A/Calfornia/7/2004(H3N2) is quickly becoming the dominant strain spreading across Canada. The report for the 5th week of 2005 indicated that all 312 H3N2 antigenic characterizations for the 2004/2005 flu season were Fujian. The first reported California/7 characterizations were in week 6 when there were 108 additional Fujian-like characterizations and 5 California-like. In week 7 California became dominant, with 38 isolates compared to just 7 that were Fujian-like. This rapid switch has correlated with an increase in flu cases across Canada, including reports of vaccinated nurses becoming ill in Ontario.
The emergence of the A/California/7/2004 strain has appeared throughout the world, including Russia where some schools have been closed for a month. California also became dominant in the US last month, when there was also an upsurge of reported cases, and clusters of sudden deaths of students in Eastern Pennsylvania and Illinois. Serological analysis of 2004 and 2005 isolates indicates that the strain is rapidly evolving, and although California will be used in next season's Northern Hemisphere vaccine, the rapid spread and evolution of the virus may limit the effectiveness of next season's vaccine.
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