Epidemiological summary of pandemic influenza A (H1N1) 2009 virus – Ontario, Canada, June 2009
Background
In March and April 2009, a novel strain of influenza A (H1N1) virus was detected in Mexico and the United States. The virus has since spread worldwide, and there have been >340 000 laboratory-confirmed cases and >4100 deaths reported to WHO as of 27 September 2009. Given the evidence of sustained community-level outbreaks of novel influenza A (H1N1) in >1 WHO region, WHO declared a global pandemic of influenza A (H1N1) on 11 June 2009, designating the virus "pandemic influenza A (H1N1) 2009 virus".
Canada was one of the first countries to detect imported cases of pandemic (H1N1) 2009 virus; 6 cases were reported on 26 April 2009 by the provinces of Nova Scotia (4 cases) and British Columbia (2 cases). Two days later, the province of Ontario confirmed 4 cases of infection with the pandemic (H1N1) 2009 virus. This report describes the epidemiology of the first cases of pandemic (H1N1) 2009 virus in Ontario, Canada, during the early course of the pandemic to assist health officials in developing policies related to the identification, prevention and treatment of infection with this virus.
