On Dec. 16, WHO was notified of a confirmed human case of influenza A(H3N2) variant virus in Canada. The case developed respiratory infection symptoms on Oct. 24, was hospitalized on Nov. 8 with the diagnosis of pneumonia, and has recovered, according to the Influenza at the Human-Animal Interface Report. The exact location in Canada was not listed in the report.
The case has confirmed exposure to ill swine on a farm. Animal health and epidemiological investigations are ongoing.
Partial sequence analysis of all 8 gene segments of the virus isolated from the case indicates they are closely related to influenza A(H3N2) swine influenza viruses currently circulating in swine in North America.
This is the first human case of A/Indiana/08/2011-like H3N2v influenza virus infection reported to WHO from Canada. Human infection with influenza A(H3N2)v viruses detected elsewhere have typically resulted in mild disease, although some have been hospitalized and at least one A(H3N2)v associated death has been reported.
Influenza A(H1N2) and A(H3N2) viruses circulate in swine populations in many regions of the world. Depending on geographic location, the genetic characteristics of these viruses differ. Most human cases are exposed to the swine influenza viruses through contact with infected swine or contaminated environments. Human infection tends to result in mild clinical illness, although some cases have been hospitalized with more severe disease and one fatal case has been reported. Since these viruses continue to be detected in swine populations, further human cases can be expected.