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What did the World Health Organization declare on April 25, 2009?
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influenza pandemic (H1N1) of 2009
Doctors at the Mexico City Navy Hospital wearing protective gear as they tend to patients complaining of H1N1 flu-like symptoms.
On April 25, 2009, the director-general of the World Health Organization, Margaret Chan, declared the H1N1 outbreak a public health emergency of international concern.1