What is a Pandemic Flu Outbreak?

A pandemic is a worldwide disease outbreak and can cause large numbers of fatalities. It can happen when a new virus strain emerges and humans have no immunity to it, meaning our bodies have no defense to the new germ. To date, there have been no cases of the Avian (bird flu) H5N1 virus in the United States, nor has there been a human transmission of the disease in a form that could fuel a pandemic.

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