large outbreak, one that spreads among a population or region. The current outbreak of a flu-like illness caused by a new virus in China is considered an epidemic.
PANDEMIC: Generally refers to an epidemic that has spread on a more global scale, affecting large numbers of people. While there are cases of illness outside China, the World Health Organization said it is not a pandemic. Exactly when enough places have enough infections to declare one isn't a black-and-white decision. But generally, the WHO is looking for sustained outbreaks on different continents.
