In Mexico, the epicenter of the outbreak, masks have become a common fixture.

CNN: Hysteria over swine flu is the real danger, some say

There have been 590 confirmed cases, including 25 deaths in Mexico -- the epicenter of the outbreak, according to the World Health Organization.

CNN: Mexican citizens to return from China

Officials said the pigs may have been infected by a Canadian farmer who recently returned from a trip to Mexico, the epicenter of the outbreak.

CNN: Confirmed cases of H1N1 virus approach 900

They said the pigs may have been infected by a Canadian farmer who recently returned from a trip to Mexico, the epicenter of the outbreak that has sickened more than 680 people.

CNN: Canada: Farmer possibly gave swine flu to pigs

Consumer spending was hurt and millions of Chinese dawned facial masks in the spring of 2003 when the country was the epicenter of a global outbreak of severe acute respiratory syndrome, or SARS, that killed several hundred people worldwide.

FORBES: Shanghai Discovers Two More Cases Of Deadly Bird Flu; More Poultry Markets Shut

Consumer spending was hurt and millions of Chinese dawned facial masks as a grim part of life in 2003 when the country was the epicenter of a global outbreak of severe acute respiratory syndrome, or SARS, that killed several hundred people worldwide.

FORBES: Shanghai Shuts Poultry Markets As H7N9 Flu Deaths Increase To Six