Mexico City ? Mexico has seen the worst of swine flu, but the virus will likely continue to spread worldwide as flu season ramps up in the Southern Hemisphere.

The epidemic peaked in Mexico, the center of the outbreak, in late April, and now has spread throughout the Northern Hemisphere, the U.S. Centers for Disease Control and Prevention said Thursday.

But it will continue to be a threat south of the equator, where countries are entering the winter months and traditional flu season, according to the CDC report, one of the most comprehensive yet on the effect of the virus on people.

South America already has had more than 600 cases, including one death in Chile, while Australia has reported more than 500.

Swine flu has hit more than 60 countries, with the United States reporting the most cases — more than 11,400, including at least 19 deaths, according to the CDC.