swine flu

The first case of H1N1 swine flu virus was discovered in a North Carolina factory farm in 1998, not in Mexico. Within months of the 1998 emergence, the virus showed up in Texas, Minnesota, and Iowa.

Chart of alert levels from World Health Organisation (WHO) http://www.who.int/csr/disease/avian_influenza/phase/en/index.html This page also contains details of what the chart symbolises and is useful to understanding the situation.

(Quote about Obama's Mexican visit was from Thomas Black, "Mexico’s Calderon Declares Emergency Amid Swine Flu Outbreak" at Bloomberg.com)