A thermal camera monitors the body temperature of passengers arriving from overseas against the possible infection of the swine flu at Incheon International Airport in Incheon, west of Seoul, South Korea, Sunday, April 26, 2009. Asian health authorities were on alert Sunday, with some checking passengers and pork products from Mexico, as the World Health Organization declared the deadly swine flu outbreak a public health emergency of "pandemic potential."Countries planned quarantines, tightened rules on pork imports and tested airline passengers for fevers as global health officials tried Sunday to come up with uniform ways to battle a deadly strain of swine flu.