Medical staff wearing protective masks stand in an assessment area for patients with symptoms of respiratory illnesses at a hospital in Singapore April 27, 2009. Countries around the world have moved to contain the spread of a possible pandemic after a new swine flu outbreak killed 103 people in Mexico. Twenty cases have been identified in the United States and six in Canada, with no deaths reported. REUTERS/Vivek Prakash (SINGAPORE HEALTH SOCIETY)
REUTERS/VIVEK PRAKASH