Unless travel to Mexico is absolutely essential, Canadian health officials are urging citizens not to go. The outbreak of human swine flu, which has so far killed at least 152 people in Mexico, prompted the Public Health Agency of Canada to issue the warning late Monday. Travellers would be wise to get flu shots and wash hands often, the agency said. The U.S. has issued a similar warning. The World Health Organization, which on Monday raised the global pandemic level to 3, has urged against sealing borders and restricting travel, advocating instead for countries to contain outbreaks at home. Outside of Mexico, where 1,900 people have been hospitalized, cases of human swine flu have been confirmed in Canada, the U.S., Europe, New Zealand and Israel—although none have died. The six Canadians who fell ill have recovered.