A deadly strain of the flu virus, which has never been seen before, has killed at least 16 people in Mexico and there are fears that it is spreading across North America. Millions of children in the vast capital, Mexico City, had classes cancelled as hospitals dealt with more than 800 cases suspected to have come from a virus mutated from pig flu.The World Health Organisation has convened an emergency committee. The Mexican Health Secretary, Jose Angel Cordova, told TV viewers: “The department of health advises everyone to avoid busy places and crowded events unless it’s absolutely necessary.” Mexican children and the elderly are being vaccinated to boost the immunity of those considered the most vulnerable in the community. In Washington the White House is following the outbreak closely. There have been seven cases of a new strain of swine-flu in California and Texas, all of whom recovered. The WHO in Geneva said on top of the confirmed deaths, a further 45 could yet be attributed to the strain.