The World Health Organization has raised its tally of confirmed human cases of swine flu to 8,451 in 36 countries, including at least 72 deaths. It says the United States has reported 4,714 laboratory-confirmed cases, including four deaths. Mexico has 2,895 cases and 66 deaths. Canada has 496 cases, with one death. Costa Rica has nine cases and one death. Spain has 100 cases, Britain 78 and Panama 43. WHO figures often lag behind those given by national health agencies. Turkey and India on Saturday announced their first confirmed cases of swine flu, Associated Press reported.