Governments around the world took steps Tuesday to curb the spread of a new strain of flu that has killed up to 149 people in Mexico in a couple of weeks and spread to Europe and possibly Asia.
In Asia, financial markets were on edge over the risk the flu could develop into a pandemic and kill off fragile signs of recovery in the global economy after the World Health Organization raised its alert level for the outbreak.
No one has died outside Mexico but more than 50 infected people have been found in the United States, six in Canada and three across the Atlantic in Spain and Scotland. Possible cases were being tested as far away as Norway and South Korea.
The Swine flu bug is curable if treated quickly with antiviral medicine but no one is naturally immune and the WHO has lifted its pandemic alert to phase 4, indicating the risk of a deadly global outbreak.
"This can be interpreted as a significant step toward pandemic influenza, but also it is a phase which says that we are not there yet," acting WHO Assistant Director-General Keiji Fukuda told a teleconference Monday.
Most Asian stock markets slipped into negative territory after tentative early gains, and the yen climbed to a seven-week high against the euro and a one-month high versus the dollar as investors cut their exposure to riskier currencies.
Drug stocks extended Monday's gains while airline stocks were hit once again. Oil dropped a further 1 percent, sinking below $50 a barrel.