Officials said the World Health Organization is likely to declare the first flu pandemic in 41 years as swine flu infections continued to climb in the United States, Europe, Australia, South America and elsewhere.
Scottish Health Secretary Nicola Sturgeon said the declaration of a pandemic - a global epidemic - would probably come after a WHO emergency meeting Thursday.
WHO spokesman Thomas Abraham said the emergency meeting would begin at noon (1000 GMT, 6 a.m.) in Geneva and WHO member nations would be informed of the result.
Officials at UN missions in Geneva also said they expected the announcement of a pandemic.
The declaration of a pandemic would push drugmakers to fast-track production of a swine flu vaccine.