GENEVA (AP) -- Organizers of big sporting and cultural events should take steps to prevent the spread of swine flu, especially if local health systems aren't prepared to handle mass gatherings, the World Health Organization said Friday.

The global body said there was "ample evidence" that any unusual gathering of 1,000 people or more can help spread infectious diseases such as swine flu.

It issued an 8-page guidance document advising organizers how to reduce crowding, promote hygiene and manage those who fall ill with the disease, but refrained from outlining specific conditions under which events should be canceled.

"Any event where the systems are stretched to the limit, so a non-routine event, that is a mass gathering for us," said Maurizio Barbeschi, one of the authors of the report.

"The mass gathering could be a G8, when the heads of states are meeting and there are 20,000 people watching," he said, referring to gatherings of leaders of the eight most powerful nations that frequently draw protests outside the meeting venues.

It would also include the 2010 soccer World Cup in South Africa next year, and the annual hajj pilgrimage for Muslims that starts later this month, Barbeschi said.

WHO has sent advisers to South Africa to review preparations for next year's sporting event, which takes place during the southern hemisphere's flu season.

The global body is providing similar advice to organizers of next year's Expo in Shanghai, China, the Southeast Asian Games in Laos next month, and the Commonwealth Heads of Government meeting in Trinidad at end of November.

Barbeschi said anyone traveling to major events such as the World Cup and the hajj should "absolutely" consider getting vaccinated beforehand if they can. This would help prevent them from catching the disease at the gathering and carrying it back to their home countries, he said.

Swine flu has killed over 6,250 people worldwide since the start of the outbreak this spring, according to WHO.

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