MEXICO CITY (Reuters) - Governments around the world rushed on Sunday to check the spread of a new type of swine flu that has killed up to 81 people in Mexico and infected around a dozen in the United States.
Mexicans huddled inside their homes while U.S. hospitals tracked patients with flu symptoms and other countries imposed health checks at airports as the World Health Organization warned the virus had the potential to become a pandemic.
Announced on Friday, the outbreak has snowballed into a monster headache for Mexico, already grappling with a violent drug war and economic slowdown, and has quickly become one of the biggest global health scares in years.
Mexico's tourism and retail sectors could be badly hit by the crisis and a new pandemic would deal a major blow to a world economy already knocked into its worst recession in decades by the crisis in financial markets.
The World Health Organization declared the flu a "public health event of international concern." WHO Director-General Dr. Margaret Chan urged greater worldwide surveillance for any unusual outbreaks of influenza-like illness.
"(We are) monitoring minute by minute the evolution of this problem across the whole country," President Felipe Calderon said as health officials counted suspected infections in six states from the tropical south to the northern border.
The new flu strain, a mixture of various swine, bird and human viruses, poses the biggest risk of a large-scale pandemic since avian flu surfaced in 1997, killing several hundred people. A 1968 "Hong Kong" flu pandemic killed about 1 million people globally.
Argentina declared a health alert, requiring anyone arriving on flights from Mexico to advise if they had flu-like symptoms. As far away as Hong Kong and Japan health officials stepped up checks of sickly travelers.
New flu strains can spread quickly because no one has natural immunity and a vaccine takes months to develop. A British Airways cabin crew member was hospitalized in London after developing flu-like symptoms on a flight from Mexico.
Mexican Health Minister Jose Angel Cordova said the swine flu had killed at least 20 and possibly as many as 81 people in Mexico, and more than 1,300 people were being tested for suspected infection. Most of the dead were aged 25 to 45, a worrying sign because a hallmark of past pandemics has been high fatalities among healthy young adults.
The government earmarked $450,000 to cover fighting the flu, and Calderon issued the government special powers to run tests on sick people and order them isolated.
TOURISTS IN FACE MASKS
In the crowded capital of 20 million people museums were closed and public events scrapped, from concerts to a running race. Sunday soccer matches were closed to spectators.
Locals hoarded bottled water and canned food, churchgoers were told to stay home and follow Sunday services on television and bewildered tourists were made to wear surgical face masks.
"It's all a bit alarming because as a tourist you don't know if you're going to be allowed home. It's worrying because there's not much information," said 29-year-old Sandy Itriago, waiting at a tour bus stop with her parents.
Trendy Mexico City districts were quiet on Saturday night as authorities closed 70 percent of nightclubs, along with stadiums and movie theaters. At least one open bar stationed medics at its doors to check clients' throats and take their temperatures.
All schools in the city, Mexico State and San Luis Potosi were closed until May 6 and some companies planned to have employees work from home.
While all the deaths so far have been in Mexico, the flu is spreading in the United States. Eleven cases were confirmed in California, Kansas and Texas, and eight schoolchildren in New York City caught a type A influenza virus that health officials say is likely to be the swine flu.
In Mexico, outside the capital, the virus has struck in central Mexico State and San Luis Potosi, the southern states of Veracruz and Oaxaca, both popular with tourists, and the northern border state of Baja California.
(Additional reporting by Stephanie Nebehay and Jonathan Lynn in Geneva, Maggie Fox in Washington, Avril Ormsby in London and Mica Rosenberg and Michael O'Boyle in Mexico City)