Governments around the world rushed on Sunday to check the spread of a new type of swine flu that has killed over 80 people in Mexico and infected around a dozen in the United States. Mexicans huddled inside their homes while US hospitals tracked patients with flu symptoms and other countries imposed health checks at airports as the World Health Organization (WHO) warned the virus had the potential to become a pandemic.

The epidemic 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. In New Zealand, 10 pupils from an Auckland school party that had just returned from Mexico were being treated for influenza symptoms in what health authorities said was a likely case of swine flu, although they added none were seriously ill. 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," Mexican President Felipe Calderon said as health officials counted suspected infections in six states from the tropical south to the northern border. Mexicans huddled inside their homes while US 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. Travelers screenedCountries right across Asia, which have had to grapple with deadly viruses like H5N1 bird flu and SARS in recent years, snapped to action. At airports and other border checkpoints in Hong Kong, Malaysia, South Korea and Japan, officials were screening travelers for any flu-like symptoms.China now requires people coming from swine-flu affected places to report any flu-like symptoms at ports of entry. Argentina declared a health alert, requiring anyone arriving on flights from Mexico to advise if they had flu-like symptoms.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. A man wears a mask as he waits inside the Mixcoac Health Center in Mexico City. A deadly strain of swine flu never seen before has broken out in Mexico, killing up to 81 people. New flu strains can spread quickly because no one has natural immunity to them 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, but tests later showed he did not have swine flu.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 masksIn the crowded Mexican 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. Turkish experts concernedThe spread of a new type of swine flu, which has killed up to 81 people in Mexico and infected around a dozen in the United States, has been met with concern in Turkey. Professor Haluk Eraksoy, head of the Turkish Clinical Microbiology and Infectious Diseases Foundation, said all countries, including Turkey, would be at risk if the flu becomes pandemic. "In a world where transportation opportunities are so developed, the virus can be transmitted to different continents within hours," he said. He also said the disease is a potential threat for humanity as it is transmitted to humans by pigs. "Pigs are different from other creatures. They have the capacity to host microorganisms in their bodies. These microorganisms may be transformed into different viruses," he said. Önder Ergönül, an associate professor at Marmara University, however, did not agree and said it is not possible for Turkey to be at risk for swine flu. "As the number of pig farms are few in Turkey, this disease is a not a potential pandemic for us," he said. He also added that though it is not under imminent risk, Turkey needs to take the necessary precautions to protect its population from such diseases. Nergihan Çelen İstanbul New flu strain is a genetic mixA deadly swine flu never seen before has broken out in Mexico, killing at least 81 people and raising fears of a possible pandemic. Here are some facts about the virus and flu viruses in general:The World Health Organization (WHO) has confirmed at least some of the cases are a never-before-seen strain of influenza A virus, carrying the designation H1N1.Although it's called swine flu, this new strain is not infecting pigs and has never been seen in pigs. The threat is person to person transmission.It is genetically different from the fully human H1N1 seasonal influenza virus that has been circulating globally for the past few years. The new flu virus contains DNA typical to avian, swine and human viruses, including elements from European and Asian swine viruses.When a new strain of flu starts infecting people, and when it acquires the ability to pass from person to person, it can spark a pandemic. The last pandemic was in 1968 and killed about a million people.Flu viruses mutate constantly, which is why the flu vaccine is changed every year, and they can swap DNA in a process called reassortment. Most animals can get flu, but viruses rarely pass from one species to another.Symptoms of swine flu in people are similar to those of seasonal influenza -- sudden onset of fever, coughing, muscle aches and extreme tiredness. Swine flu appears to cause more diarrhea and vomiting than normal flu. New York Reuters  27 April 2009, MondayREUTERS  MEXICO