Mexican and US officials are taking emergency steps to contain the possible outbreak of a new multi-strain of swine flu that has killed about 70 people and may be responsible for scores of other deaths In Mexico. Moreover, the swine fever has spread into the United States, raising fears of a global pandemic.
Mexican health officials on Friday ordered the most sweeping shutdown of public gathering places in decades. In the capital, Mexico City, sports stadiums have been empty, schools and museums have shut and public events cancelled. Mexicans have started wearing surgical masks which soldiers handed out in the streets. Authorities say 1,000 people have become ill.
Mexico's health minister Jose Angel Cordoba says the new influenza mutated from pigs to humans and is now considered a "respiratory outbreak." This, he says, is why the health ministry in Mexico City is recommending that people avoid crowded places.
Officials at the US Centres for Disease Control and Prevention describe the virus as having a unique combination of genetic material from pigs, birds and humans. They say the virus may be completely new, or it may have been present for some time, and only now has been detected through improved testing and surveillance.
The CDC says tests indicate some of the Mexico victims died from the same new strain of virus that sickened eight people in California and Texas. But authorities say the US cases have been mild and that all eight people recovered. They say none of the US patients had any contact with pigs.
Scientists have long been concerned that a new flu virus could spark a worldwide pandemic. A pandemic is usually declared when there is a new virus to which few people have resistance, which is easily transmissible and sustainable within a population and causes severe illness.
The World Health Organisation says it has sent a team of experts to the United States and Mexico to monitor the situations there. The WHO says it is convening an expert panel to consider raising the pandemic alert level. Margaret Chan, head of the WHO, broke off a visit to Washington to return to the agency's headquarters in Switzerland to coordinate a response to the emergency.
Symptoms of swine flu resemble the regular human seasonal influenza and include fever, lethargy, lack of appetite and coughing. Some people with swine flu also experience a runny nose, sore throat, nausea, vomiting and diarrhoea.
In New York City, health officials were investigating what had sickened scores of students who fell ill with flu-like symptoms in a Queens high school on Thursday and Friday. The symptoms were reported as mild. A city health official said he could not speculate about which flu strain was responsible.
Cordova encouraged people to avoid crowds and wear face masks. He said there was no guarantee that flu vaccines would help against the new strain. He added that the death rate appeared to have steadied and hospitals in the past few days had not seen the exponential rise in the number of infected people that many had feared.
The fact most of the dead were aged between 25 and 45 was seen as a worrying sign linked to pandemics, as seasonal flu tends to be more deadly among the elderly and the very young.