MEXICO CITY - The swine flu crisis deepened yesterday with the death toll mounting above 150 in Mexico and at least 16 countries reporting confirmed or suspected infections.
The World Health Organisation (WHO) warned that the virus is now too "widespread to make containment a feasible strategy".
Mexico, epicentre of the outbreak, said 152 people were now believed to have died from swine flu with more than 1 600 people suspected to be carrying the virus. Twenty of the deaths have been confirmed by laboratory tests.
The number of confirmed cases in the US more than doubled to 44 and Britain and Spain both said they had registered patients sick with swine flu, the first cases in Europe.
Canada has six cases and Israel and New Zealand confirmed their first swine flu casualties.
Suspected victims were being kept under surveillance from Australia (70 cases) to Sweden and Switzerland, which had five each.
While countries tightened borders, the WHO said research since the Severe Acute Respiratory Syndrome (Sars) outbreak in 2003 in Asia had shown that border controls were of little use halting the spread of such a virus.
"Border controls do not work. Screening doesn't work," WHO spokesperson Gregory Hartl said in Geneva.
"If a person has been exposed or infected ... the person might not be symptomatic at the airport," he said. "We learn as we go on. Sars was a huge learning experience for all of us."
WHO assistant general secretary Keiji Fukuda warned on Monday that the virus would be impossible to contain.
"I think that in this age of global travel where people move around in airplanes so quickly, there is no region to which this virus could not spread," said Fukuda. - Sapa-AFP