The World Health Organisation (WHO) has today raised the swine flu pandemic alert to level five as global fears over the contagiousness of the virus gathered pace.
Margaret Chan, the WHO chief, told a news conference in Geneva tonight that as the level was being raised to five out of a possible six, "all countries should activate their pandemic preparedness plans, and remain on high alert."
Raising the alert to level five means the WHO believes a global outbreak of the disease is imminent. WHO says the phase five alert means there is sustained human to human spread in at least two countries.
Today the swine flu outbreak claimed its first victim outside Mexico: a 23-month-old child in Texas. A health official in Houston, Texas, said the child, thought to be a boy, was Mexican and had travelled to Brownsville to visit his family in the same state when he became ill.
He was admitted to a local hospital on 13 April and was transferred to another hospital in Texas after he "became quite ill rather rapidly" .
In Europe, Spain has detected its first case of swine flu in a person who has not recently visited Mexico. It is believed to be the first evidence that the virus has been transmitted in a European country.
The case involves a Spanish man from Catalonia whose girlfriend brought the virus back with her from a holiday in Mexico.
Marina Geli, head of the health service in Catalonia, said the man and his girlfriend were two of six patients in the region to have tested positive for the virus, according to the Catalan government's TV3 television station. Contact between the two was described as "very close".
Spanish authorities have confirmed 10 cases of the disease and 53 other cases are under investigation. All had recently returned from Mexico.
Earlier today Keiji Fukuda, the World Health Organisation assistant director general, had warned that the outbreak was approaching phase five, signifying that a flu pandemic is imminent.
He said the swine flu virus was behaving like a human flu virus and there was no evidence of people being infected from pigs or pork products.
He said it was "probably unlikely" that the virus would simply stop, although it was not clear whether more serious cases would develop.
He said eight swine flu deaths had been reported to the WHO: seven in Mexico and one in the US. To date, 114 confirmed cases of infection have been reported to the WHO. They are: Canada 13, US 64, Mexico 26, Israel two, Spain four, UK two and New Zealand three.
US health officials confirmed a total of 91 human cases. "We're reporting 91 confirmed cases in the United States," Richard Besser, acting director of the Centers for Disease Control and Prevention, told a news briefing.
Besser said this included 51 in New York, 16 in Texas, 14 in California, and others in Massachusetts, Michigan, Arizona, Nevada, Indiana, Kansas and Ohio.
Five cases in total have been confirmed in the UK, the prime minister, Gordon Brown, told the House of Commons.
More than 150 people are suspected to have died of the virus in Mexico and the illness has spread around the globe. News of the first death outside the country where it originated will increase fears that a pandemic could develop.
Barack Obama said the US government was monitoring the situation and it was time to take "utmost precautions". He said he would do whatever was necessary to control swine flu and urged people to ensure good personal hygiene.
US schools with confirmed or suspected swine flu cases should "strongly consider" closing, Obama said.
The boy who died in Texas was "treated very aggressively" before he succumbed to the virus, a health official said. "All family members are healthy and well and have not had any symptoms," the official said.
Dr Richard Besser, the acting director of the Centres for Disease Control and Prevention, said more deaths in the US were likely. "Flu is a very serious infection and each virus is unique so it is hard to know what we are going to be seeing," he said. "But given what we've seen in Mexico, we have expected that we would see more severe infections and we would see deaths."
World Health Organisation experts are to hold a third emergency meeting to discuss the level of the alert.
Dick Thompson, a WHO spokesman, said the agency's director general, Margaret Chan, "has seen a jump in cases and she wants to have that evaluated by the outside experts".
He said it did not automatically mean a change in the pandemic alert level.
Confirmation that infected people in two countries are spreading the new disease to their families or contacts in a sustained way would meet the WHO criteria for declaring a phase five alert on its scale. The highest is six. It raised the level from three to four on Monday as the virus moved to Europe.
Separately, flu experts around the world were holding a telephone conference in an emergency review of the outbreak organised by the WHO to collect information on what is known about how the disease spreads, how it affects human health and how it can be treated. A report will be published shortly after the meeting ends.
Arnold Schwarzenegger, the governor of California, has declared a state of emergency, while fears were growing in New York that the virus was showing signs of transmission to others from children who had visited Mexico.
Egypt ordered the culling of all its 300,000 pigs as a precaution against swine flu, the country's health minister said on Wednesday. "It is decided to slaughter all swine herds present in Egypt, starting from today," Hatem el-Gabali said in a statement published by state news agency Mena.
France said it would seek an EU ban on flights to Mexico. Argentina and Cuba have already banned them.
The EU, the US and Canada have advised against non-essential travel to the country. The EU foreign relations commissioner, Benita Ferrero-Waldner, said the bloc was considering halting all travel to Mexico and disinfecting all airports.
In Mexico, officials are carrying out a second round of stricter tests, which have so far confirmed that seven people have died of swine flu. Results have yet to be announced on a further 13 people previously said to have been killed by the illness. The virus is suspected in another 159 deaths and 2,498 cases of illness there.
The health secretary, José Angel Córdova, said last night that the death toll was "more or less stable", even as hospitals were swamped with people who thought they had swine flu. Only 1,311 of those suspected of being infected remained in hospital, suggesting treatment works if medical care is sought quickly.
In New York, officials said 18 children from two schools were being tested for swine flu after showing symptoms, and the city's health commissioner said "many hundreds" more children who had fallen sick may be infected with the virus.
At least 10 countries around the world, including China and Russia, have introduced bans on the import of pork products, despite the WHO's insistence that the virus cannot be transmitted by eating pork.
Bavaria's health ministry confirmed Germany's first three cases of swine flu. The Robert Koch Institute said they were a 22-year-old woman being treated for flu-like symptoms in a Hamburg hospital after returning from Mexico, a man in his 30s being treated at a university in the southern city of Regensburg, and a 37-year-old woman from another southern town who recently travelled to Mexico.
New Zealand is awaiting test results on 44 possible cases, on top of 14 already confirmed.
While the latest confirmations were in developed nations, Dr Keiji Fukuda, the WHO assistant director general for health security, warned that the greatest threat was to the poorest countries.
"We know from history … that the poorer countries are the ones who really get hit the hardest, they are really hit disproportionately hard, and they also have the least resources to deal with these kind of situations," he said.
Suspected infections are being investigated in Brazil, Guatemala and Peru, all countries that would struggle to cope with a big swine flu outbreak.