The World Health Organization has raised its pandemic alert level from Phase 3 to Phase 4, indicating that the UN agency believes a potential pandemic virus has shown that it could be transmitted around the world easily from person to person.
The move stopped short of directly raising the alert level to Phase 5 on the six-point scale, which would indicate an existing global emergency in which the disease already is spreading significantly among humans around the world.
Keiji Fukuda, the World Health Organization's (WHO) acting assistant director-general, says the Phase 4 alert does not mean that a pandemic is inevitable.
"If we look at the move and the change from Phase 3 to Phase 4, what this can really be interpreted as is a significant step towards pandemic influenza, but also it is a phase which says that we are not there yet," Fukuda said. "In other words, at this time we think that we have taken a step in that direction. But a pandemic is not considered inevitable at this time."
WHO spokesman Gregory Hartl, speaking to journalists in Geneva, Switzerland, said the Phase 4 alert indicates that the virus can no longer be contained in a single country but that the danger of a pandemic still could go either way.
"What Phase 4 means basically, also, is that this is kind of the turning point. From here, it could go forward to Phase 5, which would mean that we are in a pandemic. But equally, if we see that large-scale community transmission is not sustained, we could stay at Phase 4 or even go back to Phase 3," Hartl said. "The phases do not need to be followed in a numeric order. You can jump phases. You can go backward. You can go forward. It all takes into account the scientific realities on the ground."
Nevertheless, the number of confirmed cases has been rising rapidly as more information about the illness emerges.
The WHO says there are now 73 confirmed cases of the new flu strain in five countries worldwide -- including cases in Mexico, the United States, Canada, Britain, and Spain. The UN health agency also says it has confirmed that seven deaths in Mexico were caused by the virus.
National governments also have reported confirmed cases of the new flu strain in Scotland, Israel, New Zealand, China, and South Korea.
For its part, the government in Mexico now says it suspects 152 deaths from the disease and more than 1,600 cases in which people have been infected there.
France and Australia are among the countries that have suspected cases of the illness.
Swine flu is an illness that normally occurs in animals and doesn't normally spread to humans. But the new strain of the swine-flu virus is a mutation with genetic elements of swine flu, bird flu, and human influenza.
The World Health Organization says there is no evidence that the new flu strain has been spread from contact with pigs or from eating pig meat. Rather, the UN health agency now says that transmission of the disease is human-to-human -- either by direct contact or through coughing and sneezing.
A pandemic is when a new disease appears in the human population and spreads across the world. A pandemic flu virus spreads quickly because it is a new strain and people have not yet developed immunity to it.
The pandemic alert system was introduced by the World Health Organization in 2005 to monitor the threat posed by bird flu.
compiled from wire reports