NEW DELHI: The World Health Organisation on Thursday raised the alert for swine flu to the highest `pandemic’ level, signalling that a global epidemic of the H1N1 virus had begun. The announcement followed a sharp rise in infections in countries outside North America, from where the outbreak began.

The last flu pandemic was declared 41 years ago, when H3N1 virus strain killed an estimated 1 million people in 1968. WHO’s escalation of the alert level from Phase 5 to Phase 6 means that the disease is spreading fast but doesn’t necessarily mean that it’s causing more severe illness or more deaths.

The latest flu, which has been largely mild so far, is caused by the H1N1 strain of influenza that originated in pigs. Globally, the virus has infected 27,737 people in 74 countries and led to 141 deaths. However, WHO believes that actual infections are far higher. The organization fears that the virus could infect one-third of the world’s population within a year.

The Phase 6 alert came after an emergency WHO meeting in Geneva following reports of community level transmission of the virus in Spain, Britain, Japan and Australia. WHO will now officially recommend to its 194 member countries to put in place their pandemic plans which may include social distancing measures like closing down schools and restrictions on foreign travel. Each country will decide on the measures it needs to take for checking the spread of the virus.

In Hong Kong, the government ordered all kindergartens and primary schools closed for two weeks after a dozen students tested positive for swine flu. In Australia, swine flu cases jumped to more than 1,000 on Monday and reached 1,260 by late Wednesday.

Dr Shiv Lal, director of the National Institute for Communicable Diseases, told TOI, “India will not start social distancing measures immediately but will focus on early detection and treatment because the number of cases as yet are only 15. A joint monitoring committee meeting of the health ministry will be convened on Saturday to chart the future course of action.”

Meanwhile, an foreign ministry statement said India would be seeking more aggressive screening of passengers coming in from countries affected by swine flu. “We have issued necessary instructions to our missions in the countries concerned to take up the matter with the host governments on an urgent basis,” it said.

WHO recommends consideration of exit screening for international travellers departing countries with human infection at Phases 4, 5 and 6.

Pharmaceutical companies have indicated that it could be six months before a suitable vaccine against H1N1 can be produced for global use.

Talking about the nature of the virus, WHO said, “The virus we are dealing with right now is a new influenza virus that is behaving like a human virus. The virus originated from pigs but is not transmitted by pigs. This is the basic difference H1N1 has with H5N1 bird flu virus in which those getting infected handled infected birds.”

According to an editorial in the Lancet, the next global influenza pandemic would kill 62 million people with 96% of these deaths occurring in low income and middle-income settings.

WHO has asked all countries to activate their pandemic preparedness plans. At this stage, effective and essential measures include heightened surveillance, early detection and treatment of cases, and infection control in all health facilities.